Hi Bob,
That sounds right. 200Ah x 50V (easier math than 3.2 x 16 = 51.2V) = 10kWh. My estimate of $0.45/Wh to $0.50/Wh attempts to include shipping, strapping and intercell connectors. As you describe it, your quote works out to $0.416/Wh, probably for bare cells.
The next question is which brands have 200Ah cells. CALB cells come in 180Ah, GBS stop at 100Ah. I haven't seen any published prices for Sinopoly (the new Thundersky) cells. Let's use CALB 180s as an example.
From Evolve Electric, CALB 180s cost $234/cell if you buy 16 or $3744. These are bare cells, so you need another $53 of bus bars. You also need to figure out how to strap them into blocks to prevent swelling (aluminum endplates with allthread, or metal packing straps, or...) and of course you need to add in shipping plus tax if you're local. But without the shipping, tax or strapping, you're right at $3800 for 9kWh or $0.422/Wh.
EV Source sells the same cells for $243 and they have braided connectors that cost more. So from EV source, the bare cells with braided connectors cost $3993 ($3888 + $105) before shipping, strapping or local tax for 9kWh or $0.444/Wh.
Anyway, you get the process. Let's say that you were also looking at four 234Ah AGM batteries that cost $560 each. 234Ah of 50V is 11.7kWh that costs $2240 for the bare batteries, this works out to $0.191/Wh before shipping and local taxes. Since both battery banks are the same voltage you could compare Ah (200Ah for $3800 or 234Ah for $2240) and its easy to see that Li cost about twice what AGM costs per Ah.
Lets compare just one CALB 180 to the AGM 234. The Li costs $234 for 180Ah. The AGM cost $560 for 234Ah. Which is cheaper? Using watts, we're back to Li is about $0.41/Wh or AGM is about $0.20/Wh, the voltage doesn't matter.
Since each of our projects is at a single voltage, why bother? Let's say that you found someone selling a lithium pack out of an EV, the pack is 130Ah at 120V (40 cells) for $8000, is that a good price? It works out to $0.513/Wh. You know that you can buy new cheaper. Lets say the price is $6000, now its $0.385/Wh, pretty close to the price of new. At $6000, the used cells might not be worth it. At $4500, we're at $0.288/Wh and it looks like a good deal, even if your boat is 48V. You can build a 2P16S bank for 260Ah at 48V and have 8 cells left over to build two 130Ah 12V house batteries. I would buy those batteries.
So if we think in Wh, FLA cost about $0.10-$0.12/Wh, AGM cost between $0.20 and $0.25/Wh and Li is currently $0.45 to $0.50/Wh. You don't have to think about Ah or volts. Doesn't that simplify things?
Since we discuss so many different voltages here, the common ones are 12V, 36V, 48V and 144V, talking in watts makes comparisons much easier for everyone involved. We already do for motors, it's not hard to do it for batteries too.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, Robert Lemke <robert-lemke@...> wrote:
>
> Price domestically is running $1.30 per a/hr per 3.2 volt cell. So, 48 volts @ 200 a/hr should be 1.30 X 200 X 16 (for 48 volts) = $4160.00. Sound about right?
> Bob aka "deckofficer"
>
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