Renogy 40A DC-DC Battery Charger with MPPT Solar and Alternator Dual Power Input, for Flooded, Gel, AGM, and Lithium Battery

Very useful and well built item which combines all the features of several components (that other manufacturers would sell separately) all in one compact unit.

5 stars because was refunded..

So far so good, I did have the Renogy 20amp mppt that worked great and kept my 200amph lithium battery in good order. As my fridge started drawing a bit more due to weather and cloudy days I tried a cheap dc to dc charger add on- ones available on Amazon. Even tried the one with didgital display and it was rubbish realy. The dc to dc mppt dose the job nicely. Only thing I would say is the app don’t show battery % just voltage. I know as the voltage drops so dose the capacity but it would be nice to see somthing like the app I had for the BT 1 and mppt. Also I would advise upping your cable size to the max you can as I had issues with my 60amp tripping, the cable was hot also. I dropped the max charge to 40amp and all is good until I up the cable from the 70amp I was advised.

The hairy bollox indeed

Seemed fine to start with, charge via car or solar, it gets very hot. I used a fan to keep it at a better temperature. but it just stopped working after nearly 2 months. Was still lit up but no power via car or solar. Tried to contact renogy, never got an answer to call or emails, it was past it returns date on Amazon, so wouldn’t let me send it back. I contacted Amazon but luckily it was on the monthly payment, so they just let me send it back. Got a refund on the payments I had made.

Working well, just what I needed.

Gone the full Renogy set up and this dc to dc charger and mppt is absolutely quality. For the money it’s hands down cheaper than buying them seperate and with the Bluetooth connection you have everything you need.

It’s nice thank you