Another Lipo thread

[jhautz]

Originally Posted by squeeforever

You can make a Y connector and charge them in series so it will only take 1 hour.

That assumes that the 2 packs are ballenced to each other pretty close to start with. That would increase the chances of overcharging a pack, wouldnt it?

[coolhandcountry]

I would make a y and charge in parrellal. that away you have the same in each pack. Start slow and then bump to a 1 c charge. I like this idea for it keeps the batteries the same for running in series. JMO

[jhautz]

:002: :002: So by chargeing in series it will ballance the sells from pack to pack? Then whats the point of the balancers? I thought that the balancers were needed because they batteries would not equalize to each other when charged in series.:002: :002:

[jhautz]

It doesnt matter anyway... The charger I have is only capable of chargeing 1s, 2s or 3s Lipos.

[coolhandcountry]

Balancers do a cell to cell in the pack.
I charge mine in parrlellal so the packs come out to the same voltage. I wouldn't try this with the nimhs but they charge differently.

[Batfish]

Charging multiple packs at the same time with one charger can indeed be accomplished, but you should take precautions.

1 - NEVER charge packs of different manufacturers or different capacities together with one charger.

2 - Make sure the cells in each pack are balanced to the SAME voltage before the first charge. NEVER charge packs where the cells are at different voltages.

3 - Make sure that your charger can handle whatever configuration the packs equal when putting them together. If you're charging a 2s1p 2000 pack with a 3s1p 2000 pack in series, make sure your charger can do 5s charging at 2Amps or less.

4 - Regularly balance the packs to keep them safe when doing the multiple-pack charge.

Here's an example:

A. I have two 3s1p 3200mah lipo packs that I want to run in parallel. This means I am running the equivalent of 3s2p 6400mah.
B. I balance both packs individually during a charge to bring every cell to 4.2 volts.
C. I plug the two packs in parallel and run them in my vehicle. At this point, the cells will still be balanced (or very, very close to it) because they are all pushing the same amount of power to the vehicle.
D. After the run, I keep the packs plugged in parallel and attach them to the charger, then begin charging at 6.4Amps (3200mahx2=6400mah=6.4A).
E. After the charge is complete, go back to step C.

Repeat steps C through E a few times, then go back to step B and re-balance. You do not have to re-balance every time you charge as long as you are using the packs within their stated parameters. Don't charge to more than 4.2V per cell. Don't run below 3.0V per cell. Don't let the packs heat up (run within the amp rating of the pack). When lipo packs are initially balanced, then used properly, the cells will very rarely go out of balance during the usable life of the pack.

Remember, as always, the risk of using the technologies we talk about here lies solely on the user. Make sure you excersize sound judgement and make informed decisions on everything you do, including these sometimes potentially volatile toys we like to play with. :003:

[jhautz]

Awesome info Thanks alot!!! I didn't know it was OK to charge Lipos in parallel like that.

Now I have one more question. I run 2 pack setup in series, not parallel. I have 8000mah 3s and 8000mah 2s pack (same cells, same manufacturer) that I run in series for a 5s configuration. Is it OK to charge these packs in a 5s series configuration? In the example you have above you were using a parallel configuration for discharge and charge.

[Batfish]

Originally Posted by jhautz

Awesome info Thanks alot!!! I didn't know it was OK to charge Lipos in parallel like that.

Now I have one more question. I run 2 pack setup in series, not parallel. I have 8000mah 3s and 8000mah 2s pack (same cells, same manufacturer) that I run in series for a 5s configuration. Is it OK to charge these packs in a 5s series configuration? In the example you have above you were using a parallel configuration for discharge and charge.

Yes.
You would balance both the 2s and 3s packs INDIVIDUALLY in an initial charge, run them as a 5s (series) in your vehicle, then hook them up as a 5s to your charger.
In your specific case, your charger needs to be capable of charging a 5-cell lipo, and you'd be able to charge at up to 8Amps.
You should also make sure, for safety's sake, that you re-balance your packs every few charges.

FYI - In regards to your second statement, "I didn't know it was OK to charge Lipos in parallel like that." : your packs are already parallel, I believe. The lipo packs you are using are 2s2p 8000mah and 3s2p 8000mah, correct? If so, you are already doing what I showed in my example - your packs are parallel in their packaging, whereas my packs were paralleled by my own wires.

[jhautz]

So it would be worth t for me to upgrade to the new TP charger. I could charge both packs in only an hour.

[Nick]

jhautz, the thread invader. :005:

[jhautz]

Originally Posted by Nick

jhautz, the thread invader. :005:

sorry. my bad...:007: :032:

:010: