Reversing light upgrade

[nu11eaf]

No need to get your knickers in a twist, it was just a question, and wondered if you had though about it, and had the answer, best to make sure before your first MOT is due, it does not bother me.

[cassell]

Originally Posted by nu11eaf

No need to get your knickers in a twist, it was just a question, and wondered if you had though about it, and had the answer, best to make sure before your first MOT is due, it does not bother me.

A quick look at the requirements covering reversing lamps in the UK MOT Tester's manual seems to confirm that the OP's solution is acceptable:

https://www.gov.uk/guidance/mot-insp...#section-4-6-3

[davidwf15]

Originally Posted by nu11eaf

No need to get your knickers in a twist, it was just a question, and wondered if you had though about it, and had the answer, best to make sure before your first MOT is due, it does not bother me.

Don't worry....I hadn't🙂 .... Just noting how people with dazzling lights can get away with pretty much anything 😁

[davidwf15]

better schematic attached

[piorunz]

Thanks for the pic by the way! It looks great!

Originally Posted by davidwf15

jees....(...) but you're worrying about a reversing light mounted under the bumper that will be on for a few seconds when you reverse off the road onto your drive... (...)

Relax, no one is attacking you, this is a pure question of compliance. MOT have a long list of things to check so this is an interesting to know if this is a 100% pass. Which look like it is, so any other forum member can go ahead and try your solution now without worrying about anything MOT related.

[davidwf15]

edit.... if you are going to use the bigger / higher powered light then replace diode D1 with something like a 1N5400 or P600A which are rated at 3 and 6Amps respectively

[vampwitch]

Thank you for this wonderful and so useful post. Electronics aren't my thing. Generation yes. Could I simply use a relay wired in the similar manner or would this cause an issue with the Canbus?

Thank you.

[davidwf15]

Ha
..well that's the $64000 question as (for our U.S. readers) we say here in the UK.....in theory it "should" be OK as the only additional load will be a relay coil - around 1/4 Amp or so....but when the relay releases it will produce a large reverse voltage spike which, if not clamped with a diode runs the risk of blowing the canbus module ....it might, it might not.....I didn't want to risk that hence my interface circuit which presents pretty much NO additional load and NO back EMF spike
Attached is what you were proposing, it should work without any problems but I do not recommend it "just in case"
There is one other reason for using the transistor interface..... the LED bar is in fact a series of several LED's in series / parallel.... hit it with 14V from cold and, like a traditional lightbulb the weakest LED in the strip will take the highest current and will tend to pop, with my circuit the capacitor presents a very small delay and gradual increase of voltage so that is less likely to happen.
The more expensive strips that can run on 12 or 24V are less likely to pop as they also have inbuilt regulators