Mixing Leaf Cell batches Question

[Niz76]

First off- Thanks all for the great lithium ion info shared here!

I saw someone have this conversation/debate somewhere here but can't seem to find it again- seemed to be unresolved on best practice so I'll ask here:

What's the best way to mix two different batches of 7 leaf packs?

I made the mistake of being wishy washy when ordering my cells and ordered 7 from one source on ebay and then decided to go with a 14 cell (well technically 56 cells!) pack and ordered 7 more from a different source.

They're gen1 and I'm guessing will be fairly close in ah (hopefully). Should I parallel two of the same batch with a mixed set in the middle of the "14 cell" pack or mix them in together evenly throughout the whole pack?

I guess the argument is whether two cells paralleled would be "fighting" or one half of the pack "fighting" the other half?
Hope this Q makes sense!

[Volt_Ampere]

If they are close to same, I would parallel one of each batch together. They are forced to be balanced that way.

[DaveTM]

I just completed doing just this on my cart. About two years ago I installed a 7 module Gen1 Leaf pack and after two successful years of hunting season, I decided to double the pack size. I started a thread https://www.buggiesgonewild.com/showthread.php?t=150053 when I was just thinking about it, and then continued the thread during and after I did the install.

If you look at the pic below, I assembled my 14 module pack as Old\New\Old\New...etc. Now, the pic isn't how I installed the assembled pack but that pic was taken when I wired all the modules together in order to balance them with each other. BTW if you look at the pic the "O"= older module and the "N" = the newest units I purchased.

So far I'm happy with the expansion. The test will come this fall\winter when temp's drop and I'm out in the woods 'n fields driving thru the mud and ruts. But I have confidence it will work out well.

[Niz76]

Thanks for the input fellas. DaveTM, yours is the thread I was reading. I'll be mixing mine the same way you did yours. My other 7 (actually 8- I have an extra one now hmm..) modules arrived today and I sold my lead acids today also so I guess I better get a build thread started!

[DaveTM]

Originally Posted by Niz76

Thanks for the input fellas. DaveTM, yours is the thread I was reading. I'll be mixing mine the same way you did yours. My other 7 (actually 8- I have an extra one now hmm..) modules arrived today and I sold my lead acids today also so I guess I better get a build thread started!

Yeah.....unless you drive all downhills. Both to get "there" and back!

[DaveTM]

BTW and FWIW, expanding from a 7 module pack to a 14 module pack I've noticed a longer time period is needed for the pack to charge. Now, I certainly expected this would be the case as I now have twice the energy storage capacity that I did before.

I didn't think it would take twice the time length to charge the 14 module pack.....but it's pretty close to that.

My ElCon charger is only charging at 15 amps max. That may be the reason why it takes more time.

Again....just an FYI

[Volt_Ampere]

Twice the capacity == twice the charge time with same charge current. My 17 amp charger takes about 6 hours to charge my 14 module leaf pack from 25% to 95%.

[WalterM6]

But also twice the miles driven.

[DaveTM]

Originally Posted by Volt_Ampere

Twice the capacity == twice the charge time with same charge current. My 17 amp charger takes about 6 hours to charge my 14 module leaf pack from 25% to 95%.

Yes. That's about right.

[DaveTM]

Well, today I went out turkey hunting to a farm that has been a true test of power consumption. Every time I've gone to this place I've had to watch my power consumption. Today, with two adults weighing 220-lbs each I had no problems. Went twice as far as I normally go and still had plenty of reserve power left.

IMHO.....go with as big an amp\hr pack as you can afford!!