Charging chaos: no charge despite full sunshine. MPPTs out of control!

[@evil17]

Interesting developments here Andy, this is why I do like the KISS strategy, but i know it is only a configuration issue which you will soon have sorted out. I have a 24v system installed in a 40’ bus with 2 x Renogy 40A controllers on 2.5kw of PV (ie: 10 x 250w 39voc panels in 2s5p configuration). For experimental reasons I added 2 x Maxwell 48v Capacitors in series to the solar output and the Renogy MPPT’s run directly from this 96v capacitor bank & while they seem to swap current output back & forth & sometimes uniformly, they do seem to get the job done as rapidly as I would expect them to, but one thing I have noticed with this configuration is how it helps when there is a lot of cloud shading, when using 1 or 2 MPPT controllers, the capacitors help store some of that lost charge while the MPPT is re-calculating during cloud shifts, it also helps store early morning and end of day light as well. My 2 x 24v 5kwh batteries are full by 10-11am lately and then the capacitor voltage rises to about 65v which is enough to have a shower or make a cup of coffee at the end of the day without impacting on the full 100% SOC. I also have 2 x 16v Maxwell caps in series (with balancers) between the Batteries and a 3kw AIO inverter which I have used in the past to run 12v appliances from each 16v capacitor, fridges, lights, etc, (with success), and I think this pair of caps help to reduce ripple, surge and maintain a more stable system voltage overall. I am using a 24v JK BMS on each 5kwh battery & have a Victron smart shunt as my main guage, but no communications and it all seems to work well, so far…and while it is still a work in progress my little ‘Reckless Abandon’ & getaway, I recently added a 50ltr Rheem electric hot water system as a solar dump by adding a 1800w element (instead of the 3600w it came with) and using a 240vac 4000w motor speed controller/light dimmer, so I can easily regulate the wattage output to the HW system up to 1800w from the inverter or as the sun can provide, and use a timer after 11am or by switching this output via a PV capacitor voltage above 35v-40v when the batteries are full. Just thought someone might find this info, interesting if not useful maybe in the Van/Bus community. Cheers

[@markbrettnell3503]

Glad you got it working. It's the issues like you showed that makes me hesitant about a system like yours. Especially when you NEED it to work reliably.

[@romeowhiskey1146]

Lots of drama regarding the VICTRON equipment. Getting as bad as the SEPLOS battery drama.

[@SeanMoore2008]

There's no drama here and there are no reliability issues, the unwanted behaviour is a simple matter of a misconfiguration.

[@damianhla4940]

Hi Andy, I have 6x Victron SmartSolar 100/50 running with BMV 712 together with CERBO GX. You definitely want to have all SmartSolar joining the VE Smart Network together with the BMV 712 to enable synchronised charging. Without synchronised charging, a SmartSolar may see what it thinks is a battery voltage, but in fact is another SmartSolar's charging voltage and make an incorrect decision on its charging action. Without synchronised charging, the more charge controllers there are in the same system, the more chaotic it is. With Synchronised charging enabled, you would noticed that the Blue/Amber/Green LED on each SmartSolar solar charger will flash in a coordinated manner, with each unit taking its turn. This way when it is time for one charge controller to charge the battery, no other unit would attempt to charge. Hence the charge controller would be seeing the real battery voltage and not the charging voltage from another controller. You can also control the sequence by bring each controller online in the manner you want, as each controller is connected to the battery. They should follow this sequence to wake up during synchronised charging. With SmartSolar and BMV712, synchronised charging works well using Bluetooth connection alone. You also want to enable the BMV to transmit battery voltage sense and battery current sense to the VE Smart Network. Especially with LFP battery the voltage remains relatively flat during charge and discharge phases. So voltage measurement needs to be done very accurately especially when the battery is close to being fully charged. Accuracy of 0.01v is preferred. So this is best sourced from BMS. The closer this measurement is taken from the battery, the more accurate it is. Also be aware that the voltage drop induced by power loss in cable and circuit breakers particularly, increases not in a linear manner but in an exponential manner as current increases towards their rated capabilities and limit. Most circuit breaker operate on bi-metallic strip. Some has additional coil and magnet to facilitate. The power loss is determined by I^2 x R. This power loss is translated into heat dissipation, which in turn heats up the bimetallic strip to deform its sharp until it disconnects at the rated current limit. With this in mind, the higher the current output, the higher the power loss and voltage drop there would be in these circuit breakers and even conductors if they have not been properly over sized. If you rely on the battery voltage sensor on the charge controller there would be an ever increasing discrepancies from the actual battery voltage. So the BMS battery voltage feed plays an even more important role as the system output increases. Without an accurate battery voltage, the charge controller cannot make an accurate assessment on whether to operate in bulk charging mode or when the battery is fully charged. With a system that is capable of high output, it is also vital to control the maximum current in order not to overload the conductors, the circuit breakers and the battery. This is where DVCC plays an important role. The DVCC feature is supported when the components are connected to the Cerbo GX. The CERBO GX only has a limited number of VE Direct port. I give the BMV712 preference (as obtaining timely voltage and current reading is vital) to use the VE Direct connection on the Cerbo GX, followed by the main SmartSolar controllers that brings in the bulk of the power. The auxiliary SmartSolar goes on using VE Direct to USB connection, as these have to go through USB hub connection to the Cerbo GX. This setup works perfectly and you can see all the controller reaches the fully charged status all at the same time. I also find it useful to utilise more SmartSolar controllers and having them reaching peak output over different times in a day. This way you achieve a more even and sustained high output over the entire day, instead of just having a huge peak during noon, forcing the DVCC to kick in. Because once DVCC kicks in to limit the current, you are essentially losing power for capture. It is better to avoid DVCC activation by design and group your solar panels and SmartSolar strategically.

[@OffGridGarageAustralia]

Thanks a lot for sharing your experience with that, Damian. I have set them up in the VE Smart Network again and it works great (as it did before). No problems anymore.

[@DennisLaDenmark]

DVCC is used if several power sources is connected. I use DVCC to limit the max current from mppt and MP-II in the event I'm charting the battery from the grid in the daytime. The MPPT is prioritized over the MP-II. If the mppt ramps up due to sun, the MP-II ramp down to keep the same current.

[@michimichi7534]

Using a smart bms the MPPTs are external controled using DVCC by the BMS. So the MPPTs are charging according to the CVL and CCL provided by the BMS. Works just perfect. Only drawback, if you are feeding in your DC solar production, the MPPTs are ignoring the CCL and onyl reacting on the CVL. Victron says that is a feature, a lot in the community says it is a bug (or at least room for improvment). I see you have found the thread in the victron community :)

[@galen__]

I’m looking to add another solar charge controller soon, so your efforts in this subject are much appreciated 👍

[@TheAnqueetas]

Andy, you do not need to use dvcc if you have a smartshunt. You are connected to the rPi Venus os vis usb do not use the Bluetooth network. Set your system up with the ESS assistant and this will sync all these devices. I have a similar setup and ESS controls all the devices as designed. Within ESS you use a battery mode of Optimized (without BatteryLife).

[@handymartin4496]

Andy is using the dvcc to limit the max. amperate that goes into the battery. Otherwise his BMS would cut off the battery.

[@OffGridGarageAustralia]

With the new soalr system installed, it can pump more than 270A into the battery banks. I'm not feeling comfortable with this if I'm not at home. That's not what I have designed the battery shelf for. So, yeah as Martin said, I only limit the current with the help of the DVCC. I cannot use ESS because I'm off-grid and don't charge though the Multiplus.

[@TheAnqueetas]

Of course, you are off grid, understood. In that case, as far as I understand, the dvcc requires comms with a BMS to control charge current. Your JBD BMS can do this with the right software and isolated usb device (you did a vid on just this thing not long ago), however I can’t remember whether your two other BMSs are supported with this software. You would need each BMS to communicate to the system in order for dvcc to control. Love your channel even my wife now looks forward to your videos even though she has no clue what it’s all about. All she knows is that we save a lot of money doing this sort of thing.

[@Full-of-Starships]

@@OffGridGarageAustralia Will that concern about current be fixed when you add your three Seplos into the main system? Is it mainly a concern of how much goes into each battery, or more around the busbars that concentrate and then distribute all the current?

[@TrevorFraserAU]

My recent Andy binge watching stint is getting me closer to watching the latest video, maybe one day I will be back to being able to watch one or two as soon as they are released... You give us too much cool stuff to get busy with Andy 😜

[@d3claes]

We have 3x SmartSolar MPPT RS: 2x 450/100-Tr & 1x 450/200-Tr. Each SmartSolar is connected to each other via a network cable (VE.can) and 1 SmartSolar is connected to the Cerbo GX. There is 1 smartshunt 500A in the system that is set up as a battery monitor. I have disabled DVCC. Each battery bank has a (JK) BMS, but they are not connected to Victron via canbus/RS485. I visualize the JK data using ESP32/ESPHome in Home Assistant (see syssi/esphome-jk-bms). The solar chargers work as 1 device. They are always in sync (bulk/absorption/float) and they work based on the battery voltage of the shunt. I can see that the limits for each mode are reached correctly.

[@OffGridGarageAustralia]

Ah, right, so the sync happens through the VE.CAN already even there is no smart BMS connected. Very good information, thanks a lot!

[@Shep5847]

When a smartBMS is connected, it is the boss, full stop. You set the target voltage in the BMS and all MPPTs are controlled by an “External” device. I have 2 different Batrium BMS’s in two different systems and the Batrium controls the whole charging system. When the voltage gets close to target, or if an individual cell jumps up too high to fast, the BMS tells the MPPTs to slow the heck down. And if necessary, to stop and wait for things to settle. This is common when you are approaching 100% SOC. Batrium is in your neck of the woods if you want to give them a try.

[@garymeissner6659]

I am not using any Victron equipment at this time, but I have two very different charge sources to my battery bank. The two systems here do not talk at all. I set my MPPT DC charge controller voltage a little higher to compensate for some of the voltage drop in the wire, and it's internal voltage reading error. This way it will keep pushing it's maximum current, trying to top up the battery bank to the correct voltage as long as we still have sunlight. I do see a spread of about 0.2 volts from the battery bus bar to the terminals at the inverter and the MPPT charge controller, and the internal voltage reading in the cheap controller is another 0.15 volts higher still. When the charge controller goes into absorb mode, the current starts to drop down. But as the current drops, the voltage rise from the wire resistance also drops. This causes the absorb current to remain higher for longer. In reality, the battery voltage is still climbing up and should eventually reach the true desired set voltage. As the current drops further, the voltage drop reduces and the battery voltage climbs up, and if there was no load on the system, it would be fine. But with other items (the inverter) putting a load on the battery bank, the voltage drop is constantly changing. If the charge controller does trigger to a lower voltage float setting, as it should with LFP batteries, you might lose more charge power than you should. My cheap charge controller has an additional voltage setting "Boost Charge Recovery Voltage". If the battery voltage reading falls below this, it will trigger it to go back into full bulk charge current mode again. If the Victron units have a similar function, you may want to raise that voltage setting to get them to go back into bulk charge if your loads drag down the voltage while you still have sunlight available. Just an idea.

[@MichaelTheis77]

As you were asking, multiple Mppts, smartshunt and VenusOs plus Multiplus. No VE Bluetooth network, but SCS, STS and SVS activated. So far I haven't had the issue, but the system is also quite new. I will give it a closer look in the coming days. But I would be totally lost if Victron relied on their notoriously unstable BL. What if you had your MPPTs spread around the house? How would that ever work? And additionally, I thought that to be the only advantage of DVCC.

[@peterundreginahotz6067]

Have 3 solar controllers in bt network just to sync mode(bulk,absorption,float). The shunt is not included in this network (therefore no transmission of voltage and current from the shunt). This is done via dvcc (svs - common voltage sensor). This has worked for me for over 2 years without any problems. Therefore the idea is to remove only the shunt from the network and control the rest via dvcc. Best regards Peter

[@boatelectricaldiy]

Victron equipment is somewhat complicated. This equipment, similar to say a variable frequency drive, will have settings that interfere with each other. A VFD is obviously more complicated with up to a thousand parameters, but like the Victron gear, you usually only need to change a few of them correctly for it to do what you want. I look forward to seeing you solve this problem Andy.

[@robmc3338]

Lol, I was literally getting training today on the mistakes others have made with VSDs lol

[@OffGridGarageAustralia]

Well, it is basically solved by using the VE.Smart Network which synchronises all MPPTS and also shares the real voltage through the Smart Shunt.

[@boatelectricaldiy]

@@OffGridGarageAustralia very good. How would you solve the problem if your solar charge controllers could not communicate with Bluetooth? Say, too many steel walls in the way?

[@gjbevers]

Hi Andy. I have checked my system here with 9 Victron MPPT (4 x 250V, 5 x 150V) and a MG Energy System BMS which came with the Lithium batteries from them. This BMS is a more advanced Lynxs Smart BMS, produced by Victron especially for MG Energy Systems. All the MPPT's switch from bulk to absorption, and vice versa, the same moment. In the settings of the MPPT's has to be that they are external controlled (by the BMS). When the batteries are 100% the 250V MPPT's are delivering the energy needed by the inverters, and in case they can't delver more, the 150V MPPT's are supplying. Strange enough, if I look at the history of each MPPT by Bluetooth, only bulk time is there. The same in the remote console of the VRM, only bulk time or total time is displayed. SVS, STS and SCS is disabled in DVCC.......

[@jimduke5545]

In the words of a famous Austrian song “Let’s start at the very beginning, it’s a very good place to start…” 😂 (Do-re-mi. Sound of Music 😉) One of your best videos, to date. (And that’s a very high bar you have set!)

[@OffGridGarageAustralia]

Thanks a lot Jim. Took me like 4 days to put together as I had small clips everywhere and it was a total mess to make a story out of it.

[@philbrooke-little7082]

I have multiple controllers of different makes as well as an engine driven alternator. I solved the problem of silly bickering between them by having them all set above my BMS cutoff voltage but below max battery allowable voltage (for safety) it is then a simple matter for them all to be turned off by the BMS, or even by a voltage sensitive relay, at a predetermined voltage (I use 3.5v/cell) I can then have a cut back in voltage of 3.375v/cell which avoids re-bulking too often. If you set the MPPT controllers’ float voltage to 13.5 too then when the charging cuts back in the charge sources will supply the loads and also not overcharge the battery. The controller re-bulk is set so that the normal voltage the battery reaches over night is below the level needed to put the controllers into bulk for the next day if they don’t do so automatically after sunset. This method means I can use any controllers or charge sources that were designed for lead acid and have the BMS as the final arbiter of what the battery sees which I think is the best way to avoid arguments and it keeps everything very simple. I’ve had it running for 3 years now without any problems.

[@GapRecordingsNamibia]

Hi Andy, after re-doing my solar,... Chucking out the SMA, and going full dc and lithium. I set up with DVCC, after about 4 weeks things started going sideways. My batteries were not charging fully, and the manufacturer of the batteteies asked me a few questions. After hearing that I had DVCC enabled, he told me to immediately turn off DVCC. This was not the end of it though, I have 15cell technology batteries, so I set my two mppt's to 51.80V for bulk, batteries set to recalibrate to 100% when they hit 51.75V they absorb for 1.5 hrs and go to float @ 50.25V and I set my voltage and current sens source as the batteries BMS, since making these changes my MPPT's are now synced absorbtion, float are now equaly timed. DVCC causes some very strange behavior. With all this nonsense before these changes my batteries could not even balance the cells would be 140mV on pack 1 and 230mV on pack 2, after the changes and 4 weeks down the line, my batteties are at around 25mV pack 1 and 20mV pack 2....... On non Victron lithium batteries it seems like DVCC does not work..

[@salimnaufal1779]

Hello Andy, my setup has 4 MPPTs and a smart Batrium BMS connected to the CANBUS of the Cerbo gx. It behave just like yours. I have a sound explanation for this. The BMS controls the voltage and current delivered by the MPPTs to charge the batteries. In an ideal case, all battery cells have exactly the same voltage since they are "perfectly balanced" and therefore, the BMS can still request all the power that can be generated until the batteries are 100% full. Since this is never the case, some of the cells start having a voltage above the set maximum even when the batteries are well below 100%. In order not to damage the cells, the BMS reduces the power that comes from the MPPTs until the peaked cell voltage goes down, hence reducing the overall voltage of the entire pack. I confirmed this with my BMS by observing the peaked voltages and the behavior of the MPPTs. As for the MPPTs, some giving 0 and some giving power, I deduced that this is the way Victron throttles down the delivered power. Hope this helps.

[@OffGridGarageAustralia]

Thanks a lot for sharing, Salim. The Batrium is certainly great when it comes to communication with Victron. I read a lot about it and how it limits the charging current to 0.5A to allow the balancer to work. When you say it limits the power to the battery, does it lower the CVL or the CCL in the Victron system?

[@salimnaufal1779]

​@@OffGridGarageAustralia , I really don't have the exact details as to what gets controlled as soon as cells reach a high voltage. However, using the settings of the BMS, both voltage and current are set as a function of the state of charge. When the batteries reach a set SOA, the MPPTs start exhibiting the same behavior you have seen with yours.

[@hummmingbear]

How were you able to connect your batrium to the CANBUS of the cerbo? I have a Batrium BMS and am unclear on this.

[@kocki3]

Hi Andy, enjoy your Jägermeister (08:17 timeline). Best wishes form Dortmund, Germany. Gerd

[@2bbionic]

I have pretty much the same setup like yours - 3 SmartSolars synchronized via Blutoth, a Cerbos with active DVCC and a battery with BMS. I don't have a SmartBMS (next step for me), but I've never seen such a behaviour like yours. Nevertheless, what I don't like is the fact, that I'm in doubt that the absorption and float settings are working correctly - due to the weather in lucky cold germany I'm currently happy to see the sun coming out to see my battery charging a little. In my setup, SVS is active, SCS deactivated

[@simon359]

I have a smart BMS built into my Battle Born Batteries and I use Victron charge controllers, I have no issues sinking them together! And I have them all connected to Bluetooth. I have three Victron charge controllers. They all sync together in bulk and absorption and float.

[@FutureSystem738]

Thanks Andy, interesting…. Your system is certainly complex, (and obviously not entirely foolproof.) For the foreseeable future, I’ll keep mine simple enough for me to understand. Thank goodness you’re finding out the bugs for us and sorting them. Cheers and stay charged!

[@junkerzn7312]

Sometimes dumb modes just work better than smart modes :-). I wouldn't have expected the Victron to mess up like that, though. It does bring up always having a bit of margin with settings, so everything works reasonably well even when things aren't quite synced up. In this case, you have your bulk target set to 55.2V (3.45V/cell). That might be too low to have sufficient margin to deal with all of these cumulative measurement errors, resulting in the charge controllers going into absorption too early. Hmm... I would have thought that the victron would have an option for an external battery sensor that you can wire directly to your primary monitoring point on the battery side of the smart shunt. Sometimes it is important to have a separately wired voltage sensor using wires that don't carry any current (i.e. are only used by the sensor), so their length doesn't matter and they can get an accurate voltage measurement. One last thing I can think of... connect a scope up to the battery and check the ripple. It might be significant enough that, coupled with insufficient setting margins, it is causing the charge controllers to be confused. Though I would not have expected Victron to make that mistake either. Usually when we do voltage sensors, we actually pull in and average at least 4 samples per 60hz cycle (about a 4mS, aka 240Hz sampling rate). We do that in order to remove the most common types of ripple (usually harmonics of 60hz) from the measurement.

[@OffGridGarageAustralia]

Victron has a smart battery sense device. It does the same as the Smart Shunt in terms of measuring the voltage directly at the battery level and report his back to the system so all devices can have this precise reading. And the same figure reading, more importantly, so they can sync what they are doing.

[@junkerzn7312]

@@OffGridGarageAustralia Awesome! I guess the battery voltage at the smart shunt will be fairly close. Though it may be easier and more accurate to calculate the voltage de-rating due to current with a dedicated sensor directly on the battery busses whos sensor wires aren't carrying current. I assume that Victron has a field that can be programmed for calibrating the de-rating. Probably worth testing what the voltage droop is between full load and no load at various points in the system. This also reminds me to mention double-checking the low-voltage shutdown margin to make sure the inverter still shuts down before the BMS disconnect level under full load. -Matt

[@Zirrad1]

I have two Morningstar TriStar MPPT charge controllers (a 45A and a 60A) each hooked up to a single remote battery voltage sense wire. They never switch charge state at the same time and when the batteries are near full and with a normal (300W) AC load, the smaller 45A controller often doesn't add any current at all.

[@MarkPrince1317]

Well you always doing well Andy And see that kind of situation I will divide all load and I will not put all load on one setup Best regards from Philippines 🇵🇭☕☕

[@lacrosseperson]

hey Andy, i have a similar issue with my van setup - 2x300ah 24v batteries, with 3x solar charge controllers for 3 sets of solar (3x 2p solar panels). i would fix your problem this way; 1. set the charge controllers float a few volts higher than needed, and watch the battery to the point of full charge (watching is the key here to not over charge). 2. at this point (of full charge) i would take a screenshot of the voltage that the solar charge controllers are reading off your battery, and the full voltage read via the bms'. Cut the power supply in. 3. take the difference between each solar charge controller and the average bms voltage. 4. adjust the float settings to match the actual battery bms voltage by adding the difference between the solar controller and the bms. 5. you could also apply this to the bulk and absorption voltage values too

[@lacrosseperson]

the idea behind this is that you want a real life representation of what is being sensed vs actual. so you have to test, record, and apply the respective values. i hope this helps

[@ai6mk897]

The Charge Controllers (4) can only sense the voltage at the controller and not at the battery. The amount of current each CC outputs during BULK is determined by the input power provided by the solar panels. The output CURRENT of the CC's is then summed together and fed to the BATTRY. The CC will use MPPT to maximize the current it harvests from the solar panels. The CC sources CURRENT and monitors VOLTAGE. Thee CC uses this monitored voltage to determine in what state they should be operating, BULK, ABSORB or FLOAT. Although the load (BATTERY) voltage is the same for each CC, If they are all operating independently, then they will each measure different voltages because the output current and the resistance of the path to the BATTERY of each is different. If you have a shunt this will also give you another voltage, so altogether you will have 5 different voltages If one CC is designated the MASTER it should tell the other 3 CC's what mode to be in. If this is not true then it's a design flaw and nothing you can do. The system SHOULD use the most accurate BATTERY voltage, which is the voltage measured at the SHUNT, and propagate that to the 4 CC's. A model derived from a schematic for your system might be useful to understand why it's behaving as it is. BTW, 1. SOC is only valid with the battery under NO-LOAD. SOC is a measure of the intrinsic battery voltage so if you measure it under load, you would have to compensate for the load current and internal resistance. 2. Did you ever determine why the cracked panels gave low output ?

[@Full-of-Starships]

SoC is calculated by coulomb counting, not by voltage. Absorption allows the battery to complete charging if constant-current stops because the voltage peaks "too soon" because of high currents.

[@ai6mk897]

@@Full-of-Starships Yep, that is the best way to estimate the charge left in your battery. I was just noting that IF you are using voltage to determine SOC you need to measure the voltage under no load. Even using a coulomb counter you have to determine what you think is 0% and 100%. So you define the end points and then use the coulomb counter to provide an accurate estimate of the remaining charge left in the battery during discharge. 100% should be when it won't take any more charge for the specified max voltage. 0% could be defined as after sucking out the charge in the battery spec, but as the battery ages, you may not be able to achieve this and it may result in draining the battery to a too low voltage. 0% is best defined as reaching the minimum voltage for the chemistry used, but it should be measured under no load after relaxation, which can be a long time (several hours).

[@adriandelaharpe19]

Great videos. Question, I have just installed a smart shunt , MPPT 100/30 and DC to DC XS into my camping van. Would you also recommend that I setup a smart network with the devices. The MPPT will only operate when camping and the DC to Dc will work when the alternator is charging the starter battery. So they will never work together.

[@MiranPayman]

Hello Andy, i am about to upgrade my system from 4.2kw (5.5kw inverter) by adding 8 kw inverter and 7.5 kw solar for the battery adding 300 Ah to 210 Ah. Total should be 510Ah and 13.5kwh inverters with 11.8 kwh solar panels i will use big busbar to connect the batteries then the inverter hopefully lowers the voltage drop.

[@kevinmills5293]

With a BMS connected, the SCC’s status is “external control” and absorb and float states do not occur. Both SCC’s show External Control 100% of the time.

[@OffGridGarageAustralia]

Yes, I can see that on my Pool Fence controller and the Seplos BMS.

[@offgridonthecanadianshield5185]

I am building a 48V battery box for the first time with 202A cells and a daly BMS. The output currant is 100A and the input is 50A. I ordered a Taixi single pole 63A breaker as an on/off switch to protect the BMS. 50A continuos X 1.25. Will this allow 100A output? Is this wrong?

[@jbehitech]

Low quality MPPT made in China, capable of converting over 100V from solar panels to 12-48V. To solve the problem, disconnect the input from the solar panels, then short-circuit the MPPT input using low-resistance bulbs such as 12V, 24V and 48V, which means the voltage will discharge to zero, a known problem in MPPT, then we connect the MPPT module to the solar panels again, the MPPT starts working.

[@DennisLaDenmark]

Hi Andy. I have a similar Victron setup with two MPPT 250/100 ve. CAN, MP-II, lynx shunt and Cerbo. All gear are running on ve.CAN for the DC side and ve.Bus for the AC side. The mppt are external controlled by the MP-II. Charge voltage and current are setup in the MP-II. I also run ESS assistant, but don't think this should be necessary. I don't have a external BMS connection to the victron system. I don't have any problem with bulk and absorption.

[@ksredadare]

Hi Iam using 2 Smart Mppts with a Smart Shunt and a Cerbo GX in my Camper. I've turned on all DVCC Features and the VE Smart Network at the same time. And the MPPTs are in sync all the time. I'm strugeling a bit when plugged in to shore power with the Multiplus getting synced. But this doesn't happen very often ;-)

[@OffGridGarageAustralia]

Thank you for sharing. Interesting you turned everything on in the DVCC...

[@wayne8113]

Thanks Andy

[@adventuringscotts]

Hey mate, I have 5 epever mppts in my caravan charging 660ah of lithium. 3 of them had a lithium profile from factory and change states at the same time. The other 2 I had to manually set and they stop charging before the others. I haven't investigated as it works well by dropping the charging current towards full charge.

[@cheetahkid]

I saw that, turning yourself a Frankenstein 🤣

[@theobotha1009]

Hi Andy, I would like to ask you a question. I have 2 x 275w solar panels on my mobile home. Cables come to a cut off switch to Victron 100/50 solar controller to 2 x 190ah lead acid batteries. I want to add a 2nd 100/50 controller to charge a lifepo4 200ah battery. The lifepo4 will be used on 12v underfloor heating only. Would I be able to connect the controllers from the cut-off switch and use the solar array for both. I am in the UK so not much sunshine, but some days are nice. Thanks in advance Theo

[@Jim.D]

I had the same problem, my solution was to set the absorption voltage to .05 volts above the what the voltage the battery should go to and set the absorption time to 8 hours and a tail current to 1.9 amps. Yes, I allow the solar charge controllers to stay on the network but I do not allow my shunt to be on the network. The only issue is it takes about a minute for the charge controllers to change to float after bms hits the correct voltage.

[@STRUTZKOFF]

8 hours of absorbtion ?

[@Jim.D]

@@STRUTZKOFF it won’t ever make it the 8 hours, just for the very cloudy days. The tail current makes sure of that.

[@OffGridGarageAustralia]

I don't like the idea to having a higher voltage setting in the MPPT to allow for voltage drop on the cables. If the current is small, you have this higher voltage at the battery and charge higher than anticipated. Why don't you integrate your shunt into the VE network?

[@Jim.D]

@@OffGridGarageAustralia I was using the shunt for another project and it seems to be working fine without it, so I never connected it to the network. It really cannot charge higher than anticipated since the bms will prevent that.

[@Jim.D]

@@OffGridGarageAustralia I did a test today and decreased the voltage on the solar controllers to .02 volts over the absorption set point and funny thing happened, the mode went from absorption to float without hitting the correct voltage in the battery. Going to try .03 next, .05 did it before, just fine turning it.

[@niki1541]

I have had my CerboGX, 4 MPPT and Lynx connected to my batteries before I implemented Multies. I've noticed that voltage differance was rather large (300mV) between 4 MPPTs (they were like

[@chrisporter449]

I don't understand why anyone would want more than 1 Solar Charge controller. I would just get a bigger one. My MidNite controller just does it all, I understand this channel is for testing, but all this stuff is so confusing it'll take the fun out of the whole of grid thing. God bless, and Stick it to the Man!!!

[@GapRecordingsNamibia]

1: redundency, 2: Andy is basically maxed out on 3 of the strings, the mppts can't handle any more solar panels. But, to each his own. 3: If you have different panels you will need a different mppt for each of you different sets of panels. You can't run different panels mixed together.

[@OffGridGarageAustralia]

Hi Chris, you never get only one device from each. If it brakes, you're in the dark. Multiple solar charge controllers, multiple inverters, multiple batteries. Also, you want one solar charge controller for one roof orientation/direction

[@Full-of-Starships]

@OffGridGarageAustralia @@GapRecordingsNamibia Big Shed (3200W) & Car Port (3240W) are perfectly sized to take advantage even of occasional ~120% overproduction with a "not quite 4kw" controller. OTOH, he is more than maxxed out on the East & West roofs. Basically, the 150/70 Victron can never actually accept the full 4kw from the panels with LFP batteries (despite what their sizing page says).

[@panoss3524]

Thanks for your video! I have a similar problem with temperature sensors. I am trying now t o solve it with dvcc

[@OffGridGarageAustralia]

Not the -1°C problem?

[@panoss3524]

@@OffGridGarageAustralia No I think it's temperature mine issue. The solarcharge is closing the charge for some minutes and starts again with no error. The pv voltage are fine cables etc. Maybe there is software bug with "ghosts" temperature readings.

[@panoss3524]

@@OffGridGarageAustralia today was perfect, no problem yet 😀😊

[@maritzm]

Great video/Many Thanks!! Q: How are you adding the outdoor/indoor temperatures to VRM?

[@hummmingbear]

I have the same exact issue, and was told the same things by folks on the community forums: to turn off my smart network. Turning off the smart-network caused the same issue you have. If I put the smart network back on my VenusOS devices gives an error that the devices are incompatible. It's pretty frustrating that victron doesn't have clear language on how to handle this when you have a VenusOS device.

[@tonitelaoag]

srne 40a and 60a, when the battery bank is full 60a srne stops charging but the 40a continues to give current to the system due to loads at the inverter. jbd 120a smart bms

[@robhassing7155]

What voltage do you measure at your battery terminals? Over here, my lynx shunt voltage is about 0.3 lower than what I measure at the battery. Yes without current flowing, so should be equal. That means my multiplus thinks the voltage is lower than it actually is and BMS shuts down charging because over-voltage. Solution, change set points to overcome this measurement difference.

[@boatelectricaldiy]

Calibrating electrical equipment is an important step not to be missed during installation. This is an important point.

[@OffGridGarageAustralia]

I have not measured the voltage of my batteries for a very long time. And this is not too important if the smart shunt measure say 50mV over or under the real voltage. Far more important that all devices read the same voltage.

[@automatykagliwice]

Hello Andy. Do you have connection between Vsense in multiplus ii and bussbar ?? Second thing when your MPPTs are in exernal control mode I think voltage for absorption and float may be taken from charger setting from multiplus even charger is disabled. Third thing choose correct settings in battery monitor in system setup. When you connect vsense choose vsense as battery monitor.

[@amerkhafagiable]

Does it make sence to have/assemble 48 v pack with 15 S LFP cells than 16 S ? Thanks

[@stevenlane729]

Thow it all away Andy, you need a Growatt all in one unit. Much simpler.

[@StevenRigler-m6v]

Hi I have 4 glass agm batteries but my VictronConnect has remained in bulk for two days and my battery power in running down. Can you please help

[@jasondevine6014]

So yes we go back to setting bulk and float settings the same. Especially if we aren't using victron gear. As I have said before when running a house or something with continuous variable loads getting that tail current is near impossible. The dvcc system is cool though.

[@OffGridGarageAustralia]

Setting absorption and float to the same value is not ideal as you either keep the battery on an unnecessary high voltage or don't fully charge it if the voltage is to low. Absorption and float makes a lot of sense with LiFePO4. I don't use tail current. I had very inconsistent results with clouds and also loads as you said. I've set mine to absorb for 1h before going to float. Enough time for the balancer to do its thing...

[@Amerona]

You have missed the most basic thing! Control measure every voltage point with the same, calibrated, multimeter. How do you know that the solar charge controllers reports correct value? You have 8 points with different voltage. 4 solar charger, 1 smart shunt and 3 BMS. Plus some other points. I have a boat with one solar charger, one shunt and I set the solar charger higher and higher until I get what I want at the battery. Now I will test with shunt and solar charger in network next summer. From cloudy Sweden on the other side of the globe 🙂 /Reidar By the way, Good Chanel

[@OffGridGarageAustralia]

Thanks, Reidar. The smart shunt is my point of truth as it sits very close to the 3 battery banks. If this voltage is correct or 0.05V off (to a quality measured voltage), does not matter as long as all other devices get the same information from that device. Changing the charge voltage on the MPPT to compensate for the voltage drop is a bad solution as it can overcharge your battery in cloudy weather. The current is low, therefore the voltage drop is lower and the actual charge voltage at the battery is higher than you would have at full sunshine.

[@mrblueskyoff-grid8135]

hi i have an 1800watt solar panel setup on my motorhome with 11kw of lifepo4 (32 105ah cells at 27.4v) ihave 3 mppt victron solar controllers feeding in to it and 3 dc to dc converters from the engine controlled y the cerbo i have setup up my multiplus2 has a ESS system with the ESS assistant and none of my solar controllers go independant they were bluetoothed together but they show external control Because of the ESS now controlling everything i have so much control on the portal on my phone i can even feed back to grid or load through the mains socket and have done all from my off grid vehicle. by the way love your channel have een watching from the start

[@foxythedirtydog4494]

Why not swap the batteries so you have the smart BMSs controlling the charging? I use my Multiplus to charge my battery with mains voltage and it has a battery voltage sense to overcome voltage losses in the charging cables. Do the solar chargers have this capability? I now use the Seplos BMS control charging which I think is the way you need to go.

[@OffGridGarageAustralia]

I don't have mains. It's an off-grid system. Hence, the Off-Grid Garage 😂 I have a lot of issues with the Seplos in terms of their design. Coming up soon.

[@foxythedirtydog4494]

@@OffGridGarageAustralia I understand the difference, between our systems and mentioned it for context. I know what you mean about Seplos but I am happy with mine and only needed to do some manual balancing once it was set up. The problem with your system is it is not being controlled by the battery voltage so it needs a BMS or smart shunt that the Venus os can use to control the solar chargers together.

[@ToddDesiato]

I believe the issue is line resistance to the battery. With all 4 charging, the voltage rise is high enough to hit the trip voltage, so the first one to detect it turns off. Then there is less current so the voltage rise is less, it takes a little longer but eventually hits the trip voltage. Etc. But at the last one, there is not enough charge current to overcome the load. IMO, when the first one shuts off, it's charged.

[@STRUTZKOFF]

but thats the point of the svs ( shared voltage sense )

[@TheBodo81]

I have two 150/85 regulators and I noticed that each one detects a different voltage and they are not precise on the voltage..... I solved it by adding a Smart Battery Detector, which communicates with the regulator and always sends it the battery voltage and also the temperature

[@STRUTZKOFF]

but these do that via the svs

[@KevIsOffGrid]

Are you missing the simple answer? Add 0.4v to the MPPT settings to allow for voltage drop? What you have done here is got all the issues of too low a MPPT setting and easy going into absorption too early - you have seen this in the past too.

[@OffGridGarageAustralia]

NOOO, you cannot do that! If you cloudy weather, the current is smaller and therefore the voltage drop is also less. Your batteries will charge at a higher voltage. Not good!

[@baricdondarion6228]

Sometimes it's best to just keep things simple stupid. Always enjoy your videos

[@StevenRigler-m6v]

Not sure who you are replying too

[@edgoodson3174]

My MPPT's say either EXT Control or OFF. The multiplus handles everything. None of the MPPT settings are used. All are synced to the multiplus.

[@santos5151]

Helle Andy I have a system in my rv with 2 victron mppt smart controller and a rec bms with 300ah lifepo4 battery. I have'nt seen your problem in my system. The 2 mppt are one 75/15 and a 100/20, and they both work equal hard. I also have the bmv712 but the system is totaly controled by the rec bms, without any problems. I have the cerbo gx configured for dvcc with svs, sts and scs activated, and have not seen any problems with the mppt's charging the battery. In my system both mppt show external control and not bulk, absorption or float. Because they are totaly controled by the bms. Right now my system is offline because it's winter here and the rv is shut down.

[@OffGridGarageAustralia]

Thanks so much for sharing. The REC BMS is something people have recommended. I may get one in for testing from a viewer if everything goes well.

[@davidrogers5343]

will the diction of solar panels affect the solar panel's output? and or do they all have to be just one solar creator?

[@markusschoywohl9545]

Hey Andy, cooles interessantes Video, genau das selbe Probleme hatte ich Ende letztes Jahr ebenfalls schon entdeckt.....und ich dachte es liegt daran dass die Zellen in meinem 24v system leider nicht alle die selbe Leistung aufweisen, manche Zellen haben eine Kapazität gemessen von 234ah manche 236 andere 238ah und ich dachte deshalb passiert das Problem bei mir ebenfalls weil die schwächeren Zellen mit den volt davon driften und die anderen eigentlich noch absorbieren könnten. Bzw denkst du daran liegt vielleicht der Fehler bei mir oder wie würdest du mit deinem Pack und der absorbtion voltage umgehen/angesetzten wenn die Zellen unterschiedliche ah Kapazität haben auch wenn es nur 2-4ah sind? LG Markus

[@maxgood42]

Have you tried turnning it off and back on again..... ok ... I was thinking the profiles that you origanaly programed was set to the other devices before item no [296] ( I think it was ) turned up by itself ? so maybe you need to reset / program it all again with the updated item list ?

[@launacorp]

If you set this so as you set on the start on the Vid, then don´t set absorbtion time. Instead set the tail current. So the Current will sink (instead of shutting down after defined time for absorbtion) and the voltage drop over the cables an connections can sink until the tail current (for me 200mA measured for 8S2P 100Ah Cells in a 24V System). The current can slow down, while the voltage on the cells go higher cause of the falling resistance of the connections and cables cause of lower current. I hope someone understand my thoughts

[@STRUTZKOFF]

but if you do that and you get a few clouds it will jump into float mode

[@OffGridGarageAustralia]

Tail current is bad in cloudy weather or if you have shading. The MPPT will think the battery is charged and goes to float prematurely. Not good. Tail current only works if you have persistent incoming power (charging from grid or gen)

[@airgead5391]

I have 4 Victron MPPT, smart BMS (REC 16Q Victron compatible) and two times the MPPT's are acting strange, all but one going to absorption while SOC is somewhere in the 50% range. Only resetting (by disconnecting the battery while the Multiplus II stays on) will get thing right again.

[@OffGridGarageAustralia]

Your MPPTs should be under external control, right? So there is no real Absorption or Bulk anymore even the lights suggest that. They just do what the BMS tells them to do...

[@airgead5391]

@@OffGridGarageAustralia There you have a very good point! That would suggest the REC BMS is acting strange. also suggested that by a hard reset of the BMS the problem is solved! This adds momentum to my plan to make my 280 Ah 16 cell battery a dumb one for test, cutting the CAN to the Cerbo and see what happens. On the Cerbo I get also REC warning signals when the battery temperature gets to about 10 degrees Celsius: I set the minimum temperature to 5 degrees however, and a pre-warning can't be set, isn't mentioned at all at the documentation....

[@airgead5391]

By the way I disconnect the battery by switching the BMS off which results in a disconnect by the bistable 500A relay. So the battery is disconnected bu at the same time the BMS is reset.

[@mikeunum]

Andy i saw your entry in the Victron Forum. Are all the cables from the MPPT are the SAME length? Are you using 4, 6 or 10mm2 cable from the MPPT to the battery? I use a more complicated Victronystsen and i have no issues at all. Only difference is i use Victron LiFePo batteries. The batteries running with a Smart BMS. All Hardware is from Victron

[@carmichaelmoritz8662]

On a different topic I hope to warn everybody that BMS's are no good for top balancing . I bought 2 smart BMS and two that they claim are regular. They do not properly top balance the cells. They will protect your cells and your pack from overvolt an undervolt and the smart BMS will allow you to view all your cells on your laptop or cell phone and that's basically it. I tried every setting and there's nothing a person can do to top up all the cells equally! 2-3 or four of them will reach the 3.65 volt and shut down the BMS until the voltage cell drops and then it starts all over again. The lower cells won't get enough charge to ever catch up before the bms shuts down. The BMS do not hold the top cells voltage below the cell cut off voltage so that the lower volt cells can catch up. Garbage. Maybe whats happening is certain not nice people are selling faulty BMS's. So basically I still have to top balance the other cells that have not reached the 3.65 Volt. This works for a couple charges then I have to do it all over again. The only good thing is that I no longer have to worry about overcharging any individual cell. I guess only the wealthy people are allowed to feel secure 🤣😂🤣👿🤬

[@jezzafield-jones7404]

Having a similar issue with my 12v off grid setup. My epever keeps shutting down during the day but my cheap mppts keep working all day. Some days it works and some days it doesnt

[@OffGridGarageAustralia]

What do you mean by shutting down?

[@jezzafield-jones7404]

@@OffGridGarageAustralia it turns my charge off and just sits around half a amp charge. It resets when I unplug my solar panels and reconnect. I Have found lowering my battery charge parameters prevents it happening as often but on a really hot day it tends to disconnect

[@diysolaradventures7894]

I had this problem twice i have two Victron 30/100 smart solar charge controller and one Victron Smart Shunt that's was in sync at first lit my BMS one of my cells had ran away shut my whole system down I had to wait because the first time it happened my whole solar system shutdown and when it restarted all my settings was back to default even the shunt then I was only getting on maximum charge of 26v out of 28v they kept going into absorcion & float early before the maximum voltage set in the charge controllers was reached

[@stoptheirlies]

Hi Andy, I did mention before that if you have the MPPT chargers connected to the Cerbo with cables you must not also use the Blue tooth network or the two systems will argue with each other. The DVC system is supposed to be used with something commanding it like a BMS, Having said that none of it makes a difference to the voltages, I Have shunt and three Mppt chargers, all the voltages are different I put it down to victron being shit and inaccurate. PS: I ran my own Electronics company for years, retired now, I have a good idea what I am talking about. Edit: I think you just stated your problem, "The smart BMS is not in the whole system???"

[@STRUTZKOFF]

well thats what he did a few weeks ago he disabled the smart bluetooth network and just in the video he re enabled it trying to get it to work properly.

[@stoptheirlies]

@@STRUTZKOFF That's correct but he hasn't got a BMS or apparently a shunt in controll of it?

[@OffGridGarageAustralia]

The VE.Smart Network can be used with DVCC in combination. I read all the documentation and nowhere it says you cannot do it or even you should not do it. In fact, the VE.Smart Networking manual says you can always set up the network and for example if your MPPTs are connected to the VE.CAN network at the same time they will just ignore the VE.Smart Network. So, there is no real directive from Victron in regards to this... More about this in the next video.

[@stoptheirlies]

@@OffGridGarageAustralia I never said that the DVCC could not be used in combination with the VE network? I said if it is used it must have information from a BMS . Also I said the ve cable network should not be used with the Blue tooth network. Ahh! well you see I did read in some Victron document that you should not, trouble is it was some time ago and I do not remember which one it was in, it was not the main manual. But what I do know is my system works perfectly, so you carry on.

[@MichaelAConnolly]

I have three MPPTs and as long as I am transmitting voltage from the bmv712 then all MPPTs are synced

[@MichaelAConnolly]

Also, I use the overkills (3) BMSs standalone, no comms as I am protecting cells and individual pack with these.

[@IanSHarrison]

With smart netwok off, you want to try tweaking the Absorbtion volts up a bit from 55.2 to 56, as a compensation for cable loss. That is 3.5v cell volts when Amps drops to 0 (so will not get to 3.5), well under 3.65v

[@OffGridGarageAustralia]

That is not good because if you have small currents during cloudy weather, it would charge to this higher voltage actually.

[@Full-of-Starships]

@@OffGridGarageAustralia Can you actually measure the same voltage difference between the MPPT outputs and the shunt inputs? Is this the same issue that causes your hot wiring at high currents? Could it be related to using 63A breakers with up to 70A of current?

[@einzelkampfer2006]

@@OffGridGarageAustralia I think this suggestion (higher absorbtion voltage) might be part of the solution, because at 3.45V the Voltage is not very sensitive to changes in the current. Its to close to the "flat part of the curve". Right now, when the battery reaches 3.45V it doesn't matter, if there are 20A or 60A pushed into it, the voltage stays the same. So if only one charge controller is still charging, the others won't recognise it because voltage didn't change when they switched to float. Otherwise, at a higher absorbtion voltage, the voltage will drop, when the current drops, so the other controllers will join the game again and provide a (reduced) current, to keep the voltage at 3.5V. Does this all make sense with LiFePo4? At least with lead acid batteries, multiple independent charge controllers "synchronise" their absorption via the change off the battery voltage, when the current changes. If one controller can't keep the voltage up by itself, another one provides current as well until the absorption voltage is reached and kept again. And because in absorption phase the current slowly drops, the voltage drop on the cables also gets lower. But voltage drop due to a high DC load is still a problem. Then DVCC and SVS are the far better options. Or at least charge controllers with seperate voltage sense cables.

[@keyem4504]

I saw that the MPPTs switched themselves of even when there was a high load connected. That seems strange and inefficient to me. In my grid connected system the Multiplus II simply switches to feed-in and the charge controllers continue to run full blast even when the battery is full ( as long as the inverter can handle that much current ). Any idea why it doesn't run the MPPTs at least on the level of the connected load?

[@STRUTZKOFF]

well this is off grid system, they should all stay in the same mode, when he disabled the smart bluetooth network a few weeks ago it was just using the ve netowrk to share the voltages, but seems the ve netork doesnt force them to stay in the same charge mode.

[@OffGridGarageAustralia]

You have DC feed-in enabled, that's a totally different system. They are controlled by the settings in the MPII, I believe. Not sure why they turn off though. Do more testing to find a pattern when they turn off.

[@IXISSV]

I've noticed with my smart shunt that it reads a slightly different voltage to the 100/30 scc too. I've just installed my 2nd 100/30 scc this evening, finished installing it and sat down to watch this vid 👍 But even the new 100/30 is showing a slightly different reading again to the original 100/30 scc and smart shunt 🤔🤔 I'm still waiting for my 3rd usb to serial ttl cable, then it'll all be on the Pi VRM 😁 Have you tried changing the float charge in your scc's to slightly different voltages? Would that help? Oh, and I blame you for getting me in to Victron and the Pi VRM 🙄 😁👍🥳🍻🍻

[@OffGridGarageAustralia]

Do you have them connected to a VE.Smart Network? That helps with the voltage. You need at least a smart shunt and one MPPT for that, which you have. I could change the float voltages but I don't want to. Floating at 3.35V is great...

[@paulcurtis5496]

Like# 631: dealing with my own Growatt set of issues, changing is clipping off with no error(s) both solar and generator…

[@ciciedee5474]

Tell me about the advantages of having everything communicating.

[@OffGridGarageAustralia]

3 battery banks with 100A charge current. 2 of these banks shut down due to cell balance issues. MPPT keeps pumping 280A into the remaining battery bank. Save or not save? With communication, the remaining battery can tell the MPPT to stop charging or slow down...

[@mrgruisinge]

My victron equipment is 'off' .35 volts. I have 3 MPPT RS450/100 tied together, so one master, two slaves. The remote manager is always .35 volts lower than the actual battery voltage. Charge controllers always report the actual voltage. Made me wonder but I never tried to find out why. Makes no difference where I set the fully charged voltage it's still off .35 volts. Also during charging Not all the controllers are producing the same. One will usually turn off and the other two will provide power for my loads. Sometimes just one will be working. When the batteries are fully charged just one controller will power the loads, not always the same one either. Everything is run to the Cerbo GX. So far I have had no problems that were not of my own making. I am off grid so have a generator for days when no solar or snow on the panels. Quattro starts the generator at a given voltage and shuts it off when done. Seems to cut the current for 15 or so minutes then shut the generator off. Just wish I had not started with an off brand inverter, never could get it to work with the generator. Quattro worked right out of the box.

[@OffGridGarageAustralia]

Thanks so much Gary. That is great to hear. Your RS MPPTs are connected via VE.CAN to the Cerbo, right? Do you have a smart bms as well for your battery?

[@mrgruisinge]

@@OffGridGarageAustralia Yes, connected via ve can. Signature Solar batteries. They were connected to the Growatt inverter but I replaced that a month ago with the Quattro 15kva unit and have not yet tried to hook them up to the inverter. The charge controllers have been hooked up for almost one year now and have done a good job of caring for the batteries. Grandson is an electrician so he takes care of the stuff. I think he is using the Victron professional site for help getting the batteries hooked up.

[@OffGridGarageAustralia]

@@mrgruisinge Thanks. These batteries should communicate with the Victron system through CAN as well but if it all works, it's a bit risky and could 'break' things. I do my training through Victron professional as well. It's a great service they offer.

[@kevroodenman3283]

tell us did Andy numb2 work on the settings? or the empty refrigerator cause chaos👀

[@OffGridGarageAustralia]

The fridge is nicely filled again, thanks to a lot of contributions from viewers. I'm feeling a lot better. Haven't seen Andy2 for while. Is he still around? 😉

[@hmarc417]

Maybe i am way off base here but question , is there a sens switch, setting for each controller or just one Master ? Maybe i am just imagining things that maybe should be but aren't.

[@ShaneFromSA]

If you have a Smart BMS connected then the MPPT goes into external control and only reports off or external. As it is controlled by the BMS. DVCC isn't really designed for systems without something commanding the charge like a BMS.

[@OffGridGarageAustralia]

Yeah, that is correct, I can see this in the SPAT Calibration Centre where the Pool Fence controller is connected to. It says External Control. I use the DVCC only for limiting the current coming from the new solar setup. It can get a bit too much for my battery setup. But no BMS yet... maybe soon?

[@davidrogers5343]

what are you going to do when they bring out the new battery types on market?

[@matthewwiemken7293]

Need voltage sense at the battery terminal and shared:)

[@ppi57]

Hi Andy (unrelated question) can you tell me what OS you're using to use your tester (ZKEtech 40L) on the PC. Mine does not work on Windows 10... Seller tells me to use a Windows 7 computer.

[@OffGridGarageAustralia]

I've got this running on my Windows 10 computer inside the garage but the software also runs on Windows 11 in my office.

[@OversampleReality]

I hate to say it, but using nearly 100% Victron hardware seems to me an endless cycle of firmware updates at best. Properly designed hardware will need firmware updates rarely, if ever. ~2 years using EPEVER MPPT controller with no issues.

[@FranciscoJimenez-mj4mq]

Pienso q configurar correctamente un equipo victron, no es para la gente corriente o usuario inicial. Tiene victron mucha sofisticación, eso lo hace complicado, pero cuando te haces amateur o profesional. Entiendes como funciona y se configura correctamente para tu instalación. Siempre decimos en nuestro foro, que victron es un puzzle, pero su multiforma y diversidad nos convence. Gracias Andy por su trabajo. Nos ayuda como usuarios de victron. Thanks Andy

[@PanelsUpSolar]

Were these changes tested after the last firmware update that was supposed to address the issue of the smartshunt sending erroneous temperature information to the charge controllers?

[@OffGridGarageAustralia]

That was tested before the upgrade. The -1°C problem is another wich I covered in a video here.

[@egnegn123]

You said yourself, that is not really an issue. Having different voltages on multiple MPPTs and therfore independent behaviour is expected. Normally it is not important whether you charge to 3,45 V/cell or 3,43/cell. Your charge/discharge tests have shown that normally there is not much capacity gained by charging to the slightly higher voltage. Yes the MPPTs will drop out and you will not reach the 100 % point defined by you at 55.2 V pack voltage. Are you really desperately in need to charge to your 100 % point? As this always cause stress to the batteries, especially at hot climate with accelerated calendar aging, this should be avoided as much as possible. LifePO4 calendar aging is about twice as high above about 70 % SOC as below and can be more then 5 %/year. (ref. Peter Keil, at all; Calendar Aging of Lithium-Ion Batteries) Having a synchronized voltage measured near the battery by the SmartShunt fixes this. All MPPTs see the same measured voltage and react synchronously at 55,2 V reached. Of course, you can activate DVCC that uses Shared Current Sense to control total current into the battery, as you are doing. If you have a CAN Bus connected battery, then all internal limits are provided by the battery (CVL, CCL and DCL) and Shared Current Sense (values from SmartShunt) are disabled, as full charging control is provided by the battery. Actually the charge parameters must be programmed into the battery. All the chargers are slaves to the battery. There is more information about DVCC and smart batteries in the Color Control GX Manual.

[@Dutch_off_grid_homesteading]

Heya, as I have a mpp solar all in 1 inverter I don't have that problem I hope. Oh wouw only 100 vlogs to go from the 467 vlog's that you have at this moment

[@9111logic]

Thanks Andy🙏, I was watching your video last night and wondering why connecting the smart shunt to the MPPT via Bluetooth and not by hard wiring, perhaps you can expand on this one? greetings from 🇬🇧

[@hummmingbear]

You can't "hard wire" the smart shunt to the charge controller

[@9111logic]

@@hummmingbear Sorry, I thought it was designed just like the lynx shunt but it obviously isn't

[@hummmingbear]

@@9111logic ah now I know what you meant. yes a bit different from the lynx

[@zeropointbalance7366]

Looking at your system, you seem to indicate that some controllers go into absorption before others. So what do you think triggers the transition? A voltage reading above 55.2V for some time in your case? Scenario: the system is happily pumping in 10000W or more, into your batteries which causes the voltage to rise - maybe say close to 55.1V at that high current, and a bit higher on the charge controller. Those controllers that have slightly longer leads or higher current will read higher **at the controller** for longer and maybe trigger the 55.2V threshold before others and then switch modes. Can you observe the moment it switches to float? Unfortunately the timer on one unit may be ahead of the other unit so it is hard to compare at the actual moment (you need to know when the timer started). I like to use 55.2V on my single controller (I am a fan of 3.45V), but as an experiment you could try raising the voltage on the controllers, say 56.8V just to see if you can delay this process? At that point your last online controller would be able to finish off the absorption to completely top up your battery.

[@STRUTZKOFF]

yes but they are supposed to work together with the ve network

[@OffGridGarageAustralia]

The MPPTs will go into Absorption mode as soon as they hit the 55.2V. There is no delay. They stay there for 1h (as per my settings) before going to float (53.5V). If the voltage goes slightly below that 55.2V within that hour (load, clouds), it does not matter, the time for that 1h keeps running. If the voltage goes down a lot, like to 53V for a while due to clouds and large loads connected, the 1h absorption time will be extended. That's what I have observed so far. Sometimes they stay on absorption for hours, because of clouds and the voltage going up and down all the time. That all adds to the inconsistency of charging if they are not in the VE.Smart Network.

[@StopTheBurn]

Don't listen to the experimental people out there. You are the Meister on this channel. I worked with CNC machines for years, and I always had people fooling with control parameters and messing things up. Setup a factory-recommended system, and don't mess with the parameters! Cheers Mate!

[@dierkgrossfeld1980]

Hi Andi, I guess the Problem with DVCC is that you did not select a Battery Monitor. At least in the Video I saw that there was none selected....

[@OffGridGarageAustralia]

It selects the BMS automatically as battery monitor once Victron detects it.

[@dierkgrossfeld1980]

@@OffGridGarageAustralia i also have kind of that problem with the dvcc and liontron batteries. The pylon tech quirks in dvcc assume that you are using 15s cell packs as soon as the communication protocol is pylon tech compatible. In the forum is a workaround how to disable those quirks. Worked nicely for me afterwards.

[@MichaelTheis77]

Andy, you are having "Limit managed battery charge voltage" activated. According to the Victron manual this should be turned off. Are you aware of it?

[@jameshancock]

There’s no point to absorption on LiFepo4. Just set everything to whatever your top voltage is and keep it there. CV will taper current and then the amps will go down and it will slowly get to that voltage and then stay there the way it should. And the whole thing should be using your bms voltage readings.

[@OffGridGarageAustralia]

Oh, noooo, that is not correct. Absorption is very important with LiFePO4. We have done all the testing here on the channel. If you don't absorb, you get very inconsistent charging results.

[@jameshancock]

@@OffGridGarageAustralia I’m seen your results. The science doesn’t agree. If you maintain the voltage at equilibrium it will charge completely AND enable balancing because voltage IS a pressure. It’s when the BMS is kicking on and off that you get the results you saw.

[@jameshancock]

@@OffGridGarageAustralia to elaborate: what you showed was the fundamental problem of disconnected charging, BMS and balancing that doesn’t work wholistically. Absorbing just punts the problem by doing the process below the hard stops. A system working together has the charger providing exactly the right amount of power into to the bms, and the bms knowing exactly how much it can use to shunt to the cells that aren’t yet up to level while not overcharging the ones that are. They need to talk to each other and if there are multiple bmses then the whole thing needs to be coordinated. Instead we get NO MORE POWER! OFF! Sag b/c of no more power, MORE POWER! FIRE HOSE! OH SH*T that’s too much! NO MORE POWER! Sag b/c no more power. Should be: Bms: I can use 2 more amps please Charger: Ok, here’s enough voltage to induce 2 more amps for you. BMS: Thanks! Here’s my real-time feed of what I need. Charger: OK, I’ll keep giving you exactly that! And guess what? This is EXACTLY how DC fast charging in an EV works. (And the AC/DC charger in EVs does too)

[@Full-of-Starships]

@@jameshancock What happens when one BMS says "give me 50A" and another one says "max 2A, please" (while the inverters also want 4kw to charge the Tesla)?

[@jameshancock]

@@Full-of-Starships it’s called a DC bus. Most all in one units use one at around 400v. (Nice value for PV and rectified and PFCed AC 240v and perfect for outputting 240vac from the inverter) All power sources are setup to maintain that 400v bus voltage. You can prioritize where it’s from. If 2 bmses want different amps, it’s still the same voltage either because of the bus or parallel, so the charging has to raise the voltage to provide the total amps requested by all loads and they will automatically distribute accordingly based on resistance to current. If your bms works in coordination with your chargers of various types then this is all automatic. Right now (to my knowledge) there is no system that communicates what it needs to balance properly at full charge which is the problem so you get a fire hose until the bms just shuts it off which means the bms balancing can’t keep up.

[@janetmorris6792]

Have you actualy measured your batteries with a digital meter as the calibration of the control box's may be different

[@OffGridGarageAustralia]

That does not matter and is not the problem. Even if the smart shunt measures 50mV off to what it actually is, it is important that all MPPTs get this same information from the shunt.

[@Meiestrix]

Wait... are the charge controllers connected via bluetooth and cable?

[@OffGridGarageAustralia]

Yes, absolutely.

[@gonesilent]

stupid $$$ VE direct cable cost...any other options?

[@OffGridGarageAustralia]

Yes. You can just make your own. I'll show you how...

[@romeowhiskey1146]

With respect to the VICTRON COMMUNITY responses...lots of 'guesses'. WHY aren't you getting the CORRECT ANSWER from Victron?

[@garys-half-baked-offgrid-dream]

I just want an On/Off Switch and a Dial I can turn upto 11.