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Voltage Sensitive Split Charge Relay - 12V 140A

  (36 Reviews)
Price:  £36.34   (£30.28 Exc. VAT)

Product code:  P00705



Low stock

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

Part Number:  4015

Average Rating (36 Reviews):  
Write a Review and share your opinions!

Very happy
Tuesday, 9 February 2021  | 

As usual, top gear and very happy

Wednesday, 2 December 2020  | 

Fast deliwery. havent installed it yet.

Function is good, form could be better.
Sunday, 8 November 2020  | 

The good: Small footprint, simple installation and clear instructions.
Could be better: There is a voltage-sensing cable which is quite small and positioned precariously close to the terminal of the incoming power cable. An insulation failure here seems possible and would disrupt the function and possibly something worse.
Also, there could be an on-off switch, though it is possible to install an external one utilising aforementioned voltage-sensing cable.
Lastly, the power cable for up to 140A needs to be quite thick (25mm2), cable terminals also. The terminals on the relay could be one number bigger to accomodate it.
Overall the relay itself seems to work as advertised and adds a wonderful funtionality to a camper van during the dark months when sun panels don't charge the domestic battery.

Very good
Wednesday, 26 August 2020  | 

Great product with it being dual sensing if you have a mains charger fitted it not only charges the leisure battery but also the starter battery when you are on electric hook up

value for money
Thursday, 6 August 2020  | 

This item is listed in marine catalogues
at double 12volts price, so why would
you go anywhere else than 12volt, no

Voltage Sensitive Split Charge Relay - 12V 140A
Friday, 26 June 2020  | 

Easy and effective way to add a second battery.

Voltage Sensitive Split Charge Relay - 12V 140A
Wednesday, 27 May 2020  | 

Works perfectly - simple to install - highly recommended. Fitted to my 1985 VW pickup with demountable camper with solar panels. Great item.

Voltage Sensitive Split Charge Relay - 12V 140A
Saturday, 26 October 2019  | 

Excellent technical knowledge and helpfull on the phone. This VSR was to replace my old one. It is half the price of my old VSR and is twice as good. It cuts in and charges the leisure batteries and when on hook up power it cuts in to charge the starter battery. It is duel purpose I would highly recommend this product for motorhomes and or boats a superb and well priced bit of kit.

Split charge relay
Saturday, 12 October 2019  | 

Very prompt service & quality part supplied

Split charger
Wednesday, 14 August 2019  | 

Great service and very helpful. Replacement for an old one. Easy to install and it was straight up and running. Early days yet as its only done one short trip, but all seems great and just what was needed.
I have used 12V before and have found them to be an excellent, knowledgable supplier. The get my vote.

Read all 36 customer reviews...

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