Got a question I’d like to pose. I do need to frame up the operational environment to clarify what I am asking. Please bear with me.
I have a PMG DC generator head. The head is a Werner Power F60AD, (Chinese manufactured), that I got from CGG.
It is rated up to 58.5 vdc @ 100amps. Right now it is connected to a 22hp Iseki, (Bolens knock off), tractor pto via a belt system that gives me some control over the RPM range. The gen head has max RPM rating of 3000.
My system has a 48vdc Nickel battery bank. Nickel cells are nominally 1.2vdc. Connect 40 in series to make a 48vdc bank.
I have run the the head and applied a charge to my bank for a short period of time, (5 minutes), and it appears to work.
Current and voltage measurements during the run were what I expected. The gen head did get hot to the touch. Which worries me.
Fully charging or equalizing my battery bank means that I have to drive the bank voltage to 70vdc, (40 cell bank @ 1.7vdc per cell), and hold it there for an extended period of time.
That gen head can push a maximum of 58.5vdc. With 40 cells in series, the head will only push enough voltage to raise the cells to 1.46vdc each.
The obvious answer is to lower the number of cells under charge to match the desired end point cell voltage to the gen heads capabilities.
In this case lower the number of cells in series, under charge, to 34. 58vdc / 34 = 1.70vdc per cell.
Doing this significantly lowers the resistance of the battery bank, and leaves some cells un charged. In my case 6 cells.
Here are my questions.
1.) Do you think charging a battery bank with a starting voltage of 34vdc, with a 58vdc generator is a problem?
2.) Can I lower the number of cells under charge to 20 cells, (nominal starting bank charge of 24vdc)?
The reason I ask about 20 cells is a physical one. From a cabling perspective it would be very easy for me to split my bank from being 1 40 cell bank into 2 20 cell banks.
And IF charging a 24vdc bank with a 58vdc generator is not a problem then I can completely equalize my entire bank. It just takes longer.
Thank you for your time and attention.