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.

The hairy bollox indeed

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.

5 stars because was refunded..

Working well, just what I needed.

I purchased this after buying the 170ah lithium battery from renogy..After installing the battery and charger into my motorhome I noticed that the charger wouldn't put more than 0.75 amps I to my lithium battery... at first I thought it was because my battery was fully charged but as I went away and used more of my battery it turned out that this charger won't put more than 1 amp in . I have then attached a 120watt solar panel and the app shows that even with solar at 18.7v and alternator at 14.4v it still won't put even 1 amp into my battery which left me with a flat battery that I had to remove and charge in the house.. After numerous emails to renogy and being told to reset it by disconnecting everything I am still no closer to having this resolved.. even after screenshot of their own app showing the voltages and low amps they were wanting me to check my alternator that had a split charge relay on working fine..I wouldn't recommend spending this much on a dc to dc charger from Renogy as not only are there quite a few youtube videos showing poor software in these but also the customer service is terrible.. I am still sat here with a flat motorhome battery and a nearly £200 paper weight..

Got this in the back of my overland vehicle, charging from the unit works first class, small unit very easy to install, looking forward to setting up a solar panel for stationary charging, but so far so good

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.