capacity testing Large format cells


MASSIVE restock of EV Batteries at www.batteryhookup.com 5% coupon "POWERWALLS"

CarelHassink

Member
Joined
Oct 21, 2017
Messages
172
Revolectrix Powerlab8v2, with pc link
here an example testing GS YUASA LEV50N prismatic cells 50Ah


image_fzrcbn.jpg

image_hfjiyy.jpgimage_xhbkrk.jpg
 

Crimp Daddy

Member
Joined
Feb 21, 2018
Messages
974
A RC/hobby balance charger is gets my vote. Its what I use for EV batteries and complete pack testing.

Depending on the model/brand there are feature like regenerative discharge and external discharge which can greatly improve the discharge rates for capacity testing. iCharger is known to do this well, I like their units for this type of work and they have various models in different price ranges that can all pretty much do the same thing. Im sure others can too, but I dont have first hand experience.

Balance chargers work well regardless if you are testing a single cell or a complete module as it is balance aware.


image_bvghar.jpg



image_dfkdat.jpg
 

floydR

Member
Joined
Aug 23, 2017
Messages
1,481
Thanks Chrimp daddy
I have an icharger 1010 B+ but the 1010B pdf manual dosen't say anything about regenerative discharge or external discharge, one website selling the 1010B+ has listed under features "external capacity resistor is connected, iCharger 1010B+ produces a maximum discharge power capacity of 280W (@40V/7A)." regenerative discharge has the same.
not sure I want to take a chance on letting the magic smoke out of the charger. it was hard enough getting it into the charger to begin with. :)
I will look at the other Ichargersand other Rc/hobby balance chargers

later floyd
 

daromer

Moderator
Joined
Oct 8, 2016
Messages
5,662
Icharger x or duo models are preffered.

My personal opinion doing RC for many years :)
 

floydR

Member
Joined
Aug 23, 2017
Messages
1,481
Thanks daromer and Geek
I looked and looked for the1010B+ pdf and all I could find was the 1010b pdf and I saw the link that Geek gave but figured it was the same one I had which was for the 1010b model. will look at the other Ichargers
later floyd
 

Crimp Daddy

Member
Joined
Feb 21, 2018
Messages
974
The 1010B+ is a nice unit... one of the smaller more affordable models that has 10s support. It also does regen and external discharge but at about 300 watts max.

You can make what you own work, or you can look at larger models to get more power handling.

Either way, you already have the right tool.
 

Mazlem

Member
Joined
Aug 8, 2017
Messages
100
I got an iCharger x8 to test my 25Ah cells in batches of seven. ~5.5hrs to test about 125Ah at a time and it's been rock solid.
 

floydR

Member
Joined
Aug 23, 2017
Messages
1,481
Mazlem said:
I got an iCharger x8 to test my 25Ah cells in batches of seven. ~5.5hrs to test about 125Ah at a time and it's been rock solid.

I am looking at the x8 glad to hear it works great, although I could get by with the x6.

later floyd
 

ICPete

New member
Joined
Jan 28, 2020
Messages
5
A couple of years ago I tested 400+ LTO pouches, 55 AHr each, using this discharge tester:
[img=800x600] Sourced from ebay; same vendor no longer active, but similar units still available for under US$20 each.
I bought 16 of them and mounted in pairs, all powered from one lab power supply:
[img=800x600] Discharge is up to 10A, up to 60W (I never used them beyond ~25W). They beep when discharge to a selectable voltage is finished.
Then they display the total amp-hrs and watt-hrsdischarged, and the average voltage.
In between discharge tests I charged the sixteen cells per batch connected in series, using the Chargery BMS-24T, which I found worked quite well. Here is a picture of a stack of pouches being charged:
[img=800x600] Note the plastic sheet insulators between alternate electrodes! Also how I numbered the clips I used to extend the Chargery's leads, and a bit of color coding that helped me avoid errors at connection time (as you all know, cell testing can be mind-numbingly tedious and repetitive!). The larger red and black insulated clips are simply joining pairs of + and - electrodes in series; so alternate pouches are flipped upside down.
I recorded the data using a rudimentary OpenOffice ODBdatabase:
[img=800x600] This database accepts multiple discharge session entries per cell, using the cells' serial numbers to identify them. So afterwards I could summarize the max, min, and average AH for each cell, from which I develop a sorting list to ensure each "supercell", or block, gets the same average AHrs as the others (I think of this like choosing team members for school-yard sports teams; you want to have an equal mix of strong and weak players on every team).

I have more photos showing a bit more detail of the construction of the discharge rack, in case anyone wants to see.
So to answer the OP's question, these little ebay dischargers worked well for me; and I see there are many new versions available now, with substantially higher power rating, bigger heat sinks and fans, nice enclosed cases, etc.
 

floydR

Member
Joined
Aug 23, 2017
Messages
1,481
Ok I have an icharger x8 on the way. and some balance leads will need them to test with the 1010b+ at 7 amps.( for my 36volt hoverboard battery tests/36v ups build)

On the BYD batteries need to check individual cell voltage.
A couple years ago I bought this bms:
https://www.aliexpress.com/item/32710469857.html?spm=a2g0s.9042311.0.0.63444c4dAcfK7z

Should I install it on the BYD battery then charge the battery up to 28.8v then test the individual cells?

Charge up each cell to 3.6v then test the cells?

Charge it up with bms installed and if all the cells are balanced call it good, hook to 24v inverter (1kw) with a load and see how long it last?


Later floyd
 

floydR

Member
Joined
Aug 23, 2017
Messages
1,481
I managed to check cell voltages on one battery, not too sure how accurate this is hard to hold the negative lead from my cheap harbor freight multimeter on the negative post.
vt0:26 vt1:22.6
vt2:19.4 vt3:16.1
vt4:12.9 vt5:9.6
vt6:6.5 vt7:3.2
vt8:0.0
all the vt#'s are printed on the circuit board. just a hair out of balance. Almost half a volt.
These weigh 164 lbs about 80 kg something to remember I am not as young as I once was.

Later floyd
 
Top