Wiring in leisure battery relay???

S0updragon

S0updragon

Well-Known Member
IMG_0284.JPG IMG_0283.JPG Morning all. I am hoping for advice. I have put in a loom for switches, fuse board, volt watt and amp meter. I bought a switch relay from local shop and been trying to figure out how to stick it in. I have looked on google but I'm confused. Its a maypole mp2881. I don't have any power hungry kit. Car battery, leisure battery, mains charger. I will put pics of relay instructions and hopefully someone knows. Thanks
 
Pretty sure that's the type of relay you wire into a towing hitch for running fridge and charging leisure battery in a caravan on the move, I did fit a similar one to Harvey and ended up with just a feed from alternator, earth connection and a wire going to the leisure battery. I'll see if I can get in for a look later but it might be slightly different.
 
You need to connect the switch circuit to the alternator signal wire and the other side to earth. That way the relay only clicks in when the alternator back feeds the charge that turns the warning light off. The other two connections are simple enough, one side goes to the vehicle battery live, the other to the leisure battery live/fuseboard. And the leisure battery is earthed as normal
 
cant see why not although you would need a live going to each individual battery as the relay prevents both batteries being connected when the engine is off, you shouldn't need to mains charge the vehicle battery
 
You'll get a constant live from the leisure battery but the van battery wont be connected to the leisure battery when engine is off so there is no risk of flattening it
 
And one should go to fridge so that fridge only works on 12v leisure battery whilst the engine is running, saves you draining the battery (and killing it) once stopped
 
I don't have a fridge but i could stick a socket in instead for that sort of thing. Would that go to '2' (switched supply) ??
 
Hi the Guys.
I am looking a little help please.
Today I am wiring in a maypole MP 2881 auto switch combination relay at the rear of my Jeep.

I am wiring this into the rear of my Jeep where I have a series of supplies available at a 7 pin plug.
I have a constant supply available from battery for Number (12v) on the MP2881

I have a switched supply available at rear of my Jeep for Number (6) on the MP 2881

I have a constant fused supply available at rear of Jeep for (4) on MP2881

But I don’t have a second switched supply for (2) on the MP2881.

All I am trying to do today is enable my Jeep to charge my leisure battery when I’m driving. I have no fridge or any other need for another supply for items like a fridge or tv etc.
So can I ignore Number (2) on the MP2881 or does it need to be supplied in order that the MP2881 will work properly.
Thank You.
 
Hi Rooster and welcome to the forum. Sorry I can't help with your request, electrics is not my strong point, but there are a few electrical gurus on here who may be able to help. Good luck
 
Hi and welcome. I think I bought one of them ages ago but got something else as couldn’t figure out the connections so sorry can’t help. Had a quick google search but couldn’t see anything helpful. Good luck
 
Hmm those instructions are shockingly bad and there are a confusing number of connections on that device. I thought the modern devices sensed the alternator/battery voltage and only connected the leisure battery if the voltage was over something like 13V (implying alternator was charging)? If so then why does it connect to alternator-lamp terminal?
I went the KISS route and have a high current relay which connects the leisure battery to the 'normal' battery when the alternator is running. The relay coil is connected to earth on one side and the alternator 'starter-coil/indicator' terminal. Very simple and robust.....
 
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