Can a battery have different cut off voltages?

[PCeBiker]

Jenny's on the block!

I'm promoting @Jenny Mao for @Nvreloader 's benefit too.
If you're considering new batteries, @Jenny Mao may very well have something that fits your ebike.

You did say that your used set of batteries weren't OEM, so that means the battery case isn't 100% proprietary.

Jenny's batteries are properly built with reliability, longevity and safety in mind, and the prices are Very competitive.

Here's a link to her thread.
If she sold crap, people here on the forum would have bitched about it.

Reention newly upgrade 48V 25Ah&36V 30Ah (505L) interchangeable for eBikes Surface 604,NCM,Rize,Magnum,Aventon

Hello all friends, this is Jenny from Shanghai Aijiu Energy Tech, and I am new to the forum. Thanks for your time reading the post. As a 13-year experienced manufacturer of lithium ion battery packs, we have our battery exported all around the world with good feedback. All batteries we sold...

electricbikereview.com

Here's a link to the data sheet for the SAMSUNG 21700-50E cells that Jenny is using.

https://www.dnkpower.com/wp-content/uploads/2019/02/SAMSUNG-INR21700-50E-Datasheet.pdf

 

[PCeBiker]

PC
These cells are LG 21700 brand/name.

This is the datasheet for your LG 21700 cells.

https://www.dnkpower.com/wp-content/uploads/2019/02/LG-INR21700-M50-Datasheet.pdf

 

[Nvreloader]

Hey Guys
I dug out my other OEM batt charger and got a surprise,
it's not the same as the other one.

This new one is a lot different in that it is
a 110/240v ac, internal switching for 110/240v,
54.6v - 3a, 2 led lites, complete automatic charging for CC- CV,
2 stage Charging Mode, step 1 CC and step 2 CV, then goes into a floating taper step charge mode.

I used this charger on the #4 batt and it took almost 5 hrs to get back to the 53.8V change point, charged the #3 bat on the other charger (one I have been using) and it charged back to 53.8v in just over 3hrs (normal time) as before.

I just got in after a test ride on Batt #1-2, was 50.1V and they are down to 46.7v,
after almost 40 miles @ 3-1/2 hrs all throttle, average speed of 14/15 mph,
so I'll finish up tomorrow to see how low they go, before I lose power and will use the new charger on these batts.

Question, Can I use the first bat charger to get to 53.8v and then use this step charger to finish off the batteries to 54.6V?

Your thoughts and suggestions................
Thanks,
Don

 

[Nvreloader]

Thanks PC
I read all the info, while I sipping my JD/coffee mix, resting up.
Tia,
Don

 

[PCeBiker]

Thanks PC
I read all the info, while I sipping my JD/coffee mix, resting up.
Tia,
Don

It kinda makes sense to me but I'm having a hard time comparing your 21700 cells to my 21700 cells.

Your cells show the "energy" as 18.2 Watt hours.

My cells show "standard discharge capacity" as 4.9 amp hours.

To convert my amp hours to Watt hours, I'm pretty sure I multiply the amps by the volts to get Watt hours, but what voltage?
4.20 at full charge, 3.6 at nominal charge, or 2.5 at the cut-off voltage?

Those numbers leave me with 20.58 Watt hours, 17.64 Watt hours, and 12.25 Watt hours respectively.


Maybe @Gionnirocket can shed some light on my confusion?
It would be nice to compare apples to apples.

 

[Gionnirocket]

It kinda makes sense to me but I'm having a hard time comparing your 21700 cells to my 21700 cells.

Your cells show the "energy" as 18.2 Watt hours.

My cells show "standard discharge capacity" as 4.9 amp hours.

To convert my amp hours to Watt hours, I'm pretty sure I multiply the amps by the volts to get Watt hours, but what voltage?
4.20 at full charge, 3.6 at nominal charge, or 2.5 at the cut-off voltage?

Those numbers leave me with 20.58 Watt hours, 17.64 Watt hours, and 12.25 Watt hours respectively.


Maybe @Gionnirocket can shed some light on my confusion?
It would be nice to compare apples to apples.

Good question.
Typically cells are rated in ah
Not 100 % sure but I would say the nominal Voltage 3.6 as that is the cells spec'd voltage.
The other two are described as the charge voltage and LV cut off voltage