Why does the battery show a minus voltage when checked with the voltmeter?

[ingolf915]

I see nothing wrong - from picture 2
View attachment 93436

You haven't changed any wiring, so nothing is wrong, Don't be chasing ghosts.

Now think about why a "charger doesn't work".

First answer is bad charger, but you have a second charger, presumably good. I assume it has a new mains (AC) cable and that is firmly inserted into he charger.

Second answer is the battery is at fault if it's not taking a charge. We know the bike still works, so the battery is putting out a useable voltage. What causes a battery to not charge? Is there a charger fuse on the battery? Check it.

If the fuse is good or you can't find a fuse, is your charger connector on the battery easily probed? Carefully look for 58V on its pins. That shows it's connected to the internal cells, and there is no fuse issue.

Finally and this just occurred to me, if this is a 14S lithium battery, i.e, 58.6V, it's already fully charged (your picture shows 58.46) and the charger won't charge anyway.

Sorry my messy post I understand I got really confused..
As you says everything there is okey. It´s the other cables shown that are used for charing that shows minus when measured correctly.
That the battery I got. 60V 20ah and a lot of chinatext on it

The battery indicator shows 50% charged. But you say it must be fully charged at that voltage?
It´s a good ide to drain the battery so 0% see if that resolve the issue ? Never done it before.

 

[ingolf915]

Inside the battery case is most likely a BMS. Basically a battery manager circuit board that controls charging and discharging. It is a safety device so if you bypass it, it is very easy to over charge and/or create a dangerous situation/fire.
If you want to fix it correctly, you need to open the battery case.

Must be.. probably going to send it in for repair.
What will happen if i connect the charger to the cables that are going from battery to controller? It´s then i becomes a danger as you said?

 

[ingolf915]

Who knows what he's showing the other pictures. Let's see a picture of the charge connector on the battery or bike..

I've taken apart enough batteries and the positive end of the battery always goes directly to the positive side of the out[ut connector, and also the charge connector. It's the same wire. They cannot be different.

From the battery as you see i have 2 pair of cables. 1 set of black/red that are used for charing. 1 set of black/red that goes to the controller.
That set of cables that are used for charging are showing -58V and the other set that going to the controller are showing +58V but you say thats impossblie because "it's the same wire."?
So what happen if i connect the charger to the other cables?

 

[Gionnirocket]

Must be.. probably going to send it in for repair.
What will happen if i connect the charger to the cables that are going from battery to controller? It´s then i becomes a danger as you said?

Yes it is dangerous. There will be no balancing of the many cells inside. It is very easy to overcharge if not the entire pack but individual cells which is very dangerous. Over charged cells quickly become volatile.
I recommend that you do NOT do this.

 

[ingolf915]

Yes it is dangerous. There will be no balancing of the many cells inside. It is very easy to overcharge if not the entire pack but individual cells which is very dangerous. Over charged cells quickly become volatile.
I recommend that you do NOT do this.

Thanks for all the help! Will send it for repair feels like the most safe thing to do!

 

[harryS]

Ingolf915. I would like to see a photo of the charger connector, not the wires in the middle with the insulation scraped off. What is the voltage on the charger? You ordered it, so you should know.

This must be LiFeP04, not LiPOx. if you have a 60V battery. How long have you had this scooter. Is this the first time you tried to charge it?

 

[Gionnirocket]

Sorry my messy post I understand I got really confused..
As you says everything there is okey. It´s the other cables shown that are used for charing that shows minus when measured correctly.
That the battery I got. 60V 20ah and a lot of chinatext on it

The battery indicator shows 50% charged. But you say it must be fully charged at that voltage?
It´s a good ide to drain the battery so 0% see if that resolve the issue ? Never done it before.

I found this information... This is the closest to your battery that they offer on their website now... But that doesn't mean that yours is still not available or that you can not get parts.

60V 20Ah

haoyangsz.com

If the chemistry is the same, your full charge voltage is 67.2v... So your 50% indicator is probably correct
Can you post a photo of the charger nameplate and specifications?

You can also try to contact them... But the language barrier will make things difficult.
[email protected]

深圳市浩洋新能源有限公司

haoyangsz.com

 

[ingolf915]

To make it super clear for you all! 2 sets of cables from the battery. The cables that showing -Volt are those used for charing. The other are going to controller to drive it all.

 

[ingolf915]

First one is my "broken charger" according to me. The other i my new bought charger that shows zero voltage?...

 

[Gionnirocket]

First one is my "broken charger" according to me. The other i my new bought charger that shows zero voltage?...

The new charger show 0 volts... But does it bounce up and down with different voltage?

 

[ingolf915]

true true! It bounce a little from voltage as you say! So my thought then was it´s a "smart charge" and if the BMS is broken it wont start charing? Or am i wrong?

Does the broken charger show any of intresset in that voltage?

 

[Gionnirocket]

true true! It bounce a little from voltage as you say! So my thought then was it´s a "smart charge" and if the BMS is broken it wont start charing? Or am i wrong?

Does the broken charger show any of intresset in that voltage?

Yes, that is my thought too. Smart charger require feedback from bms before full 67v output.

For more information.
In past before problem:
Did you ever test battery charge wires? If yes, was polarity correct. Red + / Black - ?
Did you ever test charger output of old "broken" charger? What was voltage?

Now with new charger... Did you ever test output before first use?

 

[ingolf915]

For more information.
In past before problem:
Did you ever test battery charge wires? If yes, was polarity correct. Red + / Black - ? (Never tested before the problem)
Did you ever test charger output of old "broken" charger? What was voltage? (No due to the light on the charger stopped working so thought okey it´s broken and bought a new one)
Now with new charger... Did you ever test output before first use? (I measured it before trying it the first time. But i was like that from the start)

Like Reply

 

[Gionnirocket]

For more information.
In past before problem:
Did you ever test battery charge wires? If yes, was polarity correct. Red + / Black - ? (Never tested before the problem)
Did you ever test charger output of old "broken" charger? What was voltage? (No due to the light on the charger stopped working so thought okey it´s broken and bought a new one)
Now with new charger... Did you ever test output before first use? (I measured it before trying it the first time. But i was like that from the start)

Like Reply

Ok.
My thoughts are still that it is a problem with the BMS.
For me, reversed polarity is not correct. I can not understand how, but the Fluke does not lie.
As a final test... Do you know anyone with a similar battery that you can check polarity and test your charger with?

Did you try to contact the manufacturer?
If you do... I suggest, short sentences with simple words and no abbreviated words.
Send photos too

 

[ingolf915]

I have another battery at the warehouse but wont go there until this weekend so will try that also.
But like you said it must be the BMS..

Tried to contact the manufacturer but yee you know how easy that is with china products haha

THANKS FOR ALL THE HELP! When it´s has been for repair I will give you the info if it was the BMS or not !