Charging multiple glider batteries

Vaughn wrote, On 1/7/2014 6:11 AM:

Hint: Because the capacity of a battery decreases over time, one symptom
of a bad battery you might notice is that it takes a charge much quicker
than a good one.

A weak battery, unless it was run completely flat, will take just as
long to charge as good battery that was discharged the same amount. You
have to replace the amp hours you took out, regardless of the capacity
of the battery.

What tells you your battery has lost capacity is it won't power your
instruments as long as it used to, or the voltage is significantly lower
after a flight than when it was new. You can also do a discharge test to
determine the capacity, using a resistance and a voltmeter (cheap), or a
device designed to do it automatically ($50-$150 range for that).

Regardless, considering the low cost of a decent 800 ma charger, I'd go
the "one charger per battery" route.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

On 1/7/2014 10:04 AM, Eric Greenwell wrote:
A weak battery, unless it was run completely flat, will take just as
long to charge as good battery that was discharged the same amount. You
have to replace the amp hours you took out, regardless of the capacity
of the battery.

OK, I should have said "A flat bad battery will charge quicker than a
flat good battery" precisely because you need to put fewer amp hours
into the bad battery before it is fully charged.

What fills quicker from the same tap, a large cup or a shot glass?

I have heard many folks say something like "that battery must be good
because it takes a good charge in no time at all."

Vaughn