Re: Problem charging flight packs
- From: "Chris" <chris584163@xxxxxxxxxxx>
- Date: Sat, 4 Mar 2006 15:00:21 -0500
Hi Earl,
What battery chemistries do you have? (NiMH, NiCd, LiPo...). Also, what
are the voltage ratings and capacity ratings of the packs that you want to
maintain? Based on this information, suggestions of what current would be
considered "fast charge" can be made.
Volts is the unit of measure of electrical potential difference and is
specified on the battery pack based upon then number of individual cells in
series connection (positive of one cell connected to the negative of the
next and so on). Amps is the unit of measurement of the flow of current
(power delivery to the load). Watts is the unit of measurement for power,
like horsepower, which is actually 746 watts, but I digress! Ah (amp hours)
or mAh (milli-amp hours) is the rating of a battery cell or battery pack of
its capacity, C. In a perfect world, a battery pack rated at 600 mAh and
4.8V would deliver 4.8V at 600 mA for 1 hour.
If a battery pack has not been used for a while, or is brand new, it
should be charged at a very low rate (i.e. C/10) for about 16 hours. In the
600 mA NiCd pack example above, this would be 0.06A or so. Once this is
done, a battery pack might need to be discharged and then recharged 3 times
(cycled 3 times) to come up to full capacity. On a charger like yours, it
would be helpful to note how many mAh were take out of the pack on the last
discharge cycle. Many agree that this number should be 80 or 85% minimum to
consider the pack in good health. During the flying season, you may find
that you want to quick charge a battery pack to get in the air quicker. The
maximum charge rate varies depending on what chemistry, capacity, and model
number of the cells, but fast charge is often .5C (~ 2 hour charge), 1C (~ 1
hour charge) or in some cases even faster. Some packs should not be charged
anywhere near this fast.
A good reference with tables and graphs is at:
http://www.hardingenergy.com/techmanual.htm
Chris
"Earl Scherzinger" <please.post@xxxxxxxxxx> wrote in message
news:%naOf.144$sp4.101@xxxxxxxxxxx
I should have payed closer attention in Radio/Electricity class in school,....
because now I need help.
I recently bought a Accu-Cycle Pro Series Elite charger from Tower Hobbies
and I'm having difficulty undestanding Volts/Amps/mAh and charging rates
for a variety of flight packs.
Can anyone suggest a chart or formula for 'safe charging', 'quick
charging' and 'cycling' battery packs?
I have back-up batteries for my transmitter and receiver, but I would like
to charge one set of batteries while flying with the others. This would be
a field 'quick charge'.
Earl
.
- References:
- Problem with GP Triton - NIMH Battery
- From: Massimo
- Re: Problem with GP Triton - NIMH Battery
- From: Abel Pranger
- Problem charging flight packs
- From: Earl Scherzinger
- Problem with GP Triton - NIMH Battery
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