| Here is the situation. I have 4 battery power packs, 10 - 3000 MAh sub
| C cells at 12 volts. I normally charge them one at a time at about 4.5
| Amps for about one hour. Then when one is peaked, I have to replace it
| with another pack and wait for an hour for it to peak.
| Repeating this 4 times and I have put in about 4 hours to get them all
| fully charged. This is kind of labor intensive, disconnecting and
| I wonder if I could wire a harness to accept all 4 packs in parallel.
| Then would it take about 4 hours to fully charge them without
| deleterious effects on each pack?
It won't work properly. The problem is that each pack will have
slightly different internal resistances and voltages, so when put in
parallel, one pack will get charged more than the others, and it may
not even peak properly, grossly overcharging one of the packs.
If your charger can handle over 20 cells, what you can do is set it up
a harness to charge two packs in parallel. Your charger will then
shut off when the first pack peaks, so if both packs are approximately
equally discharged, both packs will then be approximately charged.
You can then peak each pack at a lower rate if you need to make sure
that they're completely charged.
It's not perfect, but it'll get your packs mostly charged in half the
Or you could just buy another peak charger. It'll probably cost a
good deal less then all those packs :)
You would probably get better results if you could wire multiple packs
in Series for charging. That is if your charger can handle 20 cells or
Your last statement sounds like your wanting to cycle each pack 4
times, and finish in 4 hours.
If a Ni-cad pack is good for say 1,000 charge cycles and you cycle
them 4 times after each use. Then you will only get 250 uses from each
pack before all the charge cycles have been depleted.
Unless you meant you would like to be about to charge all 4 packs in
about 1 hour.
I realized my statements above do sound confusing, especially the
second paragraph. By "Repeating this 4 times", it was meant to say if
I charged each pack about an hour apiece. Since I have 4 packs, I'd
need about 4 hours altogether. I hope I have it right.
I also forgot to mention the packs are composed of 10 cells of NiMH
3000 mAH cells and my charger can charge 1 - 14 cells. I've been
charging each pack at about 4.5 amps.
I am wondering if the packs were to be hooked in series, wouldn't that
make four 12 volts packs into 48 volts? And if four 12 volt packs are
in parallel wouldn't it still be 12 volts?
Thanks for helping,
| I am wondering if the packs were to be hooked in series, wouldn't that
| make four 12 volts packs into 48 volts? And if four 12 volt packs are
| in parallel wouldn't it still be 12 volts?
But as I mentioned before, in parallel you can't be sure that each
pack will get an equal amount of charge. In series, you can -- each
pack will have exactly the same number of amps go through it as all
If you had a charger that could put out 60+ volts you certainly could
put all four of them into series, but I'm not aware of any standard
peak chargers that can do it. My Triton charger goes up to to 24
cells, and my Astroflight 110D can do 18 cells.
So, if you've got a Triton, you could charge two packs in series. An
Astroflight 110D, only one.
Also note that putting all four packs in series will give you up to 56
or so volts. The OSHA starts getting worried at 50 volts. It's
extremely unlikely that a mere 50 volts could kill you, but it is
possible under the right (er, wrong) conditions.
(On the other hand, if you short out 60 volts worth of packs, it'll
melt down fast and can very easily burn you or start a fire. But
that's true with just one pack as well.)