Battery split question

4326 Views 38 Replies 7 Participants Last post by Functional Artist, 2 mo ago

DaPhish

Discussion Starter · Feb 22, 2022

Hello I am very new electric conversion and ready to work on one. I have bought pretty much all the parts and in the process designing location of everything.
Below is the battery layout. There are 12 batteries total and use as 6S2P and is split to 8 back and 4 front.
The back battery will run all the way to the front and will that cause voltage difference since it is 10 ft?
Do you think this is a good idea?
I do wish to max out at 1000amp
Thanks you,
Ryan

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remy_martian

· #2 · Feb 22, 2022

What is a "battery"?

DaPhish

Discussion Starter · #3 · Feb 22, 2022

Sorry I didn't specify. It 60 cells together without BMS of 10s6P. They're from battery hookup. I am using 12 of these

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brian_

· #4 · Feb 22, 2022 (Edited)

DaPhish said:
Below is the battery layout. There are 12 batteries total and use as 6S2P and is split to 8 back and 4 front.
The back battery will run all the way to the front and will that cause voltage difference since it is 10 ft?

There is voltage drop in every conductor, and there will be more drop in the long (10 foot) connection between modules than in the shorter connection, but since it is a series connection between pairs of modules that won't matter to the balance between modules - the current goes through each of them, and that's the important part.

brian_

· #5 · Feb 22, 2022 (Edited)

DaPhish said:
Sorry I didn't specify. It 60 cells together without BMS of 10s6P. They're from battery hookup. I am using 12 of these View attachment 127747

So it's a 10S6P module, assembled from 1S2P sections with 8 Ah cells. Then you're putting those modules in parallel pairs, which makes no sense to me... but that's not what you're asking about.

DaPhish

Discussion Starter · #6 · Feb 22, 2022

To me it's already assembled and I don't have the parts to link them together into 10s12P so I personally think this is the best way for me. If you have any other ideas I'm more than happy to consider it.

brian_

· #7 · Feb 22, 2022

DaPhish said:
To me it's already assembled and I don't have the parts to link them together into 10s12P so I personally think this is the best way for me. If you have any other ideas I'm more than happy to consider it.

The parallel connections are done by bus plates. Because there is one pair of threaded sockets for each pair of 8 Ah cells, in the 6P modules the plates have three rows of holes (at the ends) and six rows of holes (3 for positive one cell group plus 3 for negative of the next cell group); to reconfigure these modules to 5S12P you would replace those plates with plates twice as long (six rows of holes at the ends and 12 rows of holes for the other plates). With 5S12P modules you would then connect all modules in series for the same 30S12P overall pack. This would simplify the BMS substantially, but if the seller doesn't offer different sizes of bus plates (they don't appear to) you would need to custom-build the longer plates.

remy_martian

· #8 · Feb 22, 2022

I doubt you'll get 1000 amps out of that setup.

500A peak, 300A continuous on a good day, imo.

Enough to maybe run a 60kW motor for 20 minutes...

DaPhish

Discussion Starter · #9 · Feb 23, 2022

I have consider that but it seems like copper busbar prices are too high that's why I followed this diagram by Orion bms and It seems like it will work for me. If it does not seem like a good idea to follow orion bms I'll find a way for longer busbars.

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DaPhish

Discussion Starter · #10 · Feb 23, 2022

remy_martian said:
I doubt you'll get 1000 amps out of that setup.

500A peak, 300A continuous on a good day, imo.

Enough to maybe run a 60kW motor for 20 minutes...

Due to the battery not being strong enough or because of my choice in wiring it?

DaPhish

Discussion Starter · #11 · Feb 23, 2022

DaPhish said:
I have consider that but it seems like copper busbar prices are too high that's why I followed this diagram by Orion bms and It seems like it will work for me. If it does not seem like a good idea to follow orion bms I'll find a way for longer busbars. View attachment 127748

brian_

· #12 · Feb 23, 2022

DaPhish said:
I have consider that but it seems like copper busbar prices are too high that's why I followed this diagram by Orion bms and It seems like it will work for me. If it does not seem like a good idea to follow orion bms I'll find a way for longer busbars. View attachment 127748

As you get the modules from Battery Hookup them, each module is wired the way the Orion diagram suggests - that's good. What you are proposing to do is connect each module in parallel with another module, which is not suggested by the diagram.

DaPhish

Discussion Starter · #13 · Feb 23, 2022

brian_ said:
As you get the modules from Battery Hookup them, each module is wired the way the Orion diagram suggests - that's good. What you are proposing to do is connect each module in parallel with another module, which is not suggested by the diagram.

So I decided to do what you proposed and this is the new diagram. Does this resolve the issues?

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remy_martian

· #14 · Feb 23, 2022

Copper prices are irrelevant.

piotrsko

· #15 · Feb 23, 2022

And welding cable in huge conductor diameters is relatively cheap

brian_

· #16 · Feb 23, 2022

DaPhish said:
So I decided to do what you proposed and this is the new diagram. Does this resolve the issues? View attachment 127749

Yes, that avoids any balance issues between modules and cuts the BMS complexity in half.

The "side view" bit doesn't apply any more.

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DaPhish

Discussion Starter · #17 · Feb 23, 2022

piotrsko said:
And welding cable in huge conductor diameters is relatively cheap

I don't think I could use welding able to link between the cells in my case

DaPhish

Discussion Starter · #18 · Feb 23, 2022

brian_ said:
Yes, that avoids any balance issues between modules and cuts the BMS complexity in half.

The "side view" bit doesn't apply any more.

Perfect I will do that, thank you

piotrsko

· #19 · Feb 23, 2022

DaPhish said:
I don't think I could use welding able to link between the cells in my case

Why not? Comes in orange, up to 600v insulation, all sorts of diameters and hundreds of different style crimp connections. You can even sometimes buy it locally

floydr

· #20 · Feb 23, 2022

How thick are the busbars on the cells now? 1/16"? Copper Sheet 1/16 Thick 52”X13” 13lbs Drop Piece It Does Have Scratches | eBay copper 1/16" x 52" x13" should be enough only $140 plus shipping it has gone up since last year when I bought a piece. You can nickel plate it fairly simply.or BatteryHook up has 6p busbars for sale now 6p 300a BUSBAR FOR SPIM08HP 16ah - Copper/Steel
Later floyd

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