How do I charge a Zippy 8s that has 2 balance leads?

I don’t have the stuff to make a custom balance/charger wire.

This battery seems to be just two 4s wired in series. So maybe it’s easier to just split it into 2x4s by de-soldering the bridging to series and solder a new main line wire to each pack.

Picture is ugly but hopefully you’ll catch my thoughts.

That sounds even better. Soldering the tabs can suck though. I haven’t tried aluminum solder though which I’ve heard of here

Could I solder a new main lead in the middle here, right on the bridging? And then when I charge the left pack as 4s I’ll use the new main lead as negative and when charging the right pack I’ll use the new main lead as positive?

Highly unconventional, I know…

why not just add some cables as 4S mains? so they are color coded correctly - otherwise this is destined to end in a disaster. We are talking about 4 thin wires - that should be super easy.

You’re absolutely right. I have to do some work now, but I’ll keep you posted.

I tried my hand at soldering some new mains on my lunch break. But I couldn’t get the tin on the old mains to melt at all. Probably my soldering iron is to weak.

Last summer I broke three 3s lipos. One cell each one. So I took apart them and made two 3s. Piece of cake just with, 60W solder iron, tin, scrissors and tape. Just remember to mark positive and negative to cells.

This is what I ended up with. Now I just need to figure out how to re-attach the balance lead and new main leads to each pack.

The balance leads were already in the right spot for (2) 4s packs I thought. It’s hard to see exactly where wires are in this photo.

Maybe you’ll get lucky soldering the tabs but in my experience sometimes they take lots of heat (quickly so u don’t damage the cells) and I used lead solder. Probablt the aluminum specific solder is better.

You could skip the soldering and make compression connections with some kind of clamp and electrically conductive paste and not risk cooking the cell. They can be even better w lower resistance if done well.

you need aluminum soldering paste. I’ve done this, with the paste it is a lot easier. I think @barajabali has a tutorial for this. The one lowguido posted above.

you can charge it like this:

If you’ve already gone through all this effort, I would split the 4s packs in half again to make a flat pack (but don’t break the wiring, if possible). They would be much thinner

Yes, that is a good thought, however, my biggest problem now is that I can’t solder new wires to the nickel-strips because I don’t have any aluminum solder paste and it seems impossible to find in Sweden. I’ve found SOLDER-IT like @barajabali used on ebay for $10 with free shipping, but I would love to find it somewhere locally so I don’t have to wait 7-14 days.

Hope your silence isn’t because your place burnt down.

$40 charger at 7amps up to 8s lipo

Nope, I’m still alive :slight_smile:

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still using that zippy?

It’s on the shelf at the moment. But it works just fine as 2x4s

I just substituted an 8S balance plug for the two 4S plugs using a posted video of the procedure to do it right. It was very easy to do but you had to be careful to not touch any two leads together. Taking apart a LiPol pack is a bad idea. Splitting it into two 4S packs makes no sense when what you wanted was an 8S pack and can be dangerous if you short circuit a wire in the pack. Amazon has the 8S leads, 10 for about $9