Sprinter Campervan On-Board Battery Charger
Updated: Apr 8, 2019
I needed a way to charge my house battery during the rare, but occasional time that I have AC shore power available. My biggest draw is my 300w 12VDC heater coil for my hot water (hot water write up here) so I needed one that could output at least 30amps @12VDC. I decided to go with a Dewalt 30amp Bench charger, this was due to its size for mounting and its availability (Home Depot).
I already have shore power input on my van from previous owner and I actually like his placement, to some it may seem in the way, but for me I like that I will never forget to unhook it.
The wiring was already in place from the previous owner. I just hooked up a USB/AC outlet to a indoor receptacle underneath my bench seat.
The Dewalt charger plugged into my interior AC outlet and I wired up the two terminals on the front for direct connection (partially why I went with this over others is because it had terminals and not just a soldered in jumper cable). However I soon discovered that those terminals are for "Bank 2" and will only provide 15amp 12VDC pass through... Not what I need. So I connected the jumpers to my battery and it performed as it should.
It seemed to adjust amperage output depending on the battery voltage (ran the heater coil as a test). I will most likely stick with this one for a bit as it does what I need pretty easily and its size works well for me. I installed a connector like this so I can directly connect the wires to the battery and reconnect to jumper cables as needed. I did this so I can use this charger for other batteries as well, when it is not being used in the van (Velcro-ed it in for now).
UPDATE: After using the charger while plugged in at Fort Wilkins State Park in Copper Harbor, MI in order to heat up my fresh water tank it seems to function perfectly for what I need. Ran a 30amp draw (300w heater coil) for 3-4 hours and the charger was able to keep up with no issues. Again my only concern is that it does not automatically turn on when AC input is detected, you do have to manually hit one button to get it to start charging.