{"product_id":"12v-40a-dc-dc-battery-charger-for-rvs-vans-boats-off-grid-systems-lithium-lead-acid","title":"12V 40A DC-DC Battery Charger - Lithium and Lead-Acid, RV, Van, Marine","description":"\u003cp\u003eA DC-DC charger takes the messy, voltage-limited output of your vehicle's alternator and turns it into a proper charge profile for the house battery. This 40A unit is the middle of Rich Solar's three-model range and doubles as a battery isolator, so it replaces two components in a van or RV build.\u003c\/p\u003e\n\u003ch2\u003eWhy this charger\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e40A output, 500W nominal, with a working range of 37-43A depending on conditions.\u003c\/li\u003e\n\u003cli\u003eSwitchable battery chemistry: 12V AGM, flooded, gel and lithium, selected with a physical mode switch rather than buried in an app.\u003c\/li\u003e\n\u003cli\u003eTwo-stage charging for lithium, which will safely reactivate an over-discharged LiFePO4 pack and take it to 100%. Three-stage for lead-acid.\u003c\/li\u003e\n\u003cli\u003eWorks with both traditional and smart (variable-voltage) alternators, which is the whole reason a modern van build needs one of these.\u003c\/li\u003e\n\u003cli\u003eBuilt-in isolation prevents reverse current between the starter and house batteries, so a flat house bank cannot strand you.\u003c\/li\u003e\n\u003cli\u003eD+ ignition terminal means it only charges while the engine is running, protecting the starter battery.\u003c\/li\u003e\n\u003cli\u003eAn LC low-current terminal lets you throttle it back for small or weak alternators instead of overloading them.\u003c\/li\u003e\n\u003cli\u003eProtected against over-voltage, over-temperature and reverse polarity. Standby draw is under 0.6A.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eBe aware before you buy\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eThe D+ cable, the LC cable and the temperature sensor are \u003cstrong\u003enot\u003c\/strong\u003e included. If you intend to use engine sensing, low-current mode or temperature compensation, budget for those separately.\u003c\/li\u003e\n\u003cli\u003eThe RJ11 temperature sensor port compensates charge voltage for hot or cold conditions, but it is for lead-acid only — it does not apply to lithium.\u003c\/li\u003e\n\u003cli\u003eEfficiency is quoted as above 85% at 14VDC and 30% load. Manufacturers quote efficiency at their most flattering operating point; expect a little less at full output.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eChoosing between 20A, 40A and 60A\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eAll three share the same feature set, the same 10-16VDC input window and the same charging logic. Only current, size and weight differ.\u003c\/li\u003e\n\u003cli\u003e20A (250W) suits a modest 100Ah bank and a small alternator. 40A (500W) is the sensible default for a 200-300Ah lithium van build. 60A (750W) is for large banks and short drive times, but it demands an alternator that can actually supply it.\u003c\/li\u003e\n\u003cli\u003eDo not size up beyond what your alternator can deliver. A 60A charger on a tired factory alternator is a good way to cook the alternator.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eInstallation\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e10.3 x 7.4 x 3.1 inches and 4.9 lb. Mount in a ventilated space with the cooling surfaces clear.\u003c\/li\u003e\n\u003cli\u003eInput operating range is 10-16VDC.\u003c\/li\u003e\n\u003cli\u003eCable and fusing must be sized for the full 40A on both the input and output side.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWarranty\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCovered by Rich Solar's standard limited warranty. No specific term is published on the product page; contact us to confirm the current coverage period.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"RICHSOLAR","offers":[{"title":"Default Title","offer_id":46391896440982,"sku":"RS-DC40","price":127.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0676\/5291\/1254\/files\/RS-DC4040ADC-DCCharger_1.jpg?v=1785837369","url":"https:\/\/sunenergydepot.com\/products\/12v-40a-dc-dc-battery-charger-for-rvs-vans-boats-off-grid-systems-lithium-lead-acid","provider":"sunenergydepot.com","version":"1.0","type":"link"}