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 ...
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Actually, Renogy recommends 4-2 awg wire on the input side for that length of run. Since your friend’s circuit length is at the outer end of the range, I’d probably have chosen the 2 gauge wire as well. The data in the box I circled is formatted a little hokey because the font is too large, but that’s what it’s trying to convey.
These DC chargers aren’t all created equal. My Redarc doesn’t run that hot at all. Not even close. Warm is the hottest it ever gets. And, it doesn’t even have fans. It’s rated to run in environments exposed to high heat (over 50° higher than the Renogy) and open weather. I could have installed it on the frame rail of the truck if that’s where it would work best. Maybe there’s a reason why the Redarc products all cost so much more than the Renogy products.
That’s not quite true, they all have upper and lower voltage limits. I don’t know about Renogy or Victron chargers, but the closer you get to the lower voltage limit with the Redarc, the less amount of time it will stay engaged. It will drop offline on its own.
I’d at least consider that there may be something wrong with your friend’s charger contributing to the “wasted current”. You’ll never convince me that using 2 awg wire on MY install would result in anything more that an insignificant amount of gain. Had Redarc recommended 2 gauge wire, of course I would have used it. But they didn’t, and I see no reason to use your friend’s install as the yardstick for what I should have done with mine.
:):)
otrfun wrote:
If you feel the case of a 40a Renogy while it's converting such a low voltage you'll be firm believer it is using 10-20a of current to pull off this conversion. The case gets *very* hot while both fans run full-on. Also, let's not forget the current consumed by the 1.3v voltage drop created by the cable, terminals, and fuses. It all adds up.
These DC chargers aren’t all created equal. My Redarc doesn’t run that hot at all. Not even close. Warm is the hottest it ever gets. And, it doesn’t even have fans. It’s rated to run in environments exposed to high heat (over 50° higher than the Renogy) and open weather. I could have installed it on the frame rail of the truck if that’s where it would work best. Maybe there’s a reason why the Redarc products all cost so much more than the Renogy products.
otrfun wrote:
Folks have no choice but to use the proper gauge cables with their inverters. Use too small of cable with your inverter it simply shuts down. Not the case with a dc to dc chargers. They will silently ramp up current draw until either your fuse or alternator gives up the ghost.
That’s not quite true, they all have upper and lower voltage limits. I don’t know about Renogy or Victron chargers, but the closer you get to the lower voltage limit with the Redarc, the less amount of time it will stay engaged. It will drop offline on its own.
I’d at least consider that there may be something wrong with your friend’s charger contributing to the “wasted current”. You’ll never convince me that using 2 awg wire on MY install would result in anything more that an insignificant amount of gain. Had Redarc recommended 2 gauge wire, of course I would have used it. But they didn’t, and I see no reason to use your friend’s install as the yardstick for what I should have done with mine.
:):)
