Couple of questions about DC-Dc charging
I've been thinking about adding a DC-DC charger now that I've added 400 amp hours of AGM batteries. There are lots of useful posts but I haven't run into a couple of things I'm curious about. One ...
Forum Discussion
Of the three DC-DC charger manufacturers install manuals I’m familiar with (Redarc, Renogy, Victron), none of their wire gauge recommendation charts go beyond 30-32 ft. I’m of the impression that their recommendations include both the + and - wires. I’ve found no instructions in any manual stating that the length of the + and - cables should be added together to get the total circuit length. I believe their recommendations assume that the two wires will be of about the same length.
Honestly, it’s not hard to end up with a one-way circuit length of over 20 ft, even on a truck camper or a class A/B/C. I made all of the cables for my install, so they are all “long enough, but not too long”. They start at the starting batteries close to the front bumper of the truck, run along the frame rail to the front wall of the bed (not the truck’s rear bumper) through the camper pigtail to the interior of the camper, then to the camper battery compartment that’s only about 4 ft back on the driver side of the camper. The total one-way circuit length is still very close to 30 ft.
There’s nothing wrong with upsizing the wire a little, as well. That’s actually what I did when I installed the first Redarc charger, which was their 25 amp model. The recommendation was to use 6 AWG wire, and I used 4 instead. After using it for a while, I decided that it worked even better than I was hoping for, and came up with some new “needs” that it could be used for if it was just a little bigger. So I bought their 40 amp charger, a couple of 60 amp fuses, and in about 30 minutes had them swapped out. Then I sold the 25 amp charger on fleabay and recouped some money.
:):)
Honestly, it’s not hard to end up with a one-way circuit length of over 20 ft, even on a truck camper or a class A/B/C. I made all of the cables for my install, so they are all “long enough, but not too long”. They start at the starting batteries close to the front bumper of the truck, run along the frame rail to the front wall of the bed (not the truck’s rear bumper) through the camper pigtail to the interior of the camper, then to the camper battery compartment that’s only about 4 ft back on the driver side of the camper. The total one-way circuit length is still very close to 30 ft.
There’s nothing wrong with upsizing the wire a little, as well. That’s actually what I did when I installed the first Redarc charger, which was their 25 amp model. The recommendation was to use 6 AWG wire, and I used 4 instead. After using it for a while, I decided that it worked even better than I was hoping for, and came up with some new “needs” that it could be used for if it was just a little bigger. So I bought their 40 amp charger, a couple of 60 amp fuses, and in about 30 minutes had them swapped out. Then I sold the 25 amp charger on fleabay and recouped some money.
:):)
