E-Scooter battery not charging.

[sam_sam_sam]

Here is a discussion about what the battery cell curve graph should look like for a good battery cell and what a bad battery cell graph would look like with pictures of each type of battery cell and how to determine weather or not the battery cell is good bad or questionable but for you to be able to determine this you have to have the battery testing machine that I mentioned above about the EBC-A10H

https://www.badcaps.net/forum/troubl...-cells-to-2-00

[sam_sam_sam]

I hope that I given you enough information so you can decide what and how you are going to resolve your issue with this problem with this battery pack and battery charger that is for this battery pack

Now you could decide that to just change the BMS protection board and use a different battery charger but I caution you about something if this scooter has micro controller that communicates with the BMS protection board you will not be able to get around this with out changing the scooter controller as well

One thing about the charger controller it might not be functioning properly to test them can be a pain in the rump because the majority of them have to see the battery voltage for them to start charging here is a way to manually trick the battery charger to come on to test it output voltage and current but I caution you that this does not always work but what you do is use a external power supply that is at the voltage level that battery charger needs to trigger it turn on the charge function have an incandescent light bulb hooked up then remove the external power supply and see if it continues to light the light bulb if it does then you can conclude that is is functioning but weather or not it is functioning correctly or not is another story more testing would be required for the conclusion of this question of weather or not it is functioning properly or not

Now you might have to check weather or not the battery charger has output voltage or not but this requires you to open up the battery charger and check the voltage and current output before the charging controller this not always easy to do if you decide to check this first take it apart and post the picture of every single boards and let see if we can figure it out

[sam_sam_sam]

Recheck the voltage on all battery cell rails how close are they to each other if they are not close to each other this BMS board might be very picky about how close the voltage differences are to each other and if this case there is nothing that you can do change it function but you have to figure out how much of different this BMS will tolerance and stay within those limitations for it work correctly or there is something wrong with the BMS protection board but this would be the last thing I would consider wrong with the BMS protection board

I once tried to figure out why a BMS protection board that has a balancing function did not work properly and it was because the difference between battery cells could not more than 0.20 volts once it reaches 4.00 on any battery cell rail I ended up not using this BMS protection balancing board because it function was that tight and could not find battery cells that would be close each and the charging curve would that close to each other

If this is the case with your BMS board then the only thing you can possibly do is to have a much better battery testing machine like a EBC-A10H that a very detailed graph chart that it creates when you are charging and discharging your battery cells but one thing you need to keep in mind that with this battery testing machine you CANNOT what ever never charge battery packs that have BMS protection boards you can check the battery cells individually or the battery pack at the battery terminals but not through the BMS board

Here is a website link to one

https://www.ebay.com/itm/12667449165...3ABFBMwMvDhO1k

You do have to have a computer that has an operating system that is Windows XP at a minimum it does work very well on Windows 7 the software is free to use and download

This how you would go about testing your battery cells this battery testing machine has a save function and you can save each battery cell performance results and compare them to each other and you are looking for three things one is milliamperes hours the charging curve and discharging cure and the time it takes to complete a charging and discharging cycle these are very important when dealing with a very picky BMS protection board the closer you can match these parameters the better the BMS protection board performances will be

Your setup parameters would be setting would be as follows discharge voltage value would be 2.5 volts the charging voltage value would be 4.2 you would use the cycle function you would set from 1 to I think most you can set it to is 5 if I remember correctly then when you are setting this up you should you the wait function in between the charging and discharging cycle and just set it for 5 minutes and if you are going to repeat how many times it repeats this setup use 10 minutes wait time in between when you set it for more than one repeat function and one last setting is turn on the monitoring function so that when it finishes the routine it will still show the battery voltage when it is finished testing this function is very important because your last function should be the discharge function so that you can see if your battery cell recovers to 3.00 or better

Here is another option but it is little bit more expensive to do this way but might be a little quicker but less accurate here is a website link to it

1S ~ 24S Lithium Battery Pack Single Cell Voltage Tester For Lifepo4 Li-Ion LTO

https://www.ebay.com/itm/404214270802?var=674091247270

and this

6pcs Splicable Battery Slot Solder-Free Lithium Battery Box Holder、

https://www.ebay.com/itm/155075483177?var=455251086921

This how you would go about doing this is that you would create a battery testing jig that you would use only one parallel battery cell rail the “S” would be how many battery cells are needed for the voltage of the BMS board requires you would still need to have an incandescent light bulb that can handle the required voltage the higher the wattage bulb you can find or use several of them in parallel to get to a wattage of at least 50 watts or more would be better

This would be how you would use this setup

First thing is to have each battery cell at the same voltage before you start then use the battery charger that you have for the scooter and charge them up until the battery charger says that it is fully charged if it gets that far but what you are interested in is if the battery voltage is close to each other if not try different battery cells until you get the battery charger to show that they are fully charged now this would require that you have new battery cells to do this the most accurate way if you are going to use used battery cells then this process will be a lot longer to match battery cells to each other

What I have described above I going to make a battery jig to exactly the same thing but with a twist in that I want to test the functionally of different kinds of BMS boards that I have and see how they function and how much lead way I have with how close the battery voltage is between battery cells and use this information for creating a battery pack according to these parameters to get the most efficient battery pack possible for running time yes this is very time consuming endeavor

But I have the battery testing equipment to do this but I have not made the jig to begin testing BMS protection boards this way yet but this project is going to have a very high priority very soon because I have several different projects that I need to get going especially getting battery powered battery packs working again because I have several that need some attention that need to pay to them there performance is very poor or they are not charging up fully and are useless this way and Home Depot does not have special buys on power tool battery packs like they used to and if they do have any the price of them are considerately more expensive than they use to be

I hope that I given you enough information so you can decide what and how you are going to resolve your issue with this problem with this battery pack and battery charger that is for this battery pack

Now you could decide that to just change the BMS protection board and use a different battery charger but I caution you about something if this scooter has micro controller that communicates with the BMS protection board you will not be able to get around this with out changing the scooter controller as well

I hope all of this information helps you get something working again good luck to you with this project

[unimatrix93]

This is the reason I harped on the idea about balancing so much because I repair power tool battery packs and if you use new and used battery cells in a pack you are going to have issues

Yes you can reuse battery cells however you need to make sure that milliamperes are as close as possible to each as you can with the battery cells that you have on hand but for best results they should at least have nearly the milliamperes per cell as you can for best results

Several things should look out for when trying to reuse battery cells is when charging them the cells should not get warm to the touch if you are charging at 1 amp or less if they do they are referred to as heater cells and consider BAD and should not be reused now one other test you should do and can be done two different ways if you have SkyRc battery tester and you have a tablet and the WiFi module or a USB cable and use your computer can wait until it is finished and look at charging curve it should go up gradually and NOT real steep then leave it hooked to charger for several hours ( if you are doing 4.2 fully charge look and see how long it stays at 4.0 volts but a better test is to discharge the battery cell to 2.5 volts if it allows you to and see if it recover to above 3.00 volts in a couple of hours if so then you should be good to go with these battery cells now if it does not recover to 3 volts then there is a good chance that the battery cell is a self discharging battery cell and should not be used

If you decide not to get a battery tester there is another option but it is less accurate and that is ge a couple MR16 incandescent light bulb maker sure they 12 volt @ 20 to 50 watt ones the 50 watt ones would be better but if can not find them you can use the 20 watt ones it will just take longer to discharge the battery cells down to 2.5 volts what you are interested in is do they recover back to 3.00 volts or higher if so then you are ready to go

If you decide this is to much trouble there is another option but this is the least accurate option to use and that you would discharge the battery cell down to 2.5 volts and leave a voltage meter on the battery cell for at least 2 hours does recover if so then you are ready go

If you decide this is too much work then the last option is change the battery pack up fully with the battery charger and let the battery pack sit for at least a month or maybe 2 months and see if any battery cells are below 3.5 volts if so you might have self discharging battery cells then these battery cells would need to be replaced as well


What you could do is invest in a SkyRc B6 version 2 battery tester at a minimum and test all of your battery cell rails and see how far off the milliamperes are between battery cell rails which should have been done before you bought replacement battery cells because now you will probably find that if you are lucky enough to still have 50 to maybe 75% battery life is left in the one that still have voltage also it not a recommended policy to use different battery manufacturers or series in the same pack unless you do not care about getting the most running time out of your battery pack

Thank you for the detailed answer.

I discharged the scooter to the level where it won't provide power to the motor. It's at 2% according to the display when I connect the charger.

It won't charge by it's original charger, it shows the charging animation but the % never goes up.

I can charge it by connecting my lab PSU to the discharge plug. Then I connect the original charger and the percentage start to rise to the level where my lab psu charges up. The problem is, that when the charge drops, you cannot charge it with original charger.

[sam_sam_sam]

I'm in the middle of doing it, I'm just very busy these days.

One question:
If the packs are inbalanced, can I balance the packs with me lab PSU without taking apart the whole thing again?
Or I have to balacne it cell by cell?

This is the reason I harped on the idea about balancing so much because I repair power tool battery packs and if you use new and used battery cells in a pack you are going to have issues

Yes you can reuse battery cells however you need to make sure that milliamperes are as close as possible to each as you can with the battery cells that you have on hand but for best results they should at least have nearly the milliamperes per cell as you can for best results

Several things should look out for when trying to reuse battery cells is when charging them the cells should not get warm to the touch if you are charging at 1 amp or less if they do they are referred to as heater cells and consider BAD and should not be reused now one other test you should do and can be done two different ways if you have SkyRc battery tester and you have a tablet and the WiFi module or a USB cable and use your computer can wait until it is finished and look at charging curve it should go up gradually and NOT real steep then leave it hooked to charger for several hours ( if you are doing 4.2 fully charge look and see how long it stays at 4.0 volts but a better test is to discharge the battery cell to 2.5 volts if it allows you to and see if it recover to above 3.00 volts in a couple of hours if so then you should be good to go with these battery cells now if it does not recover to 3 volts then there is a good chance that the battery cell is a self discharging battery cell and should not be used

If you decide not to get a battery tester there is another option but it is less accurate and that is ge a couple MR16 incandescent light bulb maker sure they 12 volt @ 20 to 50 watt ones the 50 watt ones would be better but if can not find them you can use the 20 watt ones it will just take longer to discharge the battery cells down to 2.5 volts what you are interested in is do they recover back to 3.00 volts or higher if so then you are ready to go

If you decide this is to much trouble there is another option but this is the least accurate option to use and that you would discharge the battery cell down to 2.5 volts and leave a voltage meter on the battery cell for at least 2 hours does recover if so then you are ready go

If you decide this is too much work then the last option is change the battery pack up fully with the battery charger and let the battery pack sit for at least a month or maybe 2 months and see if any battery cells are below 3.5 volts if so you might have self discharging battery cells then these battery cells would need to be replaced as well


What you could do is invest in a SkyRc B6 version 2 battery tester at a minimum and test all of your battery cell rails and see how far off the milliamperes are between battery cell rails which should have been done before you bought replacement battery cells because now you will probably find that if you are lucky enough to still have 50 to maybe 75% battery life is left in the one that still have voltage also it not a recommended policy to use different battery manufacturers or series in the same pack unless you do not care about getting the most running time out of your battery pack

[sam_sam_sam]

cell by cell - thats the whole meaning of "balancing"

I second that as well

[stj]

cell by cell - thats the whole meaning of "balancing"

[unimatrix93]

Were you able to figure out what the issue was with your battery pack not wanting to completely charge up

I'm in the middle of doing it, I'm just very busy these days.

One question:
If the packs are inbalanced, can I balance the packs with me lab PSU without taking apart the whole thing again?
Or I have to balacne it cell by cell?

[sam_sam_sam]

Were you able to figure out what the issue was with your battery pack not wanting to completely charge up

[sam_sam_sam]

Check your individual battery cell rails are they below 4.00 volts or above 4.20 volts if so that would explain why it is only getting to 21.0

If any of them are above 4.1 and are any of them below 4.0 then this explains why it is not changing correctly because it is unbalanced

[unimatrix93]

I reassembled the battery and started charging it with the original charger.

Now the battery did charge up to 9%, but now it stopped charging and the charger make this blinking every few seconds.
The battery is at now at 21.1V.

[sam_sam_sam]

When I said that if the voltage falls below 2.5 to 2.8 volts and raises to 4.2 to 4.3 I mean which ever battery cell rail reaches that threshold it stops everything regardless of weather or not the other battery cell rails are to this point or not

Unless it has a balancing function on the BMS but this only for charging not when discharging function is used

[sam_sam_sam]

This should work but what you need to do and do this several times is to run the battery down until the BMS board shuts off the battery voltage and check each battery voltage rail like you did to determine which battery cell rails did not have voltage then take a incandescent light bulb and run each battery cell down to the same voltage level then put it on the battery charger and charge them up until the BMS shuts off the battery voltage and indicates that it is fully charged and now you want to check the battery voltage again to see how balance the battery cell voltage to each individual battery cell rails there should not be much difference between them not more than 0.200 volts for best results

One note however is if when you run it until the BMS board shuts down the voltage to motor that the voltage are basically balanced if not then you have a situation where the new battery cells are so much better than the original battery cells and your running will be greatly reduced and you might make the new battery cells over time behave like the original ones are now this is the reason I mentioned earlier to replace all of them for best results

BMS basically functions this way when which ever battery cell rail fall below 2.5 to 2.8 volt it shuts down the voltage output for discharge and when the battery cell voltage rail rises to 4.2 to 4.3 volts it stops the charging cycle

This is why it is importance for the battery cell rails to be balanced as close as possible to each other for best results

[unimatrix93]

Do not attempt to recharge this battery pack until you resolve the issue with B- to B1 and B2 to B3

It is very possible that the battery cells have an issue with self discharging sin drum and if this is the case it would be better just to replace all battery cells with brand name new ones or barley used ones

Here is how you can determine if you have the self discharge sin drum let the battery pack sit for 30 days and see if the voltage between the different battery cell rails right now you have a difference of 0.3 volts if it has discharge sin drum this difference will get bigger than what you see now

It is not a very good idea to just replace the battery that have no voltage or very little voltage with new ones

Now with that said you can use battery cells that are used BUT make sure that you test each battery cell for milliamperes hour and try to match them as close as possible you can for best results the brand and series is also important but milliamperes hours of each battery cell is more important than not matching them as close as possible

For best results if I were fixing this battery pack I would replace all the battery cells with brand new or barley used battery cells that are brand name battery cells

For best results you should test each battery cell to know what the actual milliamperes hours are because if they are more than 50 milliamperes some BMS protection boards do not charge and discharge battery cells unevenly unless they have a balancing function incorporated in the BMS so this is where you have to do the balancing the battery cells as close as possible for best results

Even if the BMS protection board has a balancing function it still important to balance the battery cells as close as possible for the best possible performance so the balancing function does not have to work harder to get the battery cells balanced

Sorry for the long wait.
I replaced the faulty cells with new ones.
How close they should be in voltage? The new ones are 3.64v. I balanced the rest of the cells to 3.5V. Should I try to charge them to 3.6?

Thank you!

[sam_sam_sam]

it's a high current device,
look the batteries up here and see how much current they can dump into the load.
https://secondlifestorage.com/index..../cell-database

Thanks for sharing this information saves me a lot of time looking them up

[sam_sam_sam]

You more than likely will have to remove the battery tabbing to get to the battery cells that you need to replace anyway so that why I mention about just replacing all of them that are more or matched hopefully

[unimatrix93]

Also, I think I must remove all the metal tabs from the BMS, since I cannot open up the plastic case. I removed every screw yet the two part wont seprate. I guess The tabs are holding it together.

[unimatrix93]

It would better than not doing anything however just be aware of the fact that your running time will suffer somewhat because of doing it this way

If you are going to do it this way just have each group of battery cells basically have the same amount of voltage before you put the battery pack on the battery charger

Understood, and is it safe to disconnect the BMS from the cells? I mean it shouldn't lock itself by doing this right?

[unimatrix93]

it's a high current device,
look the batteries up here and see how much current they can dump into the load.
https://secondlifestorage.com/index..../cell-database

I couldn't find the original cells in the database but I think I found them via google:
GP INR18650/26L Low cost battery cell - 18650, 21700, 26650, LiIon and LiFe

[stj]

it's a high current device,
look the batteries up here and see how much current they can dump into the load.
https://secondlifestorage.com/index..../cell-database