Thanks for that useful insight.
Hi, What software did you use to create this schematic diagram?
Microsoft Visio. It isn’t specifically geared towards this kind of stuff but very flexible.
Which other programs do you recommend?
MS Word and MS Excel 
Google Sketchup.
AutoCad LT.
If you wire the charge connector directly across the red and black wires on the 6s balance connector, you don’t need to connect the power connectors on the packs at all and there’s no chance of frying anything.
Of course, this means you are supplying the charge current through the balance wires, but they can easily handle 5A,and it’s unlikely you’ll be charging at a higher current than this for 3S packs.
(You will need to join the red & black leads on the 3S connectors though, as per @trbt555’s original schematic).
Hahaha this diagram is actually what I needed a month ago before I made some crazy fireworks and damage my connectors as well 
Nowadays I always check with multimeter the way I plugged in my batteries and use permanent marker to mark them so I didn’t plug them wrong. But I understand the idea that positive end of the battery must go on the positive side of the balance lead and the negative end of the battery has to go to the negative side of the balance lead!
How do you know that the balance wires can handle 5a? I’m considering trying this myself
Look up ampacity for copper conductors. The max amps you can safely put through a certain cross section of copper wire depends largely on how hot it can get (how hot the insulation can get without melting). I don’t know the cross section of your balance wires but I suspect max allowable current will be well above 5A.
If you’re really worried you can try to charge one of our lipo’s (without balancing) through two wires with the same cross section as your balance wires. If they don’t get hot, you’re good to go.
@Link5505 - if you don’t want to build your own, you can buy an adapter on eBay that is wired exactly as per my diagram: http://www.ebay.com/itm/Lithium-Lipo-Battery-Balance-Charger-Twins-Adapter-Charge-For-2x3S-Cells-/172181822194?hash=item2816d61af2:g:zwUAAOSw4hdXIDvC
All you have do do is make (or buy) a set of charging leads that connect your charger power output to the Deans plug on the adapter.
Whenever I do this i get a big spark. I’m using turingy 20C 3S 5000mah lipo’s. the ballance wires are : red - yellow - white - black
I did the charge leads first. Then I started to do the ballance leads, but I get a spark whenever my red and black wires touch. This only occurs if the charge leads are connected.
your JST leads are back to front…
and that Diagram probably would have beat mine in the beautiful diagrams comp.
yea, I saw it too just now as I was looking at @trbt555’s diagram and thinking of what i could have possibly done wrong. Silly me.
I did exactly the same thing but sometimes my charger says: error Input voltage. What does that mean and how can I fix this?
Either your Voltage of at least one cell is to low or you want to charge 6S while you have a 5S battery attached.
I have two 3s lipos in series but it could be that one balance charging pin is burnt
@lowGuido I remobed the #4 black wire on pack #1 and charged like I think you say in this post, BUT when I plugged everything in my charger started smoking. The only way to make it work was to use both the Negative #4 on pack #1 and the Positive #1 on pack #2 Thoughts?
sounds to me like you just messed up the order the first time. The order in the balance wire needs to reflect the order of the batteries. You probably just paid more attention the second time and connected them properly.
I guess it is possible… However I tried it 2x and triple checked before I plugged everything in. Also while plugged in the balance charged detected 5 cells… Does that mean it was backwards?
If it started smoking then you hooked it up wrong. That charger is probably damaged now. you would have fried the resistors on the ballance connections.
You need to make sure every cell is in the correct order.