Ordered 4 cells 280ah From Shenzhen Basen, CN

[MadMax03]

"PSU"

 

[Oldtoad]

Switch Power Supply according to the manual, not in English.
SPS?

 

[MadMax03]

Well now you're just beyond my pay grade.

 

[Oldtoad]

Well, if we were wealthy and smaart we would have picked up Battleborns.
As a CP aka thrifty soul with a perspiring mind I bought these.
Otherwise, could have, should have, would have bought LTO's like you.

 

[MadMax03]

If your brain is perspiring, you're taking this way, way too seriously. And should probably see a doctor.

 

[cinergi]

Many of us, myself included, have these cells from Shenzhen Basen in the group buy: https://diysolarforum.com/threads/280ah-cells.10607/post-153051
I'll start a build thread of mine soon...

 

[EasyStreet]

Just received my cells from Shenzhen Basen. I ordered them on 9-21 and they arrived today 10-22. Cells were well packaged and the batteries appear to be in great shape.

Cell Voltage
A 3.296
B 3.297
C 3.297
D 3.296

Top Balance and capacity check coming soon.

 

[cinergi]

I'll be curious to see if anyone's labels reads anything other than 3.29 / 0.14 ...

 

[MadMax03]

Just got notification today from Shenzhen Basen that my 4 cells have shipped. See you in 28-35 days.

 

[Oldtoad]

Still charging at 3.4 volts.

 

[MadMax03]

Gonna be a while.

 

[Oldtoad]

Checked charging voltage 3.45 V.
Cells are 3.38 V.
Charging at around 1 A, seems to be getting close.

 

[Dhopewell]

Checked charging voltage 3.45 V.
Cells are 3.38 V.
Charging at around 1 A, seems to be getting close.

Have you checked cell voltage off charger lately? I’m wondering if they settle as much with a slow & low charge as with a higher voltage? In any event they seem to eventually settle around 3.35 regardless of peak voltage. I have cells I charged as packs above 3.50 and they are 3.333-3.340 now after a few weeks of sitting.

I just found this on another thread. It does indicate that SOC vs voltage depends on charge rate, and a really slow charge (under 14amps per cell is considered very slow here) gets to almost fully charged by 3.3v. Over 3.3 the voltage to SOC curve is steep so that’s a good place to balance. But the party is over by 3.4v. Starting at 3.5v it becomes possible to overcharge if you stay too long, so 3.45 looks like a really good top balance if you have the patience, or a PSU that can push 14amps per cell.

 

[EasyStreet]

Checked charging voltage 3.45 V.
Cells are 3.38 V.
Charging at around 1 A, seems to be getting close.

It's showing improvement but you still have a long way to go.

The leads that came with my power supply had a lot of resistance. I was losing .5 volts in the lead wires at 10 amps. If you back out the terminal on the power supply you can add parallel wires to eliminate that problem and put more juice in the battery. Also a higher charging voltage will get you more charging amperage.

 

[Oldtoad]

A little confused, checked twice to confirm.
This morning at start of charge cells read 3.38V. Now after a few hours of very slow charge 3.36V.
Checked power supply output 3.43V, less than 1 A charge rate.
EasyStreet, adding this after I read your post.
PS leads are crap, at start of charging these cells leads were a little warm so I backed off the voltage, no rush, just do not want damage.

 

[Oldtoad]

V reading could be temperature related.
I turn the heat down at night to the 50's.
Daytime temps are probably near 70 with the sun shining in and the heat up.

 

[EasyStreet]

Is there a reason why you are not charging at a higher voltage?

 

[EasyStreet]

EasyStreet, adding this after I read your post.
PS leads are crap, at start of charging these cells leads were a little warm so I backed off the voltage, no rush, just do not want damage.

Yes mine leads are too. The solution is to add parallel wires as stated on my previous post or replace with higher amperage leads. I measured the drop from the power supply to the battery and added jumper wires until the problem went away.

 

[Oldtoad]

Is there a reason why you are not charging at a higher voltage?

In addition to the low amperage leads, DO NO Harm. Hard to hurt the cells at a low voltage.
Found another source, hope this is credited properly.

https://www.gudgeonblog.ca/lifepo4-batteries-part-four-top-balancing-pack/

 

[Gazoo]

My power supply/charger did not come with leads. I made them using 12awg wire with fork connectors connected to the power supply and ring terminals connected to the cells. Working great. I thought about paralleling the wires but I don't see any need since the wire and terminals is working.