3 x 3s batteries wired in series how to balance charge them

[alex jones]

Hello, I have 3 x 3s lipo batteries wired in series and I want to balance charge them all at the same time. I know that I would need to buy a 10s charger...but when it comes to the balance boards or a 3 battery connector specifically for batteries wired in series I'm getting stuck.

I know you can get a 2 x 3s charge connector...has anyone ever seen one for 3 batteries?
If such a thing does exist how would you plug in the balance leads from 3 batteries in order to avoid shorting out the charger etc. (Yes those pesky little black wires).

Can anyone on here help me and point me in the right direction please.

Idearly I would like to charge my batteries in situ in side my longboard just using a xt90 connector and 9S? balance connector.

Many thanks for your time should you choose to answer the above question. I appreciate it.

(So I'm right in saying that 3 x 3s batteries wired in series = 9s
...and 3 x 3s batteries wired in parallel = 3s)

 

[Ykick]

What I gather from your description, you can either configure as 3S3P or 9S1P total pack configuration?

For my RC Lipo eBike packs I’ve learned to safely balance large/long series strings of 10S-16S, by charging individual cells that may fall behind the others. That requires careful monitoring and understand of what the cell voltages mean.

You'd need some gear like a small balance charger, perhaps a CellLog or some other version cell voltage checker? Maybe a way to apply a little load to burn off excessive voltage of the entire pack or just individual cells, etc?

Or, you get into a 10S balance charger (expensive) and PITA to sort out all the various balance connectors used in those situations. Not easy, cheap or fun, IMO….

 

[motomech]

http://www.ebay.com/itm/281826764755?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

9S can be a good configuration for many 36 V controllers, it matches their 31 V Low Voltage Cut-offs.

But if you are doing 3S/1P and the bricks are not at least 5000 mAh, you are wasting your time.

 

[dogman dan]

What you want to do should be possible. But there are so many ways to do it,, so many right ways, so many not so right,,

It's the beauty of RC packs, and the ugly at the same time.

But worth noting, some of us just found it easiest to go easy on the pack in the first place. This leaves us able to bulk charge the whole thing most of the time. But we don't need a balance every ride. So you'd need a 36v lithium charger that can have the voltage adjusted to do that,, most of them will be set to 10s.

Then just use a balance board, single cell charging, or whatever for balancing purposes.

Since many tools for this are 6s, but you can plug most of them into one section or another of the 9s plug to check voltages, or hook up to balance, as long as the device has bare male pins. ( cut away any shrouds in the way)

The wiring of the 3s to 9 s is fairly straightforward. Each pack has 4 wires. on the middle pack, the last wire (the +) of the first pack combines, a y connection into one wire, with the first wire of the next pack. then same thing to add in the last pack,


So your buy it list for this approach would be a 36v bulk charger, a small 50w RC charger, a cellog 8, and a 10 pin female jst plug with wires attached. You could buy a balance board instead of the charger, but I think in the long run you will find good uses for at least one RC charger, even if you rarely use it, you will need it once in a while. I find single cell charging the easiest, fastest way to balance a pack to full. Balance boards next easiest.

so in the end, you have a 10 wire plug, the first wire the - and the last wire the +.

 

[wesnewell]

Quick crude drawing.

 

[ron van sommeren]

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