12volt fridge
- Thread starter Mkrob65
- Start date
Thank you. Just looked again and yes it is taped over .going to get new relays but can’t see any numbers
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Yes, looks like two relays taped together.
The black/white wires go from the bodywork earth connection to the left pins of the relays. That's terminal 85.
The two light grey (white?) wires are the D+, going to the right pins of the relays. Terminal 86. They should be on when the engine starts, and off when it stops. These are the trigger wires that switch the relays on and off.
The red wires come from the terminal block just to the right. That is powered by the top terminal of the terminal block, which I guess connects by that big fuse and the blue/black wire to the starter battery.
The green wire is I guess the same wire that is in your other picture, from the leisure battery via the glass fuse. That means the left-hand relay is the split charge relay, connecting the starter and leisure batteries when the engine starts.
The grey wire is I guess the power to the fridge 12V element. The right-hand relay is the fridge relay, connecting the alternator/starter battery to the 12V fridge element when the engine starts.
The black/white wires go from the bodywork earth connection to the left pins of the relays. That's terminal 85.
The two light grey (white?) wires are the D+, going to the right pins of the relays. Terminal 86. They should be on when the engine starts, and off when it stops. These are the trigger wires that switch the relays on and off.
The red wires come from the terminal block just to the right. That is powered by the top terminal of the terminal block, which I guess connects by that big fuse and the blue/black wire to the starter battery.
The green wire is I guess the same wire that is in your other picture, from the leisure battery via the glass fuse. That means the left-hand relay is the split charge relay, connecting the starter and leisure batteries when the engine starts.
The grey wire is I guess the power to the fridge 12V element. The right-hand relay is the fridge relay, connecting the alternator/starter battery to the 12V fridge element when the engine starts.
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While fixing your problems and redoing the wire terminals, if it was my MH I'd take the opportunity to upgrade a bit.
That split charge relay is not really up to the job. Standard spade terminals (6.3mm) are OK for 15A, but are near their limit at 20A. A split charge relay would I guess take 30 or 40 amps, maybe only briefly, but if the leisure battery is quite low it might be sustained for some time. To be honest, that split charge relay looks like I would expect a 30A relay to look after some years of duty.
I would go for a 70A relay, with a socket. The power terminals are bigger, 9.5mm, so will take the amps easily. The coil terminals to trigger the relay don't take much current, so the standard terminals are fine for those.
If you go for a new fridge relay, a standard 40A will be fine. You could get a socket for that too, and the two sockets would slide together so could be fixed as one piece - no more tape required.
While you are changing things, it's worth looking at the wire from the starter battery. This really should have a fuse at the starter battery end. An inline fuse like that Maxi fuse would be OK. You don't have to put in a new wire, but if you do, make it a bit thicker.
If the Maxi fuse is quite large (maybe 50A) then a smaller fuse on the wire to the fridge relay would be a good idea. an inline standard fuse, 20A, would be OK. If you're buying a new fridge relay, you could get one with a built-in fuse holder.
www.altecautomotive.co.uk
www.altecautomotive.co.uk
www.altecautomotive.co.uk
www.altecautomotive.co.uk
That split charge relay is not really up to the job. Standard spade terminals (6.3mm) are OK for 15A, but are near their limit at 20A. A split charge relay would I guess take 30 or 40 amps, maybe only briefly, but if the leisure battery is quite low it might be sustained for some time. To be honest, that split charge relay looks like I would expect a 30A relay to look after some years of duty.
I would go for a 70A relay, with a socket. The power terminals are bigger, 9.5mm, so will take the amps easily. The coil terminals to trigger the relay don't take much current, so the standard terminals are fine for those.
If you go for a new fridge relay, a standard 40A will be fine. You could get a socket for that too, and the two sockets would slide together so could be fixed as one piece - no more tape required.
While you are changing things, it's worth looking at the wire from the starter battery. This really should have a fuse at the starter battery end. An inline fuse like that Maxi fuse would be OK. You don't have to put in a new wire, but if you do, make it a bit thicker.
If the Maxi fuse is quite large (maybe 50A) then a smaller fuse on the wire to the fridge relay would be a good idea. an inline standard fuse, 20A, would be OK. If you're buying a new fridge relay, you could get one with a built-in fuse holder.
Relay 12vdc 70 Amp switching current 4 pin. ALT/RY268763-1-09
ALT/RY268763-1-09 Pack sizes 1, 10, 50, 100 200 70 Amp switching 4 pin 12 volt DC relay unit. 2 x 9.5mm male terminals (switching contacts) 2 x
Relay base / holder for 70 Amp 4 pin relay ALT/RELH005B-1-09
ALT/RELH005B-1-09 Single 4 pin relay base / holder suitable for our 70 Amp 4 pin relay. (We also offer a 5 Pin relay base suitable for our 70A 5 pin
4 Pin automotive type 12 volt 40Amp relay ALT/RY1-1-02
ALT/RY1-1-02 4 Pin automotive type 12 volt 40Amp relay 4 pin 12 volt N/O (Normally Open) 40 Amp relay. Connections are made
PROFESSIONAL QUALITY Automotive relay holder ALT/RELH45B-NT-1-09<br>
ALT/RELH45B-NT-1-09 PROFESSIONAL QUALITY ***Terminals supplied separately*** Bulk packages available 1, 10, 100 500 (Item with terminals base
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Mines got 12v 30 amp stamped on it . Will it be ok to go higherWhile fixing your problems and redoing the wire terminals, if it was my MH I'd take the opportunity to upgrade a bit.
That split charge relay is not really up to the job. Standard spade terminals (6.3mm) are OK for 15A, but are near their limit at 20A. A split charge relay would I guess take 30 or 40 amps, maybe only briefly, but if the leisure battery is quite low it might be sustained for some time. To be honest, that split charge relay looks like I would expect a 30A relay to look after some years of duty.
I would go for a 70A relay, with a socket. The power terminals are bigger, 9.5mm, so will take the amps easily. The coil terminals to trigger the relay don't take much current, so the standard terminals are fine for those.
If you go for a new fridge relay, a standard 40A will be fine. You could get a socket for that too, and the two sockets would slide together so could be fixed as one piece - no more tape required.
While you are changing things, it's worth looking at the wire from the starter battery. This really should have a fuse at the starter battery end. An inline fuse like that Maxi fuse would be OK. You don't have to put in a new wire, but if you do, make it a bit thicker.
If the Maxi fuse is quite large (maybe 50A) then a smaller fuse on the wire to the fridge relay would be a good idea. an inline standard fuse, 20A, would be OK. If you're buying a new fridge relay, you could get one with a built-in fuse holder.
Relay 12vdc 70 Amp switching current 4 pin. ALT/RY268763-1-09
ALT/RY268763-1-09 Pack sizes 1, 10, 50, 100 200 70 Amp switching 4 pin 12 volt DC relay unit. 2 x 9.5mm male terminals (switching contacts) 2 xRelay base / holder for 70 Amp 4 pin relay ALT/RELH005B-1-09
ALT/RELH005B-1-09 Single 4 pin relay base / holder suitable for our 70 Amp 4 pin relay. (We also offer a 5 Pin relay base suitable for our 70A 5 pin4 Pin automotive type 12 volt 40Amp relay ALT/RY1-1-02
ALT/RY1-1-02 4 Pin automotive type 12 volt 40Amp relay 4 pin 12 volt N/O (Normally Open) 40 Amp relay. Connections are madePROFESSIONAL QUALITY Automotive relay holder ALT/RELH45B-NT-1-09<br>
ALT/RELH45B-NT-1-09 PROFESSIONAL QUALITY ***Terminals supplied separately*** Bulk packages available 1, 10, 100 500 (Item with terminals base
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The 30A is a maximum limit that the relay will carry without long-term effects. I'd imagine the charging current is often at 30A, or maybe a bit more. A 40A would be better than 30A. A lot of people use 70A for split charge relays, so a 30 or 40A current would be comfortably within its 70A range.
The fridge current is usually about 15A, so a 30A relay is fine for that.
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Thanks for your help . Going to order 2
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Our fridge doesn't work on 12v with engine running either so yesterday I decided to check the fuses located near the battery under the bonnet. They had rusted a bit and one actually broke up as I was removing it!! I replaced the fuses but no joy, I suspect the fuse holder might be rusted and maybe the relays too!
I've purchased a replacement 4 way fuse holder but I'm unsure which relays to purchase - as they're quite cheap I feel it's worthwhile replacing.
From the picture above, can someone tell me which relays to purchase?
Thanks
John
I've purchased a replacement 4 way fuse holder but I'm unsure which relays to purchase - as they're quite cheap I feel it's worthwhile replacing.
From the picture above, can someone tell me which relays to purchase?
Thanks
John
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The amp rating of the relay should be written on it somewhere, maybe on the top. They are 4-pin, not 5-pin.
I'd guess that 30A relay in the link (post #35) would be OK. Looking at your wires, there's two thin wires left and right, and two thick wires front and back. That would make it a 'Layout B' type as described in the link. The thin wires are the coil (85 & 86) and the thick wires are the NO contacts (30 & 87). As pappajohn says, you can buy these anywhere.
Check that the pins are standard size (6.3mm), not large (9.5mm) as found on larger relays, including the 70A relay in the link.
I'd guess that 30A relay in the link (post #35) would be OK. Looking at your wires, there's two thin wires left and right, and two thick wires front and back. That would make it a 'Layout B' type as described in the link. The thin wires are the coil (85 & 86) and the thick wires are the NO contacts (30 & 87). As pappajohn says, you can buy these anywhere.
Check that the pins are standard size (6.3mm), not large (9.5mm) as found on larger relays, including the 70A relay in the link.
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