Replace Battery, Controller, or Something Else?

[PCeBiker]

Thanks.
I tried searching for it, but I didn't know what to call it.

It's kind of expensive though, and I don't really need it.

I think that if it comes to it, I'll just charge up the individual cell groups directly at the BMS connector.

I would only need my voltmeter and my bench power supply.

 

[PCeBiker]

I might get this pinout board to plug my BMS cable into, and a 2 pin connector to feed in voltage from my bench power supply.

That would make checking and charging all the cell groups easier and safer.

 

[harryS]

I see that the battery still shuts down around 49.1V, as indicated by your accessory voltmeter. Full charge should be 54.6V, and you're getting close to that. Usually, an unbalanced battery won't read that high, But it only takes one cell group to be off by 1/2 volts, and that would cause it to shut off at the halfway point,

One has to open the battery and check 13 group voltages. That can be done by unplugging the BMS at the balance connector and then using a multimter on the pins individually. The above tool, while nice, isn't needed. Nor is it needed to connect a RC balance charger, which will show the balance voltages on its display. You do need to understand how to wire up a harness for it,. All of this is beyond what most people wanat to do though. The guy in the video is a confirmed DIY battery hobbyist,. I do wonder how his battery worked long term after he balanced it. If it got unbalanced because of failing or mismatched cells, rebalance might be temporary.





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[PCeBiker]

One has to open the battery and check 13 group voltages. That can be done by unplugging the BMS at the balance connector and then using a multimter on the pins individually.

That's the part that makes me nervous.
If I manage to touch the probes together while checking the voltage, I'll short out a cell group.
That's when bad things happen.

The above tool, while nice, isn't needed. Nor is it needed to connect a RC balance charger, which will show the balance voltages on its display.

An RC balance charger only goes up to 8S and I need 13S. My balance charger is 6S, so I'd have to charge my battery pack 3 separate times.

You do need to understand how to wire up a harness for it,.

A pinout board with a 2 pin connector will allow my to check the voltage of each cell group with my voltmeter, then I would set my bench charger to the highest voltage reading and charge each cell group to that voltage using the 2 pin connector.
I'd have to do it 13 times.
I might take a month or two.

All of this is beyond what most people wanat to do though. The guy in the video is a confirmed DIY battery hobbyist,.

.., the sales person (who is also a RC hobbyist) said it should work.

I mistook this statement by thinking the sales person is an RC hobbyist as well as the OP.

I realize now that the salesman is an RC hobbyist as well as a salesman.

I do wonder how his battery worked long term after he balanced it. If it got unbalanced because of failing or mismatched cells, rebalance might be temporary.

Good point.
If I were ever to do this I would see how long the battery stays balanced.
If it quickly goes out of balance, I'd replace the battery.

I would never try to replace a bad cell or cell group with a new cell or group.

That's how you end up burning down New York city.

Batteries do wear out. Having a bad cell group really helps to wear out a battery.

 

[ronaldrodgers]

Thank you, HarryS and PCeBiker.

 

[ronaldrodgers]

Good Morning,
The ebike battery stopped charging my lights last night. The battery's capacity according to the multimeter was 3.2 volts. I didn't trust the reading so I used the meterto measure other batteries that that I owned. This morning I retested the battery, it was still at 3.2 v. I put the battery on the charger at 8:30 Am (EST). I will report on my results tomorrow.

Interesting fact I found out this week. My battery needs to be charged while truned on according to online sources. This was not mentioned in the battery's paper work.

 

[ronaldrodgers]

Okay, it is about 12:00 AM.
Here are my readings with the time. please remember the battery was/is on the charger
9:00 ≈50v Analog
9:30 51.9 (digital) ≈51 (analog)
10:10 53.6 or 7 ≈52 (analog)
11:50 54.4 (digital) ≈53 (analog) At this time the light on the charger was green. The reason for the non-uniform time spans is because I was running errands.

 

[harryS]

Going to be 55F today and 56F tomorrow in Indy. Take a ride and see what happens. I hope to get out on my ebike this afternoon,

By the way, the battery BMS shuts off the cells from the outside world if one or more groups discharge too low. That 3.2V you read wasn't real. Just leakage coming off the battery BMS transistors. It would have been at least 40V if you looked inside at the cell outputs.

 

[ronaldrodgers]

@ HarryS- I did take a ride, about 25 miles. I saw a bird of prey flying with something in its mouth.
I took the battery off the charger after 8 hours (4:30), it was still at 54.4/≈53. So tomorrow I will take it for a ride.

 

[PCeBiker]

I might get this pinout board to plug my BMS cable into, and a 2 pin connector to feed in voltage from my bench power supply.

That would make checking and charging all the cell groups easier and safer.

I bought some neat stuff.

I might never use it, but it's to have.

Thanks @ronaldrodgers for showing me the hole with all the trinkets.

 

[ronaldrodgers]

I have not tried the battery yet. Yesterday was breezy (gusts up to 25m/h). Today was suppose to be rainy and breezy, but it is sunny. So I will test the battery today.

I bought some neat stuff.

View attachment 167794you


I might never use it, but it's to have.

Thanks @ronaldrodgers for showing me the hole with all the trinkets.

@PCeBiker-You are more than welcome.

 

[harryS]

"I have (not) tried the battery yet. Yesterday was breezy (gusts up to 25m/h). Today was suppose to be rainy and breezy, but it is sunny. So I will test the battery today."

Have a good ride, but you might want to carry that other battery or be close to home when you hit 49 volts.

 

[PCeBiker]

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.

You can sometimes "force a balance" by leaving your battery on the charger for sometimes up to a day or two.

The BMS should make sure that no cell group goes over 4.21 Volts and any cell groups that are over discharged can slowly trickle charge up to 4.21 Volts.

Some guys do this yearly as part of regular battery maintenance.

You'll need to be careful and keep an eye on your battery if you try it.

 

[ronaldrodgers]

What a morning! Sunny with a gentle breeze, 2 hours later rainy and windy.
I was able to get a 8 mile bike ride in bebore it started to rain. The bike felt easier to pedal at power level one, than the last time I rode the bike at level 1. Below is today's data and 6/23/2021. Both sets of data are from the watts meter.
1st Stop 2nd Stop
Date. 12/09/2023 06/24/2021 06/24/2021
Miles travelled. 8.2 6.46 6.47
Volts Used 2.35 1.96 1.47
Amphours 1.02 0.87 0.79
Miles/Amphour 8.01 7.44 8.19
Mile/Volts. 3.49 3.30 4.40

My thoughts: The 2023 are comparible with 2021 data. The 2021 route was most likely in the eastern section of Eagle Creek Park, today route was through the local nieborhoods. ECP route is flatter and more protected from the wind.

I plan to ride and then drain the battery as before. I will keep this thread updated as new information.

 

[ronaldrodgers]

I need to rewrite the data so that it easier to read. I going to have lunch first then work on it.

 

[PedalUma]

I like to slowly discharge by using one of those laptop cooling pads. They have two USB fans.

 

[PCeBiker]

I was thinking a usb light like this.

Do you have a cell phone?
You could probably charge it with your bike battery.

 

[ronaldrodgers]

I was thinking a usb light like this.

View attachment 167814


Do you have a cell phone?
You could probably charge it with your bike battery.

Yes, but they did not eat up power like the bike light did.

 

[ronaldrodgers]

This is the data, although there are minor differences from the previous post.

 

[ronaldrodgers]

I rode 15 miles today. After the ride all the power indicator lights still lit up. The voltage on the voltmeter was 49.2 at the end of the ride. I also used 2.58 volts on this ride. Is there a reason that .2 volts, yet went 7 more miles farther?

My rides consist of circling around my and the neighboring neighborhoods (LOL), so if power does cut out I am only 2 miles from home. My goal is to reach at least 40+ miles on this charge. I am currently doing these trials on level one. If anyone wants to see my data sheets I am more than willing to post them.