LiTime 12V 40A DC-DC Battery Charger with MPPT Solar Controller, Dual Input Smart Charger for 14.6V LiFePO4 Lithium Batteries, Fast Charging for RVs, Campers, Trailers, Solar, Home Backup and Off-Grid

Review after a year+. Have had this installed in my truck and it was worked great.

Amazing device. It was so nice to put solar and alternator through one device. Very small considering what the competition looks like. I've only been using it a few days but it's performed perfectly on both alternator and solar so far. I do wish it had some monitoring capability either through an integrated Bluetooth device or a module like renogy but there are other ways to monitor.

after only 5 months Product does not work.

I’ve bought many LiTime products in the past and have been very pleased with their quality, reliability, and performance. I should’ve read the specifications more closely before purchasing it. After receiving it, I realized that it is limited to a solar panel Voc of 26V. Most panels are substantially higher than this making this unit not very useful to me as a MPPT controller. Yes, the Voc limit is indicated in the specifications way down the page, but considering that the Voc is as low as it is, the manufacturer should do a better job of stating this more prominently. Anybody that’s moving 40A around to charge and recharge batteries is probably going to be using panels with a Voc of at least 30 to 40 V. Because of the need to protect against high Voc on a cold day with full batteries, I would expect a 40A MPPT controller would have a max Voc of at least 50 V. Nonetheless, because I did not read the specifications more closely and I was in a hurry to get my DC to DC battery charger installed, I’ve decided to keep the unit and hope to find one or more panels in the future that have a low enough Voc that I can use them as well. UPDATE LiTime contacted me after I posted this review and offered me a full refund if I was not completely satisfied. This is an example of the kind of excellent customer service I have experienced from LiTime in the past. Because it was basically my error not to be more diligent when purchasing this, I have updated my review to soften my criticism and I have decided to raise my review from 3 to 4 stars. This was my decision alone and LiTime did not pressure me to do this in any way. The unit I purchased is exactly what was advertised and performs well doing the most important function than I needed: DC to DC charging. Just make sure that if you plan to use this as an MPPT controller that you have panels with a Voc of not much over 20V, otherwise you risk damaging the MPPT controller on a cold sunny day.

Connected this to my truck battery with fused 4 gauge cable. Used 2 gauge cables to the parallel 100ah batteries which power my 1500W sine wave inverter. Used breakers between connections for safety and peace of mind. I charge the battery bank while driving. **One caveat: this LiTime 40A dc-dc charger gets very HOT**. I now aim a fan at it while driving/charging my battery bank to help cool it. It charges my batteries very quickly and has gotten me out of a pickle while out camping with very little sun/solar availability! This system is now self-contained as long as I can run the truck engine. I have all the comforts of my home kitchen including fridge, microwave, toaster, instant pot, induction cooktop; cabin heater, air filters, electric blankets and heating pads. A true “glamping” experience!

I have been using this 40amp DC-DC charger for 10 months now and it has been great. Works like it should and has been trouble free. I dont use solar so I cant judge that and I havent yet used the reverse charging so I dont know about that but I really hope that feature works. I have a 300amp alternator and a 300 amp hr battery. I like it very much

Was running this with some 12v solar panels for a while and was disappointed when I upgraded to 30 VOC CIGS panels and discovered it wouldn’t work (the overload protection would cut out at around 26v). Susan at LiTime let me know their latest version would work for my setup and arranged for a replacement, free of charge. Works like a charm now! Fast DC to DC chargers seem to be pretty popular right now, and there are a number of great options, but this setup takes all the guesswork out of combining solar and alternator charging, which means I can run my fridge all weekend without turning on my truck. It also makes disconnecting my camping setup really easy when I need to use my truck as a truck. Really glad I went with LiTime; customer support was fantastic and they really stand behind their products.

I tried installing this, but couldn't get it to work. Drove my RV down to a shop, had them install it for me. Still doesn't work. It gets 13.8 volts in, but does not charge the litime battery it's hooked up to. Tried contacting support, you talk to an AI agent that basically just reiterates FAQs, then they transfer you to a human that asks one question and never responds. If you're lucky and it works for you, great. If you're unlucky, too bad! At this point I'd suggest gambling on another brand, there are cheaper options out there.