HP97 battery pack rebuild

[Dave Frederickson]

The cells are Tenergy 2200 mAH NiCd's. The charger is also made by Tenergy and the manual highly recommends that Tenergy cells be used (of course). So far we're good. The charger includes a temperature sensor and uses the temperature and negative delta V (NDV) to detect the end of the charge cycle. The instructions state that batteries with a capacity greater than 2100 mAH should be charged at 1800 mA. If there's a concern the batteries could be charged at 900 mA. The charger is "smart" and has automatic voltage and reverse connection detection plus a number of other bells and whistles, all for less than $25 (with shipping).

So to answer Den's question, no I'm not concerned about decreasing the battery life at the higher charge current, but Dieter has some valid points which I believe could be mitigated by using the lower charging current and the temp sensor. It still beats the pants off using a Power Pack.

It should also be noted that for the NDV circuit to properly detect the end of charge the charge rate should be at least 0.5 C.

Dave