"Peter Signorini" <
[email protected]> wrote in message news:<
[email protected]>...
> BTW will the battery be damaged if fully charged then
> stored for some months?
No. NiCd and NiMH both self discharge over time - NiCd seem
to lose about 20% a month, NiMH more like 50% a month. This
means if you leave a fully charged battery on the shelf,
after month it'll only be good for 80%/50% of its full
charge, depending on chemistry. This means there's little
point in charging a NiCd or NiMH battery before putting it
in storage.
Lead-Acid batteries, such as used on some Cateye lights, are
different. They do self discharge, but it takes a *long*
time. Leaving them flat causes nasty things to happen to the
chemistry, so *always* charge your Lead-Acid battery as soon
as possible after use.
From a basic charging point of view there's not much between
NiMH and NiCd. Both like constant current. A nominal 2400mAH
battery like I believe the NiMH nightstick is will takes
around 5 hours to fully charge off 600mA, and about 10 hours
to charge off 300mA. The 600mA charger makes it easy to
overcharge - 5 hours on charge for a 50% discharged battery
could easily damage it. 300mA can be left on for longer -
you're unlikely to damage a battery if you only ever leave
it on charge for 10 hours, even if you've only been riding
for a short time. I've no idea what the capacity of the NiCd
nightstick is, but a guess would say around 1800mA - don't
leave it on charge for more than about 6-8 hours, and that's
from empty.
If you don't use your lights much, the standard charger
should be fine. If you're using them all the time it's
probably worth investing in a cheap timer to ensure the
charger is switched off after an appropriate time, or a
decent charger that does this automatically. To work out
charging time, work out how much power you've used, then add
10-20%. Nearest half hour should be fine. For example, say
you've used a 10W bulb for 40 minutes. That's 10w/6V*
(40/60) = ~1.1 amps. You need to put in around 1.2 amps, so
a 2 hour charge is appropriate. Going up to 2h 15m puts in
1.35 amps and will ensure the battery is fully charged, with
a relatively low probability of damaging the battery. I
wouldn't go beyond 2.5 hours.
If you've got an old NiCd charger you're probably better off
using this more often if you've got NiMH batteries. Assuming
you're using them for around 90 minutes a day with a 10W
bulb you're going to have chewed most of the battery. Get
home at 7 and they'll be nicely charged by 7 the next
morning on the 300mA charger. The 600mA will be done by
midnight, which means you need a timer to turn them off or
you've got to stay up and watch Sports Tonight. Eewww.
Dave - who has heard good things about "Maha" chargers,
and uses an "MW1768" charger. Google should find suppliers
for either.
--
Dave Hughes
[email protected] Random miscellany, as
opposed to that other kind of miscellany -- Patrick
Shaughnessy
