FWC wrote:
Gjac wrote:
FWC wrote:
Gjac wrote:
How much cheaper would it be to build your own? Roughly what would it cost to get the equivalent of 2 6v GC batteries say about 230 ah's?
280Ah is probably the closest 'standard' LiFePO4 cell size. For that you are looking at $600 - $700 for the cells, another $60 - $120 for the BMS and maybe $100 for wiring equipment and some sort of case. I would guess $750 - $900 all up, cheaper if you are wiling to go with Alibaba and wait on freight, more expensive if you want it shipped from the US (amazon or ebay).
This would give you ~3000 cycles at 100% DOD so about 10x the usable Ah than lead acid over the life or the battery (if you plan to use it heavily or keep it a long time).
I guess it comes down to what your electrical requirements are VS cost per AH. I was thinking the price of these batteries would come down to make them competitive with lead acid batteries because of the big push to go to EV cars, but as some report the prices have gone up along with other camping supplies. I dry camp 95% of the time and am conservative when it comes to water and electricity. 230AH batteries last a week before they reach 50% SOC and by then I am out of water. So I guess if you full time or have much greater electrical requirement then $900 might make sense VS $200 for 26v GC batteries. One would think with more batteries being produced the cost will comedown dramatically at some time in the future.
The cost of these has fallen dramatically - the cells themselves are 1/3 - 1/2 the price of what they were three years ago, and drop in batteries can be had for 1/2 the price.
The prices are very competitive with lead acid if you are thinking about the total cost of ownership, rather than just the upfront cost. For your use case a 100Ah LiFePO4 seems like it would be sufficient, which is about $300 for the DIY route or $550 for the drop in route.
If I understand your post correctly because of a deeper discharge of Li Down to 0 SOC and with 2 6v GC batteries only going down 50% SOC gives only 115 usable AH's. Is that what you are saying?