Can't parallel charge with ToolkitRC m8

[little_beach]

Hello!

So I've had the toolkitRC m8 for a while and it works fine to charge batteries one at a time.

However I just bought a parallel charging board to speed up the process, but anytime I try to charge with it I get an error message on the charger! (see attached pics)

I saw this page online so it seems that this set up should work, but somehow it doesn't:

https://support.rotorriot.com/hc/en-us/articles/360038734814-How-do-I-use-the-M8-charger-

I opened the parallel board and as far as I can tell, all connections are ok, I think I'm plugging everything in the right place, so I'm really not sure what I'm missing. Could it be that the power supply isn't powerful enough? (see attached pic)

If someone has any clue please let me know I'm sick of charging batteries one at a time haha!

Thank you!

 

[wafflejock]

Couple of things to check. First off make sure each battery is pretty close to the same voltage when hooked up to the parallel charge board, they should be within something like .1V per cell away from each other or around .4V max between two 4S batteries, .6V should be fine but wouldn't push this too much. If the batteries are say 2V off from each other then you're going to have a high amount of current flowing out of one and worse flowing into another, the cells can take discharge at a pretty high current but high current charging (which is what happens when hooking up batteries to a parallel board and they differ in voltage) will cause problems. I prefer parallel boards that have a fuse between the main battery connections so if too much current is flowing it'll just blow the fuse rather than cook the cells (the fuse should also create some resistance which will slow the balancing that'll happen when multiple batteries are hooked in parallel).

If the batteries are close to each other in voltage then hook up just the main lead first and give it a minute or two to "self balance" on the main lead, then hook up the balance wires so the cells can level out between the two batteries. Essentially with the parallel board it is doing some mostly uncontrolled charging/discharging between the batteries when you first hook them up even if not hooked to a charger this is just a natural balancing that happens like hooking a hose between the bottom of two buckets.

Next thing I'd check is the voltage coming off the main lead from the parallel board make sure you see full battery voltage there, then can check on the individual pins of the balance lead (use a wire stuck into the gnd pin for gnd and probe with red on the little metal tabs can see through side of balance lead).

 

[wafflejock]

Here's what my parallel charge setup looks like:

 

[wafflejock]

I use this box/setup for charging all my lipo stuff from 1S for tiny whoops to 5S for half my esk8 battery, when doing two 5S 5Ah in parallel I max out the wattage on the charger itself but otherwise can juice things up at 1C no problem occasionally will do like 1.5C or up to 2C if in a rush and don't care about the life of the batteries hooked up.