I had several nice chats with Mr. Ski3pin and also got the Renogy he used, but decided on the 30A unit. I figured it would get less hot, because the box and heat fins are the same as the 50A version as far as I can tell. The only convenient place to mount it was in the battery compartment on our side dinette camper. So I mounted it right over the two vent holes. I was pretty concerned about overheating inside the battery compartment. Lithium batteries don't need venting, so using the holes for cooling seemed reasonable.
Other reasons for the 30A dual-charge controller besides less heat: less stress on the alternator, charges the battery slower so maybe less stress on it (we generally drive for at least 30 minutes), possibly could have used 8 gauge wire instead of 6, but we did use 6 from truck battery to camper battery, and there's another reason but can't remember right now! It didn't cost much less than the 50A version though. That was disappointing.
Frankly, the heat hasn't been much of an issue so far (6 months usage) because our power needs are pretty low. Just a fridge, charging gadgets, lights, and sometimes the heat and fan. Our SOK 100 AH lithium battery only drains 20% per day, maybe 25% on super warm days. Solar will keep it a lot higher than that, usually 10% overnight. Most of the time our battery stays above 80% SOC. I unplug the camper, awkwardly, through a turnbuckle door on the last day or two of a trip to discharge it below 100%.
It seems like we either move every day a little bit, enough to charge it, or solar keeps it charged. The way our truck is wired we don't really get 30A, more like 25A, and it never seems to get very hot. So it charges up in about 45 minutes or less when driving.
When using our 100W flex solar panel on the ground it's only charging at around 5 amps, which doesn't heat up the charge controller. It easily keeps up a full charge if we get reasonable sun. Honestly I feel like I only use solar to save gas, which I figure is about 0.15 gallons for a charge from 0%-100%. But we've never stayed more than 3 nights without driving somewhere. The Renogy charger will produce some charge amperage even in cloudy weather, especially if we add our other 90W suitcase panel.
Basically I'm very satisfied with the Renogy dual controller and the SOK lithium battery. I'm sure the other name-brand battery manufacturers are good also. (Except our older SOK battery Bluetooth doesn't report state-of-charge correctly, so I got a cheap non-Bluetooth SOC monitor.)
Yes, this forum is fantastic for many reasons! I'm curious how Mr. Ski3pin will reply to this, as he has much more experience.
