Battery has no output but is fully charged.

[Nightdog]

Hello all,

Problem with 4 year old VIVI f46.

Battery is fully charged, but no output. I have been working on the bike all morning, finnally noticed that the battery case is broken. Should i go ahead and take it apart and look for open connections? BTW its broken by the warranty seal so thats already broken. It wont show that it is cahrging, no broken wires on the control system. Does this sound easy to fix. The reason i havnt bought a new battery is I cant find exact replacement, the discharge plate houses the control. any advice ?

 

[calab]

Use a digital multi meter and measure the voltages before the bms (a full voltage number for the battery pack), and measure each grouping (small voltage range of around 2-4.20v). Then you go measuring the switch, the led thingy and the bms output.

 

[Nightdog]

Ok The BMS is identified, since I seem to have 36 v measured at a couple points, but not at the discharge, so lets say the batteries are ok, could the BMS have gone bad. Also yes on the switch. The battery seems to be fully charged or close sometimes 4 out of 5 lights. Could the led's also indicate battery failure? thanks i appreciate trying to learn this. for now on I wont be intimidated by working on e bikes. reply expected

 

[Nightdog]

one of the points where i get 36v is the frontside of the step down for usb 5v

 

[Nightdog]

it looks like 2 leds out of 4 light when switch is depressed

 

[amberwolf]

Ok The BMS is identified, since I seem to have 36 v measured at a couple points, but not at the discharge, so lets say the batteries are ok, could the BMS have gone bad.

Measure the individual cells as previously requested; you'll probably find a cell problem that the BMS is doing it's job and protecting you from causing cell damage that can lead to a fire.

 

[Nightdog]

Ok so what do i do if i find a bad cell?

 

[E-HP]

Ok so what do i do if i find a bad cell?

Battery has no output but is fully charged.

Hello all, Problem with 4 year old VIVI f46. Battery is fully charged, but no output. I have been working on the bike all morning, finnally noticed that the battery case is broken. Should i go ahead and take it apart and look for open connections? BTW its broken by the warranty seal so...

endless-sphere.com

 

[Nightdog]

Here is what I think is misunderstood here, this is a 36v system and I am reading 36 v in about 3 points. but nothing in the output. Does that change anyones idea, plus i did the cell check and they are all aroung 4 v. Could it be something else

 

[Nightdog]

I am having a funeral for the bike because its impossible to ride without power. ordered a new bike, cant find a manufacture replacement for this one, other wise it would make a great spare bike. Will someone buy it from me? like 200 paid close to a thousand

 

[Nightdog]

Ok there is 5 cells each one reads 4.1 3.9v I still have no output to discharge. I tried to tighten the hold on that 2 wire connecter on the BMS and it went to solid 12v then I could not get it back. I may try reflow the solder joints on the BMS unlles this rings a bell with someone. what should each cell read as far as volts?

 

[E-HP]

Ok there is 5 cells each one reads 4.1 3.9v I still have no output to discharge. I tried to tighten the hold on that 2 wire connecter and it went to solid 12v then I could not get it back. I may try reflow the solder joints on the BMS unlles this rings a bell with someone. what should each cell read as far as volts?

Disconnect the (usually white) connector between the pack cell groups and the BMS. It should have 11 wires. Follow amberwolf's directions and measure each group and write them down. Measure to two decimals. You should have 10 voltages when you are done. Post the results.

Use caution. A short would be bad.

 

[Nightdog]

Hey you guys BTW there does not seem to be a fuse is that possible?

 

[Nightdog]

I hope someone can explain why I am getting 36 v in a couple points but no output. I think the cells are fine, unless they are supposed to be higher voltage than about4 v.

 

[99t4]

I hope someone can explain why I am getting 36 v in a couple points but no output. I think the cells are fine...

They already explained a very probable cause why-- the BMS will shut down the battery output when it detects a problem with (some of) the cells, one of its main safety duties.

You are receiving serious help here but it will be of no value to you unless you follow the scientific request to measure ALL 10 of the cell groups. Here is the post (Post #25 in your own thread) in case you missed it:

Post #25

I think the cells are fine...

You are just guessing until you measure ALL 10 cell groups.

I am having a funeral for the bike because its impossible to ride without power. ordered a new bike, cant find a manufacture replacement for this one, other wise it would make a great spare bike. Will someone buy it from me? like 200 paid close to a thousand

Whining might have worked for you when you were a child but we are all mostly adults here now.

Do your work to get to the next step, don't cheat; the results will tell us if your battery is worth repairing, or even possible to repair. If you need a replacement battery we can help with that also.

bike had reduced range and was fine for a while, one morning it wouyld not turn on. dont know why.

That is a common indicator that the battery cells are failing. How old is it, how many miles, how many charge cycles?

 

[Nightdog]

what do you mean" tripped"? its 36 v. meaning i get 36 v at a few points but no output

 

[Nightdog]

Ok I did all that and I have posted the results. So I am lisening and learning and trying to follow, so lighten up francis . You might have to read back in my posts. otherwise you are excused. Ill get help elswhere. if you anything to me ill quit.

 

[amberwolf]

The total pack voltage doesn't mean very much when diagnosing what's wrong with a pack that isn't working. The individual cell (group) voltages are almost always what is causing the problem.

All cells in a working pack should be exactly the same voltage. When it's full, a 36v pack should be 42v, and each cell should be 4.20v.

The varied voltages you see on the few cells you tested (as noted previoulsy, there will be at least ten sets of cells in series to test, so you will have ten voltages), show that there is at least one group of cells that's very different from the rest, meaning it has a problem.

A BMS can turn off the pack whenever any limit is exceeded, to protect you from damaging the cells and possibly causing a fire, either immediately or at any time after the damage has happened. (and you can't know if the damage will ever cause a fire until it does, and that's too late).

The limit that is probably enforced right now is the cell-difference limit, which on some BMS is anything >0.1v between any cell and any other cell. But since we don't know what all 10 of the cell (group) voltages are yet, we don't know if there is a less-fixable problem, or one that has a greater fire risk, etc.


Previously I gave you the generic testing directions that should allow you to get all the cell (group) voltages and post them in this thread. If you can take clear pictures of the insides of your pack showing the cell wiring and construction, including the places each wire is going to and from, I can put arrows on the image to show you where to put your meter wires to get all of the ten readings you should have.

Then if you are willing to test the cells and post all of the voltages you get, in the way that was requested (from most negative to most positive), we can see if any of them is worse than the one you've already seen, and go from there.

 

[E-HP]

Ok I did all that and I have posted the results. So I am lisening and learning and trying to follow, so lighten up francis . You might have to read back in my posts. otherwise you are excused.

Where are the results?
Since you keep asking about the 36v without posting a pic of where you are measuring, then I guess you want a theoretical answer, which is just that, since earlier you also mention reading 40v and “like a 13 pin connector”, so you’re being loose with the facts and we’re reluctant to rely on your descriptions. Batteries are too dangerous to be that loose, which is why we need to see the actual data rather than a casual, and obviously poor, description.
36v, if full pack voltage, combined with the earlier suspect data provided, could be:
Converting this to English “Ok there is 5 cells each one reads 4.1 3.9v”, I will guess you measured 4 groups at 4.1v and 1 at 3.9v”, so 20.3v. So, the other 5 groups add up to 15.7v to get to 36v. That would be 3.14v per cell if each were at the same charge. Or, at the extreme, 4 of the remaining are around 3.9v (15.6v), and the last is dead, totaling 36v. The differences may vary, but the point is, one or two groups may be dangerously low. If the BMS detects voltage below 3v or so it will trip and disconnect the output to prevent catastrophic failure of the pack. This is likely where you are at, which is why those ten data points are important.

Ill get help elswhere.

certainly an option. Wherever you get advice, please listen and follow it precisely and be cautious. Too many battery fires lately. Stay safe, and good luck.