Can a battery have different cut off voltages?

Yup

"The battery's 21700 battery's, 48v-15ah-720wh dual battery's"

If he can reset them in the field, he shouldn't have too much to worry about, just reset them and go easy on the throttle, but if he has to charge them to reset them, then he's in trouble.
 
My new battery resets if I remove the battery and replace it.
Assuming it shut down from voltage sag.
 
Thanks GR
I'll will do this,
take a reading on both bat's, then use both battery's and use until I feel the drop off,
then get a reading of 1 bat, then run it out until I feel/see the second drop off
of this bat, get reading, then change over to the other battery and do the same operation to the second bat?

What will the second drop off be like, should I feel or see it on the display?

I have never run my battery's down that far before............so it is an unknown to me.

I am getting too OLD to push this 90# tank, but I can walk..........LOL I'll also pack another spare bat, just in case.

Thanks,
Don
 
Nvreloader said:
What will the second drop off be like, should I feel or see it on the display?
Click to expand...

It will feel like a very heavy acoustic bike. 😂

See if you can reset the battery after it shuts down.
Remove it, reinstall it, push the buttons, push and hold the power button on the battery.


If your voltage goes back up to ~ 46v you might be able to reset it.

The BMS won't fully lock the battery until the voltage is at something like 34v or one cell group has hit its low voltage lockout voltage.

PS,.. @Jenny Mao has really good batteries at a really good price. 👍🏻👍🏻
 
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PC and Guys
I don't have any buttons on these battery's, or know how to reset them,
the only control I have is the on/off button on the display switch,
that turns every thing off or on.

Tia,
Don
 
Did you bring your voltage down lower than 43.5v and 46.6v when you were pedaling?

You really should be able to drain your battery to at least 40v before the BMS shuts you down.

I drained my battery to 39v and it still didn't shut down.
 
Last edited:
PC
The lowest I have ever had my (OEM) bat's #1/2 was 43.5v,
running both at the same time.
I have no Idea what the low set point is, yet.
This last set of Bat's #3/4 have been down to 46.6v as noted, for the first time
during the road test..
Tia,
Don
 
Well you don't necessarily need to ride it to shut down. If you get it to 40v I would stop there as that's pretty good.
Note what load your under while riding. Your display shows Amps and or Watts I assume.
 
I'm thinking outside of the box here, and GR can correct me if I'm out to lunch, but it should be possible to reset a battery that has shut down by feeding the output of the battery that hasn't shut down into the charge port of the battery that has shutdown to reset it?

Just thinkin about what you might be able to do if you are 100 miles from nowhere.

You might need a current limiter and a fully charged battery at 54.6v? Or 53.9 in this case?
 
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Guys
Thank you,
GR,
I'll stop at 40v as indicated by the Bafang DPC - 18 LCD display,
  • Full Color LCD Screen with updated sleek speedometer design
  • Shows Time, Power Assist Level, Trip Distance, Speed
  • USB output for charging cell phone or other small devices (only produces 5V and ~ 0.5amp)
  • More accurate battery gauge (choice of Percentage or Voltage display)
  • Up to 9 Levels of Pedal Assist Power
  • Easy Error Code List
  • Includes separate plus/minus/power control pad
  • Easy to use control pad to turn on the Bafang motor, adjust the Power Assist Level, and change the settings
  • Plug and play into Bafang Mid-Drive (BBS02/BBSHD) Main Wiring Harness
  • Green 5-Pin Female Connection
PC, You are correct, I have planned a 120+ mile ride as soon as the snow is gone, right now there is over 3'+ snow/ice on this trail: https://tahoepyramidtrail.org/
and this is the reason for this post.

Then the next bump to get over, will be changing the gears to fit what I want to do, if possible, and I'll start a post for it then.

I greatly appreciate the help and suggestions, as I am over my head with this stuff.
Tia,
Don
 
Nvreloader said:
Guys
Thank you GR,
I'll stop at 40v as indicated by the Bafang DPC - 18 LCD display,

  • More accurate battery gauge (choice of Percentage or Voltage display)
Click to expand...

Find out what voltage the display considers 50%, 75% etc. Then you'll know what voltage the display/controller considers to be 0%
The controller/display usually cuts power way before the BMS in the battery.

Nvreloader said:
PC, You are correct, I have planned a 120+ mile ride as soon as the snow is gone, right now there is over 3'+ snow/ice on this trail: https://tahoepyramidtrail.org/
and this is the reason for this post.
Click to expand...

My bike is upside down in the living room and I haven't worked on it in days.
I've got 2" of snow here too.
That's my excuse. 😂

Maybe a sunny spring day will inspire me🙄🤔
 
PCeBiker said:
I'm thinking outside of the box here, and GR can correct me if I'm out to lunch, but it should be possible to reset a battery that has shut down by feeding the output of the battery that hasn't shut down into the charge port of the battery that has shutdown to reset it?

Just thinkin about what you might be able to do if you are 100 miles from nowhere.

You might need a current limiter and a fully charged battery at 54.6v? Or 53.9 in this case?
Click to expand...

I looked up your ebike and it's Canbus. I don't know anything about that, so my idea won't work.
I think that third pin on your charger plug is what the charger uses to "talk" to your battery?
The third pin on my old charger is just a ground.


Screenshot_20230312-012548_DuckDuckGo.jpg
Screenshot_20230312-012504_DuckDuckGo.jpg


I think that your controller can tell the battery to shut down too?
 
PCeBiker said:
I'm thinking outside of the box here, and GR can correct me if I'm out to lunch, but it should be possible to reset a battery that has shut down by feeding the output of the battery that hasn't shut down into the charge port of the battery that has shutdown to reset it?

Just thinkin about what you might be able to do if you are 100 miles from nowhere.

You might need a current limiter and a fully charged battery at 54.6v? Or 53.9 in this case?
Click to expand...
In theory it could work but logistically it's probably more trouble then it's worth.
I think a better approach would be to know your bike and battery and to ride strategically gentle as you approach the LV cutoff.

@Nvreloader
The Watt readout on your display
LUNA_DPC18__08124.jpg



If you are putting a heavy load on the motor say by riding throttle you may see it shut down early with voltage sag.
The lower you keep your Watts by pedaling and using the lowest practical gear and PAS will show you your actual LV shut down and usable battery capacity.
 
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Art Deco said:
Yep. And you at least understand this , I'm still treading water here.
Click to expand...
You're paddling now instead of pedaling,..
Watt Hours are different in the water.

Somebody should make a waterproof battery that they could peddle to paddlers to help them pedal their power assisted paddle boat.
The paddle boat should have torque sensitive pedals.
It's the latest and greatest.
 
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