Charger problem

[allotmenteer]

Just been out for a ride this evening and on my return I put the 24V Nimh battery on charge and the red light just kept flashing rapidly. Usually it flashes fairly fast about 10 times and then there is a click and it stays on permanently until the battery is charged and it goes green.

I checked the output voltage at the socket that plugs into the battery and it reads 38.8 Volts! This is obviously not right. The battery charged just fine yesterday so it must have been ok then.

Obviously I will be contacting powacycle about it since it's only a couple of months old but does anyone have any ideas what the problem is?

Oh, the battery is just about flat at 23.6V.

Paul

 

[flecc]

That voltage is ok Paul. NiMh chargers always have a much higher quiescent voltage, for example on the one for my eZee 36 volt NiMh, it reads 53.7 volts.

Try completely unplugging the charger from the mains and battery and let it rest for a few minutes, then replug in. If necessary, try the sequence both ways, mains first, then battery, and battery first, then mains. These things can lock up, one of my three eZee ones does sometimes.

The battery is at around 29 volts or so when charged, so that 23.6 discharged isn't particularly odd. Nominal and actual quiescent voltages are usually very different. It's when under load that these batteries give their true voltage status.

P.S. I can't check my Twist's 24 volt charger as it doesn't switch on until the thermistor is in circuit, but from memory when I did internal work on that system, it's quiescent voltage was over 39 volts.
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[Baboonking]

my nimh chargers flash very fast when the chargers doesn't get a thermistor reading. Might be worth checking all connections to see if anything's loose/dirty.

 

[flecc]

Further to my post above, I have a Powacycle Windsor/Salisbury charger here which I use for incidental jobs. This morning I got it out of the garage to check your figure and this one is 37.8 volts, showing yours is ok as I said. Charger problems are extremely rare, and if my other tips don't work, the likelyhood is the thermistor itself in the battery has failed, or the connections to it aren't making as Baboonking suggested above.

But do try that replugging in different sequences first, pausing a minute or two between each for the charger to settle, as that will also remake the connections.
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[allotmenteer]

Thanks flecc and Baboonking

As suggested I tried unplugging everything and plugging in a different order but the same thing happened. After your reply flecc I tried again using my normal method of plug in wall, charger socket in battery and then turn on switch at wall socket and it worked as normal and has now charged the battery fully.

Could it have been the battery being too warm? It didn't feel very hot but I had just returned from a 13 mile high speed thrash around the area followed by 3 miles of running the pack to exhaustion. I did leave it about 45 minutes before trying to charge it but maybe I should have left it a few hours to let things settle.

Anyway, glad to see there's nothing wrong with the charger.

Paul

 

[flecc]

It's not likely warmth would affect it unless it was up to the point of charge cessation Paul, and that is just possible, since a low exhaustion level does generate a lot of heat. Anyway, I don't think it will trouble you again. As I said, chargers are very reliable, and Carl of Powacycle has confirmed that theirs don't give any trouble. Any problem is always traced to the battery/thermistor combination.
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