Hi Eric,
I have had precisely the same quote from Thundersky as well, 1.5$/AH, i.e. 0.45$/Watt-Hour, including BMS. Did that cover the shipment as well? They quoted me FOB.
I have heard many good feedback from their batteries. I know quite a few people running cars on those batteries in Australia, some are at more than 600 cycles with absolutely no noticeable degradation in performance.
After all I read just now, I am still not 100% sure whether I should go lead-acid or LFP, but I must say that I have a general feeling that the LFP will last longer and will come with less hassle.
Best Regards,
Christian
--- In electricboats@
>
> Denny,
>
> My 8kWh bank of Thundersky LFP batteries cost $0.45/watt-hour including BMS delivered to Southern California. The rule of thumb that I use for comparing AGM cells to LFP is LFP are a little more than 2x the cost, 40% the weight and 1/2 the volume.
>
> The additional benefit is that LFP are barely affected by the Peukert effect. My 48V bank rated at 8kWh has 6.4kWh usable (80% DoD) and calculates to 764.4 minutes @ 10A and 73.2 minutes @ 100A. By comparison, a 48V AGM bank with 6.4kWh usable calculates to 758.4 minutes @ 10A but only 60.3 minutes @ 100A. Carrying this to wet cells, golf cart batteries with 6.4kWh usable calculate to 756.6 minutes @ 10A and only 37.9 minutes at 100A. This means that the same amount of energy delivered at this high rate will last twice as long and go twice as far from LFP batteries instead of wet cells. LFP batteries will go 25% farther than AGM with the same energy in this scenario.
>
> Even though LFP costs have gotten much better recently, there's more to the decision than just initial price.
>
> Fair winds,
> Eric
>
> --- In electricboats@
> >
> > Christian,
> >
> > More thoughts:
> >
> > I have no personal experience with LFP batteries but I see them sold for marine use with built in battery management systems for very high prices, approx 10x the cost of old fashioned lead acid. Check Torqeedo and Mastervolt for examples. A 300 watt-hour Torqeedo LFP battery with built in BMS costs $600 ($2.00 per watt-hour) here in the USA.. A high quality AGM from Concorde is about $0.20 per watt-hour. An LFP bank needs a battery management system to monitor the discharge and recharge of each individual cell. The rule of thumb I have heard for comparing Lead acid to LFP is the LFP are 10x the cost, 1/3 the weight and 1/3 the volume....
>
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