BMS - Battery Management System (Technical) 14s8p 52 volt 25amp

[Panny]

My main ride is an EUC Modified " KingSong S22 Eagle" (126 volts)
I also have an EUC KingSong S22 Professional, Apollo Phantom V2, Apollo Ghost (stand-up scooter), A "Modified" Apollo Phantom V2 "Rocket" Lay-down Scooter (52 Volts). There are only two of these "Rockets" in the world, I know because I built them both!

I could have Saved $1000. if I knew the answers to these next questions!

I am very familiar with current battery technology and general Electricity and Electronics , But I am just a beginner when it comes to understanding exactly how to wire up a new BMS (Battery Management System).

Just recently, I realized my Apollo Phantom V2 Battery Voltage was not charging to full potential. (56 volts). I was getting 53 volts max. My run-time was cut in half.
I decided to get a new battery pack.

WOW! $1,000. once you put in the Taxes
I installed the new battery and all seems fine!

I need to know exactly what when wrong, Did I really need to spend a $1000, on a one year old scooter?
or
Could I have repaired it for about $20.
You decide!

I placed the old old battery pack on the workbench and completely disassembled it ( 14"S"series 9"P" parallel
7 out of 14P were showing 3.5 or 3.6 volts and the remaining were all above 4.0

I disassembled the pack!
Much to my surprise!

Almost all of the individual batteries were in perfect health
Individually able to charge above 4.0 volts, most at 4.2
and after sitting 96 hours on the workbench almost all were holding 4.1 or better.

Capacities of the batteries were all within tolerances 2700 MAH to 2600 MAH
Internal Resistance all between 20 to 35 m

None of the anodes' were overheating , 95 F to 103 F with a couple of exceptions at 107 F @ 500 MAH
charging or discharging fine

Either I am missing something or my BMS has a malfunction
I am presently setting it up on the bench when I realized I don't understand?

# 1 - Is it possible to use 14 single cells for the test or do I have to use all 126 Cells.
# 2 - What Voltages am I testing for ?
# 3 -There are 7 blue wires, 7 White wires, 1 red and 1 black
I am guessing each Parallel pack charges with the blue white wires at 8.4 volts,
and the red black wires checks for total Voltage 35 to 56 volts to be active!
Is this correct?


IF the BMS checks out to be in proper working order then I have to do a load test on each
one of the 126 batteries to find the low ones. ( That will take some time )

If you know the answer to these few Questions or Where I can find the answer that would be much appreciated!

 

[James340]

My main ride is an EUC Modified " KingSong S22 Eagle" (126 volts)
I also have an EUC KingSong S22 Professional, Apollo Phantom V2, Apollo Ghost (stand-up scooter), A "Modified" Apollo Phantom V2 "Rocket" Lay-down Scooter (52 Volts). There are only two of these "Rockets" in the world, I know because I built them both!

I could have Saved $1000. if I knew the answers to these next questions!

I am very familiar with current battery technology and general Electricity and Electronics , But I am just a beginner when it comes to understanding exactly how to wire up a new BMS (Battery Management System).

Just recently, I realized my Apollo Phantom V2 Battery Voltage was not charging to full potential. (56 volts). I was getting 53 volts max. My run-time was cut in half.
I decided to get a new battery pack.

WOW! $1,000. once you put in the Taxes
I installed the new battery and all seems fine!

I need to know exactly what when wrong, Did I really need to spend a $1000, on a one year old scooter?
or
Could I have repaired it for about $20.
You decide!

I placed the old old battery pack on the workbench and completely disassembled it ( 14"S"series 9"P" parallel
7 out of 14P were showing 3.5 or 3.6 volts and the remaining were all above 4.0

I disassembled the pack!
Much to my surprise!

Almost all of the individual batteries were in perfect health
Individually able to charge above 4.0 volts, most at 4.2
and after sitting 96 hours on the workbench almost all were holding 4.1 or better.

Capacities of the batteries were all within tolerances 2700 MAH to 2600 MAH
Internal Resistance all between 20 to 35 m

None of the anodes' were overheating , 95 F to 103 F with a couple of exceptions at 107 F @ 500 MAH
charging or discharging fine

Either I am missing something or my BMS has a malfunction
I am presently setting it up on the bench when I realized I don't understand?

# 1 - Is it possible to use 14 single cells for the test or do I have to use all 126 Cells.
# 2 - What Voltages am I testing for ?
# 3 -There are 7 blue wires, 7 White wires, 1 red and 1 black
I am guessing each Parallel pack charges with the blue white wires at 8.4 volts,
and the red black wires checks for total Voltage 35 to 56 volts to be active!
Is this correct?


IF the BMS checks out to be in proper working order then I have to do a load test on each
one of the 126 batteries to find the low ones. ( That will take some time )

If you know the answer to these few Questions or Where I can find the answer that would be much appreciated!

I recently had the same problem.My pack was out of balance.I manually balanced it.Dischararging the 4.2 cells& charged the 3.6 cells.I got it with in .04 volt.I ordered a active balancer so I will not have to spend hours babysitting the pack while manually balanced

 

[Panny]

I just realized I made an error in my thread it the battery is 14s9p not 14s8p I am just new at this forum and I don't know how to edit the thread, Is it possible to edit ?
Thank you for your response, Its good to know there are similar minded people.

I am still working on my phantom V2, When I ordered a new battery pack, they sent me a new battery with ONE XT90 plug on the front two small XT30 and a massive fuse holder. Obviously Apollo switched battery manufacturers. Now I am waiting for Amazon to send me a Male XT90 connector so I can modify it to connect to the two existing XT60 that originally came with my phantom v2.
It seems I am not alone with the Apollo battery problems. My other Apollo products are staring to show the same symptoms, I suspect the Chinese Batteries are the problem. I hope this new one is better!

 

[Panny]

I recently had the same problem.My pack was out of balance.I manually balanced it.Dischararging the 4.2 cells& charged the 3.6 cells.I got it with in .04 volt.I ordered a active balancer so I will not have to spend hours babysitting the pack while manually balanced

What balancer did you order? Let me know if it is any good I am looking to buy one also!

 

[James340]

What balancer did you order? Let me know if it is any good I am looking to buy one also!

I have been using the board in the right photo and it is working for the other packs.The pack that went out of balance I abused last summer.110 degree temperature and I was doing sustained full throttle on a 1000 watt DD hub motor.The photo on the left is the balancer I ordered from AliExpress.They also sell on Amazon but cost more.

 

[docw009]

I placed the old old battery pack on the workbench and completely disassembled it ( 14"S"series 9"P" parallel 7 out of 14P were showing 3.5 or 3.6 volts and the remaining were all above 4.0
.......
Either I am missing something or my BMS has a malfunction
I am presently setting it up on the bench when I realized I don't understand?

# 1 - Is it possible to use 14 single cells for the test or do I have to use all 126 Cells.
# 2 - What Voltages am I testing for ?
# 3 -There are 7 blue wires, 7 White wires, 1 red and 1 black
I am guessing each Parallel pack charges with the blue white wires at 8.4 volts,
and the red black wires checks for total Voltage 35 to 56 volts to be active!
Is this correct?

IF the BMS checks out to be in proper working order then I have to do a load test on each
one of the 126 batteries to find the low ones. ( That will take some time )

Not a 20 dollar fix, Your battery is unbalanced with half the groups probably around 3.7=3.8 volts when the rest are full charge, Some people have manually recharged their low groups amd equalized the voltages, but the nature of the battery is that it will happen again.

Here is a quick tour of the mysterious BMS. It's for a 10S battery, but extend it to a 14s. Those 7 blue and 7 white wires are likely the balance leads B1-B14. Black is B0, amd ref may be a duplicate of B14. This BMS has separate internal switches X2 and X4 on the ground leg of the charge and discharge connectors. SOme use a simgle ground fro both connectors. so only have one switrch.



When you're charging, the BMS monitors the group voltages. As soon as one group hits fiull charge, it can do two things. The first is to open the switch and shut off charging, leavng the remaining groups unable to cath up, The second is for a balance BMS. Those will bleed off charge on the higher groups, allowing the rest to catch up, A lot of batteries dom't use balance BMS. Yours is likely non-balance. If you leave it on the charger for a week, a balance BMS would probably get to 58,6V.

Yeah, you would have to load test all 126 cells individually. Take forever.

 

[Panny]

Thanks for your input, Makes sense to me!

 

[raming]

Not a 20 dollar fix, Your battery is unbalanced with half the groups probably around 3.7=3.8 volts when the rest are full charge, Some people have manually recharged their low groups amd equalized the voltages, but the nature of the battery is that it will happen again.

Here is a quick tour of the mysterious BMS. It's for a 10S battery, but extend it to a 14s. Those 7 blue and 7 white wires are likely the balance leads B1-B14. Black is B0, amd ref may be a duplicate of B14. This BMS has separate internal switches X2 and X4 on the ground leg of the charge and discharge connectors. SOme use a simgle ground fro both connectors. so only have one switrch.

View attachment 361696

When you're charging, the BMS monitors the group voltages. As soon as one group hits fiull charge, it can do two things. The first is to open the switch and shut off charging, leavng the remaining groups unable to cath up, The second is for a balance BMS. Those will bleed off charge on the higher groups, allowing the rest to catch up, A lot of batteries dom't use balance BMS. Yours is likely non-balance. If you leave it on the charger for a week, a balance BMS would probably get to 58,6V.

Yeah, you would have to load test all 126 cells individually. Take forever.

I had similar 'imbalance' issues from a heavily used (>450 Cycles) 13S3P 48V battery. After charging, I had only about 1/4 the capacity of the 7.8Ahr pack before the BMS shut down the pack!
My teardown discovered one 3cell group had 3.0V while all the others were above 4.0V.
The 3 'suspect' cells were individually tested and each had at least 80% of their 2.7Ahr rating. However, one of the cells had a very high voltage leakage rate (>10x versus 'good' neighbor). This cell's voltage leaked from 4.1V to 3.6V in less than 30days during room temperature storage.
Also, the original BMS Battery 13Cell lines terminate through PCB series resistors and have no FET's (which are used for passive balancing). So, the bad cell pack limits the total charging since the neighboring higher voltage cells reach max voltage (4.2V) well before this leakage-discharged one and, with no balancing, the out of balance cell can never catch up. The fix was to replace the 'leaky' cell and it's two companions AND to replace the OEM BMS with a Bisida replacement BMS which has passive cell balancing.
My takeaway is that one or more of the 18650 LiPO's become leaky as they age (leak at about a 3mAh rate) and therefore drop their voltage faster than the balance circuit can keep up. (See Leakage Plot)

Other observations:
1. One needs to study the more popular BMS IC databooks and PCB layouts used in these battery pack BMS units. Even then, they can be configured at different voltages, sequences and charging thresholds by the Battery Pack manufacturer; so it is not obvious how and when the Balancing circuit operates. (See photo of OEM Original with the BMS chips and Cell Sense Lines/Resistors)
2. I continued to use the repaired battery pack and soon found another 'Leaky' Maverick appeared. (I had modified the battery pack with external test points for each of the 13 cell groups so that I could monitor and/or charge each cell group... see photo).
3. I am keeping the battery pack connected to the charger (in green charge mode where balancing occurs over many hours) over several days to see if the newly added balancing circuit can keep the maverick cell group charged. (I am hoping that I can live with the maverick by keeping the balancing active between each use).