31 DC-DC battery-to-battery chargers for vans, RVs and trucks, scored on price per amp, charge current, efficiency, features and warranty.
A DC-DC charger charges a camper’s house battery from the vehicle’s alternator while you drive, with a proper multi-stage charge profile instead of the straight connection an isolator gives. These rankings compare what the makers publish on the same terms: how much charge current you get for the money, how much current there is, how efficiently it converts, which features it has, and how long it’s covered.
Charge current sets how fast the house battery fills: a 20 A charger adds about 20 Ah per hour of driving, a 50 A charger about 50 Ah. Size it to the battery and the alternator: most stock alternators handle 20 to 40 A of extra load comfortably, and lithium banks of 200 Ah or more can take 50 A and up.
Smart alternators, fitted to most vehicles built since about 2015, drop their voltage once the starter battery is full, which leaves a plain isolator charging nothing. A DC-DC charger with an ignition signal input keeps charging. Models with a built-in MPPT solar input replace a separate solar charge controller.
For boats and vans that need an isolated charger from a brand with a long track record. Buyers who don’t need isolation get more current and efficiency from the Orion XS.
Amazon $177.15For a large lithium bank charged from a conventional high output alternator, at a low price.
Amazon $195.99For smaller vans and truck campers with a 100 Ah battery and a panel or two on the roof. Bigger banks or arrays need the 50 A DCC50S.
Amazon $186.99Chargers of 30 A and less, for a single 100 to 200 Ah house battery and a stock alternator.
Top rated: Victron Orion-Tr Smart 12/12-30 $177.15
Chargers of 40 A and more, for big lithium banks and vehicles with a high-output alternator.
Top rated: Victron Orion XS 12/12-50 $328.10
Prices were last checked October 31, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
For boats and vans that need an isolated charger from a brand with a long track record. Buyers who don’t need isolation get more current and efficiency from the Orion XS.
Amazon $177.15For smaller vans and truck campers with a 100 Ah battery and a panel or two on the roof. Bigger banks or arrays need the 50 A DCC50S.
Amazon $186.99For boats and vehicles that need an isolated charger, or anyone who wants Victron Bluetooth and a 5 year warranty on a small house bank.
Off Grid Stores $162.19A low cost dual input charger for a single 100 Ah battery in a 4x4 or small camper.
Amazon $149.99For a van or camper with one 100 Ah lithium battery and a short cable run. It does the basic job well at the lowest price of the big brands.
Amazon $140.99The best all-round alternator charger for most vans and RVs with a 12 V lithium bank. It is small, very efficient and fully configurable from a phone.
Amazon Inverters R Us $328.10For mixed voltage setups, such as a 24 V truck charging a 12 V camper bank or a 12 V van with a 24 V house system.
Off Grid Stores $356.15For boats, trucks and engine bay installs that need a sealed charger with solar and Bluetooth.
Amazon $399.99For an RV owner building a REGO system who wants Bluetooth and RV-C built in. Otherwise the plain 60 A model is far cheaper.
Amazon $429.99For a large lithium bank charged from a conventional high output alternator, at a low price.
Amazon $195.99Each charger is ranked against others of similar current, and scored on its price per amp, its charge current, its efficiency, its features and its warranty.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per amp of charge current | 30% |
| Charge current | rated output, A | 20% |
| Efficiency | maker's peak efficiency | 10% |
| Features | solar input, smart alternator support, Bluetooth, isolation | 20% |
| Warranty | warranty length | 20% |
How we rank explains each factor in full.
