How long to fully discharge batteries?

[donkeyontheedge]

My wife's revo plus has been experiencing the battery problems that have been done to death on here recently and I'm going to try a full discharge/charge before I do anything else.

The weird thing is, is that when switched on/off regularly, it would very quickly get to a point where it wouldn't switch on unless it was recharged.

I decided to discharge it, so after backing it up (and it recharging) I disabled auto-off and left it on overnight. About 11 hours later it was down to 1% and finally switched off. This doesn't fit with the regular on/off usage from the batteries at all.

Anyway, there is always some charge left in the revo to keep the memory active - so my question is how long should I leave it to ensure there is nothing left (or as good as) in those batteries?

Any other tips/tricks I should be doing, please let me know!

Regards
John

[Jim Cooke]

John,

In theory, the battery is fully discharged when you can no longer turn it on and, when you attach the mains power, the Revo turns on with a hard reset. Practically speaking, you've already discharged the battery enough for what you're trying to do.

Having the machine turned on and just staying in a wait state should allow the bateries to keep the machine on for about 11 or 12 hours. The battery problem usually shows up when it's under load, like playing an alarm sound. The unit shuts down because it gets a false low battery indication from the charge circuit.

I'd now recharge it back up to 100%. I've found that it can "stuck" around 93% and unpluging and pluging back in the mains adaptor get's it going again. Once the charge shows 100% and the charge current is down to about 28mA, the battery should be good to go.