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Battle Born Black Friday Sales Today (11/27/2020)


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AndrewK,

Yes. These are two 12V batteries in parallel (2x capacity and 1x voltage)  that are both electrically attached to the trailer.  The AGMs that were replaced were two 6V batteries in series (1x capacity and 2x voltage) for 12V. 

Previously there were really four 6v AGMs in a 2S2P configuration, but this always tough to describe when typing.

I was able configure these new batteries without making or changing cables. 

Mike

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32 minutes ago, mjrendon said:

AndrewK,

Yes. These are two 12V batteries in parallel (2x capacity and 1x voltage)  that are both electrically attached to the trailer.  The AGMs that were replaced were two 6V batteries in series (1x capacity and 2x voltage) for 12V. 

Previously there were really four 6v AGMs in a 2S2P configuration, but this always tough to describe when typing.

I was able configure these new batteries without making or changing cables. 

Mike

Mike,

The point I was trying to make is if your positive and negative leads to the trailer, are connected to the same battery, that is not correct.  The positive lead should be attached to one of the batteries and the negative to the other battery.  As pictured below.

You want to draw the current across both of the batteries.

Andrew

1811149054_BattleBornBatteries.thumb.JPG.311eb24086fa27640a0f650c5f62e835.JPG

Andrew, Carianne and Buffy | San Diego, CA


2019 Legacy Elite II Hull #468 "California Burrito" | 2018 BMW x5 35d 

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49 minutes ago, C&MCurrie said:

Electrically both scenarios accomplish the exact same thing.  

According to Battle Born, in multi-battery systems, the positive and negative leads should be attached at the opposite ends of the battery bank.  This insures proper charging and current flow, through all batteries. 

Please read copied text, from Overland, from another thread. 

On 11/14/2020 at 5:41 PM, Overland said:

 … The Battleborn rep asked me how I had the battery bank wired, specifically if I had both + and - leads to the trailer connected to the same battery or to the first and last. I had them both on the same one. He told me that when they’re wired that way, the battery monitor is only getting its info on charge state from a single battery rather than the entire bank, and that can allow the other three to drift out of sync. And since the voltages on lithiums are so constant, a small drift can have big consequences. In my case, he suspected that two of the batteries had gotten so far out of sync that they were no longer contributing. He recommended rewiring them and giving the bank an overnight charge, then see where we stood. 

This is a example of problems that can occur if both the positive and negative leads are attached to the same battery in a multi-battery system.

Andrew

Andrew, Carianne and Buffy | San Diego, CA


2019 Legacy Elite II Hull #468 "California Burrito" | 2018 BMW x5 35d 

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Thanks for pointing this out.  I guess I could periodically rotate them like tires... 

I know that Overland has a 4P system and it will be interesting to find out if the cable configuration contributed to the issues that he is having with his batteries. 

 Soon I will be adding two more batteries in a bus bar configuration with trailer positive trailer connection attached at one end and the negative trailer connection attached at the opposite.  I will post images of that setup once completed. 

 

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It turned out that wasn’t the issue, rather the batteries themselves have problems.  Hopefully I’ll find out what exactly it was after Battleborn takes a look. 

You are correct that theoretically (and perhaps practically) it shouldn’t make a difference. You’ve in essence created a bus bar with the cables and it shouldn’t make any difference where along a bus the power is connected.  I could see it being a problem with marginal or undersized cables, but with 4/0 like I have there’s just the tiniest smidge of added resistance between the first battery and the others.  After hearing that from Battleborn I’ve tried to find some other reference to properly wiring the battery bank but can can only find one, from a company called Iota.  But looking at the photos from their test, it’s obvious that the battery interconnects are undersized.

So my take is that theoretically you could have a problem with the batteries wired that way, but practically, I doubt you’d have a problem unless your interconnects were undersized.

I’ll certainly make sure they’re connected like Battleborn wants, but yeah, I don’t think it really matters. 

Edited by Overland
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