BBS02 battery indicator doesn't drop

[Pizzabroodje]

Hi!

I build an ebike with a BBSHD and 52V 17.5Ah shark battery for someone.
I have a few issues though, one of which is that the battery indicator on the display (Bafang 500C), doesn't drop below 100%.
If set to Voltage, the number does drop, but it still doesn't lose any bars.
The battery has been connected fully charged, and lost quite a bit of battery since. The indicator on the battery itself did go down from 4 to 3 green lights.

 

[E-HP]

Hi!

I build an ebike with a BBSHD and 52V 17.5Ah shark battery for someone.
I have a few issues though, one of which is that the battery indicator on the display (Bafang 500C), doesn't drop below 100%.
If set to Voltage, the number does drop, but it still doesn't lose any bars.
The battery has been connected fully charged, and lost quite a bit of battery since. The indicator on the battery itself did go down from 4 to 3 green lights.

A lot of the time those bar displays and controllers are calibrated to the standard voltage (36, 48, 60, 72), so while 52 is a popular option, it’s an oddball/in between voltage. If the controller is choosing 48 as the closest option, then a 52v battery will read full most of the time.


Sent from my iPhone using Tapatalk

 

[Pizzabroodje]

Hi!

I build an ebike with a BBSHD and 52V 17.5Ah shark battery for someone.
I have a few issues though, one of which is that the battery indicator on the display (Bafang 500C), doesn't drop below 100%.
If set to Voltage, the number does drop, but it still doesn't lose any bars.
The battery has been connected fully charged, and lost quite a bit of battery since. The indicator on the battery itself did go down from 4 to 3 green lights.

A lot of the time those bar displays and controllers are calibrated to the standard voltage (36, 48, 60, 72), so while 52 is a popular option, it’s an oddball/in between voltage. If the controller is choosing 48 as the closest option, then a 52v battery will read full most of the time.


Sent from my iPhone using Tapatalk

But the 500C display should read correctly at 52V right?
I've set it 'U B E' as there wasn't a 48V option though.

 

[Chalo]

I have a few issues though, one of which is that the battery indicator on the display (Bafang 500C), doesn't drop below 100%.
If set to Voltage, the number does drop, but it still doesn't lose any bars.

My BBS02 came with the most basic display, without any numeric voltage option. I found that even with a true 48V battery, it would indicate full charge until more than a third of its range was used up. I got used to tracking distance traveled rather than state of charge.

 

[Pizzabroodje]

I have a few issues though, one of which is that the battery indicator on the display (Bafang 500C), doesn't drop below 100%.
If set to Voltage, the number does drop, but it still doesn't lose any bars.

My BBS02 came with the most basic display, without any numeric voltage option. I found that even with a true 48V battery, it would indicate full charge until more than a third of its range was used up. I got used to tracking distance traveled rather than state of charge.

Well that's the thing. This one does have a numeric voltage option and it shows the voltage even on 58V, but always show the battery as full.

I'm down to 53V now from 58. I'll have to see what it does when going a little more under 54.6V (full charge of 48v battery).

 

[E-HP]

Well that's the thing. This one does have a numeric voltage option and it shows the voltage even on 58V, but always show the battery as full.

I'm down to 53V now from 58. I'll have to see what it does when going a little more under 54.6V (full charge of 48v battery).

I just use the voltage readout to determine my charge and ignore the bar display. I consider 57 to be full and 47 to be empty to make the mental math easier.

 

[Pizzabroodje]

Well that's the thing. This one does have a numeric voltage option and it shows the voltage even on 58V, but always show the battery as full.

I'm down to 53V now from 58. I'll have to see what it does when going a little more under 54.6V (full charge of 48v battery).

I just use the voltage readout to determine my charge and ignore the bar display. I consider 57 to be full and 47 to be empty to make the mental math easier.

Do you have the 500C too? Or what display?

 

[E-HP]

Do you have the 500C too? Or what display?

Nope, just saying it could be a 52volt issue, so if you can't set the display to 52 volts, it will auto sense one of the standard voltages. So, the workaround is to use voltage as a digital version of the bar display.

 

[Pizzabroodje]

Do you have the 500C too? Or what display?

Nope, just saying it could be a 52volt issue, so if you can't set the display to 52 volts, it will auto sense one of the standard voltages. So, the workaround is to use voltage as a digital version of the bar display.

Okay I need to know if the Bafang 500C normally shows the percentage correctly for a 52V battery though.
If it's normal that it doesn't, I will indeed use the voltage as an indicator of battery life.

 

[E-HP]

For me, 52 volts is half charge, and that's the only data point I really care about when I'm on a long ride.

 

[dogman dan]

Just add a secondary two wire voltmeter if you just want volts. about 5 bucks.


Or better still a watt meter. Judging half by volts does not work all that great, but if you know watt hours, and have tested your batteries real world capacity in wh, you know exactly where you stand every mile of every ride.

A cycle analyst is the best, and worth it. But even a cheap watt meter mounted in your battery box is a big help.

 

[Pizzabroodje]

The display indeed displays percentage for 48V instead of 52V. I think that's weird though as the 500C display is advertised to work properly with 52V...
Also I noticed that the voltage on the display drops when pedaling and goes up again when stopping with pedaling.

Just add a secondary two wire voltmeter if you just want volts. about 5 bucks.


Or better still a watt meter. Judging half by volts does not work all that great, but if you know watt hours, and have tested your batteries real world capacity in wh, you know exactly where you stand every mile of every ride.

A cycle analyst is the best, and worth it. But even a cheap watt meter mounted in your battery box is a big help.

There already are volts and wattage displayed on the 500C display. Would a cheap Chinese meter be more accurate than that? A cycle analyst is too expensive.

 

[E-HP]

The display indeed displays percentage for 48V instead of 52V. I think that's weird though as the 500C display is advertised to work properly with 52V...
Also I noticed that the voltage on the display drops when pedaling and goes up again when stopping with pedaling.

Just add a secondary two wire voltmeter if you just want volts. about 5 bucks.


Or better still a watt meter. Judging half by volts does not work all that great, but if you know watt hours, and have tested your batteries real world capacity in wh, you know exactly where you stand every mile of every ride.

A cycle analyst is the best, and worth it. But even a cheap watt meter mounted in your battery box is a big help.

There already are volts and wattage displayed on the 500C display. Would a cheap Chinese meter be more accurate than that? A cycle analyst is too expensive.

Those meters also record watt-hours (energy) instead of just watts (instantaneous capacity), which is a better measure of what you've used. Meters are good for learning what you're setup is capable of, so if you go from full to empty and check the total watt-hours, that's the total usable energy your battery can store. After that, just do the math, and you know exactly what's left in the tank.

I took my meter off my bike, since the rough correlation between voltage and remaining capacity is good enough for me, since there are so many other factors that go into figuring out what the remaining distance I can travel is.

 

[Pizzabroodje]

The display indeed displays percentage for 48V instead of 52V. I think that's weird though as the 500C display is advertised to work properly with 52V...
Also I noticed that the voltage on the display drops when pedaling and goes up again when stopping with pedaling.

Just add a secondary two wire voltmeter if you just want volts. about 5 bucks.


Or better still a watt meter. Judging half by volts does not work all that great, but if you know watt hours, and have tested your batteries real world capacity in wh, you know exactly where you stand every mile of every ride.

A cycle analyst is the best, and worth it. But even a cheap watt meter mounted in your battery box is a big help.

There already are volts and wattage displayed on the 500C display. Would a cheap Chinese meter be more accurate than that? A cycle analyst is too expensive.

Those meters also record watt-hours (energy) instead of just watts (instantaneous capacity), which is a better measure of what you've used. Meters are good for learning what you're setup is capable of, so if you go from full to empty and check the total watt-hours, that's the total usable energy your battery can store. After that, just do the math, and you know exactly what's left in the tank.

I took my meter off my bike, since the rough correlation between voltage and remaining capacity is good enough for me, since there are so many other factors that go into figuring out what the remaining distance I can travel is.

Oh I apparently misread the middle part. I will ask him what he wants.
I also found some volt meters that can show the percentage (e.g. https://s.click.aliexpress.com/e/Est1weD2F). I guess that would be best?

Does the voltage on your display drop too when pedaling (or maybe when using throttle)?
If so, which voltage should I go by, the one before or after starting to pedal?

 

[E-HP]

Does the voltage on your display drop too when pedaling (or maybe when using throttle)?
If so, which voltage should I go by, the one before or after starting to pedal?

If you're pedaling or using the throttle, your motor is pulling power from your battery, so the voltage will sag a little, depending on how much power your pulling. Anytime the motor is working, the voltage will drop a little, but less if you have really good cells.

 

[Pizzabroodje]

Does the voltage on your display drop too when pedaling (or maybe when using throttle)?
If so, which voltage should I go by, the one before or after starting to pedal?

If you're pedaling or using the throttle, your motor is pulling power from your battery, so the voltage will sag a little, depending on how much power your pulling. Anytime the motor is working, the voltage will drop a little, but less if you have really good cells.

They are Sanyo GA cells, but they dropped about 2V when using 400-500 watts. Could it be worse because they are not balanced yet? I only charged (and let them balance) once after they laid still for 3-4 months after I bought it.

 

[E-HP]

They are Sanyo GA cells, but they dropped about 2V when using 400-500 watts. Could it be worse because they are not balanced yet? I only charged (and let them balance) once after they laid still for 3-4 months after I bought it.

With my cheap cells I don't get much sag when the pack is charged up, but a good amount of sag when less than half charged. I don't really notice the sag unless pulling more than 20 amps, and maybe 2 or 3 volts by 30, or more if I hit 40. From what I've read, as long as you don't store the pack fully charged or fully depleted for a long period, the pack should stay healthy when stored.

 

[Pizzabroodje]

They are Sanyo GA cells, but they dropped about 2V when using 400-500 watts. Could it be worse because they are not balanced yet? I only charged (and let them balance) once after they laid still for 3-4 months after I bought it.

With my cheap cells I don't get much sag when the pack is charged up, but a good amount of sag when less than half charged. I don't really notice the sag unless pulling more than 20 amps, and maybe 2 or 3 volts by 30, or more if I hit 40. From what I've read, as long as you don't store the pack fully charged or fully depleted for a long period, the pack should stay healthy when stored.

I didn't really notice it at above 53V (before pedalling) either.
The pack will stay healthy but still de-balance right?
500 watts would be just 10 Amps, but it sagged 2V at that power..