In my current job, I take used prius batteries and recondition them. I put them on RC chargers and the modules through charge/discharge cycles to both measure and raise the capacity. They have an initial capacity of 6000mAh and I will use modules that test between 3500 - 4000. When I put the batteries back together they can fail immediately sometimes. Are there any other tests that I can do on these modules to make sure they work?
1
-
\$\begingroup\$ Look at any datasheet for any battery and can see the types of measurements they do. \$\endgroup\$– ColinCommented May 22 at 1:09
Add a comment
|
1 Answer
\$\begingroup\$
\$\endgroup\$
3
Self-discharge rate and ESR (internal resistance) come to mind.
answered May 22 at 0:18
-
\$\begingroup\$ Do you know anything about testing for those? Also what would a high internal resistance be? \$\endgroup\$ Commented May 22 at 0:40
-
1\$\begingroup\$ You can look at your battery specs if you have them, or compare with known good units. Internal resistance on a good cell is low during most of the discharge cycle, rising at the end. A bad cell will have higher than normal voltage when charging and lower when discharging. Self-discharge will be slower to test for since NiMH batteries hold charge for months (not as good as lithium though). Most of the catastrophic failures I've seen in large NiMH banks were related to venting of hydrogen and electrolyte. You might be able to detect a weight difference. \$\endgroup\$ Commented May 22 at 3:21
-
\$\begingroup\$ That’s a good idea about the weight. \$\endgroup\$ Commented May 22 at 8:51