Communication between BMS, solar charge controller and inverter. What's the benefit?

So here I show what happens when I fully charge my battery to 55.2V and one of the battery banks is out of balance (a lot). Does it matter, is there a problem? As long as all cells stay within manufacturer specs, I think we're totally fine.
So what would a communication between BMS and solar charge controller actually do? What would it change to the current situation? How can it benefit? At this stage, I'm not sure if there is an advantage of doing it in comparison to how it is right now, without comms between the BMS and SCC or inverter. Is the monitoring aspect the only (small) advantage I can see?
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[@borealis370]

One thing I'd expect (..hope for...) from an communication setup between BMS and the other components, would be to find the same information in one place. I value , one less system to login to. I like to have as much of it as possible in one ecosystem - to me, that's the appeal of victron products.

[@ShaneFromSA]

There are several advantages. Main one being not having a smartshunt as the BMS is the battery monitor. Second is at higher charge currents like 1C you can have high cell voltage very quickly so the charger controllers can react. Also there is less loss in the breaker style BMS but if the breaker trips you have to manually reset it. This means if you get a high voltage disconnect it will be irrecoverable remotely but with coms you never get into this condition. Data logging and remote diagnostics is also a benefit. As someone who manages many Victron sites it is really helpful to see MIN/MAX cell voltages for every site to detect problems early.

[@henkbouhuyzen8255]

This is true if you have one battery with a single BMS. As soon as you have multiple batteries in parallel, it make sense to maintain one central Smart shunt so that one does not have to add all the current data form each BMS together.

[@ShaneFromSA]

@@henkbouhuyzen8255 Every installation I have has multiple packs. Most battery manufacturers have one battery take over as Master and the other packs as slaves and reports them as one big battery to the GX. These tend to be even more accurate than the Smartshunt as they take into account cable losses and don't require 100% recalibration from time to time. For DIY packs I have used the Orion BMS with multiple packs and also had great success with BMS calculated SOC.

[@henkbouhuyzen8255]

@@ShaneFromSA I build my own batteries form 320 Ah Evo cells and each 12 V battery has its own BMS. I have not seen a method to connect these BMS' es together. I build my own as I could not afford the high end brands such as battle born. And even the battle born batteries have no communication between each battery; at least there is no mention of this on their website. You must have used a specific battery brand.. I do know that I could (with some additional hardware) connect my BMS devices to the Gerbo (via a Rs 485 link)

[@ShaneFromSA]

@@henkbouhuyzen8255 Yeah, I primarily build really big systems. Like 100kwh plus. I don't know anyone that has managed BMS for 12V batteries. I only build 48v system with Victron. Pylontech, FreedomWon, BYD the batteries I mostly use.

[@pd4689]

Hi Andy, thanks for all these videos, light hearted and informative. It would be great to do an 'on-paper' video where you go through your final setup and show the system start to finish, chasing the load from how you parallel/serial your panels, diodes, fuses, breakers, MPPTs, batteries, inverters, amperage considerations when cable sizing, etc.

[@DragonsOfAra]

Yes I would like to see this too.

[@peetbraun9439]

Hi Andy, you missed one important point: The BMS is the last line of defence. You should never ever relay on the shutdown of this component in normal situations. Therefore your settings should be like that, so this situation will never occur. So shutting down a bank of batteries because one cell is high by BMS should never be an option. Having communication could be an solution, to keep absorption available until the last bank has been balanced. Grüße aus'm Schwabaländle :-)

[@OffGridGarageAustralia]

Hi Peet, I don't rely on the BMS alone. You're absolutely right! The SCC turns off charging long before the BMS kicks in and also the inverter will shut down long before I hit any low voltages. When I run these tests, I obviously want the BMS to trip to see, experience and share what is going to happen. This is also peace of mind in case I'm not at home and the 'something happens' 😉 As we have seen in this test here in the video, under normal settings and conditions, the BMS is not kicking in at all and just balances as it should.

[@diydsolar]

@@OffGridGarageAustralia Hi Andy, I think you can publish a "conclusion" video with all settings (almost) of SCC , BMS and inverter. Joined to this video will be a great point to ask community for advise, won't it ?

[@DO5DGH]

Thanks for the great video. I also use VE Solar Equipment in combination with my 2x5 kW/h PS5120E LiFePo4 batteries. In the beginning, I often asked myself whether communication with the BMS would have any real added value. However, I don't see any advantage at the moment. The VE Equipment is doing a great job w/o any BMS communicatio, too.

[@upnorthandpersonal]

It helps when you charge with very high currents: you can tell the charge controller to slow down so the BMS can keep up balancing. Staying at 3.45V you won't see this, but if you charge to 3.55V or more (higher voltage to get more current in a shorter amount of time). You're still well below 0.5C charge current as well coupled with your max solar output- once you go to 0.5C or more (think if you have 10kW array or so) you will get over voltage faster and the communication will allow this to be throttled. In other words, it wouldn't make a difference in your current set-up.

[@Shep5847]

100% agreed. Also all of the BMS details would show up in the VRM with an integration to the victron ecosystem.

[@michaelbouckley4455]

@@Shep5847 I’d like to see it. I don’t think it will be simple to connect via Raspberry Pi, to a non-Victron BMS & Battery. Andy would need a Cerbo or other Victron device, with the correct ports.

[@Shep5847]

@@michaelbouckley4455 We aren’t talking about doing it with the raspberry pi, only what can be accomplished if the connection is made. How to do it with a Pi is another story for sure though. But I do it through a CerboGX using a Batrium BMS.

[@upnorthandpersonal]

@@Shep5847 You can do that with the JK BMS by the way, there is a driver for Venus OS for it.

[@upnorthandpersonal]

@@michaelbouckley4455 There are drivers for JK and other BMS for Venus OS.

[@OneStepToEscape]

Hello, Andy It's good when every independent bms can communicate with chargers/inverters and also between each other. One of the reasons why is for the correct distribution of current between several independent parallel banks. For example, if you discharge your two banks with high current and one bms failure, then loads move to only one battery. In this case, you can lose the second one (overloads). On boats we have to calculate currents as N batteries + 1 (some kind of redundancy).in case of smart communication, the chargers and inverter know how many bms's alive, if one is dead, the current can be immediately reduced. Also, smart communications between batteries and chargers possibly can organize the correct distribution of the current between batteries, no need to have an equal cross section and length of wires, etc..

[@salarhadi2988]

Thank you Andy I think the big useful that can control the current from Mppt and do balancing with out cutoff your BMS. Thank you again for your explanation.

[@creamshop]

Why do i smile every time i see this guy!!!!

[@OffGridGarageAustralia]

Thank you 😊

[@jamesireland6752]

Hey, communication is important to extended battery life during extraneous conditions like rapid charging or during extreme ambient temperatures. Here in North Queensland my battery bank reached 40 Celsius regularly during a recent heatwave. My LG Resu 6.4 ex battery backed the multiplus down to a 16A limit which was inconvenient in my ESS but gave me comfort to know the most expensive and dangerous asset in my system is looking out for itself beyond the manual safeguards I put in place.

[@OffGridGarageAustralia]

Ah, right, that is a very good point. I never thought about temperature actually. While the BMS prohibits charging under 0° it won't slow down charging at high temperatures so the cells don't get even hotter with high charging currents. Very good example, thank you!

[@kevinmills5293]

If you set the balancing on the QUCC to start at the float voltage, it will continue to balance the cells for the whole of the float period (which can be several hours) unless the cell difference drops below the threshold. I’ve tried this and it seems to work well.

[@ai4px]

Has anyone been able to make qucc BMS stay on longer than 18 hours?

[@batterynerd8779]

Hey Andy, since you hve a Raspi, you could add a 7inch Raspi-Touchscreen. It costs around 60 $ and you would have a very nice interface with VRM. I dit it myself. It works great and costs nothing in comparison to Cerbo GX (800.-).

[@corruption902]

Redundancy is a benefit. If something goes wrong with the BMS and it's not able to shut off charging or discharging, you have something else looking in on the cell's state that can take action.

[@texciler]

With the victron equipment you can set a maximum charge/discharge current and a maximum charge voltage from a BMS. Technically it could do what you are doing manually sometimes: reduce the absorption voltage in case of a high cell imbalance to prevent single cells exceeding 3.6V. When cells get balance, increase voltage in small steps. But I doubt that you BMSes will do that. Other cases where it might improve the system (but do not apply to your setup): - reduce charge/discharge currents near full/empty with small batteries that are driven near its limits - allow small charge currents in cold conditions instead of completely disable charging - adapt charge/discharge currents in modular (parallel) systems where single batteries are frequently removed/added

[@aussieaustrian8704]

I know it’s a bit late to comment. But I think the major advantage of a BMS that communicates to the charge controllers would be for off grid systems that rarely get to 100%. For say yachts or remote static installations over say winter when solar can have days of low input keeping the batteries below 100% for long periods of time. The benefit would be that on the rare occasion that you do get into the balancing voltage, if the absorption time was too short to allow he BMS to fully balance the cells. It could throttle back the voltage for as long as it took to balance them, get them back to 100% balance and then resume normal operations. Similarly for banks with differing capacities like yours, you could find the aborb time not enough to allow the lowest SOC bank to balance if the other banks reach the balance voltage earlier (because they have lower capacity) then the whole pack will reach the cut off voltage, reset and go into float voltage before the BMS has done its job. For example your float is 3.35v and balance voltage is 3.45v. If banks 1&2 are 280ah and 3 is 320ah. 1&2 could peak first, begin to balance a lot earlier than bank 3. As bank 3 hits 3.45v the whole pack will peak and the absorption time pack 3 gets to balance could be zero before the whole pack goes into float @3.35v and stops balancing.

[@evil17]

I think what u have is good. I would consider more load dumps if you have power excesses, why throttle back your PV controllers when your batteries are full if it can dump into a Cap Bank, increasing the voltage a little under the inverter threshold, which set voltage then turn on an air con, or dump into the tesla, heat a spa, hot water tank, pool pumps, its all useable energy in whatever form u convert it, and heat pumps.can be an efficient form to use energy, so my questions are: how often do you need to top balance anyway to 100%? And why would you want to throttle back free power if it is available and you have other “Dumps” you can divert any extra power to, if/when your batteries are all fully charged, I guess you could say that batteries can come in a different form than just electrical storage, but I’m sure u have this all figured out too, dont ya! Good work!

[@tg_privat]

Maybe BMS can be used instead of smart shunt. And (in my opinion) it is much better if the load turns off when it receives a signal from BMS. In this case inverter stays on, only load is turned off. If the battery just shuts down, what happens to the inverter when it stays out of power? And also what happens to charge controllers? How the system reboots then? I think, this should not happen in any case.

[@uksa007]

The benefit is as you describe, the BMS disconnecting the battery should be the last resort when everything else has failed to prevent the over charging of cells. By slowing down the charge rate, it gives the balancer time to work.

[@OffGridGarageAustralia]

... which could take the whole day in case of the QUCC, DALY or JBD... I don't like this. The whole system is then 'blocked' just because of one high cell. If the BMS turns off the particular battery, the rest can work normally. As I have shown here with my settings, this does not happen to me under normal conditions.

[@uksa007]

@@OffGridGarageAustralia Which is caused by using a BMS that is not suitable for the capacity battery you have. Ditch the QUCC BMS and use another JK or another BMS with a more suitable balancer!!!!

[@wayne8113]

Thanks Andy

[@Sanwizard1]

Having comms would let my inverter know SOC of the batteries, instead of guessing based on a smart shunt. As an example, my MPP Solar inverter thinks my cells are at 48%, when they are actually at 90%, so I have to rely on the BMS to assure no over charging occurs.

[@OffGridGarageAustralia]

But does your MPP not charge as per voltage settings?

[@antoni_sk]

Hi Andy. I see only one main advantage in direct communication between the BMS and the controllers, and that is that the controllers measure the battery voltage at their terminals and not at the battery terminals, and there is a difference. if the regulators had their own torch voltage measuring wires, there would probably be no need for communication. I have all my controllers and bms communicated via Modbus protocol to the scada system and I see exactly what the voltage of the battery is and what the voltage of the battery is measured by the controllers at their terminals - there is quite a difference ...

[@OffGridGarageAustralia]

Yeah, OK, that's what the smart shunt does in my system. I measures at the battery level and reports these numbers back tot he SCC and inverter.

[@isogeezer]

I know it's a bit off-topic but could you set up an experiment with the outside 3 panels to characterize the possible benefits of a reflector/mirror for low azimuth solar charge optimization in the morning or late afternoon or even to get around shade tree effects? Thanks.

[@edc1569]

Communication is great with my powerwall setup as I have limited hours of cheap electricity so I need to pump electrons in fast and then tail them off, the lower current at the end of the charge cycle is helpful to let the balancer do its work.

[@martinaupperle220]

In the winter time our cells would be empty most of the time. The cells do not like that, so we want to keep them charged for, lets say 30% or so during that time. Another scenario is when you ALWAYS want to keep a certain amount of energy in you batteries to have at least some energy in case of a grid failure - maybe 50% or so. The third scenario is that we would like to operate our cells between 10 and 90% SoC. Another thing might be that you might want to do some kind of "smart charging". The charging curent should be dependent of SoC, the expected incoming PV-energy (weather), expected (planned) energy needs of the loads, optimizing lifetime of the batteries and other factors. It should be clear now that inverters NEED to know the SoC. What I do not understand is that current models, and yes, also the Victron Multiplus, do not have the capability to determine SoC. We need to connect to a BMS, and in the case of more than one battery pack this is practically impossible (there are BMS with internal communication (e.g. REC) that can handle multiple battery packs, but these are too expensive). Or we must buy another piece of hardware, e.g. the Victron Smart Shunt. Why can't the inverter do that if it is needed anyway? The inverter could determine the lower and upper cutoff voltage of the pack every now and then and do Coulomb Counting in between. Not too difficult.

[@pederb82]

Of course it makes sense to charge higher. This 3,45 is why you see the big spread at lower state of charge and the run away at higher state again.

[@mikebarry229]

Some solar charge controllers will be destroyed by being disconnected from the battery while still receiving voltage from the panels. Some sort of advance warning from the bms might give the charge controller time to disconnect the panels before that happened.

[@michaelbouckley4455]

Some Victron SCC’s are prone to damage from that, especially if the solar power is high voltage & current. On 24V 310Ah Lifepo4, I connected a 100/20 to 2x 325W panels (as recommended by Victron’s MPPT calculator) so halving the power from 1.3Kw (2S2P) to a 100/50, which was getting hot (it did burn the battery + cable & the Victrons screw terminal; as they warn in the manual) I don’t like the small connector block on Victron SCC’s, it’s inadequate; can’t get square crimped wire of the max stated size (which is quite small) into the socket. The 100/20 first developed a fault on the load, not turning off; but still measured current, for a while, until that played up, then stopped. Then the SCC completely stopped charging at 24v; but charged a low rate on a 12v system with 360W input. Both SCC’s will have to go back for repair. Now using 2x Epever 6415AN’s (2P panels, they don’t get hot, and waste power). I prefer the 6415AN’s wiring box, which is much safer. Also the 100/20 once had a fault, on the wiring at the very small terminal block, which applied 52V from solar (240W) to the battery wiring. The BMS is 10-24S (good on my 8S) easily withstand that, and shut down. It just blew a few small items, 30v max, a voltmeter 2x temperature controllers and a buck module. Have a 3rd 6415AN that’s been away 4 months, for repair to its RS485’s! Could upgrade to 2 more 325W easily 3P @ 30A; and more with the other SCC, when I get it back, maybe 2x 500W panels.

[@sreekumarUSA]

Mike

[@mikebarry229]

@@sreekumarUSA agreed, but that was not my suggestion. My concern was that once the battery is fully charged the BMS would disconnect the solar charge controller to prevent the battery being overcharged. That would leave the charge controller disconnected from the battery but still connected to the solar panels, destroying the solar charge controller. Far better would be if the panels could be disconnected before that happens.

[@MitchOfCanada]

DC relay for disconnect of solar panel could easily be done. SOC gets to 95% it will turn off? In my van I have a heating mat under my lithium battery to put heat into the battery in the cooler months. Turns on for 25 min cycling for 3 hours on the Inverter. Only takes 50 watts and my panels usually make 150watts (600 on roof). I plan on putting a dc dump load circuit on for hot water tank.

[@Sylvan_dB]

It's probably good enough without communication (I hope so, that's how mine is working!) but I think it could be better. The need for better diminishes as the cost of battery and solar decreases and personally I think we've hit the level of not needing, at least for stationary systems. I don't know if the victron communication and components are smart enough, but the optimum would be if the the solar charge controller would limit the current to the amount needed to 1) maintain battery at current voltage (e.g. while balancing) plus 2) supply any loads. This would avoid burning excess current in the balancer, hitting hv disconnect, and battery cycling near top of charge as loads discharge and drop the voltage until solar kicks in again. I believe solar ElectroDacus can do this, but as I said, I don't think I need it.

[@OffGridGarageAustralia]

That's a possibility with Victron gear and if the BMS data is available You can set up things like this. I'm with you and don't know if it makes sense and if I need it. Atm I cannot see a benefit...

[@TradieTrev]

I would explain the advantage of using your serial 485 or canbus is that you can use FOSS to log everything in the same web interface.

[@OffGridGarageAustralia]

Log means monitoring but not actively controlling, right?

[@TradieTrev]

That's correct.

[@jws3925]

I wish JK made a 12v BMS. I like how it reacted in the last video. Thanks for all the experiments, Andy. You make the comment here "there is no reason to charge higher than 3.45v per cell." If I recall, the only exception is if you need to charge the battery more quickly. I believe you gave the example of a person on a boat that wanted to maximize charging when they had sun because one never knows if tomorrow will be a good solar day or not. Does this still hold true in terms of your assessment of charge voltage?

[@dalepurdon8948]

I think Andy meant that you dont need to charge each cell to anything over 3.45v. This is different to the actual charging voltage that one uses in order to charge the cells (which I think you're referring to)

[@randyretired8443]

When one of my BMS's disconnects during charging on my 12v system I have measured voltage spikes over 21v. The inverter detected it and shut off but 21v+ for the remainder of the 12v appliances in the RV is a problem. I have top balanced my batteries so this is no longer a problem. I don't want my BMS's disconnecting unless it is a serious problem. Voltage spikes will likely cause problems eventually.

[@OffGridGarageAustralia]

If you have more than one battery and a BMS disconnects one of them, why does the voltage spike? It should stay the same as before if all other batteries stay connected.

[@randyretired8443]

@@OffGridGarageAustralia It was a bright sunny day and the solar was producing a little over 150amps into 800amps of batteries. When one, 400amp battery suddenly disconnected the voltage spiked before the solar charge controllers could react.

[@randypeterson4055]

Bulk Charge is Constant current charge. Absorb Charge is Constant voltage charge. Float Charge is also Constant voltage charge at a voltage below Absorb charge voltage.

[@OffGridGarageAustralia]

While it does not charge in float mode any more. It maintains the voltage (and current) of the battery.

[@Josh-b3c]

No I don't think you should bother top balancing the old battery until after you fix the terminals

[@Dutch_off_grid_homesteading]

Heya, I think it's verry neet that you can monitor your system from your mobile foon

[@extremeacc101]

Great video Andy also don’t forget having the BMS control the system negates the use for an external shunt. As you know this is another path of resistance which can be eliminated. Obviously you already know this but if you don’t I’m sure you will understand that all of the rack mounted batteries as well as other big branded batteries do you have CANbus communication. I am actually doing some work right now with Power Paul on the batteries he is building for me through the business. Looking at DALYBMS communication to Victron. Lots of information on the GIT hub and a few people already have sorted out communication from BMS like yours to the Victron protocol campus. Looking forward to that stage. Let me know how you go with that set up also.

[@OffGridGarageAustralia]

Yes, thank you. A communication could eliminate the need of a smart shunt. There would be no point of reporting the overall current in such a case though. I quite like the idea of having once single point of measuring of the overall battery voltage, current and SOC in the system and not multiple devices reporting slightly different values. The comms between the BMS and the (Victron) system should be fairly easy. As you said, there is plenty of info out there and Louis is working hard on this project. I will have something very cool coming up in the future. I work with a manufacturer of a BMS and they will make the communication between BMS and Victron two-way. So Victron will be able to control and set parameters for the BMS, not only reading the data.

[@extremeacc101]

@@OffGridGarageAustralia Sounds good Andy please keep me in the loop on this. I’m very interested. Thank you have a wonderful day.

[@MrAbloem]

@@OffGridGarageAustralia Andy, I am really looking for this. Only setting a max voltage to mij solar charger, shore power charger or dynamo may be not loading my boat batteries enough from time to time especially lack of sun on days we are not motoring and not shore power. By the way, thanks for all work on LifePo4 batteries. I am learning every day!

[@jameshancock]

One setting once in one place and everything just works.

[@davidbatchelor6393]

I am trying to buy 48v lithium batteries for my Sungrow system to replace the old AGM batteries. Suppliers keep telling me that the lithium batteries I wish to buy won't communicate with my inverter. Does this matter? I don't think so as each battery in the rack has its own BMS.

[@OffGridGarageAustralia]

It does not matter. I know someone who did that and the Pace BMS will not correctly communicate with the Sungrow inverter. It's a Sungrow problem though and they need to fix the firmware on their devices. He is now using the battery without coms and has setup a custom battery in the Sungrow inverter with the correct charge voltages. Works all fine. There is a slight problem, when the battery is fully empty and the Sungrow shows an error message then due to low voltage. A restart of the Sungrow fixes that immediately. It's an inverter problem...

[@camielkotte]

This is so great info from field experience. Edit: one sunny question occurred to me after reading the comments here about reading voltage at the battery terminals. Why does the BMS not make the victron shunt obsolete if BMS is connected via can/rs? Wouldn't you get the same information on your raspberry pie from the BMS?

[@OffGridGarageAustralia]

Thanks Wiley. If you have only one battery bank with one BMS and it can talk to the rest of the system it can replace the smart shunt yes. But some people (including me) have more than one battery which makes it a bit tricky with multiple BMS' connected. I really like this one point of 'truth' now I have with the smart shunt, regardless how many batteries (and BMS') I will end up with.

[@TheSmartGerman]

Well, main advantage getting SOC information than just the voltage levels. Because voltage curves are so flat on lfp.

[@OffGridGarageAustralia]

But the flat part of the curve is not relevant anyway for anything to be honest. Only if voltage rises and the battery is full it is interesting. And here again, the solar charge controllers provide a relay output which can be programmed for this. What would you want the system to do at say 60% SOC if this is been reported from the BMS to the system?

[@SVImpavidus]

Are you using the victron VRM on line to monitor and record your data. I saw that you have a pi but dont remember you using the VRM. 👍

[@OffGridGarageAustralia]

I'm using the VRM for over a year now. Link is in the description of each video 😉

[@SkypowerwithKarl]

High Andy Your system is really starting to look good. Id really like to see what the delta looks like at mid charge and at a lower voltage under moderate load, comparing the older bank to the new one. The curiosity is, how much does a good full charge delta really matter?

[@OffGridGarageAustralia]

Thank you, Karl. That was exactly my thinking. If all cells stay within the specs, the BMS should be OK to monitor and balance over time. And with the two new batteries coming soon, we won't have the issue with the old pack any more anyway.

[@Raphael_Hofmann]

I'll try the Seplos BMS with CAN communication next :)

[@user-dr2pg8fk2i]

Is there not a way to tell the controllers to stay on to meet the loads instead of pulling from the batteries, PV controller recharge batteries, repeat?

[@livingron9983]

The venus os on raspie can do this when components are all integrated. The multiplus 2 can keep the victron mppt chargers at full capacity and export to grid and/or supply loads. It can also control ac inverters (on ac output) via sunspec on modbus tcp and frequency control - in which case, the ac inverter will continue to produce output even when the grid drops off - there are a few gotchas but this is what i do on mine.

[@user-dr2pg8fk2i]

@@livingron9983 Would be great to see a video series on the process. Ideally for a complete novice programmer.

[@arminwendling629]

Hy Andy, I sie a small Solar System with gobelpower 150a BMS and 4A Balancer, A Smart solar mppt and the Inverter is from Lumentree. Batterie and mppt are conected with an Cerbo GX. I like the Monitoring oft the batterie via VR Portal. But I Wohls prefer to control the charging with the Mppt. Is there an Setting in the Cerbo to Monitor the BMS but Not Controlling the charging via bms?

[@dffghuytfvb]

Maybe a communication between BMS, charge controller and hybrid inverter might make it possible to inject the surplus on the grid while performing the balancing?

[@OffGridGarageAustralia]

That should be automatic, dependent on your inverter settings (if it is a Multiplus) or settings for your transfer switch.

[@dffghuytfvb]

@@OffGridGarageAustralia but the inverter should tell the mppt to supply full power to the DC bus.

[@nestalnevers203]

I have a 280ah 24v system, my jbd bms constantly switching off my inverter when the batteries reaches 3.65. How to avoid this. It's a schneider 2425 inverter with a midnite classic 150.

[@firpofutbol]

Andy didn't you burn a mosfet on the JK 4s by abruptly disconnecting while on a load? Doesn't abruptly disconnecting like that also damage other components like a SCC? I thought I read that somewhere I could be wrong. If the BMS tells either charge or discharge components to turn off individually it might save those components or the BMS itself.

[@BorgOvermind]

Can the JK BMS be connected to the MPP Solar inverters that have RS485 port with the JK RS485 adapter ? And what should be configured for this if it works ?

[@stupidmonkeykev]

data logging is about the only advantage i can think of.

[@manjulabw]

can you do Deye inverter review please

[@steffen1182]

1:50 orption voltage? XD

[@bryanmendoza2770]

i think it benefit more on the monitoring cells remotely. Since BMS are usually Bluetooth so we are unable to see the BMS data online. Having that communication will benefit that or even you are able to tweak your BMS settings online?

[@OffGridGarageAustralia]

I don't think you can actually tweak the settings through a communication port. The BMS just sends the information via RS-485 to whatever is listening to the data stream.

[@bryanmendoza2770]

@@OffGridGarageAustralia there should be a way to read as well as write the settings depends on the application features. RS-485 is just the medium of communication or maybe not in your current setup. i heard BITEK they have deep integration between their inverter and BMS.

[@sjdtmv]

Andy I don't if you have ever gotten into data logging at cell level and using MQTT to check the history of how each cell in the bank is going instead of only real time monitoring

[@OffGridGarageAustralia]

Thanks Ross, yes but this would be just for monitoring purposes, right? Not actually controlling other devices according to a state of a cell.

[@sjdtmv]

@@OffGridGarageAustralia Yes just for monitoring the cells history even under load and change

[@Wrenchen-with-Darren]

My only reason for communication between battery and inverter-mppt, is safty redundancy. Cost me 8 dollars for this.

[@paulcurtis5496]

The benefit could be when you have a battery who’s BMS is a black box and can’t be adjusted? Mine is a Big Battery Rhino and it is set to charge until 58.8, so I set the inverter to 56.6. Am I wrong?

[@markstemmett5296]

Microcare controls charge on voltage or SOC, no need for communication. The can commas is a marketing thing

[@OffGridGarageAustralia]

I think so too at the moment. It is a monitoring thing...

[@DanBurgaud]

5:25 has anyone seen any BMS using the Inductive (Transformer) balancing technique instead of Flying Capacitor method?

[@SabretoothBarnacle]

Is anyone else having issues with the new VRM interface not showing the AC Load and displaying '--' instead? I know it can see the Watts from the multiplus as its in the details box just below the main box !

[@igorkvachun3572]

Yes 👍 🔋💡 🇺🇦✌️☀️

[@brodn7545]

Since the amps going into the battery bank gets lower when it is almost full and then the battery bank is supposed to stop accepting charge when it is totally full, does it mean that it can never be overcharged?

[@OffGridGarageAustralia]

That depends on the settings of your charge controllers. I have set 3.45V per cell as absorption voltage. So with all cells balanced I cannot get in trouble as the maximum voltage for the cells is 3.65V. But if your balancer cannot keep up (like in the QUCC, Daly or JBD BMS) you can overcharge your cells as I have shown in the previous video.

[@pmacgowan]

Does victron have a BMS ?

[@OffGridGarageAustralia]

Yes and no. They have a few BMS but they only talk to their smart batteries and cannot be freely programmed as their charge controllers. So, it is kind of useless unless you have their batteries as well.

[@davidpenfold]

I'm using a Sunny Island 8.0H and it literally won't work with a BMS that doesn't speak its canbus dialect...

[@xpatrikpvp]

I just ordered my new victron inverter. The multiplus II 48/3000 but i don't know what fuse to use becuase the smallest megafuse is 125A and that seems a bit too much, any recommendations what should i use? I also currently have a 3s100P li-ion battery and i'm planning to reconfigure it to 14s20P and use the JKBMS and then planning to use the same JKBMS with a 16s lifepo4 battery. From my understanding the JKBMS supports li-ion and lifepo4 right?

[@helfer6pence]

125A fuse is recommended by Victron for the 48/3000 according to the manual.

[@xpatrikpvp]

@@helfer6pence Oh that seems to be a little bit high. Thats 6000W at 48V and the fuse should be 20% above the max inverter power so around 75A

[@helfer6pence]

@@xpatrikpvp I’m no expert but I thought the fuse was there to protect the cables etc. Victron recommend 35mm cables for the 48/3000, which I believe are rated for about 100 - 120A depending on the length.

[@opless]

50th! :-)

[@OffGridGarageAustralia]

Is this your worst?

[@opless]

@@OffGridGarageAustralia hahaha! No if it gets too big I don’t comment. I’m still loving your content :)

[@davidrogers5343]

put both charge controllers on a bus brand see what happens to them. if they act the same way with one solar panel power on the bus bar and one battery on another bus bar. all solar panels and batteries are not equal and charge controllers ad wires are too. try a compressor for storage,

[@davidchristensen1219]

Your logic regarding communication between the devices does not take into account loads higher than what you are showing during your testing. If you had higher loads during the charging, absorption or even float cycles, then the results will be quite different. I've seen it in my own system. That's why I'm using a custom program I've written that talks to my cell "monitoring" system which can alter the CC state and Inverter state. I also have Home Assistant integrated with this custom program to allow me to "privately" monitor my complete system as well as override control of loads as well as the solar equipment state. If you'd like to see what I'm talking about, I have another YT channel: JC/DC in the AZ that goes over my system as well as the Home Assistant integration.

[@OffGridGarageAustralia]

No, I said this in the video: this situation will only occur if there is more solar power available as your loads are. Only then is energy left over to actually fully charge batteries. If you loads are bigger than what comes in from your roof, you will discharge your batteries and no cell can actually peak with a high voltage.

[@davidchristensen1219]

@@OffGridGarageAustralia Hi Andy. I'm sorry I didn't remember this from your video. Also, I wasn't really saying that the load would have to be greater than charge, just that the load would by higher than what you were testing. That's why In my setup, I have a Home Assistant gauge that shows me to Net Charge/Load to/from the battery.

[@onmyworkbench7000]

At the end of this video you that can control all of your solar equipment by going to there website with your smartphone, then they can control your solar equipment without you knowing it, no thanks I will keep my stuff off the internet.

[@Pimpasxx]

Benefit is if you use balancer only with can comunication. Its cheaper, becouse no need bms.

[@amudlifecrisis]

It would be nice if Victron made a BMS that connected to the VRM. I like how integrated everything is within the brand.

[@OffGridGarageAustralia]

They do have a few BMSs actually but they only connect their own smart batteries. I agree, it is really time for them to release one which is plug'n play as all the other gear they have and can be programmed to the user needs.

[@firpofutbol]

Victron would eliminate the incentive to buy their overpriced lithium batteries if they did that

[@andrewbowden1076]

Mind you, the JK BMS does not shut off the battery completely. It just does not allow anymore charging during a “cell too high” situation. You can still pull power from the battery and the inverters will still stay running.

[@OffGridGarageAustralia]

Yes, that is correct!

[@seanajacobs]

Remote monitoring is all I’m looking for. I agree protections are in place in many places so control isn’t really needed.

[@OffGridGarageAustralia]

Same here. I just want to know what's going on... 😉

[@seanajacobs]

@@OffGridGarageAustralia I used JK BMS for a custom battery build for a client. I can monitor and control just about everything else remotely for them but monitoring this or even adjusting BMS setting remotely would give it a major advantage. I don’t expect remote adjustments. But monitoring would beat asking them to send me screenshots at certain moments :)

[@runneryg]

I bought an inverter from ALI EXPRESS and I have a Lifepo4 Battery the settings for the inventor are AGN AND FLD USER I HAVE IT SET ON USER THE description it says Lead Acid Lithium but he said it will work the charge on the inverter not coming on? I have all of the settings nothing only grid charging ac power all fine is there a way around this problem i am A beginner min power in 120volts i have 10 solar panels 275 every 2750 watts took some off 7 then 6 then 5 still no change from solar please help me I been trying for it work for 3 4 days now don't know if i should by an external MPPT or an external BMS AS my lifepo4 battery was complete ready made with one + terminal and one - terminal has all the dc ac air switch circuit breaker fuse on the battery it is a hybrid inverter it seems I bought the wrong inverter is it save to charge at the list? I have charged it 92% and turn it off it seems ok. i know its off topic I need help>

[@jasonbourne7171]

If i use inverter with lithium and add value manually according to lithium battery data sheet so it is safe to use battery although battery have there own bms

[@yorks_atheist3069]

Not sure your comparing like with like here, The current has to go through a non connected BMS like the ones your are using, where as with a can bus BMS like my batrium the batteries go via a trip direct to the inverter so the shunt trip provides the job of your disconnect relay and provides tapered current control etc via can direct to the GX

[@jmaus2k]

Well, there is only one right answer here. Let's have Victron give you their BMS charge controller to test so we can all see together. They call it the Victron VE.Bus BMS.

[@christophec252]

I have another deep question. How can you get 2 BMS discussion with one RS485 port inverter!!!!!

[@OffGridGarageAustralia]

That works with the right drivers and if both have RS-485. I'll show you in a future video...

[@adamharkin2637]

Hi Andy just a quick question. What screen are you using for your Victron display. Is it a iPad mini.

[@OffGridGarageAustralia]

That is my 9 year old Google tablet, a Nexus 7.

[@adamtaniasargent1386]

This channel has been a wealth of information.. A mate who is a switchboard builder/tester put me onto this channel. Keep it up.

[@DIYDaveT]

You talked about over charging, but what about over discharging. Let's say I need to stay above 60% DOD on my batteries in order to maximize the life of them. My BMS does not seem to have any control to turn off further discharge based on low SOC. But if inverter knew the current SOC and user could set thresholds then inverter could begin warning when within 5% or maybe turn on the generator or whatever in order to enforce this max 60% DOD requirement. I'm new to all of this so maybe this is already done somehow that I do not know about.

[@OffGridGarageAustralia]

OK, so if you use AGM or lead acid batteries, that is a good point and you don't want to go lower than 50-60%SOC. I have not seen a feature in any BMS yet, where you could possibly set such a threshold though. Is this something you can set in the inverter maybe and it switches to grid once it reaches the 60%? But in this case, a communication between BMS and inverter makes sense. Thanks for pointing this out.

[@alanhollister9122]

Question? What do you think the JK BMS would be showing for cell resistance per cell on your old battery? You would need to replace the Wicca bms and install the JK and I don’t know if you can do that with out disturbing the buss bar connection but would sure be interesting to see what the resistance is!

[@OffGridGarageAustralia]

I can measure this with my internal resistance tester. Wait for the next video. I will do the same with the old battery and compare the resistance with and without busbar.

[@FutureSystem738]

Thanks Andy 👍 My only comment is that I’d wish you’d done these videos more than six years ago LOL :-) When I switched from AGM to LFP batteries well over six years ago, it was a bit of a steep learning curve. For anyone doing this now, your videos are absolutely outstanding! Cheers 🥂

[@NasierOmran]

Time is not linear my friend.. so.. travel and make it happen..

[@elpihendi6793]

Hi Andy, Pylontech uses 15s configuration and you have 16s. Is there necessary change setting off battery in Victron mppt ? Thanks

[@OffGridGarageAustralia]

Yeah, the settings need to be changed for such a battery. Absorption: 16x 3.45V = 55.2V 15x 3.45V = 51.75V ... Why would they lower the amount of cells though?

[@livingron9983]

@@OffGridGarageAustralia maybe bc it makes system voltage closer to a 48v lead acid voltage allowing customer to swap out old LA batteries more easily...? I have these and they work fine with victron gear. If you tell the mp2 to talk to them via can bus then venus os can give the battery whatever voltage/current it desires at any SOC / temperature etc.

[@southeastcrypto6811]

Can you update the software on the JK BMS? I have one with 8.20G another with 10.07 ver.

[@OffGridGarageAustralia]

I don't think anyone can...

[@upnorthandpersonal]

You can't, but I've been asking the developers to release the source code. The micro is an STM32, and it has a programming header on the board. Once that happens, we can add a boot loader to update firmware through the RS485 port or even Bluetooth. I don't have a time line for any of this though...

[@mschrodter]

Love all your vids!!!! We have a three phase system set up, we have had the victron s shut down for a couple of seconds while in absorption, it happens right at the top of the charge and I'm guessing the BMS shuts down because of irregular cell Ballance. Connecting the BMS I think may resolve this but obviously this isn't the answer. Going to lower the absorption voltage a little and currently have new cells top balancing. Also have on the way JK bms's, currently installed are Daly, they are shit.

[@OffGridGarageAustralia]

What are your absorption settings right now? The Daly is not good for the balancing, no. Neither is the JBD or QUCC (unless you use an active balancer in addition).

[@mschrodter]

@@OffGridGarageAustralia we are using the victrons set lifopo4 standard settings but was thinking of lowering this by 0.2 v.

[@cood22]

Communication has advantages over no communication because BMS has knowledge of each individual cells vs inverter which has no such information. So in practical terms it will benefit in following scenarios: 1. Battery is near the top balance. Overall battery voltage is normal (charger doesn't see issue himself), but some individual cell is reaching chemistry upper limit. BMS informs charger to reduce charge current so that balancer can cope or switch on some smart load (water heater etc. ) to dump the excess energy. If allowed dump excess energy to the grid. 2. Battery is near empty. Overall battery voltage is OK (inverter doesn't see issue himself), but some cells are nearing critcal low voltage. Information to the inverter could either switch off non-critical loads or switch on generator or perhaps take energy from the grid.

[@OffGridGarageAustralia]

Thanks for your comment. OK, so both scenarios you explain make sense. Without communication, the BMS would just turn off this battery bank, right? If you have more than one battery bank, this is not a problem at all in either way as it will join the other battery banks again once the situation is cleared. I actually don't like the case where the BMS tells the chargers to slow down (in case you have more than one battery bank) . This means the charging process of the whole system is dependent on this one cell in one of the packs. While other banks may still be able to take energy, they won't get it any more. It would also start to discharge all banks now if the load is higher than what comes form the sun (which may be nothing due to the throttling). In case of the low voltage, The BMS would turn off this one battery bank and keeps the load alive with the others in place. It's a different story if you have only one battery though and your suggestions do make sense in this case.

[@cood22]

@@OffGridGarageAustralia If you turn off battery banks one by one eventually you will only have one left. In which case you would still need to take action based on BMS data. Throttling charging doesn't mean stop charging. It means to slow down. All packs will still get energy, just at slower rate. This throttling will only happen at very top voltages, so this slowdown is not for very long. Also charging/discharge limiting is just one option of actions. Don't forget dump loads, generators, charging from grid/ dumping to grid etc

[@arrongrist868]

The benefit of communication between BMS and the inverter/charger is being able to operate the Battery bank within a SOC window (10% to 90%). The more we are able to stay away from the state of charge extremes the better it is for cell life expectancy and capacity degradation. I have to ask, how are you getting on with the Victron equipment in general? You have had it for a while now, so should be getting a feel for its bad points and its good points. I have been studying datasheets and Specs for so many inverter/chargers and so few of them state any performance information about "No Load" power consumption (Quiescent power draw). Victron seem to be one of the few. This baseline power consumption is so important for any system that is storing energy in batteries, and even more so if you are off-grid. I bought another hybrid inverter, which had an issue with the screen hanging when trying to set it up. In the process of fault finding and letting them update the firmware (did not fix it) I become aware that the "No Load" power consumption of the unit is around 65W to 67W (1.6KWh per day, Booo!) The "No Load" consumption of the Multiplus 2 is around 11W (264Wh per day, Hoorah!) according to the datasheets. Are you able to confirm this? Background energy consumption may be worthwhile topic to cover. cheers, Arron

[@SailingCatamaranElement]

Right now, while you are in the garage, you are able to monitor/review the individual cells of each battery via Bluetooth. But what happens if you decide to go on vacation for 2 weeks? You are able to see the overall picture of your systems via the Victron VRM portal when away, but you are not able to see view the cell level data if you suspect something is wrong while away. That is where the Canbus communications can potentially come in. I live aboard a sailboat and am currently tied up in a marina in Phuket Thailand awaiting my shipment of 16 x 304Ah batteries in order to build a 12v 4S4P pack (our vessel has 12v systems) and I intend to install a JK BMS unit with each 4S pack with a voltage booster as you have shown is possible on your channel. A sailing lifestyle however, involves touring on shore for days or weeks from time to time and while away from the boat, I would like to monitor/review the battery packs at a cell level when I am away, but we will see. There is a person on the Victron forum working on the task...I would also like to mount 4 inexpensive 485 monitors to the bulkhead in order to "view at a glance" cell voltage data for my battery packs, which I have not noticed that you have tested on the JK24s BMS...Future Video???....Really enjoy your series, keep up the fun!

[@jackiedines5229]

JK are bringing out the 4S version in April, much better than using the boost option!

[@SailingCatamaranElement]

@@jackiedines5229 Thanks for the heads up!!! Where are you getting this information from? I am also interested in both the Canbus ports and RS485, which they reduced to a single less functional port on their recent 8s model, but I do like the fact that I can add my own p- and b- leads to the length that works for my battery setup...crossing my fingers for a good product- will still be purchasing the 24s model for now, as the new product will be untested, I do no expect my batteries until May, so the timing is interesting...

[@OffGridGarageAustralia]

As soon as the 12V version is available, I will get it and test it here on the channel. I am following this project as well on Github and will be connecting my BMS to the Victron Hub at some stage. Maybe just for monitoring purposes though. That's why I do all this testing with high and low voltage so I don't actually need to see the individual cells if I'm not at home. I know how the system reacts and what will happen if I go to the extremes.

[@jackiedines5229]

@@SailingCatamaranElement They told me after I asked them for their recomended booster. Given the one I bought from Ebay crapped itself pretty quickly. Probably due to my inexperience in using this stuff. Now due to the crappy batteries I got I am not going to use the JK BMS, rather a cheapie that gives no data at all. I will monitor cell voltage with a simple monitor. Where are you getting your batteries from?

[@philgavin]

What if on occasion I have 2C of charging available, ( and discharged batteries) but I want to limit charging to 0.5C to ensure battery longevity. The BMS would presumably trip on its overload setting. Using inverter communication I could still limit and control the charging rate? That and I just want to see it in action, you do it so we can all learn --- the raison d'être of this channel.

[@thepatjack97]

Id like to see how you connect the jk bms to the raspi/ VRM for monitoring purposes

[@MitchOfCanada]

Setting Charged/Absorb/Float to something around 90% would keep you safe with a bit of overhead if your loads are not too high as you said for the charging. Having a dump load circuit would be nice when at 90% charge or so. charge up hot water or heat up rocks for heat sink load for night,time. or pump water into a tank. dc activation when it detects bank voltage at 90% And turn off when at 85%

[@paulcurtis5496]

I literally logged on to see if you had posted yet!

[@BenCos2018]

same lmao

[@hannesmagnusson4366]

In my system I separated the load and the charge site with the victron battery protect. So in this case of an peaking cell, just the charging site turns off and the load are still online. So I don't have an complete disconnected battery bank.

[@SylwerDragon]

I don't see reason to connect chargers to inverters as such..but i see benefits to connect chargers to bms .reason is ..those chargers don't have sense wires..so they don't know exact voltage on the end of the cables..they can see only voltage at the start of the cables..so that is reason why they have to be connected to bms..because bms is connected directly to the batery terminals..or it should be to be exact..

[@mdavidopie6993]

I'm testing a small solar system with victron components and a battery I assembled from parts. The battery management system does not have low temperature protection and it does freeze around here. Having communication between my shunt with the added temperature sensor and the charge controller allows me to have low temperature charging protection. I also get an accurate temperature of the battery displayed and that is fun.

[@a-c-g]

Hi Andy! Brilliant video as always! Thank you very much. What is your cutout voltage set in the Multiplus-II? Cheers.

[@OffGridGarageAustralia]

I have 40V as UVP set in the MPII. At least I believe so...

[@pieterbarneveld9518]

I agree there is no advantage to the system having them communicating to each other.. except there is more risk of complications when the system gets older. Less wires the better..

[@kevinmills5293]

There are advantages to the BMS talking to the charge controllers but I have a lot more confidence in the Victron gear to charge the battery properly and I wouldn’t want to defer control to the BMS in case it screws up and tells the Victron SCC to over volt the charging.

[@albinb.g.gulich9818]

Wie kommuniziert dein Multiplus mit dem Venus OS? Danke, viele Grüße.

[@upnorthandpersonal]

VE.bus to USB adapter.

[@kamalof09]

Nice information

[@chuxxsss]

Looking forward to you hooking them up for monitoring and such like. Have a great Sunday, beautiful down in Victoria today.