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.

Well made unit that does what it's designed to do: control, optimize, and monitor DC to DC solar panel and alternator charging of your 12 volt house battery system. This all-in-one charging controller is easy to install for a person with a basic understanding of an off grid 12 volt electrical system; the included instruction are very clear and informative. The features via the optional BT-2 bluetooth module (highly recommend) are comprehensive and make monitoring your system status via your phone a must (and a pleasure). The unit also treats your battery right via multi stage charging that will extend the life of your battery.

updated 2025. New app updates to the Bluetooth module have not solved the problem. You can not connect to this charger using Bluetooth alone the app requires a working internet connection to revalidate your login every so often. Which means this product is unusable for people camping offgrid. Pros: None Cons: Huge Inefficient compared to inexpensive MPPT setups No Battery nor charging status Bluetooth module does not work offgird I got this to replace my MPPT 15Amp charger. The Renogy setup is significantly worse. My old charger could run my fridge indefinitely with the same 110W panel. With the Renogy I am out of power sometime while I sleep. This thing is huge. It’s like 4 times larger than a similar MPPT system. There is no screen or way to see the charging rate and battery status. I bought Renogy’a external display but it does not give enough detail. So I also bought their Bluetooth module. The Bluetooth module plus app give amazing detail but only work with a recent internet connection. The docs say you can login to the app and then use it offline with Bluetooth, but this is a lie. Do NOT expect that to work. The app re validates the login token. I just tried it after a few months of not using the app and it gave me an auth token error and said I needed to login. Dealbreaker! I do NOT recommend.

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 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.

I actually haven’t fired this controller up yet but wanted to clarify this unit doesn’t need a BT-2 unit as many reviewers suggest. Here is response from Renogy service: Based on the provided information for the RBC40D1S charger, the unit has a built-in Bluetooth communication function. This means you can connect directly to the Renogy DC Home or Core app via Bluetooth to monitor and adjust settings; an external BT-2 module is not required for this model. Since the RBC40D1S has integrated Bluetooth, the BT-2 module is typically used for Renogy products that do not have built-in Bluetooth. It is possible that the BT-2 is not compatible with your specific charger model.

Nice charger. East set up. Let’s you charge at 10,20 or 30 amps. Has some good info in the app but you have to buy the Bluetooth adapter for charging options and info. Dc to dc and solar