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Old 08-08-2011, 04:54 PM   #96
herrhelmet OP
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Joined: Mar 2008
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Quote:
Originally Posted by Sparrowhawk View Post
What's the difference in the way you and ballistic calculate an amp-hour ratings?

I assume cell-construction wise the SYCL 4.6 AH batttery is the same as the 8 cell Ballistic battery since both use A123 cells, the main difference being the hard-shell case for the Ballistic. The SYCL is listed at 4.6 AH while the Ballistic specification lists 15 Pbeq A/H. How does one compare the different specifications?
Both batteries use identical cells. I started using the 2.3, 4.6 and 6.9 Ah because that's how A123 Systems rated the cells

http://www.a123systems.com/products-...rical-cell.htm

A bank of four 3.3V cells = 13.2V at 2.3 AH. 2 banks in parallel doubles that to 4.6, etc.

Ballistic and other manufacturers are going with the Pbeq rating to make it easier to compare to lead acid. Even though their actual AH capacity is less they have a more favorable discharge rating, so they use that chemistry term.

You could compare a 15 Pbeq A/H battery to the lead acid with the same A/H rating. But the CCA of the LiFePO4 will always be higher.

Ballistic also lists a slightly higher CCA rating for their comparable units. I can't honestly say why. It's possible because of their construction, less current is lost going through the cables that the Sycl batteries have.
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