Thread: Discussion New Spektrum DX7S.........
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Old Sep 24, 2012, 10:04 PM
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Recently bought a DX7s and am a bit annoyed at the NIMH battery and method of charging.

Because it didn't show max charge on the icon after charging initially for 10 hours, I reconnected the 12v input for several hours - voltage didn't increase above 5.4 and quickly reduced to 5.2. As I now understand, this may be normal behaviour.

The real problem, as it seems to me, is how to tell when the battery is fully charged. Since it won't automatically shut down when fullly charged, are you supposed to just feel the pack and if it's warm or hot shut the charging down? Or - is it OK to turn the transmitter on and note the voltage while the charge cord is still connected? Or - should the charge cord be disconnected first then turn on the transmitter to check voltage?

I understand that it isn't good for these packs to renew charging when the pack is warm, charge several times per day, leave the pack fully charged, or over-discharge. NiMN batteries may output higher voltage for longer periods than other rechargables but with my DX6i it's so easy to just install 4 fresh batteries and not worrry about doing damage to an expensive pack. It also seems to me that it is not such a good idea to use the in-radio charger that will not automatically shut off at full charge.

- Does anyone remove the pack and charge with their LiPO charger on NiMH mode?
- At what voltage should this pack be left for storage - I've read that NiMH cells should be left at .9v per cell. If the radio has a 4.3 volt alarm to shut off then how do you get down to the storage voltage?
Also, how much life will be lost if the pack is left with usable voltage for long periods of time?

The LiPO pack is the better option, particularly since charging shuts down at full charge. Bit expensive - that's all.
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