Merlin M-Power VSR — Voltage Sensitive Relay, 12V 140A
Compact 140 A voltage-sensitive relay that connects the second battery once the engine battery is charging and separates the banks when the engine stops. The economical way to add a house or leisure battery.
Delivery & shipping
- Free local delivery — Trang · Krabi · Phuket
- Thailand-wide courier, typically 1–3 days
- Worldwide shipping by courier & sea freight
Fair price check
Our price is the manufacturer's home-market RRP — what this gear sells for where it's made. Branded marine equipment in Thailand typically retails 15–90% above that, when prices are published at all. Ours doesn't.
About this product
The M-Power VSR is the simplest split-charge device in the Merlin range. When the engine battery rises above the connect voltage the relay closes and the alternator charges both banks; when it falls back below the disconnect voltage the relay opens, so house loads can never drain the start battery. No wiring to the alternator or ignition is needed — two heavy cables and an earth.
Key features
- 140 A continuous rating for 12 V systems
- Automatic connect / disconnect on sensed voltage — no ignition feed required
- Protects the start battery from house loads
- Compact, sealed, quick to install
- Ideal first step for small boats, vans and 4×4s
Where it fits
Small boats and RIBs adding an electronics or trolling battery, campervans, service vans and 4×4s with a leisure battery. For larger alternators, two-bank management, or lithium-compatible logic see SmartBank Lite, Advanced and PRO.
Specifications
| System voltage | 12 V |
|---|---|
| Rating | 140 A continuous |
| Function | Voltage-sensing battery combiner (VSR) |
| Manufacturer | Merlin Power Ltd, UK |
Worldwide delivery. Price shown is for the goods; freight to your door anywhere in the world is quoted at cost and invoiced separately. Merlin products are built in the UK — stock items typically dispatch within 1–3 working days, built-to-order kits within 30 days. Thailand customers: we consolidate into our regular air-freight consignments to Trang, Phuket and Bangkok. Not sure which version you need? Email hello@drakemarine.com or WhatsApp +66 99 406 4680 with your battery and charging layout and we will spec it for you.
Why buy Merlin Power from us
Merlin Power has designed and built battery management electronics in the UK for more than 20 years, with the same technology fitted to lifeboats, emergency-service fleets and NATO armoured vehicles. We supply the full Merlin range with system design support: tell us your alternator, battery chemistry and loads and we will specify the right controller, contactors and cabling, and pair it with matching batteries, charging and renewable inputs where it makes sense. Every unit carries Merlin's manufacturer warranty and is supported by Merlin's UK technical team.
Downloads & software
Datasheets, installation manuals, programming guides and the free PC configuration software for programmable units are published on Merlin Power's manuals page and software page. We can also send the relevant PDF with your quote.
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