Battery cutting out at

P

Pager880

1 W
Joined
Jul 1, 2023
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56
Location
Portsmouth uk
Hi all I have a 48v electric scooter...use mostly every day on a journey to my dad's .what takes 6 minutes so 12 ISH minutes a day ...it is a emoko hdv3...Iv replacement the controller.before .as gets blew ...it's been fine for months...and all of a sudden got to my dad's off a full charge .on way back cuts outs ...and as soon as I put the charger in comes on ...take the charger back off .run it off the floor .lasted 15 seconds.then cuts out again....won't turn on .till I put the charger back in it . Can anybody help me please .....will upload a pic of battery..specs ... anything I can do ...is it the BMS...or bad pack ......any help would be Verry much appreciated please
 

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Best guess at this point is a bad cell (or parallel group of cells) that trips the BMS and shuts down.

BTW - How often do you balance the battery pack? (Leave it on the charger overnight?)
 
Diggs said:
Best guess at this point is a bad cell (or parallel group of cells) that trips the BMS and shuts down.

BTW - How often do you balance the battery pack? (Leave it on the charger overnight?)
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I often charge overnight ...leave it and unplug in the morning.....I don't no haw to balance the battery.haw do I do that ..
 
Leaving it plugged in overnight should be balancing but would need to be checked that the charger is holding ~54.6 volts during the night after the initial charge is done. In turn, this shouldn't be done every charge and is hard on cells and could cause premature failure which is what I'm guessing happened here. How many cycles/charges would you guess are on the battery pack?
 
I got the scooter used and was in Verry good condition.....I had it about a year /year and half ...when I fist got it .only used to charge 1nce a week .....but don't leave it on overnight all the time as my partner likes to remind me that green is it done 😂😂😂😂. it deffo charges to 54.6 ..as tested with multimeter on dc mode .....
 
Pager880 said:
Just tested again after a full charge to 54.6. Let it runn off floor went down to 51.v cut out completely no power ......
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Low cut-off should be around 39 volts. It still appears that you either have a group of cells going low and tripping the BMS, or your BMS has failed. I would bet on old cells failing.
 
Diggs said:
Low cut-off should be around 39 volts. It still appears that you either have a group of cells going low and tripping the BMS, or your BMS has failed. I would bet on old cells failing.
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Any idea of how I test that .I have a multimeter 🫣 just took battery out tested on multimeter and only getting 3.98v ......and as soon as I put thr charger in really quick and take it out .says 50.7v .....then I will run it then cuts out at 50.1.
 
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Only way to really know what is going on is to be able open the battery pack and get access to the cell groups. There should be one group that is lower than the rest causing the shutfown. Else it's time to suspect the BMS if all cell groups measure the same.
 
Diggs said:
Only way to really know what is going on is to be able open the battery pack and get access to the cell groups. There should be one group that is lower than the rest causing the shutfown. Else it's time to suspect the BMS if all cell groups measure the same.
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Well opened the pack up today......as it stopped holding charge..as soon as I took charger out.voltage would drop to 0...so bypassed the BMS . voltage went up to 53.7.....and stays at that . Will test tomorrow.and see if it runs below 51v ......if it do I will replace BMS .if not I will get a cheap Chinese pack ..of internet .this pack says it's 13s6p...as I counted the cells thire is 65 ..in 13 groups of 5 ...so is it a 13s5p thave just labeled it wrong 🤔
 
Measure each group of 5 cells individually before and after it shuts down. You'll probably find one group much lower than the rest. (Max would be around 4.2 volts when charging and probably ~4.0 at rest. Shutdown would probably be anything below 3.0 volts.)
 
Diggs said:
Measure each group of 5 cells individually before and after it shuts down. You'll probably find one group much lower than the rest. (Max would be around 4.2 volts when charging and probably ~4.0 at rest. Shutdown would probably be anything below 3.0 volts.)
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Probably just try a find a new pack . For it as . tested today went down past 50v ..but got home at a snail pace 8mph ....so don't no weather to run thr batt flatt ...and give a good charge see if that helps ...but because IV bypassed BMS .will it cut off at saty cut off ..🤔
 
IV stoped using it now ...but can't find a replacement battery...the size this one is ...plus's it says it's 13S6P....but it only has 5 battery s. In 13 rows.....so do that mean it's a 13S5P....I can't find a battery that's long like this one
 
Charging unattended is risky even with a good pack.
A good pack isn’t based on where you buy it, but the cells it’s made with, and the quality of how it’s constructed. You should know what cells are used at minimum.
 
E-HP said:
Charging unattended is risky even with a good pack.
A good pack isn’t based on where you buy it, but the cells it’s made with, and the quality of how it’s constructed. You should know what cells are used at minimum.
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Ok thanks for the advice ....so will I need a 13S5P....as it has 5 battery's in a row .but 13.rows ..I will ask the sellers what cells that are 👍👍👍👍
 
Pager880 said:
That haven't replied yet as soon as that do ..I will let you no ..have u got any links to wear I can get one please
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The only pic I have if my battery...is of the BMS .....but u can see. It has 5 rows of batteries laying flat..13 sets of 5 .....and it is labeled 13s6p....but surely it's a 5p..at as 5 batterys in each group....I don't no whqt cells that are .. nothing on them except 18650 3.6v
 

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It would be interesting to hear what they say since there are no cells made that can meet the fake specs in the listing. Sorry, I can’t provide any suggestions that are in that price range,
 
Pager880 said:
The only pic I have if my battery...is of the BMS .....but u can see. It has 5 rows of batteries laying flat..13 sets of 5 .....and it is labeled 13s6p....but surely it's a 5p..at as 5 batterys in each group....I don't no whqt cells that are .. nothing on them except 18650 3.6v
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based on your description and pic, it’s a 48v 12.5Ah pack, can’t tell what brand of cells.
 
S
E-HP said:
based on your description and pic, it’s a 48v 12.5Ah pack, can’t tell what brand of cells.
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ok it's a cheap pack anyway... Chinese that lie ...as on the sticker says 15ah...and 13S6P.. but it's definitely a 13S5P....and no brand on cells just pink
 
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