diy solar

diy solar

Alibaba LiFePo4 batteries

3.65 is fine but not necessary. Just keep an eye on it and make sure the voltage at the battery terminals does not exceed that. Don't rely on the meter that's on the power supply...
 
upnorthandpersonal said:
3.65 is fine but not necessary. Just keep an eye on it and make sure the voltage at the battery terminals does not exceed that. Don't rely on the meter that's on the power supply...
Click to expand...
Ok and for top balancing I'm looking for the amps to go to 0 right?
 
Chefwhowa said:
Ok and for top balancing I'm looking for the amps to go to 0 right?
Click to expand...
Yes. The cells are not completely ballanced till the current is zero.

diysolarforum.com

Top Balancing LiFePo4 Cells using a low cost benchtop power supply.

To get the paper, click on the orange at the top of this page. This is a tutorial with detailed steps on how I top-balance my LiFePO4 Cells using a low-cost benchtop power supply. To get the tutorial, click on the orange "Download" button...
diysolarforum.com diysolarforum.com
 
FilterGuy said:
Yes. The cells are not completely ballanced till the current is zero.

diysolarforum.com

Top Balancing LiFePo4 Cells using a low cost benchtop power supply.

To get the paper, click on the orange at the top of this page. This is a tutorial with detailed steps on how I top-balance my LiFePO4 Cells using a low-cost benchtop power supply. To get the tutorial, click on the orange "Download" button...
diysolarforum.com diysolarforum.com
Click to expand...
Thank you, I been watching Will's videos for over a year now and watch him top balance these cells.
 

Attachments

  • 20210222_151541.jpg
    20210222_151541.jpg
    118.2 KB · Views: 3
Did you do a pre-charge in series or did you go straight to top balance. With 7A of current I am guessing there was no pre-charge. This is fine but it might be a long time before they are balanced.

Also, with 7A of current I can almost guarantee the voltage at the cells is somewhat lower than 3.65V. This is unfortunate because that means some of your energy is being lost in the lines. However.... it is not a problem. Just be patient and once the current goes down the voltage drops will go down. When the current gets to zero, the voltage drops will also be zero.

Just don't raise the power supply voltage to try to speed things up.
 
FilterGuy said:
Did you do a pre-charge in series or did you go straight to top balance. With 7A of current I am guessing there was no pre-charge. This is fine but it might be a long time before they are balanced.

Also, with 7A of current I can almost guarantee the voltage at the cells is somewhat lower than 3.65V. This is unfortunate because that means some of your energy is being lost in the lines. However.... it is not a problem. Just be patient and once the current goes down the voltage drops will go down. When the current gets to zero, the voltage drops will also be zero.

Just don't raise the power supply voltage to try to speed things up.
Click to expand...
I understood everything thank you and yes you're right I didn't pre-charge them. Yeah I'm off the next 3 days so nothing else to do. So I can wait for them. I have another 8 cells to do after this set.
 
Chefwhowa said:
Is that voltage good?
Click to expand...
3.265 DC v is fine. Ideally you would not have the voltage drop between the supply and the cells, but it is not a problem if there is.

As long as the voltage at the supply is not above the target voltage, everything will eventually equalize to the power supply voltage.

As @upnorthandpersonal said, measure the voltage at the power supply with a reasonably good volt meter. The displays on the low cost power supplies are sometimes off by as much as .05V (Usually it is more like .02V)
upnorthandpersonal said:
3.65 is fine but not necessary.
Click to expand...
A lot of folks only top balance to 3.6V. I like to go to 3.65V because I like to run my system chargers at close to 3.6V and want to top balance to a higher voltage. This level of detail is more a personal preference than anything else
 
FilterGuy said:
3.265 DC v is fine. Ideally you would not have the voltage drop between the supply and the cells, but it is not a problem if there is.

As long as the voltage at the supply is not above the target voltage, everything will eventually equalize to the power supply voltage.

As @upnorthandpersonal said, measure the voltage at the power supply with a reasonably good volt meter. The displays on the low cost power supplies are sometimes off by as much as .05V (Usually it is more like .02V)

A lot of folks only top balance to 3.6V. I like to go to 3.65V because I like to run my system chargers at close to 3.6V and want to top balance to a higher voltage. This level of detail is more a personal preference than anything else
Click to expand...
Thank you again! This is my first time making my own batteries. Kinda scary not to lie but I believe I watch enough of Will's videos that I have it down. And with you guys help too. So now I'm just waiting for the current (amps) to get to 0 and than I can add my bms to make my battery.
 
Lets gues they are ~50% full
and that you have 280ah cells.
and that you have 8 cells in parallel.
and you are getting 2 amps throuhgput.
I make that ~23.3 days.
 
You must log in or register to reply here.

Similar threads

A
Advice for small battery
Replies
8
Views
398
Alicanto
A
Alkaline
EVE Official Alibaba Store, the end of Luyuan and other alibaba sellers?
2 3
Replies
50
Views
5K
Emily Wong
Emily Wong
S
Going to Lifepo4
Replies
5
Views
574
Simonbr
S
cooldog
Alibaba / Docan experience
Replies
14
Views
1K
AshleyL
A
Daniel LS
Victron SmartSolar MPPT: Charge 2 batteries via "Load Output" + "Boost Converter" ?
Replies
0
Views
226
Daniel LS
Daniel LS
Back
Top