Help! Ebike problem battery not charging

[Gallasam]

Hi there ancheer ebike owner

So I used to be able to use this bike on full power, recently only lowest power setting is ok. Anyway recently whenever I put the charger into the charging port the light stays green indicating it's not charging or the battery has full charge (it doesn't it has 50% ish) and the journey doesn't last the length I need it to before bike starts cutting battery off. I've got a multimeter the battery itself is fine emitting 36v and 8ah like it should be. Any ideas on my next move is the charging port broken or is it the motor? Need experienced help has anyone experienced this before? And yes I've replaced the charger same thing is happening

 

[vfr400]

Did you look at the charge port? You should be able to see if it has damage. Look for damage or burning of the earth blade, assuming that it has a 5.5 mm jack.

The other thing to check is the charge fuse/s in the battery and charger. The easiest way is to measure the voltage on both the charger and charge socket.

 

[Benjahmin]

When you say, ' only the lowest power setting is OK', what do you mean?
How old is the battery and bike?

 

[Deleted member 25121]

Are you able to monitor the battery voltage when the motor is running under some load, for example by applying some brakes to the wheel?

 

[Nealh]

The battery should read 41.5 - 42v fully charged, the charger should read 42v output when plugged to the mains and switched on, so you need to confirm both first.
If charger is ok and battery voltage is low then you likely will need to open the battery to take extra voltage measurements as well as checking for any fuse or wire issue.

Likely wire issue could be faulty discharge or charge connection.
Other voltage measurements means checking the 10 cell groups measurements by disconnecting the BMS multi wire connector (voltage sense wires) and probing it to get
10 cell group readings. Post pics of your BMS connector so we can guide you in probing.

 

[Gallasam]

Did you look at the charge port? You should be able to see if it has damage. Look for damage or burning of the earth blade, assuming that it has a 5.5 mm jack.

The other thing to check is the charge fuse/s in the battery and charger. The easiest way is to measure the voltage on both the charger and charge socket.

Yes looked at the charge port couldn't see any burning. There was a spark when I tried to put the multi meter probes into the charging port (on second tthoughts it might not have been wisest idea sticking metal probes into a charging port) the idea was to attempt to measure input I guess. Only real way to see is take the bottom of battery apaer which I'll do

 

[Gallasam]

When you say, ' only the lowest power setting is OK', what do you mean?
How old is the battery and bike?

In answer to your first question the bike has 3 assist settings. It used to last the 7 mile round trip using max assist now however it can only last the journey using lowest assist setting. Although now it wont charge it doesn't make the journey at all. The bike isnt old it's just short of a year old. I've already attempted - unsuccessfully I might add - to get help from manufacturer.

 

[Gallasam]

Are you able to monitor the battery voltage when the motor is running under some load, for example by applying some brakes to the wheel?

I'm not entirely sure what you mean here. Presumably your after me putting bike upside down and pushing it while operating the battery however To measure the batterys voltage the only way is to remove the battery from its holder

 

[Gallasam]

The battery should read 41.5 - 42v fully charged, the charger should read 42v output when plugged to the mains and switched on, so you need to confirm both first.
If charger is ok and battery voltage is low then you likely will need to open the battery to take extra voltage measurements as well as checking for any fuse or wire issue.

Likely wire issue could be faulty discharge or charge connection.
Other voltage measurements means checking the 10 cell groups measurements by disconnecting the BMS multi wire connector (voltage sense wires) and probing it to get
10 cell group readings. Post pics of your BMS connector so we can guide you in probing.

Ok I can tell you know your stuff you completely lost me there aha firstly the battery is a 36v, when I put the probes into the positive and negative connections it does read 36v so that much is correct. Regarding the charger what do I do? Presumably not measuring it while in mains metal probes dont usually go well with leccy lol

 

[vfr400]

You switch your charger on, hold the negative probe to the outdide of the jack and stick the positive (red) one up the middle. Your meter should be set to read DC volts.

From what you've said, it seems that you don't have a basic understanding of how electricity works, which worries me a lot.

When you stuck your probes in the charge socket, you have to avoid shorting out the pin to the blade, which requires careful and precise placement. If you have a charge fuse in the battery, it's almost certainly blown now. You need to check again to confirm whether that's so. If you can't do it yourself, find someone that can.

 

[Nealh]

Though you say you have a meter and can check voltage it also depends on your abilities.
The battery is 36v nominal voltage but will charge up to a maximum of 42v so somewhere along the line it isn't doing so.
You can check battery voltage whilst it is plugged in and charging, you can tell if the battery is charging by probing the discharge connector, the important thing is not to let the probes touch each other wise you will get a spark/bang and as mentioned probably blow the battery fuse.
Even if you have not opened a battery before we can guide you if you are able read and carry out the step by step simple instructions.

 

[Deleted member 25121]

I'm not entirely sure what you mean here. Presumably your after me putting bike upside down and pushing it while operating the battery however To measure the batterys voltage the only way is to remove the battery from its holder

Either put the bike upside down or better still put it on a cycle repair stand, operate the motor while gently applying a brake on the wheel and use your meter to monitor the battery voltage somehow, it sounds as though you would need to remove a cover somewhere to access the battery supply.