Batteries

[BRYAN ASTONParticipant @bryanaston57723]

greetings all

I have just spent six months on a off in hospital and have obviously not been down the pond sailing my scale boats, however I now intending to resume to when the weather warms up,

my question is this, as my many 7.2v NIHM batteries have have not been charged up for many months are they likely to have deteriated and will not hold a charge.

I don’t want take a boat down the pond and find the batteries only last for a few minutes .

Bryan

[BRYAN ASTONParticipant @bryanaston57723]

7.2v nihm

[Dave MilbournParticipant @davemilbourn48782]

Bryan

Some cells will be OK while others may not. A lot depends on the state of charge you left them in and under what conditions they've been stored. I'd advise a slow-charge and then, if you can, check the voltage across each individual cell. If you push a pin through the heat-shrink you can find a contact where the cells join. Any cell showing much below 1.2v should be regarded as suspect.

If all seems OK then several slow discharge/recharge cycles will do them good. By "slow" I mean less than C; C being the capacity without the H bit e.g. a 3300mAH pack has a C rate of 3300mA. I usually charge my NiMH packs at approx C/10 for 14-16 hours.

Glad to hear you're out and about again.

Dave M

[BRYAN ASTONParticipant @bryanaston57723]

Thank you Dave

They were mostly fully charged before I changed my address to the local hospital, I will take your advice and slowly charge them up again.

regards

Bryan

[Dave MilbournParticipant @davemilbourn48782]

Bryan

Before you do that, you might discharge each pack until the total voltage is about 6.6v – no less. Use a car bulb or similar as a load. Once the voltage gets below 7.2v it starts to drop quite rapidly, so do keep an eye on it! Then slow-charge the pack as described.

Dave

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