Veruzend kit and 18650 cells free to local

[Mikebike]

Tried to build a battery and I seem to have failed miserably.

Cells won't charge/discharge evenly. I thought it was the bms so I tried a new bms. Same issue.
My guess is that I must have some bad cells that they sold me from Veruzend when I bought the kit and the batteries together a few years ago.

All new kit, all new batteries. Been sitting for 2 years and battery is holding a charge perfectly. Only known issue is the unevenn charge/discharge on the groups?

Local battery person to come get this and use the individual cells for a proper build.
Will need to cell test each cell as I assume due to uneven charge/discharge to find bad the bad cell/cells??

I don't have the time or desire to deal with it anymore.
Looking to meet other e-bikers in the area for joint rides and building cool stuff.
Will give this battery/kit to someone local who wants to extract the cells and get some use out of them in exchange for a few hours labor/help on my custom van build.

 

[amberwolf]

It's easily possible that the problem is the connections themselves; it has not been unknown for Vruzend and similar style batteries to have such troubles, where some cells in various groups don't make as good a connection as the rest, so the resistance is higher and then they charge and discharge differently than the rest of that group.

 

[Slowpoke690]

True. If the plastic ends aren’t extremely tight and even sometimes if they are you don’t get a good connection. I used the same style and finally got rid of it. Still have my cells and then some. Gonna get me a good welder. Wish I was in Virginia area. I’d take them off your hands. Unfortunately Wilmington nc is a bit far. Good luck with the van tho.
Eric

 

[Mikebike]

Thnks for the replies.
You are bringing to light problems with the Veruzend kit that I had not considered.
It seemed like the connections were good when I built this?
It went together well and I liked the concept.

Making me consider taking this thing apart and testing every cell since there are no locals interested in taking this off my hands.

 

[eMark]

The caps were made to be a very TIGHT fit with the predecessor V.1 Kit. Then the much needed shoulder bolts were included with the V.2 Kit. The cells no longer need to fit so TIGHT in the caps now that the V.2 Kit comes with 8 shoulder bolts that need to be tightened SNUG.

Even though the shoulder bolts seem tight i'd go back and make sure they're really tightened SNUG. I've found that you can tighten the shoulder bolts as far as possible without fully compressing the spring leaf contact inside the caps.

Even so after sitting for two years some of the cells (25r?) could be sub-par. Probably the fault of the BMS not being disconnected when putting battery in storage. Halfway decent chance at least 30 of the 40 cells are still usable. A worthwhile learning experience for a newbie as a 1st time DIY 10s3p build (25r?) ... series, parallel, bus bars, balance leads, etc.

Decided not to use a BMS as i bottom balance the p-groups before bulk charging to 4.10V with top voltage of p-groups always within 15-20mV of each other. After 270 cycles going on the 3rd year with my 10S3P 30Q ("141" & "6T") experimental Vruzend V.2 Kit :thumb: