Battery Power

[Eltommo]

Hi all, I a liilte confused so hoping someone out there can help. I was checking a sunlova 38v battery was reading 38v when powered on. The battery itself had been behaving erratically when installed on back and kept losing connection when going over a bump etc. No obvious faulty connections, (spare battery works fine no connection errors). However now there is no power output, no obvious short occurred. I have trued to reset bms by putting on charge. Any suggestions or has the battery finally given up? Thanks for your help

 

[flecc]

Hi all, I a liilte confused so hoping someone out there can help. I was checking a sunlova 38v battery was reading 38v when powered on. The battery itself had been behaving erratically when installed on back and kept losing connection when going over a bump etc. No obvious faulty connections, (spare battery works fine no connection errors). However now there is no power output, no obvious short occurred. I have trued to reset bms by putting on charge. Any suggestions or has the battery finally given up? Thanks for your help

The Sunlova battery isn't 38 volts, it's actually a nominal 36 volt one, and like all lithium 36 volt batteries it should measure 41 volts fully charged.

If that battery is only measuring 38 volts fully charged, that could be the problem, the voltage collapsing when you apply power and load.

When it's fully charged, check the voltage on your other battery that works ok. It's probably about 41 volts as it should be.
.

 

[Eltommo]

Sorry my mistake yes 36v, the problem is there is nothing now, even after a 5 hrs charge, no voltage showing.

 

[flecc]

Sorry my mistake yes 36v, the problem is there is nothing now, even after a 5 hrs charge, no voltage showing.

Does the charger light show it as charging and switch off afterwards?
.

 

[Eltommo]

No, it just stays on red as if charging then when I check voltage hardly anything. I did the bms reset by disconnecting harness and noticed two pins seem to have scorch marks. Still nothing. Thanks for your help

 

[flecc]

No, it just stays on red as if charging then when I check voltage hardly anything. I did the bms reset by disconnecting harness and noticed two pins seem to have scorch marks. Still nothing. Thanks for your help

Check the fuses, usually two of them. It will be the output fuse if it's blown, usually a circa 20 amp, either blade type like cars use or a tubular glass metal ended one.
.

 

[Eltommo]

Check the fuses, usually two of them. It will be the output fuse if it's blown, usually a circa 20 amp, either blade type like cars use or a tubular glass metal ended one.
.

Yes I did that, it was the red blade fuse, that's all I could see.

 

[flecc]

Yes I did that, it was the red blade fuse, that's all I could see.

If that fuse is ok and your now unable to get any voltage, there's likely to be an open circuit somewhere. However the 38 volts you were measuring before when fully charged does indicate at least one cell failing anyway.
.

 

[Eltommo]

If that fuse is ok and your now unable to get any voltage, there's likely to be an open circuit somewhere. However the 38 volts you were measuring before when fully charged does indicate at least one cell failing anyway.
.

Thanks for your help, I appreciate it. Will relook at again to see if I can find offending circuit.

 

[Pokitren]

Hi all, I a liilte confused so hoping someone out there can help. I was checking a sunlova 38v battery was reading 38v when powered on. The battery itself had been behaving erratically when installed on back and kept losing connection when going over a bump etc. No obvious faulty connections, (spare battery works fine no connection errors). However now there is no power output, no obvious short occurred. I have trued to reset bms by putting on charge. Any suggestions or has the battery finally given up? Thanks for your help

Well, if the other battery works fine, but apparently the problem is with the first one...

 

[Eltommo]

Well, if the other battery works fine, but apparently the problem is with the first one...

Yes correct, I am trying to understand what the problem is so I can try and fix. Hence my question.

 

[grissgray]

Did you have any joy on your battery,
I have a similar problem on charge all day and only getting 31v

 

[Nealh]

Did you have any joy on your battery,
I have a similar problem on charge all day and only getting 31v

Your bms isn't switching to allow current to flow, the reason being will be a low or duff cell group. One will have to open the battery to check the 10 cell groups or sipky buy another battery.

 

[grissgray]

Your bms isn't switching to allow current to flow, the reason being will be a low or duff cell group. One will have to open the battery to check the 10 cell groups or sipky buy another battery.

I bought a new battery and when I plug it in too my sons D4s its showing lower power 1 bar of power

When I plug it in my d4s it's a full battery
Any ideas

 

[cyclebuddy]

I bought a new battery and when I plug it in too my sons D4s its showing lower power 1 bar of power

When I plug it in my d4s it's a full battery
Any ideas

Check the P1 setting on your Sons bike is set to 36 and not 48. The D4S is a 36-volt system; the Yolin display can be set for both 36 and 48v systems. If wrongly set to 48v, the controller thinks the fully charged 36v battery is a flat 48v one.

 

[grissgray]

The P1 is wrong it's showing
P1 is 48
P2 is 200
P3 is 29

When I try change p1 too 36 it won't save
Also what are the p2 and p3 ment too be set at

Thanks

 

[cyclebuddy]

P1 is system voltage = 36 (volts)
P2 is wheel size = 200 (20.0")
P3 is max speed = 25 (km/h)

 

[grissgray]

P1 is system voltage = 36 (volts)
P2 is wheel size = 200 (20.0")
P3 is max speed = 25 (km/h)

View attachment 47234

Thank you very much It works now
however it randomly turns off when I am using the bike, any ideas

 

[cyclebuddy]

If the whole bike goes dead, a battery issue. The bullet connectors are a known weak point and melt if not tight. Might be LVC if you draw too much current and the battery is old/weak/failing or quite low on charge.

If the display stays on just the motor cuts out check all the controller wiring.

 

[grissgray]

If the whole bike goes dead, a battery issue. The bullet connectors are a known weak point and melt if not tight. Might be LVC if you draw too much current and the battery is old/weak/failing or quite low on charge.

If the display stays on just the motor cuts out check all the controller wiring.

Thanks for the reply its a new battery I've checked the wiring and all seems fine