Hmmm. I consider the prismatic LiFePO4 cells to be 3V nominal, i.e. 4 cells replace a 12V battery. If you put 17 cells in your bank, I would call it a 51V system.
We all know that a 12V battery that only shows 12V at rest is in a very discharged state. We also know that L/A cells are nominally 2V but really somewhere above 2.1V and we build 6V, 8V, 12V, 24V, etc. from the appropriate number of cells (notice the whole numbers) That's why I call the Li cells 3V to do the similar kind of math.
As far as the 48V rated components, a 48V FLA battery under charge will often exceed 60V, my 16 cell Li charging profile maxes around 59V. This means that old school flooded batteries expose systems to higher voltages than most modern battery types. Given that, I feel comfortable labeling my system as 48V.
What we do see is that new technology cells may require a rethinking of standard voltages. What will happen when somebody build a new battery that runs between 1.2V and 1.4V per cell? It's too high to be called 1V and too low to be called 1.5V like a dry cell.
I guess that time will tell....
Fair winds,
Eric
--- In electricboats@yahoogroups.com, "Tom" <boat_works@...> wrote:
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> I agree Eric, I have never had my "48V" bank below 50V. So can I really consider it to be a 48V installation? What if I added another cell to make it a 17 cell bank? Where does a nominal voltage end, if it can be incremented 3.2V at a time?
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> Probably a moot point, and I'll probably never get called on it, but it would be nice if this was better defined in the regs and standards.
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> -Tom
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