How to charge two 2S batteries simultanously with Accucel-8?

[Pekka L]

I have not found a adapter for charging two 2S (identical 4500-5000mAh) batteries simultanously with Turnigy Accucel-8.

There is adapters aveilable for two 3s batteries thou... Is there some more simple way to connect two 2s batteries to the charger and that is why I have not found any adapters or what?

I know that it won't really speed things up because the 150W limit, but it would make charging one 4S set easier and more simple.

[JimClark]

everything you need right here

http://www.progressiverc.com/adapter-cables-and-boards/parallel-cables.html

You need JST-XH for the Turnigy charger

[JimClark]

So you need one of these

http://www.progressiverc.com/parallel-2x-balance-adapter.html

And one of these

http://www.progressiverc.com/parallel-t-plug-adapter.html

depending on what connectors you are using

[mdunham]

you could also try checking out Wizard 122's thread
http://forums.offshoreelectrics.com/...ad.php?t=14054

[785boats]

Pekka.
I have the Accucell8 charger & regularly parallel charge pairs of 2s & 4s 5000mah packs on it. It is quicker than charging packs singularly.
All you need is a parallel adapter for the main power leads.
The balance plugs Just plug into the ports on the side of the charger.
The 2s plugs will easily push into the 3s & 5s ports. All the pins are paralleled inside the charger. For the 4s packs I simply use the 4s & 5s ports. Obviously the left hand locating tab does not line up but a little wiggle & the plug will slide in.
Just make sure that the negative (black) pin connects to the extreme right side pin in the ports.
And ALWAYS connect the power leads together in parallel BEFORE connecting the balance leads. This allows any out of balance voltage to equalise through the power leads so that any current flow won't flow through the balance wires & pins. They are only rated to 3 amps & if the pack voltages are too dissimilar higher current than that can flow for a few seconds.
All the best
Paul.

[Pekka L]

But would it be better to charge two 2S pacs in series, so charger can "see" all cells independently and balance those correctly?

Or do you trust that two cells parallel will balace them selves when connected parallel and charged with low current? It should work as long as the cells are in good condition, but if there is one that is damaged it could damage the cell connected to parallel with.

Also if I charge 2S with 7A(max current) = charging power is (8,4Vx7A) 58,8W max. But when charging connected in series as 4S max charging power would be double (16,8V*7A) 117,6W and batteries would be ready faster.

Currently I already charge my batteries with 7A. If I connect battereis parallel it will take about the same time to charge them as it does now. Only improvement would be that I don't need to change to the second battery when first is full.

[JimClark]

You can charge paraelell ad still balance that is what one of the cables I showed you are for

[Pekka L]

I don't need to charge them parallel, it doesn't make it any faster...
Series would be nice.

[JimClark]

Parelell is safer

[Pekka L]

Why?

Charger will monitor every cell independently when charged in series...

I'm just a simple electronic engineer, so I don't understand everything.

[JimClark]

This will explain better than I can

http://www.rchelicopterfun.com/parallel-lipo-charging.html

[Pekka L]

Still it is not really speeding up the charge process for me.
I'm already charging one battery with the maximum current output my charger gives (7A).

Only way to really speed this up is to charge two 2S batteries in 4S configuration with the same 7A current, but of course with double voltage. So basicly I would charge two batteries in the same time that it takes to charge one now when chargen separatelly.

Connecting two pacs parallel and using the same voltage and still the same max current charger can give will double the charging time (same time per pac than now).

Now I'm using only 7Ax8,4V=58,8W charger power to charge my batteries. This would not change when charged paralle (same voltage and current at max). In series this would be doubled and I could utilise better the capasity (150W) of my charger.

[LarrysDrifter]

Why?

Charger will monitor every cell independently when charged in series...

I'm just a simple electronic engineer, so I don't understand everything.

Nobody cares about what you do for a living. Jim is trying to help you do something in the safest way. No need for sarcasm.

[Pekka L]

I'm not lookin for the safest way.

[785boats]

Pekka.
As an electronics engineer you would have easily understood all that information in the link that Jim posted. (nice one Jim) I assume you read it all?
It is the best way to charge multiple packs, and the safest. Why don't you want the safest way?

Also if I charge 2S with 7A(max current) = charging power is (8,4Vx7A) 58,8W max. But when charging connected in series as 4S max charging power would be double (16,8V*7A) 117,6W and batteries would be ready faster.

It doesn't work like that. When you have them in series you have twice the capacity to put into the pack so it takes roughly the same amount of time. But you still have to charge the second pack at the same amount of time when doing them individually so yes, charging in series will be shorter than charging two individual packs.
Charging in parallel with the max current of 7A is some where in between. Longer than a 4s pack, but shorter than individual packs.
Each pack will be getting a charge current of 3.5A for the first part of the charge until they reach constant voltage (8.4V).
I think you'll find that parallel charging multiple packs is the more common way to do it, but if you are bent on series charging give it a try & let us know the results.
Another option is to get another charger & do each pack on it's own charger at the same time.
Cheers.
Paul.