Problem with Kungber power supply not charging in CC mode

[lonewolf754]

The problem I'm having with this charger is that I can't get it to charge
in Constant Current mode. I first set the voltage to 3.6, then touch the
positive and negative of the charger together to set the amps to 9. When
I hook the positive and negative outputs to the 280AH Eve cells, which I
have paralleled, the charger shows the proper voltage of 3.6, but the amps
are only at 3.8. The cells are now at 3.32v so I believe it should charge in CC mode.

The seller tells me that I need to raise the voltage to 3.8, 3.9, or 4.0 in order
to get the charger in Constant Current mode. The seller says that the charger "thinks" that the battery is almost fully charged so it switches to Constant Voltage mode for the final absorption of the cells.

Anyone that has dealt with this, please inform me if this is what I need to do. These are 280AH Eve cells and I must charge them in the house. I don't want to do anything wrong that could possibly cause a fire or cause one of these cells to vent.

I purchased these cells from Amazon using Will's link from his site and they're supposed to be Grade A cells. They have their posts welded and their numbers have been rubbed out. They are not swollen, and they hold their voltage without any signs of self discharge. The seller of these cells said that they were purchased by a company but were never used. They purchased them from the company, welded the terminals, and rubbed out their identification numbers as requested by the company they purchased them from.

 

[Just John]

The problem I'm having with this charger is that I can't get it to charge
in Constant Current mode. I first set the voltage to 3.6, then touch the
positive and negative of the charger together to set the amps to 9. When
I hook the positive and negative outputs to the 280AH Eve cells, which I
have paralleled, the charger shows the proper voltage of 3.6, but the amps
are only at 3.8. The cells are now at 3.32v so I believe it should charge in CC mode.

The seller tells me that I need to raise the voltage to 3.8, 3.9, or 4.0 in order
to get the charger in Constant Current mode. The seller says that the charger "thinks" that the battery is almost fully charged so it switches to Constant Voltage mode for the final absorption of the cells.

Anyone that has dealt with this, please inform me if this is what I need to do. These are 280AH Eve cells and I must charge them in the house. I don't want to do anything wrong that could possibly cause a fire or cause one of these cells to vent.

I purchased these cells from Amazon using Will's link from his site and they're supposed to be Grade A cells. They have their posts welded and their numbers have been rubbed out. They are not swollen, and they hold their voltage without any signs of self discharge. The seller of these cells said that they were purchased by a company but were never used. They purchased them from the company, welded the terminals, and rubbed out their identification numbers as requested by the company they purchased them from.

You need better cables. (seriously, if it isn't putting out 10 amps, that is the problem)
Many people report changing for good quality cables went from 3.5 amps to 10 amps.
The seller is an idiot. He is trying to say nothing is wrong with the power supply (likely true), but raising the voltage to overcome the bad leads is not the answer.

An intelligent businessman would offer to sell you the correct leads to hook it up.

 

[lonewolf754]

Thank you Just John for your response, and sorry for the late reply.

Yes the cables that came with the power supply are getting a little warm when I charge at 7 amps. The power supply only charges in CC mode
if I raise the voltage up to 4. I have to be careful because the cells maximum voltage is 3.65. I did find that if I hook 4 cells in series the charger
will charge in CC mode and I don't have to up the voltage pass the cells maximum of 3.65. I don't understand this.

Thank You.

 

[Just John]

Thank you Just John for your response, and sorry for the late reply.

Yes the cables that came with the power supply are getting a little warm when I charge at 7 amps. The power supply only charges in CC mode
if I raise the voltage up to 4. I have to be careful because the cells maximum voltage is 3.65. I did find that if I hook 4 cells in series the charger
will charge in CC mode and I don't have to up the voltage pass the cells maximum of 3.65. I don't understand this.

Thank You.

The solution is not to increase the voltage to overcome bad cables, it's to make the correct cables.

1/4 inch ring connectors (crimp) and 10 gauge stranded wire are available in almost every Home Depot or Lowe's in the USA.

Most power supplies allow you to unscrew the outer cover on the banana jack plugs and slip a ring connector on, then screw back on the cover to make a nice tight and low resistance connection. The 1/4 connectors also fit nicely on the M6 sized battery terminals.

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

 

[lonewolf754]

Thank you for letting me know what I need to do. I'll get to Home Depot tomorrow and pick everything up.

Thank you.

 

[lonewolf754]

The solution is not to increase the voltage to overcome bad cables, it's to make the correct cables.

1/4 inch ring connectors (crimp) and 10 gauge stranded wire are available in almost every Home Depot or Lowe's in the USA.

Most power supplies allow you to unscrew the outer cover on the banana jack plugs and slip a ring connector on, then screw back on the cover to make a nice tight and low resistance connection. The 1/4 connectors also fit nicely on the M6 sized battery terminals.

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

I became impatient and cut up my smaller wire, put them together for a bigger gauge wire and crimped on ring connectors that I have and
the charger is now in CC mode at 3.6 volts. The charger is working like it should now. Thank you for your information, you fixed my problem.
I appreciate your knowledge. Thanks again Just John.

 

[Just John]

I became impatient and cut up my smaller wire, put them together for a bigger gauge wire and crimped on ring connectors that I have and
the charger is now in CC mode at 3.6 volts. The charger is working like it should now. Thank you for your information, you fixed my problem.
I appreciate your knowledge. Thanks again Just John.

You're very welcome, it is a common problem.