Dead Oset 20R

[bostit]

Looking for a bit of help with my sons 20R. Little used 2015 model, bought it a couple of months ago with LiPo battery already fitted, last ridden about 10 days ago. Plugged in the charger this morning and it was flashing to indicate an error! 

Checked battery voltage - 51V. When the battery is connected to the bike, the bike can be switched on the power lights illuminate on the throttle for a moment and then the power relay drops out. I've checked voltage too and from the key switch 51V, too and from the handlebar switch 51V and to the controller 51V until it shuts down. I have 51V each side of the main fuse and I have 51V supply onto the relay until it switches off. If I connect the battery -ve to the relay it holds in for a short time and then drops out. I've jumped out the handlebar switch to eliminate that with the same result as before.

Obviously the battery charger error is a worry but given the battery is showing 51V consistently can I eliminate it or should I focus on that? I know these are rated at 48V so is 51V too much?

Can anyone suggest what I could/should test next?

I don't like to be beaten but a bit stumped at the minute!

[timdog]

I'm no electronics guru so you will probs get a better answer,  i had issues with relays due to them not being a sealed unit. If its same as my sons, under mudguard his packed in twice due to muck getting in. Once totally dead, another time intermittent cutting out( could hear it click on then go off.)

i regularly take it off and clean/wd40 it. My charger also packed up with the flashing error and it would keep clicking. New one ordered and fine. Not sure where your lipos from if poss problem with the protection circuit re overcharging etc?mine are in sealed pack and reading over 48v when charged.

poss try borrow a charger?

 

[gwhy]

what battery is it ? .. I know you said its lipo but how many cells do it have ? ... normally a lipo 48v battery has 12 cells and this should be a max of 50.4v . if it is a battery with a bms then it may be 13 cells as this is the more nearer a true 48v battery but the voltage would then be 54.6v fully charged ... or is it a li-ion battery with bms .. basically what im getting at is do it have a bms and if so then there are 2 possible problems ( dependent on how many cells it has )  it is a faulty bms or the battery has a bad cell. what charger are you using for your lipo's ? 

a bms would turn the battery off if there is a fault with the battery or the rest of the wiring on the bike as soon as you put a load on to it.

if there is no bms fitted then you defo need to know how many cells it has as 51v is way over the top for a 12cell lipo battery and could be dangerous on the other hand if its 13cell then its not charging at all and you still need to work out what is going on.

you can test to see if its a bms problem just by connecting the battery directly to the motor wires ( wheel off the ground ! ) it will either spin the motor up full speed or not. 

 

edit:

on the charger is should say the exact voltage output... is it the correct charger for the battery you are using i.e was it supplied with the battery .. common output voltages of (48v) Li chargers are 50.4v,  54.0, 54.6v, 57.6v  this is the fully charged voltage of the battery that you are charging and should never ever be any higher thats why its important to know how many cells you have and what chemistry .. lipo4 is another common chemistry used for batterys but the cell voltage is lower than lipo.

also if there is a bms fitted it could be that the battery is being turned off because there is a low ( bad ) cell in the battery.   

 

Edited June 17, 2017 by gwhy

[bostit]

Thanks for your suggestions, unfortunately the batteries are sealed into a rubber case so I have no external identification marks which is why I sound so vague, I guess attacking it with a craft knife is the only way ahead. 

The charger is a Model:L200CM-48 (no makers name given), output is given as DC54.6V 3.5A, battery type suited 13cells li-ion pattery pack.

I had formed the opinion it has Li-Po batteries from the sticker on the side cover which states 20S Li-Po supercharged, unlike the Li-ion stated on the charger.

I am measuring 43V today (haven't touched anything since saturday) charger still showing an error and nothing now when the battery is on the bike. 

Any advice gratefully received!

[bostit]

looks like 13 cells with a bms.

[gwhy]

li-ion and lipo cells have the same voltage so can be charged the same , to a absolute max of 4.2v per cell  , lifpo4 is different and has a max absolute charged voltage of 3.7v per cell.  the chargers are the same and the only difference is the total charge voltage need to be set at the correct output voltage for how many cells you are charging. if the charger states 54.6v and you have counted 13 cells then this is correct for lipo/liion 48v battery. ok now from what you have described my best guess is that you have a faulty cell which is bad news and the bms is shutting the battery down but it could be a faulty bms draining a cell down. can you get access to the bms ?  there is a long connector with 14 or 15 thin wires on it .. unplug that connector from the bms then very carefully ( dont short any thing out !! )  measure each cell voltage, this can be done on the long bms connector . connect the neg meter lead to the main neg of the battery then start at one end of the bms connector plug measure each wire using the positive probe of the meter ( use a pin that fits into the hole on th econnector ) as you move along the connector measuring each cell they should all be the same difference between each one i.e a fully charged battery will be hole 1= 4.2v, hole 2=8.4, hole 3= 12.6 ect, and if you start from the other end it will be 54.6, 50.4, 46.2  ect a difference of 4.2v per cell. I think you have a very bad cell in the battery and this will show up if you test this way, as a good battery all the cells will be the same voltage. if there is a low cell then leave the bms connector off for 24 hours then measure again to see if the bad cells voltage comes back up and this will indicate that it is a possible bms fault.

I have no idea what it would say 20s super charged on the battery if you counted 13cells ? ... any chance of posting up a pic?

the charger will show a error because there is a fault with the battery. One thing you can test though with the charger is measure the output voltage as it should be 54.6v  if its lower then this is what have dragged the battery voltage down.. post up results

 

edit:

if all the cells are the same voltage then you need to also disconnect the main neg wire that comes from the cells to the bms to stop the bms from doing any more damage.

Edited June 19, 2017 by gwhy

[gwhy]

Also on a side note.. always put at least some charge back into a battery fitted with a bms after use especially if you don't intend to use it for a good few days, no need to fully recharge it .. charge for maybe a hour before storing it.  and always disconnect the battery from the bike never rely on the key switch you fully turn the bike off especially if the bike has a pre-charge circuit fitted as this will drain the battery. 

 

Edited June 19, 2017 by gwhy