The battery builders club

This big boy.
(Haven’t actually charged and used the plug tho, 1/2 way through my build still)

@glyphiks is a bad influence.

2 Likes

What do you need?

yeah its fairly easy.
V (voltage) = I (current) * R (resistance)
so this means I = V/R

So lets assume were going to connect a full 30Q at 4.2V to an empty one at 3.2V

A new 30Q has an internal resistance of around 20 mOhm or 0.02 Ohm and there are 2 of them in series. Voltage difference is 1v.

V/R = 1/0.04 = 25A.

The problem with this video is you dont know what resistance these (probably recycled) cells are.

Wiring these 2 in parallel will give an observed voltage of 3.7V. Does this need to be factored in?

Found a helpful post which agrees with you @ducktaperules :slightly_smiling_face:

2 Likes

I routed balance leads through a “waterproof” connector here. These were 25mm and soldering was tricky. not awful looking, definitely keps water out, works well.those smaller connections look trick

6 Likes

oh yes. This is what I want.

Also my battery drained itself overnight to 8v, I left it on btw…

Its officially useless. I wonder what could have caused it, anyone have any suggestions? Im not too bothered about the whole situation since the battery was a 10s2p 30T but would be nice to get to the bottom of it.

The battery has been through about 30 cycles and has always been balanced afaik

How does this not short your battery? You have 12s split into the same dual 6s charger?

So this is one of the few pics I took before poofing half of that duo charger (RIP). It works fine as long as you sever the 6s to 6s series connection (that’s what that massive thermal breaker switch is supposed to do). If you forget, you instantly short out one side of the charger (edit: @whaddys, lol) . I did this twice already, @Arzamenable you know what I’m talking about. So beware.

The upside is that now all of my duo chargers are singles now and you can charge both sides at the same time with separate chargers without separating the 2 6s packs.:man_shrugging:

2 Likes

Someone mentioned building without a breaker switch .

if you have two independently grounded hobby chargers, or if you only charge one side at a time, no split nessesary

2 Likes

How do you split the 12 leads into 6 and then also, how do you know which of the 12 groups have been split into the 6?

Is it safe to make my series connections with one long strip of copper braid like this? Assuming I isolate between the rows of course

How exactly would that work? You have to connect to both ends of each battery

1 Like

Could you not have a loopkey that separates the two packs with a 3d printed cover on the loopkey which covers the two balance/charge ports when it is plugged in? This way it will be almost impossible to forget to separate the pack.

1 Like

haha, yeah some kind of mehanical lockout, for sure. but…

  1. I don’t have a 3d printer or CAD skills other than in Paint.
  2. By the time I got around tl thinking about it, all my duo’s were poofed and that was that, lol

Also, what happens if you turn on your board while balance charging both batteries? would it power on?

Sorry, like this

I think I would do 12awg actually instead of copper because I want to make it flexi

Edit: I suppose I’d have to break up the connections. Nm. Don’t mind the noob

lmao I was like bro you’re gonna have an explosion on your hands shorting out the packs

2 Likes

:joy::joy:still learning over here hahah