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BrianG · 01.19.2011, 06:33 PM

How are you measuring IR? The best way IMO is to measure voltage unloaded, then measure again at X load, then take the voltage difference divided by the load current. Do that over the course of the discharge cycle to get a graph of IR. I think you'll find the IR for the poor performing cells is higher than the others.

When cells are in parallel, you are getting some conflicting results because a good cell is somewhat compensating for the not-so-good cells, and the not-so-good cells are surely affecting the performance of the relatively good cells. Basically, parallel cells masks each cell's true performance. Which incidentally, is one reason I don't like any kind of 2p+ setup.

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BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	01.19.2011, 06:33 PM How are you measuring IR? The best way IMO is to measure voltage unloaded, then measure again at X load, then take the voltage difference divided by the load current. Do that over the course of the discharge cycle to get a graph of IR. I think you'll find the IR for the poor performing cells is higher than the others. When cells are in parallel, you are getting some conflicting results because a good cell is somewhat compensating for the not-so-good cells, and the not-so-good cells are surely affecting the performance of the relatively good cells. Basically, parallel cells masks each cell's true performance. Which incidentally, is one reason I don't like any kind of 2p+ setup.