Here are the symptoms I had with a Carrera Crosscity: it was working correctly last year, then it was left over the winter and now on the first attempt to use it this spring it did not work. The bike display did not come on and the charger LED went immediately from RED to GREEN when connecting the battery. With the battery removed and the switch turned on, there was no voltage present on the +/- terminals of the battery connector. I checked that there was voltage on the charger's plug, so I knew that there was something wrong with the battery. It goes without saying, if you are going to open up the battery pack then you need to be very careful, it is energy dense, and you don't want to short anything out! I disassembled the pack and measured about 40V across the main connection points to the end cells, so I knew that it was unlikely that there was a problem with them. I then suspected the BMS and so I carefully removed that from the pack to inspect. In doing so, I discovered that 4 of the 0603 SMT inductors (arrowed in the photo) were measuring open circuit. They should be less than 1 ohm. They didn't look electrically damaged, they looked like the metal endcaps were corroded, so it could have been a manufacturing problem since there were no signs of water ingress. I replaced the faulty inductors with some new ones and that fixed the problem with the pack, the battery charged, and the bike worked. The exact inductance of the inductors is not that important, they are probably only there for EMC purposes. You could just remove any faulty inductors and replace them with a thin piece of wire, just be careful that you don't short out anything else! I hope that is helpful to someone else.
How many Samsung 29Es are in this battery? Is it easy enough to replace them all and reassemble? I've ordered a new one of these batteries as my current one is holding less and less of a charge but I wouldn't mind having a go at DIY-ing the old one once I get my new battery.
30 X 18650 cells of your choice! They're fine to do, you can do them all in a line instead of how these are built, and it still fits, which is way easier.
@@EbikeRepairs Thanks. Another daft question - is there a higher capacity alternative to the 29Es (2850mAh) that is the same size? I've seen the Samsung 30Q Battery (3000mAh) which look like they might be a possibility?
Hi mate I have a cross city e bike with 2 battery’s bike been sitting in shed for a year now battery’s in dormant mode won’t charge . What do you suggest any method of trying to wake them up etc? Many thanks in advance
Hi mate my partner has got an ebike 36v 10 amp hours she says it keeps on cutting off so she had to turn the power off and back on again then it's fine get so far up the street then cuts out again could this be a problem with one off the battery banks the battery still reading 36 I tried all the connectors to the wheel brake sensor etc etc r today seem to be fine I think you have dealt with one of these batteries before it is the post seat Mount battery looks like a square on
Here are the symptoms I had with a Carrera Crosscity: it was working correctly last year, then it was left over the winter and now on the first attempt to use it this spring it did not work. The bike display did not come on and the charger LED went immediately from RED to GREEN when connecting the battery.
With the battery removed and the switch turned on, there was no voltage present on the +/- terminals of the battery connector. I checked that there was voltage on the charger's plug, so I knew that there was something wrong with the battery.
It goes without saying, if you are going to open up the battery pack then you need to be very careful, it is energy dense, and you don't want to short anything out! I disassembled the pack and measured about 40V across the main connection points to the end cells, so I knew that it was unlikely that there was a problem with them.
I then suspected the BMS and so I carefully removed that from the pack to inspect. In doing so, I discovered that 4 of the 0603 SMT inductors (arrowed in the photo) were measuring open circuit. They should be less than 1 ohm. They didn't look electrically damaged, they looked like the metal endcaps were corroded, so it could have been a manufacturing problem since there were no signs of water ingress.
I replaced the faulty inductors with some new ones and that fixed the problem with the pack, the battery charged, and the bike worked. The exact inductance of the inductors is not that important, they are probably only there for EMC purposes. You could just remove any faulty inductors and replace them with a thin piece of wire, just be careful that you don't short out anything else!
I hope that is helpful to someone else.
I'd only add that I recommend checking every cell group at the balance wires not just the overall pack voltage, as you can have out of balance cells.
Thankyou for a nice video!
My pleasure! ❤️
Love your videos!
Aloha from Hawaii!
Thanks dude! Aloha 🌺
I love your videos
Thanks so much! It's really nice to hear great feedback
How many Samsung 29Es are in this battery? Is it easy enough to replace them all and reassemble? I've ordered a new one of these batteries as my current one is holding less and less of a charge but I wouldn't mind having a go at DIY-ing the old one once I get my new battery.
30 X 18650 cells of your choice! They're fine to do, you can do them all in a line instead of how these are built, and it still fits, which is way easier.
@@EbikeRepairs Thanks. Another daft question - is there a higher capacity alternative to the 29Es (2850mAh) that is the same size? I've seen the Samsung 30Q Battery (3000mAh) which look like they might be a possibility?
Yes MJ1 cells from LG or Samsung 35e... 3.5AH per cell... All 18650 cells so the same exact physical size!
Just finding the cells I guess
Had the same battery case. Got broken on many places. Dont use it anymore.
They're brittle if left in the sun...
is there rebuild off battery pack coming
One day! Loads of them around from much larger CZcamsrs, though. 👍
What could cause all cell groups to go bad?
I think it got left to sit for a VERY long time!
Hi mate I have a cross city e bike with 2 battery’s bike been sitting in shed for a year now battery’s in dormant mode won’t charge . What do you suggest any method of trying to wake them up etc?
Many thanks in advance
Send them down to us and I'll have a go at it for you!
@@EbikeRepairs
Thanks mate I will send them what’s the address of you guys ?
@@EbikeRepairs please let me know where to send them .
Thanks
Is there a fuse inside that battery pack?
I'm not sure - it's gone back now. Sometimes they do, sometimes they don't! Usually a blade fuse like from a car, if it does.
Hi mate my partner has got an ebike 36v 10 amp hours she says it keeps on cutting off so she had to turn the power off and back on again then it's fine get so far up the street then cuts out again could this be a problem with one off the battery banks the battery still reading 36 I tried all the connectors to the wheel brake sensor etc etc r today seem to be fine I think you have dealt with one of these batteries before it is the post seat Mount battery looks like a square on
Almost certainly a bad cell group or bad BMS. If you want to send it to us we could take a look. Thanks!
@@EbikeRepairs sounds like a plan what soft of price would it be mate