Renogy 12V 20A DC to DC On-Board Battery Charger for Flooded, Gel, AGM, and Lithium, Using Multi-Stage Charging in RVs, Commercial Vehicles, Boats, Yachts, 20A

All good

I use this in my overlanding setup. I have a 24v system in my Toyota landcruiser and I needed somthing to connect from my 24v to 12v converter to charge an auxiliary battery. In my situation, my alternator puts out 24v, that will fry this thing. So! I wired it to the output of my converter (12v out). I asked the question before buying this and everyone said 'no it won't work'. I bought it anyway cuz my options were limited. Well, it works. My aux battery has been staying charged while I drive and my fridge freezer has been staying cold. Mission accomplished.

This is exactly what I wanted and worked exactly the way I wanted it to. I got a 12 V DC car fridge for our 4,000 mile, 2 week road trip. I installed a 2nd “house” battery in my vehicle and used this to charge the 2nd house battery while we were driving. The house battery ran the fridge during the night while we were stopped, and got charged during the day while we were driving. I never drained my primary battery for starting my vehicle. This product perfectly charged my battery at the optimal voltage and current limit to prevent overheating the battery and prevent overloading the alternator on my vehicle. Since both batteries and the charger were in the engine compartment, I installed a switch so I could turn off the charger in slow traffic when there wasn’t good airflow, then turned it back on at highway speeds. This product was exactly what I wanted. Hopefully it lasts a long time, I really like it. Instructions were good. I basically installed it just like the instructions and diagram showed.

This charger is for my pickup bed/camper and charges a lithium battery. The power supply is isolated from the starter battery. This charger is set up to isolate itself from the starter battery. I didn’t read carefully about the two wires that appeared to be optional. They’re described in the manual and one is required. When the charger wouldn’t charge and I read instructions more carefully, I discovered the unit required connection with one of those little wires to a power source only on when the ignition was on. I made a wire, plugged it in the appropriate slot (requires a very small blade screwdriver) and connected it to the already isolated positive power wire input to the charger. Started the engine and the battery said it was charging at 20 amps. Perfect! The second little wire allows you to charge at 10 amps. I’m adding rocker switches to these wires so I can turn them on or off easily. There is a warning about using this charger around flammable fumes so I want to easily turn it off when hauling fuel.

This was installed in a travel trailer and so not exactly according to the manufacturers instructions. I did however stick to the underlying principles specified therein. It is located in the pass through storage area in the front which has little to no ventilation and on a sunny day, it gets very hot. Never measured the temperature in there but I assume it’s similar to the rest of the inside of the trailer @ 100+. Output naturally went to the onboard battery and input came from the “solar prep” port provided by the trailer maker and also from the 7pin wiring which is fused in the truck at 30amps (although the wiring is a little light). For the controls, the makers want two wires to see a 12volts “signal” from the input side,mone to switch on/off and the other to reduce the maximum charge rate. After a little searching I found a switch panel intended for car/truck applications which also contained a volt meter and usb charge port. This was most useful to provide a switch as the on/off for the charger. Another switch for the charge rate reduction function and the final switch to allow the voltmeter and usb port to be isolated when not required. To date, I have this working from my “solar shed”, maintaining the AGM battery at 13.2 volts. To reduce the maximum charge rate a little (because of the light wiring gage in the truck) and because I don’t like to push the charge volts high on AGM batteries, I set the charge voltage to 14.1Volts. Very happy with the way this is working out so far.