Can a battery have different cut off voltages?

[Gionnirocket]

As long as you monitor you should be ok. You still have the BMS Overcharge protection if the charger is still outputting after the green light on the charger indicates a full charge.
It takes a bit of skill but implementing an inline voltage / watt meter will remove all the guess work. You can even use a multimeter but that will require a charge extension cable or hacking into the charge cable itself.
My little hack on the subject. . .

$10 DIY Smart Charger Alternative / Ver. 2.0

I've been experimenting with an easier way to achieve a 70% - 90% charge or a storage charge for my battery other than just timing it and I came across an inexpensive solar charge controller that I thought I might be able to adapt. In the end I am able to achieve my goal, but it didn't end up...

electricbikereview.com

 

[PCeBiker]

My display shows Watts and Volts. The only thing it doesn't show is total Watt/hours consumed, but I can just guesstimate that.

I can set my controller to output a constant Wattage, so if I set it and keep track of time, my guesstimate should be pretty accurate.

 

[PCeBiker]

My little hack on the subject. . .

$10 DIY Smart Charger Alternative / Ver. 2.0

I've been experimenting with an easier way to achieve a 70% - 90% charge or a storage charge for my battery other than just timing it and I came across an inexpensive solar charge controller that I thought I might be able to adapt. In the end I am able to achieve my goal, but it didn't end up...

electricbikereview.com

I checked out your project and I have a question.
I found all kinds of charge controllers on AliExpress but they all seem to be 12v or 24v

Would I need a 48 volt charge controller or am I only interested in the difference between the battery voltage and the charger voltage?

I'm trying to wrap my head around this.

 

[Nvreloader]

Thanks guys
I have a question,
Can I use the OEM discharge pins of the battery, that fit the bike's battery slot's,
these pins are at the other end of the battery, from the charging plug,
so I won't have to shut off and test and then start all over again etc.
Should read the same, using the V meter?

Tia,
Don

 

[Gionnirocket]

Thanks guys
I have a question,
Can I use the OEM discharge pins of the battery, that fit the bike's battery slot's,
these pins are at the other end of the battery, from the charging plug,
so I won't have to shut off and test and then start all over again etc.
Should read the same, using the V meter?

Tia,
Don

Yes it should read the same.

 

[Gionnirocket]

I checked out your project and I have a question.
I found all kinds of charge controllers on AliExpress but they all seem to be 12v or 24v

Would I need a 48 volt charge controller or am I only interested in the difference between the battery voltage and the charger voltage?

I'm trying to wrap my head around this.

I would have to see it to know for sure but typically the operating V range is charger / battery V
This unit operates from I believe 6v to 60v

 

[Gionnirocket]

My display shows Watts and Volts. The only thing it doesn't show is total Watt/hours consumed, but I can just guesstimate that.

I can set my controller to output a constant Wattage, so if I set it and keep track of time, my guesstimate should be pretty accurate.

I use this with a standard charger.
When used with a Desktop Power supply the readouts are duplicated.

 

[Nvreloader]

GR Thanks
I'll set the timer for every 10 minutes and then take a reading, I'll make notes.
Tia,
Don

 

[Gionnirocket]

GR Thanks
I'll set the timer for every 10 minutes and then take a reading, I'll make notes.
Tia,
Don

When I do such projects I set up an old ip camera and I can monitor it from the couch
First thing you're going to have to deduce is whether or not your charger is still putting out. You said that your charger fan shuts down at green light so I'm thinking not... but what the hell do I know

 

[Nvreloader]

GR
As I understand it all,
if I get an increase in the voltage readings, when the charger is charging,
I should see an increase in the readings?
If I get NO increase while running the charger, then I am beating a dead horse,
just quit while I am ahead etc.
You know more than I do, so that has to account for something........LOL
Tia,
Don

 

[PCeBiker]

When I do such projects I set up an old ip camera and I can monitor it from the couch

I can see my project from where I park myself.
No need for that fancy ip stuff.

 

[PCeBiker]

If I get NO increase while running the charger, then I am beating a dead horse,
just quit while I am ahead etc.

You can still be delivering current while the voltage remains the same when you're in CV mode.

My voltage has been steady for about 5 hours now but the batteries are still taking current.

If your voltage doesn't go over 4.21, then you're fine.

EDIT: 4.20 X 13, so 54.6 volts.

 

[PCeBiker]

I would have to see it to know for sure but typically the operating V range is charger / battery V
This unit operates from I believe 6v to 60v

It doesn't have a box, but it's cheap.

https://a.aliexpress.com/_msJpsGW

 

[Nvreloader]

Well guys
I am beating a dead horse,
#3 bat = (new battery's just bought)
took a reading = 53.9v, started/attached charger, run for 3m/40s, reading of 54.0v,
fan stopped, left on charger, but have Grn lite for 30min, no change in v reading = 54.0v for the last 30 min

#4 bat = same method and same results, added .01v to 54.0 and then no change after.

So, I guess I am 53.8/9v for max charging on these 2 battery's and chargers.
It is nice to know that I shouldn't have a blow up, unless I do something stupid.......LOL

Now on to the road testing again, come on wind/snow shut, I want'a test ride.
Tia,
Don

 

[PCeBiker]

Well, you certainly won't overcharge your battery then.

Next, it would be good to get a current reading while the voltage is at 53.8/9v

They may very well still be taking on a charge.

 

[PCeBiker]

So, I guess I am 53.8/9v for max charging on these 2 battery's and chargers.

As an experiment, I decided to charge a few cells to 53.8/9v (4.14v in my single cell case) and see what happens after the light turns green. (Switches to CC)

I'm gonna let er rip at 2 amps for the 3 cells.

They started off at 3.73v

They won't take 2 amps so it went to CV right away.

I turned the current down to 1 amp to turn on the red charge light. (CC mode)

I turned it up to 1.3 amps to speed things up a bit.

There, the light just turned green (switched to CV mode)

It's still drawing 1.250 amps.

I'll see how long it takes for the cells to stop charging. (Current drops to ~0)

 

[Gionnirocket]

Well guys
I am beating a dead horse,
#3 bat = (new battery's just bought)
took a reading = 53.9v, started/attached charger, run for 3m/40s, reading of 54.0v,
fan stopped, left on charger, but have Grn lite for 30min, no change in v reading = 54.0v for the last 30 min

#4 bat = same method and same results, added .01v to 54.0 and then no change after.

So, I guess I am 53.8/9v for max charging on these 2 battery's and chargers.
It is nice to know that I shouldn't have a blow up, unless I do something stupid.......LOL

Now on to the road testing again, come on wind/snow shut, I want'a test ride.
Tia,
Don

Kinda what I was thinking... But this is actually good news as it means that the issue on the high end is the charger, not the battery. And when I say issue... Very minimal as you are still reaching 97%..
I would be very interested to see the white paper on your specific cells as perhaps this may be what the manufacturer specs.
Now let's see what happens when you discharge. Follow my previous comments as you can't get a definitive answer with them running in parallel. OK to do from the beginning, but once you feel the power drop or get in the low 40's V range, run them individually and take note of each LV cutoff and any sagging.

Stay close to home...

 

[PCeBiker]

I have 2 different sets of OEM batteries, both the same as far as battery types, 21700 cells,
one has a cutoff voltage of 43.5V = 29.0% v of charge and,
the other has this reading of 46.6v = 49% of charge, as I have just found out.

.OK to do from the beginning, but once you feel the power drop or get in the low 40's V range, run them individually and take note of each LV cutoff and any sagging.

I bet if Nvreloader ran a single battery from the second set, you could trigger a battery shutdown as high as 48 volts at full throttle?

I bet you could get a single battery to shut down in twenty minutes if you really tried?
It would be a good way to find out the highest battery shutdown voltage.

Can you reset your battery after that happens, or do you have to charge it to reset it?

 

[Gionnirocket]

I bet if Nvreloader ran a single battery from the second set, he could trigger a battery shutdown as high as 48 volts at full throttle?

Are not his batteries massive? 24ah? 30ah? That should be nice number of cells in parallel and should be able to unload without too much stress.
Now if there is a defect. . .

 

[PCeBiker]

I think they are 15ah