Steven C Veal <[email protected]> writes: > Last night I installed new NiMH batteries (the Powerex 2700 MaH > variety) into my week old KX3 for the first time and set them for a 12 > hour charge. After the charge was complete, the KX3 PS display > indicates a power supply voltage of only 10.8 volts, which drops to > well below 10.0 volts on transmit.
Those are not the low-discharge variety, so are likely totally discharged on arrival. 2700/200 is 13.5h, and you need to charge more than rated capacity because charging is not 100% efficient. So for 2700, 16h is definitely warranted, and I might recommend 18h on first charge, but you can't set that. I'd give it another 4h, maybe 6h (humuan in the loop timing control from 8h :-). Undercharging is scary because it can lead to cell imbalance and you really don't want to reverse bias NiMH batteries. 10.8V/8cells is 1.35 V/cell. For a NiMH under any load, that's very much charged. 10.0V is 1.25 V/cell. At rest, that indicates a discharged cell, but under any significant load there is no problem. Set your BAT MIN to lower; probably 8.4V makes sense (1.05 V/cell, which you may well see under transmit loads), or even 8.2V. When doing test discharges on NiMH cells, I use 200 mA and discharge to 0.9V, using a MAHA C9000. That corresponds to 7.2V for 8 cells. I recommend getting one of those chargers and measuring your cell's capacities before putting them into service and then yearly or if they seem to be acting up. I have been happy with the powerex/maha batteries, but have found that the regular (non-Imedion) ones self discharge quite rapidly. 73 de n1dam
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