Spotlamp, wiring and current/amp help please

[anonymous-user]

Hi all,

I'm building a silly dune buggy thing out of an MX5, and I need some electrical help.

I have bought a heap of brand new Hella spotlamps to decorate the vehicle with. I have a row of 4 x Hella 500 round lamps for the front nudge bar, and a row of 4 x Hella Comet rectangular lamps for the roll bar.

I could have just bought one of those silly bright LED light bars for around £50 off Ebay, but I think rows of Hella lamps with the white 'HELLA' covers on are far cooler

I wasn't even going to bother wiring them up, but I thought I might as well.

Can someone please give me advice on what sort of thickness or gauge of positive feed cable I will need for each bank of 4?

All the lamps take H3 bulbs, and I don't know wether it will be better to just get a load of new LED bulbs which appear to be anywhere from 5watt to 30watt each depending on which one you choose, or just stick with old school 55w halogen bulbs.

Would it be too much for the MX5 battery/alternator to have all 8 lamps come on with full beam?

Some advice and pointers would be helpful.

Thanks

[SS2.]

Current = Power / Voltage

4 x 20w LED bulbs = 80w / 12v = 6.7A.

2 core cable with conductors of 0.5mm2 per core would be fine for that.

I'd fit a relay for the lights ie run a permanent (fused) 12v to the relay, with the main beam circuit being used to energise the relay.

ETA - like this:

Edited by SS2. on Sunday 10th March 20:34

[LFB531]

With all the lights on using 55w bulbs, including headlights plus a few ancillaries, you'll be drawing the best part of 50 amps. No idea what the Mazda alternator puts out but then, how often would you have the lot on?

A decent relay set up as suggested would be the way to go if you decide to stay old-school.

Oh yes, and set the tick over to 1500 rpm

[anonymous-user]

Thanks for the answers so far!

I was going to use a relay activated by the main beam as suggested, but I will install a switch in this relay wire so that the lights can be turned off and not come on with main beam.

They will only be used occasionally for a bit of fun when driving round fields etc

I probably won’t use them at all on the road, and just leave the covers on the lamps.

The 50 amps thing worries me a bit, hence why I was looking at the LED bulb options.

The lights are just for show, but it would be good if they could all be lit up with main beam if required.

[anonymous-user]

I have thought of another option...

I could just fit all the lamps with small 3 watt led ‘sidelight’ bulbs and then they could come in with the normal sidelights.

They would obviously be no good as spotlamps, but at least they would be lit up all the time at night and look cool?

[Penelope Stopit]

Lord Marylebone said:

Hi all,

I'm building a silly dune buggy thing out of an MX5, and I need some electrical help.

I have bought a heap of brand new Hella spotlamps to decorate the vehicle with. I have a row of 4 x Hella 500 round lamps for the front nudge bar, and a row of 4 x Hella Comet rectangular lamps for the roll bar.

I could have just bought one of those silly bright LED light bars for around £50 off Ebay, but I think rows of Hella lamps with the white 'HELLA' covers on are far cooler

I wasn't even going to bother wiring them up, but I thought I might as well.

Can someone please give me advice on what sort of thickness or gauge of positive feed cable I will need for each bank of 4?

All the lamps take H3 bulbs, and I don't know wether it will be better to just get a load of new LED bulbs which appear to be anywhere from 5watt to 30watt each depending on which one you choose, or just stick with old school 55w halogen bulbs.

Would it be too much for the MX5 battery/alternator to have all 8 lamps come on with full beam?

Some advice and pointers would be helpful.

Thanks

That's 440 watts = approx 37 Amps @ 12 Volts

You need to post back with the alternators maximum Amps (current) output and also post what other electrical equipment is being powered

If you are powering the engine/ecu and fuel pump with nothing else in use, the alternator will power those 2 rows all on at the same time

Wire each bulb using standard 14/030 cable that can handle approx 8.5 amps, earth the lamps as close to them as possible (@ main mounting bar is good) run 4 x 14/030 cables from each row to seperate fuses, an 8 way blade fusebox will do the job as it will give you 1 fuse for each lamp

Use 2 x 70 amp relays, 1 for each row https://www.ebay.co.uk/itm/Automotive-Relay-12V-70...



Fusebox Link https://www.ebay.co.uk/itm/12V-24V-Universal-8-Way...



Switch the relays with your own switches powered by the lights on or main beam cable

[SS2.]

A lot will depend on what you are trying to achieve - function or appearance ?

[anonymous-user]

Lord Marylebone said:

I have thought of another option...

I could just fit all the lamps with small 3 watt led ‘sidelight’ bulbs and then they could come in with the normal sidelights.

They would obviously be no good as spotlamps, but at least they would be lit up all the time at night and look cool?

[anonymous-user]

SS2. said:

A lot will depend on what you are trying to achieve - function or appearance ?

Appearance.

I just like lots of spotlamps purely for the looks on an off road type vehicle.

Which is why I bought rows of old-school Hella lamps as I thought they would look better than one of those big LED light bars the Americans now fit to their pickups.