Voltage Sensitive Split Charge Relay - 12V 140A

Price:  £36.34(£30.28 Exc. VAT)

Product code:  P00705


In stock  

In stock

  (18 Reviews)
Thinking of installation a split charge system? Why not check out our Made-To-Measure Split Charge Kits


12V, 140A rated voltage sensitive relay for split charging applications in camper vans, motorhomes, 4x4s and boats. Allows charge to flow into one battery (or bank of batteries) only when a charging voltage is detected at the other battery (dual sensing operation).

  • Dual sensing operation - charges from starter battery to leisure battery when alternator is running and charges from leisure battery to starter battery when mains charger is connected.
  • Relay connects when sensed voltage reaches 13.7V or higher
  • Relay disconnects when sensed voltage drops to 12.8V or lower
  • Maintains battery isolation when not charging, so starter cannot be drained by leisure use and vice-versa.
  • Ignition protection to UL1107
  • Fully automatic operation
  • E Mark approval
  • Virtually zero voltage drop
  • Protects sensitive electronic equipment from harmful engine start-up spikes
  • Well proven design with 1000s of units operating in the field
  • Terminal connections marked on inside of unit for easy installation

Note: The benefit of this type of relay is that it does not require a connection to the alternator or any modifications to the existing vehicle electrical system.  Simply connect the +ve terminals on each of your batteries to the terminals on the relay and the black relay wire to a common -ve point.

An LED indicates when the relay is ON (contacts closed). Fixing holes in the body allow the unit to be mounted to a bulkhead and body cut-outs offer various cable routing options.

Fully encapsulated electronics make this unit splashproof and particularly suitable for harsh environments (marine use, vehicle engine bays etc.)

Sold individually. 

IMPORTANT NOTE: These relays are not suitable for vehicles with 'smart' or 'intelligent' alternators. As a guide this applies to vehicles having engines that comply with Euro5 emissions standards and onward, often also incorporating regenerative braking (if in doubt please consult your vehicle manufacturer to confirm). If your vehicle has a smart alternator then you will need to use a battery-to-battery charger instead of a VSR.


  • Sensing mode: Dual (2-way split charging, starter to leisure and vice-versa)
  • Voltage rating (nominal): 12V DC
  • Current rating: 140A
  • 'Cut-in' voltage: 13.7V
  • 'Cut-out' voltage: 12.8V
  • Terminal size: 2 x M6 studs and nuts
  • Other connections: Ground wire to connect to common -ve
  • Ground wire: 1mm2 - 50cm long approx.
  • Fixing hole dia: 5mm
  • Overall dimensions: 67 (W) x 67 (H) x 50 (D) mm


For more information on our battery-battery chargers and VSRs check out our YouTube Video 

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Average Rating (18 Reviews):  
Write a Review and share your opinions!

Split charger relay
Friday, 31 March 2017  |  Michael

As they say, it does what it says

Thursday, 23 February 2017  |  Tom

works well charged all the batterries fitted in my motorhome via the solar panels!

Tuesday, 22 November 2016  |  Emil

The product is accurate to what I expected.

Split Relay
Tuesday, 9 August 2016  |  David

These are the units we fit to the window cleaning system which all the window cleaners are using. They are on and off all day 5 days a week. Not had one fail yet.
Customer service was 1st class when I had to contact them.

Excelent service
Thursday, 4 August 2016  |  Alexandre

Order placeded on weekend, item received on the third working day (in Portugal ).

Simple and effective
Tuesday, 7 June 2016  |  Mick

This was easy to install in a campervan conversion. It worked exactly as expected.

Split charge relay
Monday, 18 April 2016  |  Ian

Very good product. Works very well and easy to install.

Split Charger
Tuesday, 1 March 2016  |  Patrick

Delivered within 24 hours. Two technical queries were answered promptly and expertly with the offer to provide further help if necessary. A first class product from a customer focused company. Many thanks.

Thursday, 5 November 2015  |  Jim

The unit is not compatible with my charging system. I can't return it as Iv'e discarded the packaging. Thanks for your excellent service though.

split charger
Friday, 24 July 2015  |  Jan

fast delivery to belgium
easy to install
works perfect

Read all 18 customer reviews...