Battery Power

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

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.

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

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?

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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

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.

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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.

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

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.

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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.

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

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...

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.

Did you have any joy on your battery,

I have a similar problem on charge all day and only getting 31v

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.

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

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.

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

P1 is system voltage = 36 (volts)

P2 is wheel size = 200 (20.0")

P3 is max speed = 25 (km/h)

 

P1 is system voltage = 36 (volts)

P2 is wheel size = 200 (20.0")

P3 is max speed = 25 (km/h)

 

[ATTACH type=full" alt="47234]47234[/ATTACH]

Thank you very much It works now

however it randomly turns off when I am using the bike, any ideas

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.

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

however it randomly turns off when I am using the bike

You need to be far more specific. It turns off and you need to switch it back on, or it comes back on itself after a while, or the power just blips out for a second or two... over rough ground, up hills, or at any time over any terrain... is it totally random or in sequence with other events eg. after a long period of riding... does everything die or just the motor assist... does the display stay on or die too? We're not psychic. You need to say exactly what is happening for someone to second guess a likely cause.

 

First though, fully charge the new battery to a measured 42 volts, then take it for a ride and let us know.

The bullet connectors are a known weak point and melt if not tight.

 

Yep, which is why I switched to soldering - these got too hot

 

 

You need to be far more specific. It turns off and you need to switch it back on, or it comes back on itself after a while, or the power just blips out for a second or two... over rough ground, up hills, or at any time over any terrain... is it totally random or in sequence with other events eg. after a long period of riding... does everything die or just the motor assist... does the display stay on or die too? We're not psychic. You need to say exactly what is happening for someone to second guess a likely cause.

 

First though, fully charge the new battery to a measured 42 volts, then take it for a ride and let us know.

 

I feel like I should make a new post it's bad manners hijacking someone else post,

 

 

So the bike is fully charged 42v and showing full battery on the clock,

I double checked all the wiring made sure everything is connected correctly and tight,

 

When I turn on the bike it could knock off in a couple of seconds or stay on for 10 to 15 minutes

 

Any ideas

 

Thanks

I think I might found the problem, it seems too knock off when the bike is been moved or bumped,

I think I have a loose wire in the display when I turn the handle bars it powers off and also its the only connector other then the power supple that if you disconnect and connect back together you need too power the bike back on

 

wish me luck

I think I might found the problem, it seems too knock off when the bike is been moved or bumped,

I think I have a loose wire in the display when I turn the handle bars it powers off and also its the only connector other then the power supple that if you disconnect and connect back together you need too power the bike back on

 

wish me luck

 

Problem solved Thanks everyone for the help I'll do my best too help others