Can I charge batteries with a DC to DC charger will connected to a charge controller?

[Rover]

Hi,

Do you know if I can charge batteries with a DC to DC charger when connected to a charge controller? I would like to backup my solar van system with 12VDC to 24VDC charger.
I not sure if the charger and charge controller will be able to run at the same time. I think the charge controller will sense the charging and stop charging because it will seam that the battery is charged when the charger turns on. I would like to use my Van to power the house if the power goes out. Has anyone done something like this? Thank You

[chrisski]

Hi,

I not sure if the charger and charge controller will be able to run at the same time.

I can only speak for my Victron Charge Controllers and my RV's built in AC to DC converter, but on a cloudy day when the batteries have gone down to 72% with little hope of them getting recharged on the panels, I've turned my generator on and flipped the circuit breaker for the converter. The Charge Controller delivers 20 amps to the batteries and the Panels deliver up to 10 amps to the batteries. The voltage does not climb above 13.6, so my guess is that the charge controller and panels at the same time through my MPPT controller does not receive the trigger it needs to switch from bulk to absorb, 14.7 volts, so I am able to use both at the same time.

I'd also be interested in the output of the alternator. You mention a house, and most alternators won't deliver near their rating unless they are at the engines max RPMs. So, my 120 amp alternator would struggle to deliver 20 to 30 amps at a lower RPM, which unless this house is very small, won't power much. Also, my truck tracks hours, and excessive idle hours wears the engine down just like miles.

I'd think a good $780 quiet inverter generator outputting 2.2kw would be a better fit to power a house. These can adjust speed based off the load, which your van won't. You can get a much cheaper generator that's a bit noisier and puts out more power for less money. Even cheaper used on Craigslist.

[Rover]

Thanks for the input,

Powering the house will only happen around ever 2-3 years and I hope for only a day it will need to power the freezer, TV, a few lights and charge some phones etc. The van has a 250 AMP alternator and with 1200 watt solar array it should run fine in the day time. If I need to I'll idle the van with the freezer off and after the bank is charged run it again. I'm not to concern because the freezer can be turn off all night without defrosting.