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Best "blue" prismatic LiFePo4 cells for weight effiency

the_tux

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Feb 17, 2020
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Hi,
after a lot of back and forth with some aspects in my planning, I'm slowly making progress.

I'm looking for batteries for a 48v kit with at least 10KWh of capacity. Originally I planned for 16x280ah prismatic from Xuba which is nice and actually a bit more than I probably need. The alternative would be 32x105ah in a 16s2p configuration. I need to buy a 2nd BMS but I like the idea of having some redundancy in the case on trips over.

Looking at the different options out there it seems they have different energy densities:

280ah (Xuba & Haomi) - 5.2kg - 53.84ah per kg
105ah (Xuba) - 1.98kg - 53.03ah per kg
105ah (Haomi) - 2.012kg - 52.18ah per kg
152ah (Xuba) - 3kg - 50.6ah per kg
120ah (Haomi) - 2.9kg - 41.38ah per kg

so the first 3 are very similar but the 120ah one seems to be worse in terms of energy density. There are a few more where the numbers don't much up. In what sizes do they make these cells actually? Are some of them just bigger ones that just happen to not bring the full capacity (same as with CPUs)?

In this case I probably go with 105h in 16s2p as the 120ah is too much of a weight trade-off for me unless anyone has a tip for me before I'm getting crazy crunching numbers ;-)

thx
 
Looks like you have it all figured out.
As recommended elsewhere be sure you get grade A cells and guaranteed capacity in writing.
With that many cells, i often wonder about getting an extra cell or two in case there are any duds. Or if something happens during shipping.
Would a replacement, potentially many weeks out be from same batch and similar enough to the others? I dunno, just wondering.
 
Looks like you have it all figured out.
As recommended elsewhere be sure you get grade A cells and guaranteed capacity in writing.
With that many cells, i often wonder about getting an extra cell or two in case there are any duds. Or if something happens during shipping.
Would a replacement, potentially many weeks out be from same batch and similar enough to the others? I dunno, just wondering.

OK, thanks. Do you think the difference in weight with the different vendors is just due to the margin of error? I always thought they sell the same stuff.
Getting 1-3 spare cells, especially when talking about 32 total makes sense, good idea
 
I have never considered weight. My primary concern has been quality/performance, cost and perceived trustworthiness of the vendor.

I suppose shipping speed and cost (related sometimes) depends on your situation.
 
If you were considering 3 spare cells, why not 4?
3 are fairly useless but with 4 you could make a handy 12v battery.
I have 1 spare and i cannot locate a single use for it...other than a spare sitting idle.

Sorry for the feature creep...
 
If you were considering 3 spare cells, why not 4?
3 are fairly useless but with 4 you could make a handy 12v battery.
I have 1 spare and i cannot locate a single use for it...other than a spare sitting idle.

Sorry for the feature creep...

good point, I just thought about replacing individual cells. Weight is a concern since I'm driving a van with a GVW of 3.5t, I have about 1.3t to work with, total. Batteries are heavy and so are solar and water. I try to get the maximum performance out of a minimum of weight.

48V are because I want to run everything fully electric (cooking, incl. convection oven), for heating there will be an additional diesel heater. I therefore want to go with a 5000w MPP solar all-in-one unit. I'm more scared of higher amps than higher voltage ;-)

Maybe I'm just freaking out in isolation right now but I also want to get stuff in as long as there are some shipping routes open
 
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