Duration of 1st charge of drill battery

My portable Tesco drill has a 9.6V 1000mAh battery pack. I don't know
what type of battery it is. The power supply "brick" outputs 12VDC
400mA to the charging stand which the battery sits in.

The instructions say to charge it for about 5 hours each time it gets
run down ... not to carry on charging because the charger does not
switch off when the battery is full ... 10 hours is the maximum
permissible.

Should the first charge be for a longer time to equalise the cells so
they are all fully charged. Maybe, 16 hours? Or would this be too
damaging?

 

My portable Tesco drill has a 9.6V 1000mAh battery pack. I don't know

16 hours looks like a substantial overcharge. If the DC supply is
actually delivering 400 mA, then a 1C charge time for a 1000 mAh pack
would be only 2.5 hours... throw in some losses and inefficiency and
I'd expect that 4 hours probably tops the cells up pretty well. The
5-hour number they give is probably quite reasonable. Anything much
beyond that, and you're simply trying to force current through
fully-charged cells, and heating them up as a result.

Even if the cells aren't *perfectly* matched in the pack, I'd expect
them to be within perhaps 10% of one another. A 6-hour charge ought
to be adequate to ensure full charge even if there are differences
between the cells.

 

Follow the manufacturer's instructions.
Ed

 

almost certainly low end NiCd

lord no, 5 hours is a heavy enough charge already

 

Most of these cheap drills with even cheaper chargers seem to recommend a
stupidly long initial charge. Perhaps they want to make certain the rot
sets in early.

A 5 hour charge type suggests all the 'control' consists of is a series
resistor between an unregulated DC supply and battery, so the likelihood
of overcharging is pretty real.