Split charge relay really needed?

[Irishrebel]

I posted my original problem under 'Split charge relay, and towbar price. Help!' and have found out a lot and made SO many calls to different suppliers and fitters... now I have a new question.

IF the only thing the relay does is cut off supply from your engine alternator/ battery to the caravan fridge & battery when engine is turned off, then I thought I could have twin sockets with no relay, and just unplug the grey lead manually each time I park the car.

Rang the cheapest fitter to arrange this, but he believes the relay also acts as a failsafe in case the wires to the caravan overload and start to melt, so it's unsafe to do this, but I should "ask someone who knows", so I'm asking: can I have two sockets without the relay?

Tim.

 

[Rod_5041370]

Without the relay, if your car battery were to fail and you tried to start your car , an attempt would be made to use the caravan battery to power the starter motor.

Ok if only a fuse blows, but failing that the wiring through the caravan and car would "fry", possibly causing a fire.

 

[Rod_5041370]

Without the relay, if your car battery were to fail and you tried to start your car , an attempt would be made to use the caravan battery to power the starter motor.

Ok if only a fuse blows, but failing that the wiring through the caravan and car would "fry", possibly causing a fire.

I,ve just read your other post and the excellent replies from Rob but would add that an intelligent split charge relay is probably less than

 

[Irishrebel]

I,ve just read your other post and the excellent replies from Rob but would add that an intelligent split charge relay is probably less than

 

[ProfJohnL]

Hello Tim,

Rob has given a very full description on your other question, how ever it seems you are still uncertain about the split charge relay.

Rod has given part of the reason why a Split Charge Relay, Is necessary. Fundamentally automatically it only switches power to the caravan battery charging circuit when the engine and alternator are producing enough output.

When the alternator cannot supply enough to charge the caravan battery, it is important to isolate the the caravan battery so it cannot reverse feed back to the car. This is because the car and its systems can use some very large currents which, as Rod points out, may overload the wiring from the caravan.

Automatically isolating the caravan battery from the car when there is insufficient charge from the alternator also prevents the caravan from discharging the car battery which might prevent you starting the car.

Whilst manually disconnecting the caravan at a site would prevent total discharge of either the car or caravan batteries through the wiring. What happens if you forget? It is not always apparent but there are times when driving when the alternator is not always providing enough power and the caravan battery would then be supplementing the cars systems. With a proper relay control the caravan will be disconnected at all appropriate times.

For your families and your own safety splash out on the proper relay.

 

[SirRogerFFS]

HI Tim .

I agree with everybodies comments on here, I am now looking at Towsures catalogue a smartcom splitcharge relay will cost you

 

[rosies]

Hello Tim I personally think that the non relay method would be more costly for you . Two seperate wires, all fused , would be needed , running from your vehicle battery to your 12s socket . Whereas with a towsure smartcom relay your would need only one ( high amperage ) wire , fused , running from battery to smart relay then two wires from your grey 7 core back to the smart relay .

Green to pin 4 ( caravan internal and battery charge ) and red to pin 6 , fridge . plus both earths .

As previously said , a towsure smart relay complete with high amp wire for

 

[Irishrebel]

Thanks everyone. I've really learnt a lot now. I can afford to pay for the 2nd socket and wiring, just felt I was being overcharged for what intuitively seemed simple in addition to all the work required for a towbar and single socket.

I looked up the Towsure catalogue: the smartcom relay is only

 

[ProfJohnL]

Thanks everyone. I've really learnt a lot now. I can afford to pay for the 2nd socket and wiring, just felt I was being overcharged for what intuitively seemed simple in addition to all the work required for a towbar and single socket.

I looked up the Towsure catalogue: the smartcom relay is only

 

[mike_374361599]

it seems that people didnt want to fit your relay thats why there price's are so high, they wanted to make some profit on there parts.

to fit the relay yourself wouldnt take you long and wouldnt involve any major or heavy work.

mike