Not all lithium acts like this.
While a fairly flat discharge curve is seen with Lithium Iron Phosphate (LiFePo or LiPo), it is not the case for Lithium Ion chemistries. As example, the batteries in my pack---Fully charged they reach 49.2v. Fully discharged voltage is about 30v (2.5vpc). That's a nom. 40% drop in voltage making it quite easy to estimate the remaining capacity of the pack by voltage monitoring alone.
From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Larry Brown
Sent: Sunday, October 29, 2023 5:39 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Need 48v 200A for Electrictyacht 10kW motor, should 1 get 4 x NPP12V 200Ah Li or 2 Dakota 48V 96Ah?
Unless I'm wrong, my understanding is that lithium doesn't drop in voltage as you deplete them like lead acid and the voltage stays high right up until they reach capacity. So the only accurate way to gauge loss is through a battery monitor watching the draw from the system. But drain from low temp which I don't even know if it's a thing wouldn't be tracked with a monitor. You'd have to draw it down when you get it ready in the spring and watch the monitor to see how long it lasts. That would be the sure way. But I don't think they lose much from temp. I just understand they perform better at optimal Temps and worst at extremes. There are experts in this list so I'll let them chime in and maybe learn a thing or two 😁
On Oct 28, 2023, at 10:52 PM, THOMAS VANDERMEULEN <tvinypsi@gmail.com> wrote:
Very interesting, Dan. Thank you for the information. No doubt your batteries are of nobler pedigree than mine. I was always over-protective of our kids as they were growing up, but it never did me or them any harm. In any case, there's still the matter of getting one of those 48v monoliths into my motor space without a hoist and without cutting the opening bigger.
To each his own, I guess!
You're on Erie, then; what port?
Cheers!
[-tv]
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