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Old Aug 04, 2003, 03:01 AM
Wan
Guest
n/a Posts
Battery flight packs, parallel charging?

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
reconnecting.

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?

Wan
Old Aug 04, 2003, 03:01 AM
Doug McLaren
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

In article <7387603e.0308032016.79b70e66@posting.google.com >,
Wan <wanjung@toast.net> wrote:

| 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
| reconnecting.
|
| 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
time.

Or you could just buy another peak charger. It'll probably cost a
good deal less then all those packs

--
Doug McLaren, dougmc@frenzy.com
"What a waste it is to lose one's mind. Or not to have a mind is being
very wasteful. How true that is." --Quayle
Old Aug 04, 2003, 03:01 AM
Tommy
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

"what you can do is set it up
a harness to charge two packs in parallel."

Don't you mean charge the two packs in SERIES?.

Regards

Tom Watson
Sydney Australia


"Doug McLaren" <dougmc@frenzy.com> wrote in message
news:HClXa.155189$xg5.6473@twister.austin.rr.com.. .
> In article <7387603e.0308032016.79b70e66@posting.google.com >,
> Wan <wanjung@toast.net> wrote:
>
> | 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
> | reconnecting.
> |
> | 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
> time.
>
> Or you could just buy another peak charger. It'll probably cost a
> good deal less then all those packs
>
> --
> Doug McLaren, dougmc@frenzy.com
> "What a waste it is to lose one's mind. Or not to have a mind is being
> very wasteful. How true that is." --Quayle



Old Aug 05, 2003, 03:00 AM
Doug McLaren
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

In article <9HnXa.11238$bo1.2591@news-server.bigpond.net.au>,
Tommy <billbloggs_@bigpond.com> wrote:

| "what you can do is set it up
| a harness to charge two packs in parallel."
|
| Don't you mean charge the two packs in SERIES?.

Yes, of course. Thanks.

--
Doug McLaren, dougmc@frenzy.com
When I read about the evils of drinking, I gave up reading. --Henny Youngman
Old Aug 05, 2003, 03:00 AM
emcook@yahoo.com
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

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
more.

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.


On 3 Aug 2003 21:16:13 -0700, wanjung@toast.net (Wan) wrote:

>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
>reconnecting.
>
>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?
>
>Wan


Old Aug 05, 2003, 03:01 AM
Wan
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

emcook@yahoo.com wrote in message news:<7ntsivo01phlpd00akiq0964enle00met7@4ax.com>. ..
> 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
> more.
>
> 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.
>
>
> On 3 Aug 2003 21:16:13 -0700, wanjung@toast.net (Wan) wrote:
>
> >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
> >reconnecting.
> >
> >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?
> >
> >Wan


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,
Wan
Old Aug 05, 2003, 03:01 AM
Doug McLaren
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

In article <7387603e.0308042039.64b83e02@posting.google.com >,
Wan <wanjung@toast.net> wrote:

| 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?

Yes.

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
the others.

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.)



--
Doug McLaren, dougmc@frenzy.com For adult education nothing beats children.
Old Aug 06, 2003, 03:02 AM
emcook@yahoo.com
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

Like Doug has stated when batteries are connected in parallel they may
not charge equally.

One battery pack could hog the majority of the charging current
resulting in 1 fully charged and 3 partially charged packs.

And you can probably forget about peak detection working if the
batteries are wired parallel.

Charging is series is the only way to insure a full charge.

If you always run the batteries dead during use. You could buy 4 cheap
wall charges and hook them all to an appliance timer and charge the
packs for X number of hours.

Hook them up, set the timer, leave, come back, their ready. No work,
no hassle.


>
>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?
>


Old Aug 06, 2003, 03:04 AM
David AMA40795 / KC5UH
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

The GP Triton will handle 24 cells, so you could charge 2 of your
packs in series. Cannot think of one that will handle 40 cells.

David

On 4 Aug 2003 21:39:42 -0700, wanjung@toast.net (Wan) wrote:

>emcook@yahoo.com wrote in message news:<7ntsivo01phlpd00akiq0964enle00met7@4ax.com>. ..
>> 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
>> more.
>>
>> 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.
>>
>>
>> On 3 Aug 2003 21:16:13 -0700, wanjung@toast.net (Wan) wrote:
>>
>> >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
>> >reconnecting.
>> >
>> >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?
>> >
>> >Wan

>
>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,
>Wan


Old Aug 06, 2003, 03:04 AM
Turd Ferguson
Guest
n/a Posts
Re: Battery flight packs, parallel charging?

emcook@yahoo.com wrote:
> Like Doug has stated when batteries are connected in parallel they may
> not charge equally.
>
> One battery pack could hog the majority of the charging current
> resulting in 1 fully charged and 3 partially charged packs.
>
> And you can probably forget about peak detection working if the
> batteries are wired parallel.
>
> Charging is series is the only way to insure a full charge.
>
> If you always run the batteries dead during use. You could buy 4 cheap
> wall charges and hook them all to an appliance timer and charge the
> packs for X number of hours.
>
> Hook them up, set the timer, leave, come back, their ready. No work,
> no hassle.
>
>
>
>>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?
>>

>
>

The Astroflight 112D can charge 1-40 cells. $149.95 at:
http://www.astroflight.com

 


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