Should I be worried?

[John Frum]

Started a few hours ago so well see.

Here's hoping you get a good result.

I've been thinking more about it.
Even if you get a "grade a" result and the battery is good for the rated cycles which(will take years to demonstrate btw).
The QR codes make the batteries traceable to origin.
Any company on either side of that transaction is not doing their own reputation or the industry's reputation any favours.
The Lifepo4 goldush depends on consumer confidence in the longevity of these batteries.

Just my opinion of course.

 

[gmehal]

Ok Im not sure im doing things right so I need a little help. Below is the battery I have and how im charging a single cell for AH test.

What voltage should I get the cell to?

Seems like my bench power supply has been hanging around at these numbers for roughly half an hour now. Is it fully charged? I keep hearing 3.6v is correct

Thanks

 

[gmehal]

Ok heres where I an 5.5 hours later and still going. I can only turn up the amps this high otherwise the low voltage alarm goes off. Anyone else experience this?

 

[John Frum]

What charge voltage did you use?
What charge amperage?
How much current was flowing when you terminated the charge?
What was the resting voltage before you started the discharge test?
How long did you let it rest before the testing the resting voltage?

 

[gmehal]

What charge voltage did you use?
What charge amperage?
How much current was flowing when you terminated the charge?
What was the resting voltage before you started the discharge test?
How long did you let it rest before the testing the resting voltage?

see image in the previous 2 posts for the v/a coming out of my power supply. Thats the max it would go. Also terminated at this point as it sat there for 2 hours with no change

3.25 was resting voltage before discharge, maybe 2 hours before i started discharge

 

[John Frum]

see image in the previous 2 posts for the v/a coming out of my power supply. Thats the max it would go. Also terminated at this point as it sat there for 2 hours with no change

3.25 was resting voltage before discharge, maybe 2 hours before i started discharge

Sorry not looking at image, my vision is not good.
Charging voltage should have been 3.6 or even 3.65
Charging current up to 0.2c and until it current approached 0?
Did the charge current approach 0?

 

[gmehal]

Sorry not looking at image, my vision is not good.
Charging voltage should have been 3.6 or even 3.65
Charging current up to 0.2c and until it current approached 0?
Did the charge current approach 0?

No will not go charge to 3.6, only 3.2~. Am i using my power supply wrong? Hook up positve and negative leads, Screen shows 3.3v, Turn current to max and it only goes to 1.54A, power supply gets warm like its working but numbers never get to 3.6v

 

[John Frum]

3.2 volts in the nominal voltage of a lifepo4 cell.
If you can't charge the cell properly the discharge test won't tell you much.
Is it a cc/cv power supply?
If yes set cv to 3.6 volts and cc to 80 % of PSU's continuous rating or 0.2C whichever is lower.
The charge curve is very flat so be patient.

 

[gmehal]

3.2 volts in the nominal voltage of a lifepo4 cell.
If you can't charge the cell properly the discharge test won't tell you much.
Is it a cc/cv power supply?
If yes set cv to 3.6 volts and cc to 80 % of PSU's continuous rating or 0.2C whichever is lower.
The charge curve is very flat so be patient.

Yes, again in the photo above you can see the PSU, it has a fine and course CV and a single CC knob. When I attach it to battery the only thing i can alter is the CC and it maxes out at 1.58A. Am i doing something wrong? After 2 hours at the setting in previous photo the numbers never changed. I would think I would see some progress towards 3.6 but did not.

 

[Opie91]

I think the Protek 3006B only has a max output of 1.5 amps, so your seeing the max your power supply can put out.

If that is correct then it is going to take days for you to see a voltage rise to 3.6

 

[gmehal]

I think the Protek 3006B only has a max output of 1.5 amps, so your seeing the max your power supply can put out.

If that is correct then it is going to take days for you to see a voltage rise to 3.6

Ahhhh. thats may be it. Hadn't thought of that, bought that thing years ago. I just ordered a 10A one from Amazon that should be delivered today.

 

[gmehal]

Ok so far with new bench charger I’ve gotten battery up to 3.31v shooting for 3.6v. Seems to be taking forever!! Is that normal? Here’s a photo. Amps do keep dropping but super slowly. Am I right to assume when Amos are at zero it’s done?

 

[Opie91]

How goes the battle?

 

[gmehal]

Funny you should ask! Just finished testing one cell. Was able to get about 196AH when I decided to stop. Was pulling about 9amps the whole time, knocked it down for that last few hours. So I guess these are good cells?

 

[Opie91]

Sorry, I'm not the best person to ask about LifePO4, I purchased the same cells and was hoping to learn a bit from your experience.

I do have quite a bit of experience with large NiCad batteries banks, similar in some ways but way different in others. I'll let someone else chime in as far as the health of that cell goes.

Best of luck!

 

[gmehal]

from what i understand at or above the rated AH is good! Hooked up my Electrodacus sbms0 last night last night to 4 of the cells, one step closer to the full build.