What is the Best and Safest Way to Connect Lithium Batteries in Parallel for RVs and Boats or Homes?

[@offgridwanabe]

What about Method C, all cables the same length go to a bus bar then a large cable goes to the charge / discharge apparatus.

[@TravelingLightReflections]

An advantage to your suggestion on method C is that you could use smaller wires to each battery. The disadvantage it that there would be more connections. Connection failures are the most common failure in a working system. This usually comes from a failed wire terminal or lug crimp. Limiting the number of connections is a high priority in my personal opinion. But your method C would serve the same purpose. There are applications where your method C is a better choice, for example when the batteries can not be installed next to each other due to space constraints.

[@richardstott7777]

Option c also means any problem with a connection affects only one battery and will be easier to detect.

[@bigKDL]

@offgridwanabe is spot on the way he describes is the only way to perfectly balance all the batteries traveling light is wrong

[@JFSmith-nb8hf]

My batteries are connected with 1/8 in. x 5/8 in. copper buss bars, I think the resistance would be negligible. On the other hand, it would take very little effort to move one cable to the other battery. Good advice, thanks.👍👍

[@malk6277]

I came to make the same comment. Seems to also lend itself to safer isolation of one battery or the other: if for instance you want to work on one battery bank while the other continues to provide power.

[@titusllewelyn]

I am a retired electrical engineer. I designed a numer of devices that used large industrial batteries. Your suggested method would help a little. The danger in connecting batteries in parallel is that if one cell in one battery develops an internal short that heat will be generated and a massive amounty of current will flow from the the other batteries. A fire could result.

[@hansonic2938]

Thanks for the warning. What about placing a fuse on each battery terminal directly to prevent this worst case?

[@titusllewelyn]

@@hansonic2938 - Good Question. You Tube is full of ideas. No matter what you do, remember that no two batteries are the same. Also remembeer that the battery is part of the charging system. All batteries have an unwanted internal resitance. Lithium Ion batteries have a low internal resistance. You connect batteries in series to up the voltage. When connected in parallel the current is upped. A fuse would add to the resistance and lower the power delivered by a small amount. It would also become part of the charging system. I have a 48 volt golf cart with 4 12 volt lead acid batteries. I use a BatteryMINDer Model 483CEC1 48 V 3 Amp charger that pulsates the batteries. It is temperaturre limited and can stay on the cart charging 24/7 if I wanted. It charges overnight. The original charging system was left intact. I personally do not like paralleling at all.

[@balsmit1]

​@@titusllewelynhow about using a terminal block sir?

[@titusllewelyn]

@@balsmit1 - It is not the type of connection. It is just not recommended to parallel batteries. To get more current batteries are connected in parallel. To get more voltage batteries are connected in series. That is in use. If they are charged in parallel the charger can not determine what is happening with each battery. Perhaps in a model plane or something it might be OK to use, but for charging the batteries need to be seperated.

[@mytubing101]

That is when a balancer comes in to play

[@davidrogers-b1r]

use a bus bar with two or more batters.

[@TravelingLightReflections]

If done by a professional who can guarantee twice as many crimps will all be done perfect. For the small gain in similarity I would rather see beginners do it with less crimps. Pro do not need this video.

[@floydfan5993]

I like the fact that manufacturers are now coming out with larger capacity batteries and in most cases eliminating the need for multiple batteries connected in paralell or series.

[@TravelingLightReflections]

Yeah, it makes things easier. I am using 4 12V 300Ah LiTime batteries in my RV power system. I would have gone 48V but I was using a 12V Victron Multiplus 3000VA inverter.

[@YouTalkinToMeBro]

So...are you hinting at a review of a 48 volt inverter? Lol There's so much so all this. Especially for a 61 year old solar virgin!

[@guydemers7607]

@@TravelingLightReflections , wow, that is a pretty substantial size system, you must have many days of reserve battery capacity.

[@TravelingLightReflections]

@@guydemers7607 I live all summer off grid with the system in a 28ft 5th wheel. During the winter we stay in RV parks and are usually plugged in. I built the system gradually, not intentionally. I upgraded RVs before we went to full time and then a month after. So, I reused system components as I designed the system for the next RV. I went with the 1200Ah because solar barely recharges the batteries when it is full grey cloud cover and we get next to nothing when its raining. There are times this lasts for over a week. We usually keep the inverter on 24/7. The inverter, Starlink and the 12V refrigerator use a lot of power. When we get under 50% we turn off the inverter at night. This saves a lot of energy. We have not used a generator in over 2 years. So, we are happy with the system. Check out my Power System Calculator. I developed this from 6 months of data collected from my Cerbo. It helps decide on both what size batteries and who many watts of solar you may needs. I broke the weather into 4 main categories. The biggest unknown is what your personal daily power use may be. You can play with that and plug in considerations. I added a section that tells how long you may need to run your generator to recharge at a reader's request. kzbin.info/www/bejne/o3qulGtnhriSfNk

[@TravelingLightReflections]

@@YouTalkinToMeBro I built my system with a 12V inverter because I did not expect to go as big as I did with the system in the end. If I had only know now what I did not know then!!!! I already spent the money on big copper. If I had gone with a 48 volt system I would have needed to install a drop down converter for the 12V RV part of my system. But....... Instead of 107mm2 wire (4/0) I could have used 1/4 of that size and gone with 27.6mm2 (3 awg) wire and saved a lot!!!!! I probably would have gone with 2awg because of the availability. Here is an article I wrote on my website that brings you through my story of trying to make coffee in the RV and how this brought me through many inverters as I upgraded RVs. I tried to put some humor into it. www.travelinglightreflections.com/choosing-how-to-power-you-rv

[@leapnlarry]

This is one of the first things i learned when i designed my solar system 4 years ago, very true. I should make a short about it. Larry

[@TravelingLightReflections]

Yes, you should. So many DIYers just to method A, because I do not realize there is a difference.

[@ThomasNowicki-m5s]

@@TravelingLightReflections if u use lithium batterys ther is not difference wireing can be a topic on led acid coz this stuff age with any current movment or voltage... on lithuium batterys its not matter. if i pull 2 parrallel batterys 50% energy off off its 1/2 charge cycle for ea of them, it not matters in any way if battery 1delivers 53% current and battery 2 47% current coz after the draw both battery will balance them to 50% and for both batterys it was 1/2 cycle in total. use thick wires reduce the different in current draw to near 99% the same .. over all pointless video for the lithium age, where this batterys last ~25-30 years to there dead and if lithium battery 1 will be dead in 29,5 years and battery 2 in 30 years who cares..... on the other side lead acid degrade very fast with ea current movement after 2-3 years they are become near useless so make any wire theroies will not change anythink on this part that this batterys fast become for garbage.

[@wrxs1781]

I have my two LIPO r/v batteries hooked up like you diagram but negative on battery two, they charge o'k with my NOCO 10amp charger, and also solar. So far no issues. I also supply the power to the r/v with an Anderson connector, and when towing or not in use I always pull the plug.

[@TravelingLightReflections]

Hi Thanks for commenting. I am not sure how big your batteries are but is sounds like you are running pretty low currents. The higher the current the more important in is to use method to help balance the batteries. Anderson connectors are great! I use them too.

[@aaronsmith593]

That is an excellent idea, it will cut down on cable and buss bar resistance to electrical flow. 😊

[@TravelingLightReflections]

It's the best way to do it, but most people don't do it!

[@prepparig144]

Great video, very helpful. Also viewed that video link you put in one of your responses of the person testing the 3 setups. It's all black and white now. Thank you!!

[@TravelingLightReflections]

I am glad it was helpful for you. Thank you, I appreciate the feedback!

[@notconnected3815]

I think that the point here is, that all batteries should have the same overall cable length (positive and negative added together). Because i guess modern batteries have such a low internal resistance, that it forms a voltage divider with the (also very low) resistance of the cable. The effect could alternatively be minimized by using thicker cables, that have significantly lower resistance compared to the battery's internal resistance.

[@TravelingLightReflections]

Yes , I would agree. That is great, short and complete summary of the idea.

[@ThomasNowicki-m5s]

yes you are 100% right where the wires is placed not matters, the thickness of the wires matters. thick wires =lower resistasnce =smaller drifts=same current flow = not important where the wires is. i use thin wires on lithium coz it not matters if current differs so %. a half battery drain on 2 batterys is for lithium batterys 1/2 cycle........

[@abejeffcruz7555]

How about the connection from the batteries going to the inverter sir do you have a video regarding on it?

[@ThomasNowicki-m5s]

anythnik what is really important is to use thick wires !!! connect batterys together like i do = differenz in curretn flows, on lithium batterys that is no problem coz a haft cycle is a half cycle for them not importand if battery 1 delivers 2-3% more current. if u use thick wires =lower esitaqnce= current matches more. same on inverter use thick wires = no resistance + no warm wires more and stable current. the thicknes of the used wires is more important then where u place it. the fats degration from lead acid you can not stop on any way also thick wires will not help that this stuf becomes fast usless.

[@TravelingLightReflections]

I do not have a video about this. Make sure you use good copper cables. Do not to tempted to cheaper use Copper Clad Aluminum (CCA). Use wire the in the size recommended by the inverter manufacturer or larger. Run the Red positive cable directly from the battery to the inverter and be sure to put a fuse in it. Run the negative directly to the battery, unless you have a shunt. If you have a shunt, run the cable from the shunt to the inverter. If this is the case, be sure you cable running to the shunt is big enough to handle the loads on everything in the system. Windy Nation on Amazon is a company I get good caple from. There are many others. You can also but cable with lugs already crimped on. If you crimp your own like I do, I only but black cable. I wrap my positive cables with red electrical tape like a candy cane. This way I never run out of one color. If you have not crimped you own cables you may want to stick with buying cable with lug terminal already installed.

[@Ed19601]

I have a very hard time to believe this. Any regular wire will have a negligentv esistance. Are you using meters of resistance wire to connect your batteries.?

[@TravelingLightReflections]

I do not have a video recording of this but if you do not believe this watch this video. He recorded the currents for each battery. Ohms Law, V=IR or I=V/R. At a constant voltage, current is inversely proportional to resistance. kzbin.info/www/bejne/laG0YYqgpbh4l5Isi=VJ-nIWsvUDvWNpU5

[@whochecksthis]

It is more about voltage drop, from load vs cable length, don’t forget contact resistance as well… When two identical batteries are connected together, the shortest path has the least resistance, coupled with voltage drop and load drop, the closest short cable battery drains faster than the further ones. Forcing round trip through both batteries equally, the batteries experience equal resistance, and equal voltage drop, resulting in more even discharge.

[@Ed19601]

@@whochecksthis voltage drop is the result of resistance. Not sure what connectors you are using but those also should not have any relevant resistance

[@whochecksthis]

@@Ed19601 … everything except a superconductor has resistance, and when you connect to the closest side of the closest battery, the further lengths have resistance. It adds up, resulting in uneven discharge.

[@starcruiser9325]

@@whochecksthis Spot on. When there’s hundredths of a volt between 90% and 100% charged, every micro ohm matters. Connecting in the way shown is the correct way to negate any differences and is so easy to do.

[@tedosan]

Silly question - I have (2) 5200 mAh batteries I'd like to use to control the steering servo from an RC car on my pontoon boat project. Works fine with 1 battery but I would think 2 wired in your method B would give me longer run time. Any thoughts are appreciated. Thank you for your video.

[@TravelingLightReflections]

@@tedosan I would not think the loads would be high enough to make a difference in how they are wired. Of course adding twice the mAh will give you more run time. Are these servos for a sail winch? That is a lot of power! My method B in the video is mostly for high current discharging and charging of large 100Ah and up batteries. Back in my RC days I would parallel batteries for longer run times but I always charged them as the pack . Hope this helps.

[@tedosan]

@@TravelingLightReflections Thank you for your reply. The servo is a standard rc steering one. It may be overkill for what I'm doing, but I like to McGuyver things! Thanks again.

[@mannyfragoza9652]

would it make any difference if you turn one battery opposite to the other and connect them diagonally Red to Red black to black?

[@TravelingLightReflections]

For parallel, as long as you run black (neg) to black (neg) and red (pos) to red pos it will work. However when possible arrange the batteries so you have the shortest cables connecting them. Also, try to make all red all black the same length if you can.

[@mannyfragoza9652]

@@TravelingLightReflections thanks

[@ThomasNowicki-m5s]

nothing matters. the battery with the lower internal resistance delivers or draw more current. only look to use thick wires, anythink other is 100% not important.

[@TravelingLightReflections]

@@ThomasNowicki-m5s kzbin.info/www/bejne/laG0YYqgpbh4l5Isi=5f3AITrXq593UIaD

[@falcorthewonderdog2758]

No mention of any lithium battery monitoring device. You can't just hook lithium batteries to a system designed for lead acid you need a charging controller to isolate the lithium battery for the lead acid battery.

[@TravelingLightReflections]

If you are building a lithium battery from lithium cells you need a Battery Management System (BMS) for each battery. This BMS will manage the cells contained in each battery, as a unit. This video is about batteries. All lithium batteries already have BMSs managing the current and voltage of the cells. No large lithium batteries are sold without BMSs. You can get small lithium batteries for model aircraft that do not have BMSs. The ones that do not have BMSs will have balancing leads with a JST connector. However, this video is about power system batteries.

[@louf7178]

In hydronic system piping design, this balancing technique is called "reverse return".

[@TravelingLightReflections]

Thanks for comparative relationship. I appreciate it.

[@princesunnyboy]

How to connect with 3 batteries or more?

[@TravelingLightReflections]

Many people suggest using a bus bar. If you can make every cable the same length and insure every connector is crimped perfectly then a bus bar is a good choice. To contradict this though, using a bus bar means 2 times as many connector to crimp and more chance of a failure. Also with today lithium batteries the BMS's also regulate charge so it become near impossible to get all cells and all batteries perfect. So, for beginners doing the work themselves and making your own crimps, I would put the 3 batteries in parallel and not use bus bars. If you are a pro you probably not interested in my input but if you can get excellent crimps then go with bus bars. Of course bad crimps are dangerous in all cases. I am just suggesting using as few as possible. Also, I always put the system under a high current load and use an infrared thermometer to look for hot spots that need to be repaired.

[@brycemcleod1]

Can the two lithium batteries be separated by distance... One under the bonnet of a car and the second in the boot of the car? I currently have a itech lithium battery under the bonnet that i run my camping fridge off and want to add a second to double the capacity

[@TravelingLightReflections]

You can do this under two conditions. One, do not use the chassis as a ground. Run equal length wire Red positive as Black Negative. Because you are running parallel batteries you can should wire larger than your expected load and fuse the positive wire. Being as your system currently has a battery that already handles your load, your single battery under the bonnet, will still get a large percentage of your load, unless you run third wire as I showed in the diagram. In other words. The positive load wire from the positive of battery 1 and the negative load wire from the negative of battery 2. My concerns are, the cost of the wires, the voltage drop, any heat and protecting the wire from a short. Hence the fuse between the batteries. Is it possible to by a double size battery that with will fit in the bonnet? The cost may be more for the battery but it will save a lot on wiring, components and work. It will also be safer. So, yes this is possible but use GOOD wire, fuses and do not use the negative as ground. Determine your max current before you buy wires. This is one source to look at a good variety of batteries. www.litime.com/?ref=q12mEP4EB0Q2EJ

[@Bilskirnir030]

Can you define/elaborate on “a period of time”. Days, weeks years? Running time/idle time etc. thanks in advance

[@TravelingLightReflections]

I do not have a definitive or data based answer for you. I can give the best science or physics based answer though. It takes the batteries a long time depending on how hard you are using them. You will not see an effect within days or weeks but over months and years. However, the harder that batteries are worked, the greater the in use difference, in each batteries discharge you will get. Let me explain that. Think of it like this, In example method A, if you pull a high current from the batteries, battery 1 has slightly less resistant than battery 2. Battery 1 will discharge slightly more than battery 2. It would be working harder to supply the load. It would essentially lose more energy and its voltage would be slightly lower than battery 2. When this high discharge current is removed, Battery 2s voltage would be slightly higher and it will charge battery 1 until they are balanced. This process happening over and over is what method B prevents. Method B just simply prevents this by the physical nature on the wiring. Each battery the same wire length as all the others. Therefore each has the same resistance in the circuit. This is because they are all in a loop, as opposed to a string with one on the end like method A. So, method A is not going to ruin your batteries but method B is better for them. If you have new lithium batteries I would recommend changing the wiring to method B as earlier a possible. They last a long time and method B will help make them last. If you are running lead acid, leave them alone. They don't last that long anyway. If you are only, ever, running very low currents, it is probably not worth changing to method B either unless it is a simple task. If you are running an inverter from your batteries, I would make the change as soon as possible. Also if you are running more than 2 of any type of batteries I would change it. I know I did not exactly answer your question but I hope I least gave you a better understanding of how battery 1 gets "exercised" more then battery 2. Oh, part 2 to your question, I kind of answered but, this is only happening during "running time" and mostly during high current loads. During "idle time" the batteries balance each other to equal loads. JT

[@Bilskirnir030]

Cheers. I think the “buzz” word is current. Less pressure on the battery and adding a fuse. @@TravelingLightReflections

[@djperfecto1]

Dear friend thanks for your video...what is the proper connection of the power inverter?direct positive and negative one battery 1 or 2? Or positive on battery 1 and negative one battery 2? Thanks!!!

[@TravelingLightReflections]

If you have a 2 battery setup with the batteries in parallel, then the inverter should be connected the same as any charger. Use method B. Regardless of whether the battery is being charged or discharged the connections should be the same. Throughout the batteries' life it will get an equal amount of charge as it get discharge. I hope I answered your question.

[@djperfecto1]

I have connected as the B...I was not sure but finally is the best way.also the chargers cables are connected as the B. Thanks a lot!!!!also I don't know if you can help batteries during day are full charge 13.8v as the panels produce power.with no loads and the 12v power inverter off at next morning controler shows 12.7v.batteries are 2x 12v gell deep cycle 150ah each connected parallel.any ideas?connections are ok charger is an mppt powmr 60a maximum

[@TravelingLightReflections]

@@djperfecto1 Your batteries look like they are okay. The float voltage is also higher than the resting voltage. Your solar controller is correctly bringing the batteries up to 13.8 volts. When it shuts down the battery voltage settles down to it's resting voltage. For AGM the fully charged resting voltage can be between 12.7 and 12.85. It depends on the manufacturer and also on the whether there is any voltage drop in the device you are reading the voltage from. Regardless, from all that you have told me, your system is working fine.

[@user-zy2kh2rp4m]

My electric scooter has a 48v 30ah LFP battery. And I want to add another 48v 18ah battery to it. Can I connect both positive and negative in parallel at the charging point?

[@TravelingLightReflections]

Theoretically you can connect these 2 different batteries in parallel. However, I would not recommend it. Others may say it is okay, but I personally would not recommend it.

[@user-zy2kh2rp4m]

@@TravelingLightReflections ok sir but I can use it through change over switch. This way I can use both the batteries one by one.

[@TravelingLightReflections]

@@user-zy2kh2rp4m It is most important that you keep the voltages of all of the batteries in a parallel system equal. If by using a change over switch, you will be connecting and disconnecting the second battery, You will cause a rush of high current between any battery of unequal voltage. If you intend to always keep them isolated from each other and charge the 30Ah and 18Ah separate, you can use a change over switch. Just never connect them together when they have even slightly different voltages. With Lithium there could be a bit SOC difference with a slight voltage difference. This can cause a very high current enough to melt small cables.

[@user-zy2kh2rp4m]

@@TravelingLightReflections sir ji I will use both batteries separately. When I will switch the change over switch on mode A, scooty mains positive and negative will connect on battery 1(30ah). Then scooter will use battery 1 and charging also. When I will switch the change over switch on mode B, scooty mains positive and negative will connect on battery 2(18ah). Scooter will use and charge only 2nd battery. At that time 1st battery will be fully disconnected. What do you think sir about it?

[@TravelingLightReflections]

@@user-zy2kh2rp4m Sounds good!

[@TheCSRTech]

In what way is hook-up B SAFER than hookup A?

[@TravelingLightReflections]

It can keep you from overloading one of the batteries.

[@TheCSRTech]

@@TravelingLightReflections Nope, incorrect, try again.

[@makantahi3731]

ok, do you have any physical reason why you claim that the faulty method is faulty, for example the resistance of the wire, are we talking about the distance between the batteries in cm or km, if it is in cm then the voltage drop through the wire in the further battery is negligible, that's how I charged several batteries at the same time and the farthest battery had a difference of maybe 0.02v on a total of 5m of cable. your correct method is correct only because it equalizes the currents of both batteries, regardless of how good the connection is, for example if the clamps are connected to an oxidized contact, it can happen that only half the current flows through the wires that would otherwise flow if the connection was good, this way how much as long as this current flows equally from both batteries

[@TravelingLightReflections]

Resistance is directly proportional to the length of a wire. In other words, a wire 2X as long as another will have 2x the resistance. If batteries are wired piggyback like in Method A the battery at the end will have a greater resistance and it will get/give less while being charged rapidly or used heavily. Of course, their voltages will even out over time as they equalize. However, the first battery will get charged fasted and will then charge the second. The same works in reverse. This put a higher workload and more abuse on the first battery. It will wear out faster than the other. If you are only using very low currents on these batteries then it will make little difference because the charge/discharge of each will keep up with each other. However, the faster/harder the batteries are used, the more important it is to try to keep a balance current flowing in and out of them. Look for other KZbin videos that explain this. The main idea is keeping all the batteries in your bank the same. You do not want one battery charging others nor do you want to pull more current from one than the others. Inevitably, they will all balance and equalize because they are in parallel. It is just that one will go bad before the others. You do not want a bad battery in your bank and you do not want to replace only one battery in a bank. Ideally you want them all to wear out equally at the same time and replace the entire bank at the same time.

[@makantahi3731]

@@TravelingLightReflections ok, generally well explained, but without measurement units, how many ohms is the greater resistance, how many amperes is the difference in currents, what is the difference in voltage in volts between the batteries, what is the voltage drop in volts due to the increased resistance... with a sufficiently thick wire that is well connected at a length of less than half a meter, negligible

[@TravelingLightReflections]

I do not have bluetooth batteries but the guy in this linked video does. He did a great job of demonstrating the effect of 3 different ways to set up your batteries. Check it out. The drops are significant. Also, when using lithium batteries, they have a low voltage vs state of charge curve. This means that having a your voltage match during both charge and discharge is much more important than with a lead acid. In truth, you will never get all batteries to perfectly match, but you can get them as close as possible by setting them up correctly. For 3 batteries, you may even want to use bus bars. My only concern with bus bars is that people watching this video are likely DIYers. Bus bars use a lot more connections. These crimped connectors can introduce an area of high resistance if not done perfectly. Personally, for a 3 battery setup I use the way I showed in the video. (Less connections and closely balanced system) For a 4 battery setup I use bus bars. When the bank is built, I crank up the load and use an infrared thermometer to check ever connection for heat not matching the others. Yeah, watch this video. It is long but worth it. kzbin.info/www/bejne/laG0YYqgpbh4l5Isi=uQw4q4-d-cchyZsH

[@makantahi3731]

@@TravelingLightReflections thanks, i made battery from 20 Lion18650 cells, 16 v, 20Ah, 5 in parallel connection and 4 of them in serial connection all are soldered, all are connected a little bit on wrong way but that was the easiest way, and every 6 months i open cover to check states of cells before charging and after and no bigger differences than 0.1V between the highest and the lowest voltage , no bms or any electronic device , just wires and cells

[@TravelingLightReflections]

​@@makantahi3731 The chemistry on those cells are a little different from LiFePO4. I have made batteries from the small A123 size cells fr hobby use. I soldered a small 22ga wire off each connection and put them into a JST connector. I use this for balancing each cell in the battery. Astro Flight used to make a plug in balancer for this. Now hobby chargers often have them built in. Mine were up to 5Ah not 20Ah. What are you using these for?

[@Ferd414]

My gawd, what a load of handwavium! It's a pretty clear demonstration that someone has learned just enough about electricity to think he knows something, but not enough to know what he's talking about... On paper, yeah, there's a VERY slight difference (specifically the (almost nonexistent) resistance in the connections between the two batteries). In the real world, unless one is running insanely long connections (and more importantly, current paths that are different lengths) between the batteries, the difference between your "method A" and "method B" are so small as to be effectively nonexistent.

[@TravelingLightReflections]

It is sad that you are so swift with to type but are making only assumptions. You are totally and completely wrong. You do whatever you want. Start with research.

[@Ferd414]

@@TravelingLightReflections It's even sadder that someone would flog such a BS theory as having any reality to it...

[@TravelingLightReflections]

@@Ferd414 Here watch this. kzbin.info/www/bejne/laG0YYqgpbh4l5Isi=DAo1h8wpof1Z7kX8

[@Ferd414]

@@TravelingLightReflections Why would I wanna blind-click on a video and give you another hit on a pile of hot garbage? Dude, walk away. You clearly don't have any friggin' idea what you're talking about, yet you're pushing it like there's even a hint of reality to it. Go back to the books and learn how electricity actually works.

[@twofingers2233]

To the source? Shouldn’t you be saying the load?

[@TravelingLightReflections]

I may have used the term source when I meant load. If so thank you for pointing this out. Being as we are talking about batteries where the current can flow both ways depending on whether it is being charged or being discharged. I wish I had put more emphasis on this.

[@davidbuchanan327]

Good info for me as Im currently designing my system in my Lance truck camper. Space is limited and the camper came with only one battery. I have removed the microwave and added 2 lithium batterys, solar charge controller and some fuses and buss bars in that space. From the buss bars in that space I will connect to the camper battery. So I will have 3 100ah batterys and 400 watts of solar and a 2000 watt inverter. The camper also has a propane generator which connects to a transfer switch. I hope it all works when Im done.

[@TravelingLightReflections]

Check out this power system interactive I created. It may help you predict how well you planned system will work. kzbin.info/www/bejne/o3qulGtnhriSfNk

[@bivideo7]

This is absurd. The only cause of the problem you're trying to solve is corrosion in the cables. If the cables are correctly sized and remain clean this is pure fantasy. It's about charge voltage.

[@TravelingLightReflections]

@@bivideo7 The problem is getting DIYers to understand how to arrange their parallel batteries so that the resistance is distributed better and each battery gets equally discharged under heavy loads. I see the first method too often. I looked at your videos, you are a smart guys so I am guessing you did not actually watch the video. Corrosion is not mentioned or a concern. You know enough about electricity to know that the first battery will get worked harder than the one with longer wires.

[@firecloud77]

Now do it with 4 batteries.

[@TravelingLightReflections]

I would recommend using Bus Bars, with all cables that are going from the bus bar to the batteries being the exact same length. Keep all your cables as short as possible too.

[@firecloud77]

@@TravelingLightReflections Impact Battery has an article showing how to achieve "Perfectly Balanced Charging." Google: "How to Charge Lead Acid Marine and RV Batteries in Parallel"

[@Jarda_B]

The resistance of the cable it not as big as you think, if you are not cheepo. if you use 16mm2 cable to cenect them and have proper conection it will not go over 1 ohm in total. 1m of cable like this have 0,00013ohms, if it will not go over 0,5 ohm there is not going to be a noticible difference.

[@TravelingLightReflections]

I knew there was a difference under load that would balance out as the batteries recharge. I have had a lot of people's comments telling me I am wrong. I went looking for other videos and found this. I was shocked at the difference. I created this video based on theory. This video shows actual tests in action. Even though the resistance is low, it still follows that if the cable length is doubled, so is the resistance. I learned from the links video too. I am curious how the quality of a crimp affects the performance. I originally made my video to help people see that they could easily use method B. Here is the other link. kzbin.info/www/bejne/laG0YYqgpbh4l5I

[@starcruiser9325]

When you’re talking hundredths of a volt between 90% and 100% charged, every micro ohm matters and the way you’ve shown it is the correct way to easily equalise between battery 1 and 2 when wiring direct and not from a busbar.

[@bubbafrump74]

If that makes ANY difference at all, it would be sooo negligible as to be completely pointless. Especially with just 2 batteries.

[@TravelingLightReflections]

Do you have a clamp type amp meter? If you do, test it for yourself.

[@noutilitybill]

This all sounds like a bunch of batteries or kids whining about who got breast fed more(or less) from their mother(inverter and length of cables). I believe Andy from OFF GRID GARAGE covered most of this but now lets add a twist.The bus bar method C is your best bet.Lets say you have 5 batteries 3 batteries with one type of 100ah cells and same BMS a 4th battery with EVE 100ah cells and the same BMS as the earlier 3 batteries and a 5th battery 300AH with a different BMS.All these sets of batteries will have a different internal resistances and having different lengths of cables(more resistance) going back to bus bar and then the inverter.Use quality BMS's for safety,using different BMS's is irrelevant does not count or affect the situation. Safety #1 The inverter is set to charge at say 56V.Safety #2 The BMS is only going to breast feed(charge) until its full charge voltage(Most quality BMS's designed by the manufacturer have settings you can change) is reached.The batteries with bigger AH will take longer to charge.The batteries with longer cables will take longer to charge than same AH battery with shorter cables.If you think any of these batteries SOH(State of Health) is going to be affected by these different parameters,you were probably not breast fed enough and your brain did not develop fully.The batteries could care less who is sitting next to them.They will charge and discharge on their own terms under this situation they are in.Now if you charge by solar there will be days that the batteries all fully charge (sunny all day) or partially charge( not so sunny or you need more panels if sunny all day). It all boils down to charge/discharge cycles and the temperature of the cells when you charge them and how much time you keep your batteries fully charged .You should if you can charge your batteries to full charge once in while and you should not discharge below 20%,I like to be closer to 40% for longevity.Some say between 20 and 80% is best.Enjoy

[@geoffculp2019]

Seems like there could be a diod on the discharge if 1dosent charge or disharge as much it wont be drawing away from others of more capacity n maybe have sepret wires between each for balance charging and monitoring each and not having to unhook them not shure what size diod can carry what ampraje though ones in a car alternator seem big to me guess there called a bridge rectifer in an alternater to though.

[@TravelingLightReflections]

The BMS takes care of the balancing among the cells that make up each battery.

[@EarlBalentine]

Mine batteries look like the Method B.

[@ntal5859]

MY.. not MINE. or are you making LANDMINES.

[@TravelingLightReflections]

Mine do to!

[@ThomasNowicki-m5s]

there is nothing wrong with the wire is where it is. the only important part is use thick wires=no resistances= batterys same charge thin and flimsy wires couse resistances= drifts next part: if you use lead acid with thin wires yes they are little off and one battery will degrade 1-5% faster about the current flows to rebalance them but nowadays anyone use lithium batterys and in this case its not importand in any way coz they count only full charge cycles over time..... and sorry if lifepo battery one will have after 15 years and 3500 charge cycles 81% SOC left and battery 2 will have 82%....who carss this batterys can not be killed on any way... another iportent part: battery 1 have 20 mohm battery 2 have 30 mohm = totaly different discharge currents controler from the internal resistance,= different charge or discharge current !!!! old-fashioned pseudo theories are really worth a video with nothing eccential cleared? i use thin wires on lifepo couse it not matters they balance on any after any shift on use and the cycles over time still the same....so pointless video. the really importand part is step away from lead acid stuff.....

[@TravelingLightReflections]

From the details and quality of your post, you sound like a smart guy. So if you have two lithiums in series, check the current going into or out of each battery when wired as method A. If not look at You will see they are quite different and the difference becomes greater as the currents increase. This is especially true of lithium batteries because of their low resistance. Yes, they of course will balance out over time but.... the first battery's BMS will show it is charged before the second in line. For a simple change of wires, you can closely eliminate this. Yes, I firmly agree lead acid is old tech and the use of properly sized wires are extremely important. I made the video because this other wiring method is so simple to do, but so often overlooked. Thanks for your comment. I was emailed you original pre edited version and the edited one. I can see you put a lot of time and thoughtful thinking into it. Actually here is a link to a video that it better than mine with more detail and visual values to look at. I tries to make mine short and simple. I get a lot of negative one or 2 word replies from people who have no clue. Your reply had quality and informative info in it. I only disagree on some of it. Think you will enjoy this video. kzbin.info/www/bejne/laG0YYqgpbh4l5Isi=5f3AITrXq593UIaD

[@nickj7335]

Thanks

[@TravelingLightReflections]

Your welcome. It is an easily overlooked installation error but so easily fixed.

[@rithlim6016]

Great video! I could be wrong but I think in "Method B more extreme example", if you connect the positive load cable to Battery 3 (versus Battery 4) and connect the negative load cable to Battery 2 (versus Battery 1), you'd get a more even distribution of power while charging and under load. This will better help the lifespan of all the batteries.

[@TravelingLightReflections]

You may be right.

[@thanhha2686]

Cannot believe there were folks making video bc they think they know better. Not necessarily smarter.

[@TravelingLightReflections]

I can not believe you wrote that comment. Do you think this is wrong? If so, do whatever you want. Or, do some research.

[@Brahmachari__Abhinav]

Whatt? 😂😂😂 Both ways are literally same😂😂

[@TravelingLightReflections]

Which battery has longer cables in method A? Which has longer cables in method B? See, method B both batteries to have the same resistance in the cables for both batteries. That is why I made the video. This is not obvious. Most people will just automatically use method A but method B is much better and uses the same wires!

[@ntal5859]

In method 1, ALL the current passes via the negative and positive post(terminal) of battery(1) so in effect that will have twice the power loss of terminals COMPARED TO battery(2), assume both batteries supply 50% of the current... So in long term applications you will see a drift in both charge and discharge of both batteries. For the dummies out there, imagine two garden hoses and you trying to force both into one. at the point where they join it will have losses.

[@TravelingLightReflections]

It is much greater too, at high currents.

[@papasfixitshop7982]

Poppycock!

[@TravelingLightReflections]

Just for a moment, rethink your thinking and include OHM's law in your thinking. Doe wire length affect resistance and current flow. Which battery has the longer cables? By how much? Does method B change how the cable length affects the batteries? Also think how easy it would be to arrange 2 batteries in this manner compared to method A. I am just sharing a concept that most people do not even realize and can easily change. If you really believe this is "poppycock", I am sorry I cannot help you.

[@brianrhodebeck6465]

You didn't mention, Lithium batteries. Having B u s s bars with charging on each Battery is equally Charged

[@TravelingLightReflections]

It is not actually equal but closer with a bus bar and only if the crimps are done perfectly. Plus with the bus bar you have 2X as many crimps. I removed that section of the video because I made the video to stop DIY people from doing Method A.

[@dany67230]

Method B Not the best method also

[@TravelingLightReflections]

Care to elaborate?

[@DirectCurrent4u]

This is correct!💯

[@davidbalgosky4107]

To expand on that you are correct with load using method B but add to it the charge circuit should also use method B bur reverse the + and the -

[@LarryWebb-g5d]

​@@davidbalgosky4107 So your saying use method 2 but then add the battery charger with its positive going to battery 1 and the chargers negative going to battery 2 ?. What if your going to add 2 battery chargers ? I assume the one battery charger would be applied to battery 1 and the other battery charger applied to battery 2 ?

[@DM20Trading]

Why not correct? What's your best way?

[@sleddy01]

I love videos that open with music i hate

[@TravelingLightReflections]

Thanks, Not sure what to say but....

[@93556108]

Would like to share this video this video with its optimal connection and why it is so? kzbin.info/www/bejne/laG0YYqgpbh4l5I

[@TravelingLightReflections]

Hi, I have posted this video in replies I have made to people who think that I am full of crap. He using hard data because he has bluetooth built into his batteries. It is a great video. It shows the huge difference with the piggybacked set up compare to the others. He uses 3 batteries not 2 as I have shown. The difference with my version (method B) show a very close voltage drop with the middle battery. He uses buss bars if I remember in his 3rd trial. I personally feel that this video is being watched by DIYERs Bus Bars use about 2 times as many connections. The risk of poor connection is not worth the minimal voltage drop difference he was getting. However if you are using 3 batteries with very high currents, maybe bus bars are a better choice. For 2 batteries I never use them. For 4 batteries I always use bus bars. To answer your question of "why is it so?" the current always flow highest through wires with the least resistance. It also flows highest from great differences in voltage. The idea with a bus bar is to have all the cable the same length so the resistances with all be the same. Then, "if" the batteries are perfect, their will not be significant differences in their voltages, so the currents in and out of each individual battery with be the same. There are always minor variables but this gets everything as close as possible. It a piggyback system like my Method A, the first battery has very short wires with much lower resistance so it discharges high then the second. (of course they them slowly balance out). In Method 2, this simulates having the same length wires on a bus bar. However with three batteries it will not be quite as balanced. As I mentioned before, it is close enough in most cases and uses less connections and crimps which are the most common area of failure. I hope I answered your question. BTW, I made this video because I kept seeing people using Method A because they did not know the difference. Method B is just as easy! So I want to share this. Maybe I could do I video with 3 or 4 batteries and multiple shunts.

[@93556108]

@@TravelingLightReflections thank you

[@MrSummitville]

Method B More Extreme also wrong.

[@TravelingLightReflections]

See my other responses.

[@ChrisBrocksmith]

NO

[@TravelingLightReflections]

.

[@fitzwilly7132]

What a load of bs!!! How do the batteries know who is 1 and who is 2???? What a load of crap!!!!!

[@TravelingLightReflections]

@@fitzwilly7132 The longer wire has more resistance. In fact if one wire is twice as long as another identical wire it will have twice the resistance. But really don’t take my word. You do what you want.

[@bcrew63]

Better yet, follow mfg recommendations

[@TravelingLightReflections]

In some cases this works.

[@falcorthewonderdog2758]

Yeah that's not going to make any difference.

[@TravelingLightReflections]

It does. It actually makes a big difference. That is why I made the video.

[@mattxr6t]

As an auto elec, yes, it does make a difference.

[@slowbrezze]

wow Ai is doing it's job living loud with Andy

[@GetOnEmTV]

Dudes actually right I'm about to drop a video on this right now I actually killed one of my lifepo4 batteries because of this. Let them sit in the garage for a whole year connected the same way as in the original diagram not the second diagram(the way hes showing you to do it) and the one works great and the other one won't take a charge but I saw a video where you can jump start the one that doesn't take a charge with the one that is fully charged and it'll actually charge back up normally

[@Brian-jz1pi]

I would love to know the reasoning behind it it wouldn't make any difference it makes total sense open up a lithium ion and I believe they're in seres.

[@kschildt1]

What a load of BS! As long as the cable is the proper size for the amperage required and the battereis have the same characteristics...

[@TravelingLightReflections]

You should do some scientific test before you call this BS. There is an incredible difference between the load on battery 1 and 2 in method A when you piggy back and pull off the same battery.

[@kschildt1]

@@TravelingLightReflections No there is not. And your electrical engineering masters degree is from?

[@nixxonnor]

@@TravelingLightReflections If the cable cross section is correctly dimensioned for the current going through the cables it does not matter how you connect the wires to the load/charger. When charging the batteries, they will all get up to the same voltage as the charger is topping off / trickle charging

[@TravelingLightReflections]

@@nixxonnor What you are saying is true only if a low current is being trickled into or out of the battery. As the current gets higher, is when this becomes more extreme. Electricity always takes the path of least resistance. In Method A you can have a huge difference in the current coming out of battery 1 compared to battery 2. Some other critics here are correct that for more than three batteries a bus bar is better. With the bus bar the currents in and out of each battery is closer than my Method B. However, This way doubles the # of connections. A failed terminal/lug crimp is the most common failure. Making good high amp connections takes practice. This video was made for DIYer, not professionals with lots of experience. I made it because I see too many people parallel batteries like Method A. I also made it short so people would watch it. If I was to remake this video I would add the bus bar method too. Even with the bus bar, under heavy loads, there is still a current difference within the batteries. The difference is slightly better and ONLY if the crimps are perfect and the wire lengths are exactly the same.

[@NackDSP]

@@kschildt1 You apparently forgot your first year high school electronics. Draw the equivalent circuit with the resistance of each cable segment and battery ESR. Maybe capture the schematic in LTSpice and run the simulation with a 200 amp load. Look at the difference in current from each battery. Some engineers graduate with a 2.0 grade average and others with a 4.0 average. So you barely got an engineering degree ten years ago, that isn't the same as being correct. You apparently didn't study logic.

[@lormicidemoise9509]

Not good

[@TravelingLightReflections]

Okay

[@paulna5526]

wrong

[@TravelingLightReflections]

Thank you for your well thought out and detailed expert response about this.

[@zigmass4899]

[@TravelingLightReflections]

Peace