# Charging voltage

#### superway

Joined Oct 19, 2009
125
Hello,

I have a DC electronic load and a DC power supply. I would like to set current limit on DC supply with 5A, 7A , 9A step to charge 4 batterries 54.5V. Can anyone show me how to setup the load and DC supply to get current limit? On the DC supply, there is a current limit pot and voltage adjust pot.
Thanks

Ken

#### MrChips

Joined Oct 2, 2009
30,984
Set the voltage to 54.5V. Connect the batteries.
Increase the current setting until the current reading reaches 5A or stops increasing, which ever comes first. Your DC supply will now be both voltage and current limited.

#### superway

Joined Oct 19, 2009
125
Thanks Mrchip.
But batteries are very low discharing now. When applying 54.5v to batteries, it will draw alot current from batteries and it might be more than 5A at initial charge. So that's why i have to use DC electronic load first to set initial charge 5A. My question is how to adjust current limit on power supply with electronic DC load connected to DC supply output ?

Thanks

#### russ_hensel

Joined Jan 11, 2009
825
What is the role of the electronic load? If the ps has voltage and current settings it would seem the answer is none. Do you really have a 50 + volt supply at 9 amps ( 450 watts? )

#### superway

Joined Oct 19, 2009
125
Specs for initial charge is 5A @ 54.5 vdc
For second charge cycle is 10A @ 53.5vdc.

But my batterry string is read only 30Vdc. So I have to base info specs above to charge my batteries 5A @ 54.5Vdc. For initial charge, do I have to adjust the PS about 35vdc and increase gradually or adjust to 54.5vdc immediately?

My current limit pot on DC supply just the pot with the label 20% to 120%.

Thanks

#### crutschow

Joined Mar 14, 2008
34,700
Just do the adjustments as stated in post #2 by MrChips. If you start with the minimum setting on the current limit pot and increase it until it reaches 5A, then the current will never exceed that, no matter what the battery voltage.