Alternator chargers
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Our selection
Renogy RBC40D1U-BT2
£189.99 £109.99
(10)
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
The Renogy RBC40D1U-BT2 is a 12V onboard DC-DC charger with output adjustable across 4 levels (40A, 30A, 20A or 10A), designed to charge the leisure battery of a van, motorhome or 4x4 from the vehicle's alternator. The Bluetooth BT-2 module is included in this bundle, for live charge monitoring via the Renogy DC Home app. Compatible with lead-acid batteries (AGM, Gel, flooded) and lithium LiFePO4, it reaches 94% charging efficiency. Unlike the DCC50S from the same range, it has no built-in solar MPPT controller: it's a pure alternator charger, with no solar panel input.
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.
Renogy DCC50S
£299.99 £199.99
(9)
Recharge your auxiliary battery while driving AND from the sun: the Renogy DCC50S combines a 50A DC-DC charger and an MPPT solar controller in a single unit, made for vans.
- Charge current: 50A (12V)
- Inputs: Alternator + solar (built-in MPPT)
- Power / efficiency: 660W, up to 94%
- Compatibility: Lead-acid (flooded, Gel, AGM), lithium LiFePO4
- 50A DC-DC charger and solar MPPT in a single unit
The Renogy DCC50S is a 12V dual-input on-board battery charger delivering 50A. It recharges the auxiliary (service) battery of a van or camper from the vehicle's alternator and/or from solar panels, thanks to a built-in MPPT controller. With 660W of power and 94% efficiency, it is compatible with lead-acid (flooded, Gel, AGM) and lithium LiFePO4 batteries. Its voltage-sensitive relay (VSR) isolates the two batteries, and an optional Bluetooth module allows monitoring via the app.
The Renogy DCC50S is one of the key pieces of equipment in a converted van, and in use it delivers on its promises. We installed it to recharge an auxiliary lithium battery, with one input from the alternator and another from roof-mounted solar panels. The result is impressive: while driving, the service battery recharges at 50A, far faster than with a simple split charger, and once parked, the MPPT controller takes over with solar. Having both functions in a single unit greatly simplifies installation and wiring. The voltage-sensitive relay cleanly isolates the starter battery, avoiding a dead battery in the morning. Adding the optional Bluetooth module lets you monitor charging on the app, which is very handy. Points to plan for: you must size the cables properly (50A is a lot of current) and set the right battery profile, and with a smart alternator an ignition wire is needed. But for a serious van or 4x4 installation, it is a sure bet.
EcoFlow Alternator Charger Plus 1000
£329.00 (4)
Up to 1000 W from the alternator while driving: the DC-DC charger with a dedicated solar port and reverse charging, that never drains the starter battery.
- Alternator charging: 1000 W max, up to 75 A (12V/24V input)
- Starter battery maintenance: 100 W, protects the starter battery
- Reverse charging: Up to 75 A, tops up the starter battery if needed
- Connectivity: Wi-Fi and Bluetooth, EcoFlow app
- Simultaneous alternator + solar charging, up to 1000 W
The EcoFlow Alternator Charger Plus 1000 is a DC-DC charger that taps the alternator's current while driving to charge a motorhome or van's leisure battery at up to 1000 W, roughly 10 times faster than a cigarette lighter socket. A dedicated solar port lets you combine alternator and solar charging at the same time without tying up the power station's XT60 port. A maintenance mode protects the starter battery, and a reverse-charging mode can even top it up from the station if needed. Compact (1.7 kg) and controlled over Wi-Fi and Bluetooth via the EcoFlow app, it includes a 125A fuse and comprehensive protection.
The Alternator Charger Plus 1000 genuinely changes the game for anyone who drives a lot in a motorhome or van: no more waiting hours to charge a large leisure battery, up to 1000 W flows straight from the alternator while driving. The real highlight is the dedicated solar port: you can plug in panels in parallel without tying up the station's XT60 port, combining both sources even while parked. Reverse charging is a welcome safety net, able to top up the starter battery from the station if needed, without ever draining it by mistake. Full Wi-Fi and Bluetooth control through the EcoFlow app lets you check the active mode without popping the bonnet. Compact and light (1.7 kg), it installs easily near the battery. Our one reservation: you need a compatible EcoFlow power station to get the full benefit.
Sterling Power BB1230
£118.80 (4)
Charge your leisure battery up to 20 times faster than a basic split-charge relay: the Sterling Power BB1230 boosts current from smart alternators too.
- Charge current: 30 A (12V)
- Battery profiles: 9 presets: AGM, LiFePO4, Gel, lead-acid
- Input: 11-20V, smart Euro 5/6+ alternators
- Protection: IP21, spark-free, OEM lock
- 30A without touching the alternator, 9 battery profiles
The Sterling Power BB1230 is a 12V 30A battery-to-battery (B2B) charger, built to quickly recharge the leisure battery of a campervan, motorhome or boat straight from the vehicle's alternator. With 9 preset charge profiles (AGM, LiFePO4, Gel, flooded and sealed lead-acid) and compatibility with smart Euro 5/6+ alternators, it installs without touching the alternator or voiding its warranty. An optional remote display is available.
We wired the BB1230 between the starter and leisure batteries of a converted van, following the supplied diagram: nothing to touch on the alternator side, just two hefty cables and the recommended fuses (50A for a 30A input, wire it thin and it runs hot). The result is clear: the leisure battery tops up far faster than with a basic relay, and the LiFePO4 profile suited our lithium battery perfectly. The small box stays out of sight under a seat, with a fan you can hear under full load without it being unbearable. The part that takes patience is programming a custom profile: buttons and LEDs do the job, but the interface is far from intuitive at first, you have to follow the manual step by step. On a recent smart alternator, budget for running an ignition-sense wire too, for reliable charge triggering. For a van or boat that just needs a real boost from the alternator, without necessarily adding solar, it is a solid and notably cheaper option than rivals at the same current.
Votronic VCC 1212-30
£212.83 (3)
Driving alone is not enough to properly charge a large leisure battery: the Votronic VCC 1212-30 makes full use of the alternator's current, up to 30A.
- Charging current: 20A limited, 30A max
- Compatibility: Lead-acid, Gel, AGM, LiFePO4 lithium
- Recommended battery: 60 to 260 Ah
- Weight: 280 g
- Compact DC-DC charger with included temperature sensor
The Votronic VCC 1212-30 is an onboard 12V DC-DC charger, designed to charge the leisure battery of a motorhome, van or boat from the alternator. With a current limited to 20A (30A maximum) and an included temperature sensor, it works with lead-acid, Gel, AGM and LiFePO4 lithium batteries, for capacities from 60 to 260 Ah. Compact and reliable, it automatically compensates for line losses and Euro 6 smart alternators.
We fitted the Votronic VCC 1212-30 in a converted panel van, with a 100 Ah LiFePO4 leisure battery wired to the alternator. The result: charging while driving is noticeably faster than the old split-charge relay it replaced. The supplied temperature sensor clips easily onto the battery, and once the right charging profile is selected (LiFePO4 in our case), the unit runs without any further fiddling. The fan kicks in under heavy load but stays fairly quiet. On a van with a smart Euro 6 alternator, we had to wire in the ignition line to reliably trigger charging, a step that is not to be skipped and is well explained in the manual. The only downside: at 30A, the recommended cable gauge is fairly heavy, and the housing gets noticeably warm under full summer load. For a serious van or motorhome build combining alternator and lithium battery, the VCC 1212-30 largely delivers on its promise.
Fossibot FAC580
See price and availability
Up to 580 W from the alternator while driving, 6 times faster than a cigarette lighter socket, compatible with 99% of third-party power stations.
- Power: 580 W max, up to 45 A (12V/24V input)
- Charging speed: 6 times faster than a cigarette lighter socket
- Compatibility: Whole Fossibot range and 99% of third-party stations
- Weight: 0.8 kg, wall-mounted
- 580 W while driving, compatible with 99% of third-party units
The Fossibot FAC580 alternator charger is a DC-DC charger that taps the alternator's current while driving to charge a power station at up to 580 W, roughly 6 times faster than a standard cigarette lighter socket. Compatible with the whole Fossibot range and stated compatible with 99% of third-party power stations (45-48V input), it combines two charging modes, engine running or off, a 92% efficiency rating and comprehensive electrical protection. Compact (0.8 kg), it mounts straight onto the vehicle bodywork.
On the road, the FAC580 genuinely lives up to its promise: wired to the starter battery, it charged our station at around 200 W with the engine simply idling, and considerably more once actually driving. Installation is straightforward, though the 5-metre input cable is a bit bulky to route neatly through the engine bay. The real strong point is the stated compatibility with almost every third-party power station, not just the Fossibot range, which is handy if you already own a station from another brand. The cooling does its job well, with no overheating noticed even on a long summer drive. One gripe raised by several buyers: the unit has no built-in fuse on the input cable, so you really do need to fit one near the battery yourself, as the manual itself recommends. For its very reasonable price against the competition, the FAC580 remains an excellent deal for anyone who drives a lot.
Victron Energy Orion-Tr Smart 12/12-30 Isolated
See price and availability (17)
Boost your leisure lithium battery from the alternator while keeping both circuits electrically apart: the van-life reference, with Bluetooth built in.
- Charge current: 30A continuous (40A for 10s)
- Isolation: Galvanic, 200V DC
- Power: 360 W at 40 °C, 430 W at 25 °C
- Compatibility: Lead-acid (flooded, Gel, AGM), lithium LiFePO4
- 200V galvanic isolation and built-in Bluetooth
The Victron Orion-Tr Smart 12/12-30 Isolated is an alternator (DC-DC) charger that tops up the leisure battery of a van, motorhome or boat from the starter battery, at a current of up to 30A. Its isolated design keeps the two circuits galvanically separate (200V of isolation), a genuine safety benefit whenever the two battery grounds cannot be tied together. Compatible with lead-acid and lithium LiFePO4, it is configured and monitored via Bluetooth and the VictronConnect app.
You fit the Orion-Tr Smart 12/12-30 Isolated for one specific reason: to electrically separate the leisure battery from a starter battery whose ground cannot safely be tied to it, typically a converted van whose onboard electronics are sensitive to interference. Once wired in, the unit charges the leisure battery at up to 30A while driving, which on a 100 to 200Ah lithium bank makes a real difference over a simple split-charge relay. The VictronConnect app is genuinely pleasant to use: pick the battery profile, set the engine-detection threshold, and watch the charge in real time from the passenger seat. The casing runs properly hot at full power, which is expected given the conversion involved, but it is worth planning a bit of ventilation if it is mounted inside a closed locker. The price sits a step above a basic battery isolator, and it is worth checking you genuinely need the isolated version: the cheaper non-isolated model is plenty if the two battery grounds are already common. For a van or a boat with two separate circuits, though, this is exactly the right tool, reliable and well thought out.
CTEK D250SE
See price and availability (9)
Alternator AND solar panel in a single 0.7kg box: the CTEK D250SE recharges the leisure battery without ever needing a separate solar regulator.
- Charge current: 20 A (12V)
- Inputs: Alternator + solar (built-in MPPT)
- Compatibility: Lead-acid (WET/AGM/EFB/Gel), LiFePO4 lithium, 40-300 Ah
- Protection: IP65, temperature sensor, smart alternators
- Dual alternator and solar input in one box
The CTEK D250SE is a 12V 20A onboard battery charger with dual input, built for vans, motorhomes and 4x4s without mains access. It recharges the leisure battery from the vehicle's alternator AND from a solar panel thanks to a built-in MPPT regulator, so no separate solar controller is needed. Compatible with lead-acid (WET, AGM, EFB, Gel) and LiFePO4 lithium batteries from 40 to 300 Ah, it also works with smart alternators and automatically switches to the starter battery once charging is complete.
Fitted to a van already equipped with a roof solar panel, the CTEK D250SE immediately simplified the wiring: no need for a separate MPPT regulator, everything happens inside this 700-gram box. On the road, the leisure battery takes its 20A from the alternator, and once parked, the solar input takes over with no intervention needed. The lithium profile handled our LiFePO4 battery perfectly, with a genuine automatic switch to the starter battery once charging finished, a real plus for winter storage. The IP65 rating let us mount it near the wheel arch without any extra protective enclosure. The only downside compared with more powerful units like the Sterling BB1230: 20A stays modest on a large leisure battery, so a full charge takes longer. The price, around £240-250, is justified by Swedish build quality and installation simplicity. For a van that already has solar in place, this is the simplest option to set up.
