Looking for recommendations for a DC-DC charger to install in my Sprinter to charge my AC300/B330
I would not recommend a DC to DC charger since you will be limited to about 30 volts output which will limit your charge rate to around 375 watts. If that is sufficient for you, go for it. If you need a higher charge rate your would need to go with a 12 volt to 120 volt inverter connected directly to your vehicle battery and use that to AC charge your units or alternatively you could use a 12 volt to 48 volt or higher step up converter to increase your charge rate. Both option have been discussed on this forum with many examples shown.
I would prefer to use a DC-DC converter at 12 to 48V at 20-50 amps. The AC300 has a 12 amp limit. Is it OK to use the input amp converters and the AC300 just limits it to 12 amps? I would prefer not to use an inverter due to the loss involved. Are there adjustable voltage converters available to select the increase voltage desired? ie 12 to 24,36,48?
On the AC300 you can change the DC input to other, and add a dc to dc step up boost converter 12v - 48v, this is powered off the alternator and puts out 480 watts into the ac300.
input is 12v at 40amps, output is 48v at 10 amps. 480 watts total
I did this on a Class C motorhome, I also have 825 watts on the roof (525 watts & 300 watts), but when I charge with the vehicle alternator I disconnect the 300 watt panels and plug in the (DC-DC) alternator wires.
Just to clarify the space on the roof is limited so line- #1 has 3- 175watt panels connected in series and line #2 has 3- 100 watt panels in series. I wish I had the room for all the same size panels.
The 48 volts output from the converter at 12 amps will be approx. 575 watts of charging power. I have seen lower output adjustable step up converters but am not aware of an adjustable converter that has the desired output wattage.
The amps are fixed at 10. I used this item Daygreen 12V 24V 36V to 48V 10A 480W DC DC Step Up Boost Converter.
So 48 volts at 10 amps is 480 watts. The AC300 has a max 12 amps input and I was concerned if the boost converter was also 12 amps there might be an issue.