Better reversing lights - at last

[dieselV6]

Hi

I finally managed to brighten up the reversing lights on my Superb. The trick is to put stronger bulbs and in addition to put a load sharing relay to rear 12V socket. A relay is neccessary because even with stock bulbs the voltage at the reversing lights is a pitiful 10V, with uprated bulbs it drops to a silly 8.5V. Net effect of adding the relay is 11.6V at the bulb for 2x 35W 860lm lights, and about 3x (three) times more light than stock install (stock bulb is 460lm at 12V, but only 200lm at 10V).

If you just do the relay and stay with stock bulbs, you get 2x more light.

Here is what you need:

2x Ancor GY6.35 to BA15S low profile bulb adapter, got it from Internet somewhere. Must be low profile, high profile adapters as sold for most LEDs will make the bulbs stick out too far.

2x Osram Halostar IRC bulbs GY6.35 12V, 4000hrs, either 25W/560lm if you tend to use reversing lights for a long time or 35W/860lm if not, I got mine from Screwfix. These are halogen HIR bulbs, quite efficient and very long living so you are likely to only need them once. You need to cut bulb's legs a little to fully fit in the adapter.

1x fused relay, I had an old one from Halfords, put 15A fuse in it

2x 90SQ045 or similar high current Schottky diode, these are 9A/45V, anything over 6A/25V is OK, from Maplin/RS/Farnell/Rapid/Conrad, take your pick

First step is to put the diodes in line with reverse lights, at rear cluster plugs, diode stripe on the bulb side. I use crimp connectors. At this point it makes sense to also crimp in 1 cable each side from the bulb end to the relay, and 1 cable from the other diode end (on one side only) to drive the relay. This completes a bypass circuit which will come in handy should relay fail or if cigarette lighter fuse blows. You can run load cable to the other light above trunk opening, under the parcel shelf.

The relay gets connected in the following way:

85: reversing lights in (ie not bulbs, the other diode end),

86: ground,

30: boot cigarette lighter socket +,

87: both reversing light bulbs (after diodes).

The relay can be mounted on bottom outer light cluster mounting screw, you need 1 additional nut and a spring washer or locktite/superglue.

Whilst I was at it, I also connected grounds on each light cluster to chassis (inside metal panels behind the sound proofing). This buys another 0.2V at each light, and for all lights, stop/fog etc. I also grounded cigarette lighter socket there. Dremel small holes, clean surround to shiny metal, screw in small cable eylets (I used small M3 eylets with old computer case screws and twin beryllium copper washers on each side. Coat finished and connected ground points with some vaseline or other grease of your choice to prevent corossion.

Finally, put the bulbs in, wrap/protect all cables and you're good to go

Edited 3 February, 2012 by dieselV6

[Cown]

A chance of any pictures and links to where you bought your stuff? I'm really considering this.

[dieselV6]

A chance of any pictures and links to where you bought your stuff? I'm really considering this.

This is a picture of driver side rear cluster with fused relay attached to bottom mounting screw.

Note you cannot see the diodes because they are wrapped with harness tape.

There are actually quite a few other mods on these lights (brakelights on rear fogs, isolated LED fog/tail, towbar connections),

that went there over the years.

here

These are rear lamps, stop lights are Philips Vision Plus or similar (light up quicker), indicators are Osram Diadem (blue transparent bulb turning yellow only when it is on), reversing lights are Osram Halostar IRC GY6.35 35W. Bottom are 3W Luxeon red tail/fog LEDs, that also light up when stop lights are on.

here

Close-up of Osram IRC lamp that I picked up in my local Screwfix (link here), with low profile BA15S adapter. I got adapter at leisure-electrics which has since closed down, but there are several places selling them. It has to be low profile, without tall ridge around the BA15S base.

here

I do not have picture of stock lighting, but I do have a picture when using uprated bulbs without relay (I pulled out the fuse), which were still providing better lighting than stock:

here

And finally, here is the picture taken with same exposure time/aperture of 2x 35W Osram IRC bulbs with relay in action:

The camera does not do it justice, in real life the difference is more noticeable.

here

I hope this helps.

[Cown]

Holy ****, that's an impressive upgrade. I'm gonna write that on my summer project. Thx a lot for this. :-)