Renogy RBC40D1U-BT2
(10 reviews)
The Renogy RBC40D1U-BT2 charges your leisure battery at up to 40A from the alternator, with Bluetooth BT-2 included. No solar MPPT, unlike the DCC50S.
- Charge current: 40A adjustable (40/30/20/10A)
- Input: Alternator only, no solar MPPT
- Bluetooth: BT-2 module included, DC Home app
- Compatibility: Lead-acid (AGM, Gel, flooded), lithium LiFePO4
- Adjustable up to 40A, Bluetooth included, no solar MPPT
Detailed overview: Renogy 40A Bluetooth DC-DC Charger
The Renogy RBC40D1U-BT2 is a 12V onboard battery charger, designed to charge the leisure (auxiliary) battery of a converted van, motorhome or 4x4 from the vehicle's alternator. Its output current is adjustable across 4 levels, 40A, 30A, 20A or 10A, letting you match it to the cabling and fuse already in place, or limit charging on a smaller battery.
Unlike the Renogy DCC50S from the same family, which combines a DC-DC charger and a solar MPPT controller in a single unit, the RBC40D1U-BT2 focuses purely on the alternator input: it has no solar panel input. For a setup combining alternator and solar, you'll need to add a separate MPPT controller.
The Bluetooth BT-2 module is included in this bundle (unlike other Renogy chargers where it's an optional extra): it plugs into the RS485 communication port and lets you follow charging live from the Renogy DC Home app, with up to 365 days of data logging. The charger automatically detects whether the alternator is running, only charging when it is, protecting the starter battery. On a vehicle with a smart (Euro 6) alternator, you need to connect the supplied IGN signal wire to trigger charging, as alternator voltage alone isn't always enough to activate it automatically.
With 584W of output power and 94% charging efficiency, the RBC40D1U-BT2 is compatible with lead-acid batteries (AGM, Gel, flooded) and lithium LiFePO4, via dedicated charging profiles and configurable lithium activation. Multiple protections (reverse polarity, overvoltage, undervoltage, overcurrent, overheating) keep the installation safe, and the unit benefits from quieter natural cooling than the previous generation. Compact at 236.5 x 152.5 x 58mm and 1.88kg, it mounts easily near the leisure battery. For an alternator-focused nomadic setup with no need for solar, it's a complete, well thought-out solution.
Comparison
How does the Renogy RBC40D1U-BT2 stack up against other DC-DC chargers on the market?
| Criterion | Renogy RBC40D1U-BT2 | Renogy DCC50S | CTEK D250SE | Victron Orion-Tr Smart 12/12-30 |
|---|---|---|---|---|
| Charge current | 40A adjustable (40/30/20/10A) | 50A | 20A | 30A |
| Solar MPPT input | No | Yes (built-in) | Yes (built-in) | No |
| Bluetooth | Included (BT-2) | Optional | Built-in | Built-in |
| Lithium compatible | Yes | Yes | Yes | Yes |
| Observed price | £110 | ≈ £199 | ≈ £195 | ≈ £165 |
The Renogy RBC40D1U-BT2 stands out with Bluetooth already included in the price, where the DCC50S sells it as an option and the CTEK D250SE, despite its built-in solar MPPT, remains pricier for a lower 20A current. The Victron Orion-Tr Smart matches its built-in Bluetooth but with no solar input at all, just like the RBC40D1U-BT2. For anyone who only needs to charge from the alternator, with no solar, the RBC40D1U-BT2 offers the best current-to-price ratio of this selection.
Related video
Video: Renogy 40A DC to DC Battery Charger | UNBOXING & How It Works - Published on 30/01/2023
Our tester's review: Gilles Caron
We fitted the RBC40D1U-BT2 in a converted van to charge a lithium leisure battery, set to its 40A output. On the road, charging is fast and noticeably stronger than a simple battery-to-battery relay. The Bluetooth BT-2 module is already in the box here, unlike some other Renogy chargers where it's sold separately: the DC Home app shows current, voltage and battery type live, handy for checking the install without popping the bonnet. On a vehicle with a smart (Euro 6) alternator, we had to wire the IGN signal lead to trigger charging, otherwise nothing happens, worth planning for before buying. The one real downside for van or motorhome use: no built-in solar controller, unlike the DCC50S from the same brand, so you'll need a second device if solar panels are also planned. For anyone who only needs the alternator, the RBC40D1U-BT2 gets the job done without complication.
Frequently asked questions: Renogy 40A Bluetooth DC-DC Charger
No. Unlike the Renogy DCC50S from the same range, the RBC40D1U-BT2 only charges from the vehicle's alternator. To combine solar and alternator charging, you'll need a separate MPPT controller.
Yes, on this RBC40D1U-BT2 listing the BT-2 module is supplied in the bundle, ready to plug into the RS485 communication port. It lets you follow charging via the Renogy DC Home app.
Output current is adjustable across 4 levels: 40A, 30A, 20A or 10A, chosen to match your battery capacity and installed cabling.
Yes, but you need to connect the supplied IGN signal wire to trigger charging, as the voltage from a smart alternator alone isn't always enough to activate it automatically.
The RBC40D1U-BT2 is compatible with lead-acid batteries (AGM, Gel, flooded) and lithium LiFePO4, via dedicated charging profiles and a customisable user mode.
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Published on 04/09/2026