Lipos cells

[Frank Dalby - Smith]

Any chance the mag could produce an article on the Checking of Lipo's individual cells with a digital meter. It is not clear to me how the various manufactuers cells are wired to the many different types of plugs availble. Are the various in line balencers interchangable with different manufacturers packs????? This information would be most useful.

[RCM&E]

Hi Frank – thanks for the input. I'll mention it to Graham (RCM&E editor) and see what he thinks. In the meantime, does anyone else out there have any advice for Frank on this subject?

[Tim Mackey]

Frank. The various lipo packs unfortunately do have different wiring codes and plugs on their balancers. You will however find that ususally, irrespective of colours, one "end" wire will be either negative or positive of the first cell, with subsequent wires being the opposite terminal of the same cell, and so on. Take a typical 3 cell pack -(3s)
lets say the plug has 4 terminals - forget the colours.
start at one end, apply the -ve tip of your M/M and then touch the pin of the connector next to it with the positive probe. You will likely see 4.2V ( assuming pack is charged ). If you see -4.2, reverse the MM leads.
So assuming the polarity of this first celll checking was correct IE first pin was negative, and second was positive, that is the first ( or last it doesnt really matter ) cell of 3. Now...the positive probe of the mm is on the positive terminal of the first cell, AND the negative terminal of the second, so take the mm negative probe, put it on that second pin ( negative of the second cell remember ), move your mm probe to the 3rd connector pin, and this should read 4.2V, meaning that this is the second cell in the pack. Get it ?/
Continue like this, until you have established the series wiring of the pack.
It helps to make a note of things as you go along.
These days, I use just one balancer ( F.Power ) for ALL my packs, and I have cut off the original balance plugs 1 LEAD AT A TIME to avoid shorts - and refitted the matching F/P connector , wired up so as to fit the findings as above. Just do the same procedure for your particular balancer plug requirements. HTH

[Bladerunner]

Make sure the vendor that sells you the balancer can supply an appropriate socket for your battery pack. Alternatively there are now modules which provide multiple-socket adaptor boards to solve this very problem. I would not recommend purchasing lithium battery packs without a balance adaptor of some kind.

[Frank Dalby - Smith]

Thanks for the advise. I think I have got it but it would be very helpful if you could show a diagram. I think also that it proves the point that a full article in the mag with wiring Diagrams and photos would be most welcome. Iam sure that many others would benift to.

I have tried to upload a diagram as an interpritation of your explination but could not make it work.
safe flying

Frank

[Tim Mackey]

I am also having a few problems uplodaing certain files...send me an email and I will return one with diagram.

[Martin McIntosh]

I have devised a simple-ish method of reconfiguring 3s packs so that they can be charged with the cells in parallel, i.e 640 3s1p charged as 3p1s @ 2amps. Requires 2x 3 pin servo plockets and 2x 2 pin shorting plugs. this gives you a balanced pack every flight, with 1 hour charge. Interested? Contact me.