12V 20A DC to DC Battery Charger
Sold by Renogy UK
From £89.99
Renogy UK's price when we last checked, on 2 September 2026. They run promotions and price by variant, so confirm the current price on their page before you buy.
Buy at Renogy UK (opens Renogy UK in a new tab)This is an affiliate link. Renogy UK takes your order, payment and delivery — Roam Wired is not the seller. If you buy through it we may earn a commission, at no extra cost to you. How we make money
How buying this works
Roam Wired does not stock this item. The button above hands you over to the seller's own shop, where you place the order, pay and arrange delivery directly with them. Nothing is added to a Roam Wired basket, and we never see your payment details.
We list it because it is the part our calculator would specify for a build like yours, not because we make the most on it. How we make money
Delivery and returns
Delivery cost, delivery time and the returns window are set by the seller, not by us, and Roam Wired's own £10 / free-over-£250 UK delivery does not apply here. Check their delivery and returns terms on their product page before you order.
Your consumer rights, including the 14-day right to cancel a distance sale, are against the seller who took your order.
Warranty and support
The manufacturer's warranty is handled by the seller you buy from. If something fails, raise it with them and quote their order number — we cannot open a claim on your behalf.
Happy to help you work out whether a part is right for your build: get in touch, or run the numbers through the free electrical calculator.
Free power calculator
Is this the right size for your van?
Tell the free calculator what you’ll run and how long you’re away. It works out the power you need and builds your kit.
Overview
12V 20A DC to DC Battery Charger
20A, 292W, and a smart-alternator input range that starts at 12V. The smallest of Renogy's DC-DC chargers — right for a modest leisure bank, or a second vehicle where you want alternator charging without running heavy cable.
- 20A maximum output, 292W
- Euro 6 smart alternators, 12–16V input; traditional alternators 13.2–16V
- 94% charging efficiency
- AGM, gel, flooded, LiFePO4 and user profiles
- Reverse polarity, overvoltage, overcurrent and over-temperature protection
- 1.5kg, 236.5 × 131.5 × 60.5mm
Why a Euro 6 van needs one of these
A modern smart alternator drops its output voltage as soon as the starter battery is topped up — often to around 12.5V — because the ECU is chasing emissions figures, not charging your leisure bank. A split charge relay simply passes that low voltage through, and a lithium pack will barely take anything from it. A DC-DC charger takes whatever the alternator gives and boosts it to a proper charge profile, which is why it is not optional on anything Euro 6 and later.
Sizing and cable
20A into a 100Ah bank is a reasonable match — roughly five hours of driving from empty to full, which suits a van that moves most days. Terminals accept 10AWG to 8AWG. Size the cable for the run length, not just the current: a long run to a rear locker needs a step up to keep volt drop sensible.
Before you order
Fit the specified fuses at both ends — 40A on the input, 30A on the output — close to each battery's positive terminal. The charger needs an ignition trigger so it only runs with the engine on; check your vehicle has an accessible switched live before you start.
Renogy's published figures
Taken from Renogy's own specification for this product, on the date shown by the price. Anything wired into 230V mains should be signed off by a qualified electrician.
Build notes for this part
Get the sizing and fitting notes.
Useful product advice, installation considerations and occasional offers for this part of your van build.