C-40 current limits

[RogerAS]

All,

Sorry, but I need to confirm something before buying more PV panels.

I have ~750 watts of PV now charging a 12V battery bank which is controlled by a C-40. How much current can the controller handle before the magic smoke is released?

If I add another 750 watts do I need another C-40?

I can't find my manual and I really don't understand the PDF.

Thanks,
R

[mike90045]

750W / 14V = 53 amps    40 amp controller.


750 x .8 (standard PV de-rate) = 600 / 14 = 42 amps


It will likely work, unless you have a sun tracking array, or a oversize battery bank.  From first power up, to array perfect alignment, might be 3 hours, and in that time, the batteries may have charged enough, that they won't pull the full 40 amps from the array.   

My guess is that it will work for a while, but better consider upgrading to 24V,  which at 750W , is only 27amps, well within it's spec.

[RogerAS]

750W / 14V = 53 amps    40 amp controller.


750 x .8 (standard PV de-rate) = 600 / 14 = 42 amps


It will likely work, unless you have a sun tracking array, or a oversize battery bank.  From first power up, to array perfect alignment, might be 3 hours, and in that time, the batteries may have charged enough, that they won't pull the full 40 amps from the array.   

My guess is that it will work for a while, but better consider upgrading to 24V,  which at 750W , is only 27amps, well within it's spec.

I would upgrade to 24 V but that would mean buying a new large output inverter, changing out all the existing DC loads to 24V, finding another set of wind turbines and a new engine driven charging system (alt).

I have a 1,320 AH battery bank configured to 12V, but that's about to be replaced as those are nearing the end of the service life after 6 years.

It looks like I just need to buy another C-40.

Thanks,

R