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Lifepo4 pack question


#1

Hello,
Forgive me if this has already been asked. I recently got a 36volt 5ah Lifepo4 pack from a friend. I am aware that the chemistry is more stable and there is a voltage difference between LifePO4 cells and 18650 lipos like the ones in the Space cell. I’m wondering if anyone knows what the battery settings would be for programming a Vesc to use this type of battery. I also noticed that this Lifepo4 pack is made of 12 lifepo4 cells (12S?) as well, I suppose that is to account for the voltage difference and is normal for Lifepo4 packs. If anyone could shed some light or share their insight on these types of battery packs, I would greatly appreciate it. Thanks.


#2

can it deliver enough constant amps? it seems to be a 10s 2p or something.

You will need a continious discharge of 60+A


#3

LiFePO4 can deliver higher currents than lithium ion cells.

@themegak

Could you take pics of your battery? 12S lifepo4 should be a voltage total of 38.4, not 36.


#4

If it’s 12s it should be a 38.4v nominal pack. Do you know what cells they are specifically? Like @XIII said, it should have an adequate discharge rate if you’re using it for esk8.

The main settings you’ll have to set on the VESC is the battery cutoff start and end.


#5

it came from her metroboard that used to power a 63mm single drive motor. So i know it’s up to the task of powering an Eboard.


#6

Your probably right about the voltage, I’m going by what the label said on the battery pack itself. I’m pretty sure it has adequate discharge rate for esk8 as the battery pack came out of a metroboard single drive 63mm motor setup. What do you think the cutoff would be for this type of battery ?


#7

It’s hard to tell without knowing the exact cells.

36v sounds like a 10S lithium ion pack.

Could you get pics of the cells?


#8

I was thinking the same thing but the label says 36 volt 5ah lifepo4 and does have 12 cells. Below are the pics.

View of the 12 Cells

Side View of the BMS


#9

Prismatic pouch LiFePO4 I guess. Still should be 3.2v. Maybe that just had the sticker and round to the nearest voltage that had. They usually don’t have that high of a current rating. 12S seems risky.


#10

Can you get a picture of the bms. Or try to find the serial or part number on it.

The problem here is the discharge rate. but for the capacity it’s good for around 8-10 miles.

In the VESC configure the voltage cut off at 30V that’s 2.5V per cell. Wich is a safe cut off for this chemistry.


#11

Attached below. Remember this came out of a Metorboard Electric Skateboard. The board was a slightly bigger deck version of this board, except it used a beefier older motor which they don’t use anymore.


#12

Anyone know what the actual cutoff values would be for this kind of battery ?


#13

For the lifep04 chemistry is 2.5 V
They can go down to 2V.

This is the chemistry battery I use in my boards.


#14

Cut off values are up to you, but maybe go for 2.7v cutoff start per cell and 2.5v end. For a 12S pack it’ll be 32.4v start and 30v end.


#15

Sweet. I’m curious how you have your battery arranged in your enclosure. As you can see from my pictures above, the pack i have is only 5ah and is really thick. What does your battery look like ? I like the stable chemistry of this battery but the size is ridiculous and I will have to take it apart and rewire if i want a slimmer enclosure under my deck. Curious on what your set up looks like.


#16

thanks for the info. Appreciate it.


#17

You will need to split the pack to be able to fit it under the board. On my board I’m using 8in wheels so I have enough clearance.