Help deciding how to assemble my 12v 16 cell battery bank

[Firstascent]

Hey everyone!

looking for some input on assembling my 12v bank with 16, 280aH cells. I was set on a 24v system but then victron released a 12v only multiplus II, sooo now I’m going 12v route haha.

for what it’s worth, I’m not concerned about BMS options as the Batrium will support either of these configs and more.

Option 1 (first photo) is my preferred method, I like that if a cell goes bad I can easily remove a “battery” (4s pack) from the bank. But I’m curious on any input to parallel connect the two sides not yet connected to complete the bank. I would also only need to make/buy just a couple bus bars to parallel connect these two sides.

Option 2 works but I don’t like this method because it involves me buying/making a lot more bus bars since the ones I have that were supplied are too short for most of the connections due to battery config.

 

[snoobler]

Please walk me through how you get Option 1 to work - where you plan to parallel things and where your main terminals are because what you have laid out won't work.

 

[FilterGuy]

I assume this is option 1:


If the Batrium can handle that configuration I am impressed. That would be pretty advanced.

Assuming you are correct about the Batrium handling it, I would use something like 1/4" x 1" copper bar to fabricate the end busbars. With that the resistance would be so small any imbalance would be minimal.

I assume this is option 2:



This layout makes no sense to me.

 

[Firstascent]

The photos @FilterGuy referenced are opposite of what I was referring to.

this is option 1, the left and right side are identical in a 4S2P config as shown. But yes not sure how I’d connect them together, in this config, for a 4S4P. Or maybe it’s not an option.



In option 2, the bus bar I’ve highlighted below when the cells are side by side in this way, are too short. So yes I’d have to get new and cut new bus bars.
i should also mention that I’m not 100% sure the Batrium can handle it but am fairly certain. In the software config you can tell it exactly how you’ve config’d your pack (4S2P, 4P4S, 4S12P, 4S, whatever!) and you install a cell monitor on every single cell. Batrium support have also confirmed it can handle any of these configs easily.



Really I just need the pack in this general shape, and I would like the main Pos and Neg terminals to be located next to or close to each other instead of one on either side of the entire pack.

 

[snoobler]

That confirms it. Option 1 won't work at all.



Left side is what you have. You can't just randomly parallel terminals. There needs to be 12.8V between the parallel connections. You have 3.2V between your main terminals, and you have two unjoined (-) terminals which have 0V between them.

Your configuration can only be made to work as indicated on the right side. Remove the busbar between the 4th and 5th cell and join the far (-) terminals. The circled terminals are your main terminals now.

 

[snoobler]

This would allow you to use your existing bus bars, but you would need to add new main bus bars:

 

[Firstascent]

That confirms it. Option 1 won't work at all.

View attachment 42407

Left side is what you have. You can't just randomly parallel terminals. There needs to be 12.8V between the parallel connections. You have 3.2V between your main terminals, and you have two unjoined (-) terminals which have 0V between them.

Your configuration can only be made to work as indicated on the right side. Remove the busbar between the 4th and 5th cell and join the far (-) terminals. The circled terminals are your main terminals now.

Ah yes, I see what I did there. I’ve been staring at this too long trying to make it work how I want haha. I should know better, but I’m human

This would allow you to use your existing bus bars, but you would need to add new main bus bars:

View attachment 42408

thanks, this may be my best bet, I’ll play around with this one, appreciate your input and examples