Replace Battery, Controller, or Something Else?

R

ronaldrodgers

Member
Hello, I hope everyone is having a good day. I have a 2014 Raleigh Tekoa. In 2019 replaced the original battery with a Unit Pack Power 48V13AH battery. I installed a 200A voltmeter on the bike when the battery was replaced. When I first purchased the battery, it would be drained at 40 volts. I keep the battery inside, except when it is in use.

My motor shuts off after about 10-20 miles depending on the power level. I can turn the battery off and then back on, with no code errors, and the motor will power up for a short distance (less than a mile). After the motor quits, the voltmeter reads around 48-49 volts, and I confirmed this reading with a multimeter.

If the battery was going bad wouldn’t the reading be closer to a 40 volts? Or do I have a controller issue? Does anyone have another idea(s)?

Thank you for taking time to read this.
 
ronaldrodgers said:
Hello, I hope everyone is having a good day. I have a 2014 Raleigh Tekoa. In 2019 replaced the original battery with a Unit Pack Power 48V13AH battery. I installed a 200A voltmeter on the bike when the battery was replaced. When I first purchased the battery, it would be drained at 40 volts. I keep the battery inside, except when it is in use.

My motor shuts off after about 10-20 miles depending on the power level. I can turn the battery off and then back on, with no code errors, and the motor will power up for a short distance (less than a mile). After the motor quits, the voltmeter reads around 48-49 volts, and I confirmed this reading with a multimeter.

If the battery was going bad wouldn’t the reading be closer to a 40 volts? Or do I have a controller issue? Does anyone have another idea(s)?

Thank you for taking time to read this.
Click to expand...
Sounds like a battery issue. The cells or a battery management system. What does your battery charge up to in volts? 54? It will act as you described if it cannot hold a charge properly.

How many times do you think you have dicharged and charged (cycled) the battery since 2019?
 
You probably have an unbalanced battery. When the battery is reading 49 volts, some of its cell groups have reached their low voltage limit, shutting off the battery, even though the rest of the cells are still well above half charge, When you go to recharge it, the good cells quickly hit full charge and shut off the charger, but the weak cells remain starved..

There's very little you can do, except buy another battery. UPP doesn't use balance BMS, which would try to equalize the disparate cells. Try to get a battery advertising name brand cells (LG, Samsung, Panasonic, etc) in the bnxt battery. Quality cells tend to stay in balance much better.
 
ronaldrodgers said:
If the battery was going bad wouldn’t the reading be closer to a 40 volts? Or do I have a controller issue? Does anyone have another idea(s)?
Click to expand...


You can try to revive your battery somewhat by connecting your battery to a very small load after your BMS has shut down the battery.

If you have a USB port, you could drain the battery down through that, or connect it to a 5 Watt light or something.

You should be able to bleed down from 49 Volts to closer to 40 Volts if you drain it down very slow.

The BMS should still protect the battery from over discharge and pull mostly from the half charged cells.
 
Thank you, PCeBiker. I will try what you suggested. I report to the threat after I drain the battery, by riding, and then continue draining the battery with the 5 volt light. This will occur tomorrow, because it is raining in Indy.
 
ronaldrodgers said:
Thank you, PCeBiker. I will try what you suggested. I report to the threat after I drain the battery, by riding, and then continue draining the battery with the 5 volt light. This will occur tomorrow, because it is raining in Indy.
Click to expand...

Keep an eye on your battery while doing this and/or keep it in a safe place in case something goes wrong.

As far as I know, it shouldn't burst into flames if something goes wrong, but the battery could shut down completely and stop taking a charge.
It sounds like your battery is almost shot though, so I think it's worth a try.
I would try it if it were my battery.

ronaldrodgers said:
I report to the threat ...
Click to expand...

I know that's a typo, but keep any potential dangers or losses in mind while you do this.

I don't think that you have too much to worry about.
 
I started my ride and went about .6 miles and my chain started to jump off the front sprocket. So I will be running a bike light off the battery through the USB port. The battery on the bike light is very low. I will report after I get some results.
Now I need to work on the front sprocket of the bike.
 
ronaldrodgers said:
I started my ride and went about .6 miles and my chain started to jump off the front sprocket. So I will be running a bike light off the battery through the USB port.
Click to expand...

It's probably even better to run the battery down slowly starting from a higher state of charge.

It could take a LONG time to drain the battery though. Most USB ports are 5 volts with a 2 amp max, so 10 Watts.

It could take a day or two?
That gives you time to work on your e-bike.
You can use your headlight as a work light. 😂
 
PCeBiker said:
It's probably even better to run the battery down slowly starting from a higher state of charge.

It could take a LONG time to drain the battery though. Most USB ports are 5 volts with a 2 amp max, so 10 Watts.

It could take a day or two?
That gives you time to work on your e-bike.
You can use your headlight as a work light. 😂
Click to expand...
LOL Yeah, I could use tonight to check, clean and re-oil the chain and front sprocket. I would rather ride in the winter sun, than work on my bike. I took my other bike for a 20 mile ride.

The battery did go down 0.2 v during my ride. 😂
 
11/29/2023 Update- When checking out why the bike chain was skipping/jumping off the front sprocket/chainring there were three issues; 1) worn front sprocket/chainring, 2) a bent outer plate on the chain, and 3) a chain that needed more oil. I am working on these issues. Sprocket/chainring is on order.

I am charging, discharging, and recharging bike lights and old phones. I have also contacted the Batteries Plus store and will be bringing in the battery at a later date to check the balance of the battery. So far the battery has gone down 1 volt. 🤔

Also the battery was bought in 2021, not 2019
 
12/01/2023 Update
I recharged the battery yesterday. Leaving it on the charger longer than needed. Using a multimeter its capacity was 54.5 volts. While on the charger its capacity was 55.6 volts.

Today I took it to Batteries Plus. They were not able to help me.

Tomorrow I am going to the Indy RC hobby Raceway and store to see if they can help me. They have assisted me in the past. My sprocket/chainring will be here next week.
 
Update-
On 12/2/2023 Went to Indy RC store showed them the Youtube video about balancing an ebike battery, the sales person (who is also a RC hobbyist) said it should work. On my way home I stopped at EZ Bike Rental to ask what they do for batteries that need balancing. EZ Reantals were closed. I also got the sproket/chainring on Saturday as well.
On 12/3/2023 installed the new chainring on the bike. I did send an email to EZ Rentals
I took Monday off from this project.
12/5/2023 Rode 13.2 mile on the bike on Level 2. The beginning wattage was about 53.4 the ending was 48.?? I was able to ride the bike on Level 1, but seemed that no power was getting to the motor even though the on bike watt meter was recieving power. After the ride I plug an old phone into the battery. It was recording sounds and the flash light was on. The multimeter measured the battery's capacity as 49.1 when I started charging. After 2 hours of phone charging the reading was the same. There is another bike rental company in Indy and I will check with them tomorrow.
 
Is this the Youtube video that you are referring too ??


That's pretty cool !!

That's right up my alley. I've got a bench power supply and can use it to charge individual cell groups.

I can just plug into my BMS connector and charge each cell group individually up to the same voltage with just a two wire lead from my bench power supply.

I've got a Li-ion balance charger too, but it only goes up to 6S and I need 13S for my 48 Volt battery.
 
Last edited:
Yes, that is the video. The person at Indy RC was able to find a contection for a 13S, for the battery charger. I don't have the instrument to read the individual cells, the balance charger, nor the connector. I am looking at roughly about 1/2 for the cost of the battery to purchase those items. I need to locate the individual instruments, possibly rent them locally.

Tomorrow I plan to reach out to another ebike rental company as well. BTW the recharging of the bike light brought the power capacity down 1 volt. I won't leave items plugged into the battery while we sleep.
 
ronaldrodgers said:
I don't have the instrument to read the individual cells,..
Click to expand...

Do you happen to know what this instrument is and where I can find it?


Screenshot_20231205-170122_YouTube.jpg


I want one. 😂

I don't really need it, but I think that it's fricken Cool 😎. 😂
 
 
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