Extreme Team issues - post here

[augiedoggy]

Either they somehow are bad cells or you werent actually on the correct leads for positive and negative of each cell...
Also this may seem obvious but be sure to test your meter.. It would be an expensive mistake to ditch the battery pack only to find out your meter or leads were bad or not set up correctly. my good fluke meter in my work toolbag recently failed me and I was getting some seriously screwed up readings.. had to disassemble and resolder my lead jacks to the main board to fix it. I suggest testing it on a 9v or even some AA batteries to make sure your getting the 1.5 and 9v DC there..

[Pat911]

Batteries could be toast but let’s do some diagnostics first. Something is not right. The dash meter shows 86v but you’re getting some cells at around 0v.

Use your multimeter to check the real pack voltage, from the positive and negative terminals of the battery, before the BMS. So the main pack positive and B- on the BMS.

You have connected the BMS correctly? B- to battery negative and C- to the cart.

Make sure your multimeter batteries aren’t flat.

[jonr3]

Originally Posted by Pat911

Batteries could be toast but let’s do some diagnostics first. Something is not right. The dash meter shows 86v but you’re getting some cells at around 0v.

Use your multimeter to check the real pack voltage, from the positive and negative terminals of the battery, before the BMS. So the main pack positive and B- on the BMS.

You have connected the BMS correctly? B- to battery negative and C- to the cart.

Make sure your multimeter batteries aren’t flat.

I'll be the first to admit that I know practically nothing about lithium batteries, but I don't understand how a 1-year-old battery could be toast - especially since it had a 70% charge when I parked it (and put the cart in "tow") and about a week later it's dead?

I've got the battery back on my work bench and removed the lid, but that's as far as I've gotten. I was too pissed to even want to look at it, if you know what I mean. I even sent an email to Extreme Team telling them to send me a certified check refund for their POS battery - HA! Like that will ever happen.

I'm going to put some fresh batteries in my VM and check the leads again as well as the + and - before the BMS. I'm 99.9% certain that I wired the BMS correctly, but I will check everything again.

Quick questions though: How difficult is it to rewire each of the cells using the new leads that came with the BMS?

[Volt_Ampere]

Measure your cells directly with your DVM before doing anything else! A defective BMS can drain your batteries over time. Cells won't self discharge so if they are dead, something discharged them.

[jonr3]

Originally Posted by Volt_Ampere

Measure your cells directly with your DVM before doing anything else! A defective BMS can drain your batteries over time. Cells won't self discharge so if they are dead, something discharged them.

How do I do that?

[Pat911]

What Volt_Ampare said, a faulty BMS can kill the cells.

To do that you’ll need to disassemble further. You will find 16 individual cells in there with two terminals on each. They will be rectangular in shape. Measure the voltage on each cell. It should be around 3.2v each. Once you have access to the terminals you can rewire.

[Volt_Ampere]

You should verify by this method that your cells are good before you proceed! If they are very low in voltage (directly at the main terminals on each cell) you are SOL.

[Pat911]

Originally Posted by Pat911

Use your multimeter to check the real pack voltage, from the positive and negative terminals of the battery, before the BMS. So the main pack positive and B- on the BMS.

Can you do this as well please. Make sure the charger isn't connected.

Also just realised it's a 72v battery, so you'll have 24 cells in there, not 16.

[jonr3]

I was able to measure the cells last night.

I put the negative probe on the cell with the black wires and left it there. I touched the positive probe to each of the connections on the individual cells. (see attached) Is that right?

I have not had a chance to change the batteries in my VM yet, but I will this weekend and will measure the cells again.

I noticed that the rows of cells on the right are much lower than on the left, and the one cell only reads 367 millivolts...

[Volt_Ampere]

NO. You want to measure across EACH individual cell. I can already tell from your picture that your batteries are way discharged - Toast.