mbloof wrote:
Honestly you have to take ANY "reviews" on Amazon with a LARGE PORTION of SALT - %99 of them have no idea what they actually have or how to test/review it!
However, let us talk about Batteries specifically shall we?
How many consumers have AH meters? Programmable power supply? Load testers? Current meters? Even a DVM? (are any of the above even calibrated?)
Lets face it, the average Joe/Jane consumer has nether the expertise or the equipment to properly test/review a battery.
While it MAY be different for LFP batteries, the seemingly endless flood of useless/overrated consumer Lithium replacement batteries from China is what I'm basing my opinion on.
Well then again there is the popular CATL 280AH LFP battery cells which I see listed having anywhere from 240-340AH on Amazon (for the SAME cells).
(keep in mind much like FLA's, (while the number is growing) there are a limited number of Lithium and LFP OEM's in the world.
- Mark0.
Ya you have to read review some have no clue or just say "delivered fast" but I think the big thing to understand is how LiFePO4 chemistry works. New they are typicly rated from 3000-3500 cycles @ 100% discharge, by limiting your usage range say you keep it between say 20% and 80% with the off run to 100% to top balance and keep the usage and charging under 0.5C you could bump that cycle number up to 7000 or higher.
but here is the magic about this chemistry. if you did 800 cycles on a typical GC2 battery it would be done (on average) so wouldnt hold a charge bal bal bal... on a LiFePO4 when you reach the cycle life you still have 80% of the capacity left and the degradation slows down.. so you could have another 3000 to 20000 cycles untill that battery wears out if you treat it nice.. Personaly I think the battery would age out before it would die from cycles.
so alot of these 200 buck 100AH batteries you can buy were built using B grade cells, is that bad, I don't think so as long as you know that.. in my opinion they would still out last a FLA battery and give you more usable capacity for the same price.. the bad thing is they were advertising them as "A" grade and a typical "A" cell will pull more than its rated capacity. now a cell can be clasified as "B" grade for several reasons, a blemish, a barcode that doesnt work, doesnt pull over capacity.. (typicaly a "A" grade 304 eve cell will pull 310AH or higher new) but what lest scrupouls builders were doing was taking used cells which could be classed as "B" but shouldn't and building these batteries out of them. so they may have only had 200 to 2000 cycles on them but you didnt know so you might hit that 80% capacity faster than expected. EVE has cracked down on this by changing how there Bar codes are put on the casing so its not a sticker anymore or ink and on "B" grade batteries there is no bar code at all so places cant sell a "B" battery as a "A"
As for Catl cells, they would be a third choice for me but they use the same outter casing for simular capacities, what you have to look at is the weight
so the Catl
240 is 5.1Kg (+/- 10g) 207 x 173.9 x 71.3mm
the 280Ah is 5.34Kg (+/- 10g) 207 x 174 x 72 mm
302Ah is 5.51Kg (+/- 10g) 207.2 x 174 x 71.65 mm
With Eve which is the only cell I'll buy for DIY builds there is a 4mm hight difference between there 280AH and 304AH and almost a 0.3kg weight difference also
