Electrical problem

I did my run up this morning and all was well until I pushed past about 75% throttle. The display on the throttle showed a rapid decline in voltage all the way to zero then the machine shut down. After that there was no power until I waited about 5-10 mins then again the same thing happened.

I should also note that I was using 4 of these batteries here https://m.alibaba.com/product/60775263631/China-Rechargeable-22-2V-22000mah-6S.html?spm=a2700.galleryofferlist.normalList.181.2b36715fYjtTLg&redirect=1

Nice price on the batteries. Hoping that wasn’t the problem.

Check the batteries after the drop with a voltage checker… that will confirm if it’s the batteries or not. Sounds like a problem with the PCB to me. Can you feel the board for heat immediately after shutdown?

Do those batteries have a balance connector? If so check the voltages of each cell.

Ok here’s what happened. One of my solder joints was bad and caused me to be running off of one of the pairs of batteries so I was only using 2 batteries. I checked the batteries and the charger says, “battery disconnect” the charger also shows one of the cells going to 0V then back up to 5000mv and nearby cells are at 5000mv

Are you talking about your own solder joints in your wiring or inside of the batteries?

In my wiring. One of the brass bolts on the pass through connectors came unsoldered. This cause the system to run on 2 batteries. And after I fixed that I ran it on 4 I went to a higher power this time before failure.

I don’t know what’s going on. My smart charger reads 5s and reads “error battery disconnect” same as when I don’t plug in the main terminals. Then if I quickly start charging and switch to the view of each cell one cell becomes 0v and then jumps up to 5v as well as a cell or 2 next to it that read 5v the entire time. What could this be?

You should measure the resistance of each cell…
My newer batteries are 1.6 to 2.1 mOhm each cell - this is when they are new.
The 2 year olds I own are 1.8 to 2.5 and one cell has 4.5 resistance - still no problem.
If one cell has more than 10 mOhm resistance than it is time to say goodbye!

Every time I charge my batteries I note the resistance of the cells for each pack and put it in my notebook! If you look at the resistance history of your cells you will know when they are going south.

The overcharging of cells can only happen if you manually bulk charge 6S batteries and
not balance charge. If one cell is bad the charger don’t care and just charge 5 cells to 25.2 volts.

This sounds like you have these batteries:

Hope it will work out for you!

My smart charger won’t charge or discharge them anymore. I charged it to 4.2 v per cell and now some of them are at 5v the cells I bought said they were 25c I’m thinking I should go with bonka now

This is my order invoice for 8 new bonkas are these the right ones? They’re much cheaper. Do I need to specify that they will be used in 2s2p up to 2s4p?

Here’s what it did

one of the tabs used to solder the packs together burned like a fuse.

That tab looks like a clean cut in the picture. You think it looks like it melted in person? Perhaps it was making and breaking contact while in use and charging. Are the others like that?

It looks like a weak point. It’s exactly on the 90 degree bend. I think the others will be the same I want to try for a refund before I open up the other packs. My guess is the bend used in manufacturing weakened the piece of sheet metal used between the tabs. This bend couldn’t handle the high current and melted. I don’t think it came back together as there was a small amount of separation between the two pieces of metal.

Hey Paul I got up and running. Thank you again for everything. Would you mind printing out a few things for me again?

Sure! PM me what you need.