The Rich Solar 12V DC-DC Battery Charger is an on-board charging solution designed to charge a compatible 12V auxiliary or house battery from a vehicle starter battery and alternator system. Available as 20A, 40A, and 60A models, this charger family combines battery isolation and controlled charging for properly configured RV, van, boat, commercial vehicle, and off-grid mobile power systems. Rich Solar lists compatibility with AGM, flooded, gel, sealed, lithium iron phosphate, and lithium-ion battery categories, while the manual identifies selectable STD, GEL, AGM, LFP, and POWER positions; battery mode must be selected according to the connected battery manufacturer’s specifications. The charger supports traditional and smart alternators, while its D+ ignition connection is designed to activate charging only when the engine-running signal is present. Model selection, wiring, fuse sizing, battery settings, ventilation, and installation conditions must be confirmed for the exact system before use.
This DC-DC charger is designed to connect between a 12V starter battery and a compatible 12V auxiliary or house battery. Rich Solar describes the unit as combining battery isolation with controlled alternator-based charging to help prevent reverse current between the starter and auxiliary batteries.
Choose RS-DC20 for 20A and 250W nominal output, RS-DC40 for 40A and 500W nominal output, or RS-DC60 for 60A and 750W nominal output. Each model uses a 12VDC nominal input, operates within a listed 10–16VDC range, and is rated above 85% efficiency at 14VDC and 30% load.
The mode-selection switch allows setup for supported battery types, including lithium iron phosphate, AGM, flooded, gel, and sealed batteries. Rich Solar documents two-stage charging for lithium batteries and three-stage charging for lead-acid batteries, with lithium activation designed to assist supported over-discharged lithium batteries after the correct battery mode is selected.
The charger includes documented over-voltage, under-voltage, over-temperature, reverse-polarity, and short-circuit protection functions. A D+ ignition terminal is required for normal operation, while an LC terminal can limit output to 50% of rated current for smaller or limited-current alternator applications. Rich Solar also identifies an optional RJ11 temperature sensor for temperature-compensated lead-acid charging only; the sensor is not for lithium batteries and is not included.
Designed for compatible 12V starter-to-house battery systems, these chargers help manage alternator charging for mobile and off-grid electrical setups.
Select 20A, 40A or 60A output according to system requirements, then confirm battery mode, cable size, fuse protection and installation location before operation.
Need help choosing a DC-DC charger for your vehicle or auxiliary battery system?
Contact TrueStead Supply for charger sizing guidance, battery-mode support, and quote assistance.
✔ Charging system guidance ✔ Battery compatibility support ✔ Quote assistance
Contact Us for a Quote| Brand | Rich Solar |
| Product Type | 12V DC-DC Battery Charger / Battery Isolator Charger |
| Available Models | RS-DC20 / RS-DC40 / RS-DC60 |
| Manufacturer-Listed Battery Compatibility | 12V AGM, flooded, gel, sealed, LiFePO4 / LFP, and lithium-ion battery categories |
| Selectable Mode Positions | STD, GEL, AGM, LFP, and POWER; select the correct mode according to the connected battery manufacturer’s specifications |
| Input Application | Compatible 12V starter battery and alternator system |
| Input Nominal Voltage | 12VDC |
| Operating Voltage Range | 10–16VDC |
| Charging Profile | 2-stage for lithium batteries; 3-stage for lead-acid batteries |
| Charging Voltage by Mode | STD: 14.4V ±0.1V; GEL: 14.6V ±0.1V; AGM: 14.8V ±0.1V; LFP: 14.6V ±0.1V; POWER: 13.2V ±0.1V |
| Float Charging Voltage | STD: 13.5V ±0.1V; GEL: 13.5V ±0.1V; AGM: 13.8V ±0.1V; LFP and POWER modes: not applicable |
| Installation Location | Install in a dry, cool, ventilated location away from liquids and excessive heat; maintain at least 1.97" / 5 cm clearance on all sides according to the manual |
| Battery-System Limitation | For 12V battery banks only; do not connect higher-voltage battery systems, according to the manual |
| Cable and Fuse Sizing | Cable gauge and fuse sizing vary by charger model, input/output side, and cable-run length; follow the manual’s wiring-and-fusing table for the exact installation |
| Input Current Limiting | RS-DC20: ≤34A; RS-DC40: ≤68A; RS-DC60: ≤100A, according to the manual |
| Efficiency | Greater than 85% at 14VDC and 30% load |
| Alternator Support | Traditional and smart alternators |
| D+ Ignition Terminal | Required for normal charger operation; designed to activate charging from an engine-running signal |
| LC Current-Limit Terminal | Limits charger output to 50% of rated current when connected according to manufacturer instructions |
| Temperature Sensor Port | RJ11 port for optional lead-acid temperature sensor; not for lithium batteries |
| Included Accessories | D+ cable, LC cable, and temperature sensor are not included |
| Protection Functions | Over-voltage, under-voltage, over-temperature, reverse polarity, and short circuit |
| Operating Temperature | -4°F to 122°F / -20°C to 50°C |
| Listed Certifications | CE, RoHS |
| Specification | RS-DC20 | RS-DC40 | RS-DC60 |
|---|---|---|---|
| Rated Charge Current | 20A | 40A | 60A |
| Output Nominal Power | 250W | 500W | 750W |
| Operating Current Range | 18–22A | 37–43A | 55–65A |
| LC Limited Output | 10A | 20A | 30A |
| Dimensions | 8.4" × 7.4" × 3.1" | 10.3" × 7.4" × 3.1" | 12.3" × 7.4" × 3.1" |
| Weight | 4.0 lb | 4.9 lb | 6.2 lb |
Rich Solar DC-DC 20A / 40A / 60A Battery Charger Specification Sheet
