Budget 90ah 48v lifepo4 battery build (under a grand)

[augiedoggy]

well I am tickled pink with the performance of my battery and the solar panel roof. its never had any need to be connected to the charger as even though we cover it during the week. The solar panel roof keeps the panels topped off and charged throughout the weekend just fine.

My inlaws are so impressed im building a 36v version of a lifepo4 pack for them now. I picked up 12- 72ah cells for $37 each from the battery hookup.
They only have 144a continuous discharge but that will be fine for the application and use they will see.

[augiedoggy]

The made a mistake on tho battery cells above from the battery hookup, They were $28 each not 37

[augiedoggy]

Well ive just pulled the trigger on another upgrade to play with this winter... Ive got a pack I recently made for my electric riding mower... it uses the samsung 64ah SPI 150a output cells. Well I noticed that BMW uses the exact same cells in these packs

https://batteryhookup.com/products/b...2-7kwh-samsung

So I bought 2...

I plan one taking the 16s lifepo4 pack I built for my cart and swapping that into the mower and taking the 2 packs I just bought from battery hookup and combining each pack with 7 more cells from my newly built mower pack to create 2 72v 19s 64.5ah packs I will be combining in parallel to have 128ah 72v capability. (I know many "72V" nmc packs also use 20s but I will only have a total of 39 cells and due to how they are pre wired and compressed I find this will be the best way to move forward. also the absolute max of my onboard solar roof mppt boost charger is 85v and I would rather not max it, espacially since I expect the 6-7amps of charging I get now to likely drop to like 3-4 amps at the 78-79v ill have it charging at.

we shall see how this works and if I even change something along the way because I dont really need the 128ah of range of more than 15a out continuous output because I never even hit 100amps with my current pack even at WOT with passengers but I havent done at terrain with it yet. I may even reuse the smaller 120a jk bms along with a bigger 180-200a jk for the second pack... not sure yet I really would like the 2amp active balancing.
I wonder if JK has a way to control both bms from the same touchscreen interface, I could make a multicontact switch I guess. Also I dont really need the interface for both since I have the bms app but I do like to monitor things.. its how I found out I barely use the amp capacity I have now.

all in all I will have paid with shipping $780 total for the 39 64ah cells and likely about $210 for both bms with the touchscreen interface to this will be just over a grand but for 128ah and 72v its still a value.

I will be powering my stock GE 36v motor with this and for my typical 5mph with the occational short WOT blasts it should work very well from the older threads I read about the GE motors being built to handle much more voltage.

[Pat911]

I may even reuse the smaller 120a jk bms along with a bigger 180-200a jk for the second pack... not sure yet I really would like the 2amp active balancing.

You can set the balance current in the JK App. 2A is the maximum but you can dial it down.

[augiedoggy]

Originally Posted by Pat911

You can set the balance current in the JK App. 2A is the maximum but you can dial it down.

Yes I like the 2amps though.. my 120a jk in my mower only has .6amp worth of balancing and it took forever. I have up to 4amps of active balance in my jbd/lifepo4 pack now.