OK we know that putting a relay in the headlight circuit is a good idea. Is the problem only that the switch can't take the load or is the wiring under size as well? After trying to make sense out of other people "modifications" I would like to keep some things easy to interpret by some future repairer - might even be me and if I am to run heavier wire to the headlight would like to keep the Blue with white/red traces for identification.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

The switch can take the load alright. It's just that the simple mechanical switch doesn't make a particularly good connection. When combined with 40 year old wiring, you end up with un-bright lights.

It's both. After 40 years of switching, the switch contacts are probably not up to high-current duties any more. Same goes for the wiring, which was never really all that capable to begin with. Not to mention safe

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Simon

The adventures of an owner builder in the Tallarook Ranges

on a related topic. what size fuse should be fitted when installing relays?

I didn't point out I have a brand new loom -so new wiring. Just wondering if the gauge should be heavier after the relay. or if if will be OK

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

I think mine is 30A.. each 60W high-beam needs 5A, so anything above 20A will probably be fine.

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Simon

The adventures of an owner builder in the Tallarook Ranges

I used heavy gauge wiring from the starter solenoid to the (fused) relay, then standard from the relay to the lights.. but the heavier gauge wire you use, the better the lighting will be.

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Simon

The adventures of an owner builder in the Tallarook Ranges

You can work out the current your headlights are going to draw from the wattage on the bulbs.

If you headlights are 60/55 High Beam/Low Beam bulbs, then using the higher value of 60watts/12Volts you get a current of 5 Amps. Multiply by the number of lights (2) and you need a fuse of 10 amps minimum. Make it 15 to allow for overshoot and you have a winner. If they're 100 watt high beams, then you will draw 17 amps, so make it a 20 amp fuse.

Those old switches have shitty old dirty contacts, crummy crimp and/or solder connections and tiny cracked copper conductors. Operate the relay off the original light wiring, but for the actual light 12 volt supply, run a new 2.5 sq.mm flexible wire from the supply to the relay and from the relay to each of the lights. And make sure you also upgrade the black return wires to ground as well or you have wasted most of your time.

2.5 sqmm has a current rating of about 20 odd amps, so will provide plenty of current for the job. Don't buy the crap from supercheap (It is rubbish...dodgy conductors, funny size..save it for the big stereo boyz) Drop into an auto spark and they will have the size you want and the blue colours you need to make it look authentic as part of your loom. I did this with my original loom recently before I reassembled it. The relay is hidden in the dash, and the replacement blue/white and blue/red wires are neatly integrated into the loom.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

David.

This is best relay around I found. Kev put me onto it when the smoke escaped from my wiring.

"New Era" NLR132 Relay Twin Headlight 2 x 30A
NA Auto 94-96 Urana Street, Jindera NSW 2642 ~ Ph02 60263391

http://www.naauto.biz:8080/naauto/catal ... product994

Comes with all instructions and works well. Even what size wire to use.

Want to best part.
Cheap.
Cost me $26 + $7.53 shipping

Shop around. this is the cheapest price. Thats if you can find other people selling them
Repco used to, but last time I when in and asked them, they all scratch their heads.

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"Boris" - '69 Cooper S Mk 2

IMO there are 3 main reasons it's worthwhile to fit a headlight relay:
1. It takes 99% of the load off the dipswitch. This is most important on Mk2 on cars with the dipswitch/blinker switch, these switches easily overheat and burn the contacts out.
2. Headlights are brighter due to less voltage drop. More V at the lights.
3. You can easily fuse the headlamp circuits for protection, the New Era relay has 2x30A blade fuses already.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

The later rocker (Clubbie) switches are crap IMO. The original toggle switches can handle the current OK with standard lighting. Also, indicator switches incorporating high beam dip/flasher need relays for both high & low beam circuits.

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1967 Cooper S - new front bearings to do.
1965 Cooper S shell - Slow progress. No time or money!
1966 Deluxe- next rustoration!
Mk 2 & XJ6 Jags. Less said the better.

Relays are just remote switches. You use the existing switch and wires to switch the relay(s), which places very little load on the old wiring and switches. You run heavy duty cable from the solenoid (battery cable) to the lights and then to earth.

The less resistance in the wiring the more wigglies there are to turn into light. The closer the relays are to the lights the less cable you need which in turn reduces the wiring resistance.

I=P/V..so you decide what power bulbs you want to run ..100watts is good so two lights, voltage is given (12) makes a 20Amp relay quite adequate. Bosch make units that are economic and available (and come with installation instructions). Add another relay to run the high beams and the furry critters will show up nicely.

The existing wiring will run the low (powered) beams quite happily.

Cheers, Ian

Already have the above relays - Just want to keep the colour codes right - will get some 25amp wire in the correct Lucas colours to keep everything neat

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

I spliced the relay into the existing wiring, I just cut the 2 wires up near the heater duct inlet.
For power I ran 4mm² marine cable from battery cable and earth.
I'm running Wipac Quadoptic halogens, I think 55W. Wires stay cool, lights are bright as.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Same here, incredibly good lights, easily as good as our Territory. Amazing how much better than the Lucas candles they are, especially given they're both 55W..

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Simon

The adventures of an owner builder in the Tallarook Ranges