12V to 24V DC Charger

[Riverbug]

Anyone have experience with DC to DC charging from 12V vehicle to 24V battery bank? How well does it work? Any concerns with it?

I use 36V to 12V step-down converter in my boat, no problems at all after several years. Wondering how well it works going the other direction.

[MoonShadow_1911]

Anyone have experience with DC to DC charging from 12V vehicle to 24V battery bank? How well does it work? Any concerns with it?

I use 36V to 12V step-down converter in my boat, no problems at all after several years. Wondering how well it works going the other direction.

Same concept. You just need a step-up DC-to-DC converter.

Victron Energy Orion 12/24-Volt 8 amp DC-DC Converter Non-Isolated, High Power https://a.co/d/4ecSL4v

[Riverbug]

Same concept. You just need a step-up DC-to-DC converter.

Victron Energy Orion 12/24-Volt 8 amp DC-DC Converter Non-Isolated, High Power https://a.co/d/4ecSL4v

Thanks. So for use with 24v lithium battery bank, does this replace the typical DC to DC charger altogether to avoid the lithium bank pulling too much from the alternator? Or is this used in line after the DC to DC charger to then convert from 12v to 24v?

[MoonShadow_1911]

Thanks. So for use with 24v lithium battery bank, does this replace the typical DC to DC charger altogether to avoid the lithium bank pulling too much from the alternator? Or is this used in line after the DC to DC charger to then convert from 12v to 24v?

In place of a 12vdc-12vdc charger. The model I linked only provides 8 amps. Victron does make others that are higher amperage. Just make sure you aren't "out pulling" your alternator. 8 amps should be plenty to keep your battery bank "topped off".

[Riverbug]

In place of a 12vdc-12vdc charger. The model I linked only provides 8 amps. Victron does make others that are higher amperage. Just make sure you aren't "out pulling" your alternator. 8 amps should be plenty to keep your battery bank "topped off".

Thanks again. I'll read up on these things.

[SolarPoweredRV]

Thanks. So for use with 24v lithium battery bank, does this replace the typical DC to DC charger altogether to avoid the lithium bank pulling too much from the alternator? Or is this used in line after the DC to DC charger to then convert from 12v to 24v?

Yes, your 12v to 24v DC to DC Converter would replace a 12v to 12v DC to DC Converter.

With a 24v battery bank you want to choose a Dc to DC Converter that makes sense for the size of your battery bank. For example: my battery bank is 500ah at 24v (or 1,000ah at 12v), if I were to choose the above suggested 8 amp, DC to DC Converter, I would be able to put a total of 80 amp hours of energy (at 24v) into my battery bank on a 10 hour travel day. That is not very much energy when you have 500ah of energy storage (even less on a shorter travel day). Consequently, I chose the 20 amp Victron 12v to 24v DC to DC Converter to install on my Tow Vehicle.

When you are installing your DC to DC Converter, you really need to look at the specifications of the Converter to ensure you get your cables and fuses sized correctly. In my case, I have a 20 amp output at 24v, which equates to 40 amp output at 12v. Additionally, my Converter has the capability to supply 30 amps (at 24v) for a short period of time (surge capability), this means my cabling needs to be capable of carrying 60 amps at 12v and my fuse needs to be 80 amps. I bought 50 feet of red and 50 feet of black 6ga Marine cable and used self sealing heat shrink tubing over every crimp connector (by-the-way, I use a hydraulic crimper for all cable connections). I used the 6ga cable all the way from the truck battery to the camper battery, technically, I could have used smaller gauge cables on the 24v side of the Converter, but I chose to stay with the 6ga because of the long run from the truck to the camper batteries.

For my TV to Camper connection, I installed a "Lift Gate" connector (both male and female) similar to the one linked below. I installed this connector next to the 7-pin connector in the bed of my truck (yes, it was emotional to put such a big hole in my truck).

Amazon.com/2-Pole-Die-Cast-Trailer-Connector-Female

Installation notes:

I have a 2019 F350 Diesel, there is next to zero space under the hood to install any accessories. I wound up installing the 80 amp, "resettable" fuse up front just behind the headlight. I also made my positive connection directly to the battery cable. I used the body for the negative connection. The DC to DC Converter was placed on the back wall of the passenger compartment behind the passenger seat. I ran a 16ga wire from the 24v post up to the dash and installed a digital voltage meter to monitor the Converter output. I also installed a 2 position switch (pole 1-off-pole 2) and connected a 12v hot wire to the second pole. This allows me to switch from 24v monitoring to 12v system monitoring with the flick of a switch (very useful).

I ran the 24v cables out the bottom rear of the passenger compartment and through the frame cross member to get back to the drivers side, I then ran the cables along the frame rail and up into the truck bed at the back of the truck.

To mount the 2-pole connector, I took a piece of hard wood (approx 6" x 10") and mounted two 3/4 inch strips, vertically, on the back, this provided enough height to span the raised ribs in the truck sidewall. I drilled a 1.5 or 2" hole in the wood to accommodate the connector and then mounted the wood to the truck using a self tapping screw in each corner. The next step was to drill a big hole into the truck sidewall using the hole in the wood plate as a guide. After the hole was drilled and the connector was test fitted I took the wood off and sprayed it down with Rustoleum Truck Bed Liner spray (I love this stuff) to make it water proof.

Good luck, I hope this helps.

[lawyerforfun]

Yes, your 12v to 24v DC to DC Converter would replace a 12v to 12v DC to DC Converter.

With a 24v battery bank you want to choose a Dc to DC Converter that makes sense for the size of your battery bank. For example: my battery bank is 500ah at 24v (or 1,000ah at 12v), if I were to choose the above suggested 8 amp, DC to DC Converter, I would be able to put a total of 80 amp hours of energy (at 24v) into my battery bank on a 10 hour travel day. That is not very much energy when you have 500ah of energy storage (even less on a shorter travel day). Consequently, I chose the 20 amp Victron 12v to 24v DC to DC Converter to install on my Tow Vehicle.

When you are installing your DC to DC Converter, you really need to look at the specifications of the Converter to ensure you get your cables and fuses sized correctly. In my case, I have a 20 amp output at 24v, which equates to 40 amp output at 12v. Additionally, my Converter has the capability to supply 30 amps (at 24v) for a short period of time (surge capability), this means my cabling needs to be capable of carrying 60 amps at 12v and my fuse needs to be 80 amps. I bought 50 feet of red and 50 feet of black 6ga Marine cable and used self sealing heat shrink tubing over every crimp connector (by-the-way, I use a hydraulic crimper for all cable connections). I used the 6ga cable all the way from the truck battery to the camper battery, technically, I could have used smaller gauge cables on the 24v side of the Converter, but I chose to stay with the 6ga because of the long run from the truck to the camper batteries.

....
Good luck, I hope this helps.

Just a small note thanking you for this info. I'm not even remotely in a similar situation, but came across this post during a google seach. I needed to figure out a 12v-->24v @ 20amp step up plan to power a portable AC unit for my Fummins 350. My install ended beneath the rear seat, ran the hot lead from the battery through the firewall, along the side trim and then to seat - negative to the seat mounting. Also included a toggle switch to let me disable converter when I'm not using it.

All the other tips on the converter choice, wiring, fuse sizes, etc were great. Got it all done in a single night.

Thanks again!