Renogy DC to DC Charger with MPPT 12V 30A Multi-Stage Charging - Smart On-Board Battery Charger for Solar/Alternator Input - Charges Lithium AGM Gel Flooded Batteries in RVs Cars Marine

I rarely leave reviews and in most cases only when I am really annoyed by a product. But this unit is really great at a very resonable price! Works very well, is compact, and has many great features that only a combined dual (solar and alternator) charger can provide. For example charging my starter battery when the solar battery is full. I think I had a small parasitic drain on the van which caused the battery to be empty after a few weeks of not driving. With the renogy charger that is no longer a problem. And of course the main function to support dual charging is also great. I specifically used the smaller version (30A) to limit stress on the alternator . That is probably the only missing feature I can think of: configure the max draw from the alternator in the app. But with the 30A version that is not really a problem. And I anyway only have 400W of solar, so 30A is fine.

I have a cargo trailer that I use for work with a 2000 watt inverter to run power tool chargers & lights in the trailer. I have a 200 watt solar array connected to the solar input as well as the vehicle smart alternator input. The (2) 100 Ah AGM batteries stay charged through this device to where I never have to plug in my trailer to the house to charge my batteries. What I like about this product is if it’s cloudy and I’m using power then the vehicle will charge the batteries as I’m driving from job to job or I can start the truck for a few minutes and get a charge. This device also prevents voltage feeding back to the vehicle from my trailer batteries as it would if it were connected straight to the battery output from the truck. It also prevents overcharging of the batteries, extending the life. Lastly, the ability to change battery types on this device makes it great to use for different battery chemical types. The price is a little high but it does exactly what I need in just one device.

I bought this to replace my previous model Renogy (that I accidentally burned up by overpowering it with solar) and its been running strong since June. I like having both the mppt and the alternator charging in one unit especially with the size constraints of my battery box. Pretty easy to install, a lot more fault tolerant than the previous model and I'm happy with it.

So it does work. My alternator does charge my battery perfectly. But as for the solar MPPT portion.....not so much. I'm on day 2 of renogy support to figure out why I have optimum solar input from a 100 watt panel coming in, but the controller is not sending it to charge my 100ah lithium battery. The input of the solar is 17.65 and outgoing is 0. Seems like the controller is not doing is job or is stuck in a mode to prevent that power from passing through to the battery. **UPDATE** The charger has essentially failed completely. It will still charge both batteries via alternator power, but it will not keep them separated when the engine is off. Regardless if the D+ ignition wire is connected to a switchable on/off power source or not. To prevent parasitic draw and killing batteries, alternators, and starters, I have to physically remove the main ground wire from the charger every time. Renogy support offered no help or resolution. And every specialty shop i have reached out to for help with these issues refuses to work on eenogy products because they are garbage. Same your time, effort, and money and buy victron.

I have run through a dozen different products from Renogy, and I think this is a my favorite. In use for several months at the time of this updated review. Most people will need the bluetooth module for configuration. Because the charging amps are configurable (In 10A increments) this is the perfect product for a boat with an outboard. I have mine set to charge at 20A, and it does a great job detecting when the outboard is running and charging my LiFE4Po bank. It also works great with solar. The way this device works and is wired saves a lot of room, wiring, and complexity on any boat/RV. One major complaint: The PV Voltage is ridiculously low. I upgraded from a 200w panel with a really low PV voltage, which worked fine, to a 300w panel with a normal 36V PV Voltage and now I have to upgrade. It's not clear if the 50A version actually has a higher rating, there is a lot of conflicting information. Two minor complaints: 1) I wish the charging amps were configurable to an exact number or at least 5 amp increments. For some small outboards on boats even 10 amps is going to be too much. 2) I wish there were a way to keep the device from turning on from incoming solar. I don't think this is a feature on any other solar charge controller, but it is annoying to have to install a breaker or switch just to keep the unit from turning on every time the sun is out.

I use this in my overland Sequoia build. This keeps my second battery charged from the alternator when running and uses my solar panel when not running. It protect my trucks battery from being drained. I thought it stopped working and worked with Renogy product support and they were amazing, they tested the product on their bench and ruled it out as the problem. I was able to find that the problem was actually my solar panel. Recommend this unit for anyone who has an overland build or enjoying that Van life.

So I have had this about 2 years and there has been no issues with this and my batteries or truck. This will provide 30 amps to lithium batteries, and pulls about 40 amps from the truck to get that power. I do use the solar side with some moveable panels when I need it, and it has helped keep the truck topped off when connected. I liked it so much when I sold my last rv I removed it and installed it in my new one.

I have it charging a little battery bank, it works and my only problem is overcharged batteries, possibly from other renogy components but it keeps things charged for now