What on earth?

[Manni]

Hi everyone,

I'm finishing installing my aux lights (mainly thanks to BTBR's detailed instructions provided with the Nippy Norman autoswitch kit ) but I'm facing a weird problem .

I first setup a set of Micro DE on a Migsel lightbar with an autoswitch, and they worked fine (to my surprise!). I took the earth from the M8 bolt on the front of the frame as indicated by BTBR in his instructions.

After a slow motion minor crash against a car door (don't ask ) , the plastic back of the left micro DE popped and pulled the wires, probably causing a short. The bulb was blown and the positive wire disconnected. I replaced the bulb and reconnected the wire, but since then, the lights don't work. No shorts (tested), the relay is fine, the fuse is fine, the autoswitch is fine, I still have 12V coming from the live lead when I switch the circuit on with the autoswitch... but the earth is gone from the bolt! If I connect the lights' negative direct to the battery, it works, if I connect it where it was connected on the chassis, it doesn't. The earth is still connected to most parts of the chassis, but not on that bolt anymore...

Forgive my ignorance, but what could have produced that??????

I guess I could run a negative lead from the battery, but out of curiosity I'd like to know what may have happened (and make sure there is no catastrophe in the making!).

Second question(s): I've wired a set of FF50 as well through a separate circuit with a second autoswitch but I'm using the same positive wire coming from the battery to go to the two relays (the second live wire piggybacked from the first relay) for the two circuits (Micro DE and FF50). Is my fuse (10A) going to blow if I switch both circuits on? Should I run two different positive wires from the battery separately to the two relays, with two separate 10A fuses? Or can I use one higher amp fuse to handle the two circuits with one wire? I made the second loom using the wire included with the lights, the first one was already made and came with the first autoswitch.

Thanks for your help (and sorry for such a long winded post)!

 

[Gas'd Off]

Recommend you put in an extra fused line from the +12v. Hella50 + DE's both running will draw a fair current. Your single wire carrying that current could over heat and melt before the 10 amp fuse blows. Not good. Then again the wire could be man enough. You need to do some calcs and relate that to the cable capacity(if you know it).
W/I*V.
V/I*R.
If you tell us what the lamp wattages are we can work out what size cable you need to carry the current

 

[Manni]

Thanks for the reply atkule. First of all I got both lights working now (I'll post some pics a bit later). Still don't know why earth disappeared from the first bolt , but I took it from another bolt under the tank, it's all fine now (or should I say for now? )...

Re the 12V wire, it's only the live bit coming from the battery to the first relay (that was part of the loom that came with the first autoswitch). After the first relay, both looms are completely separate.

The Micro DE are PIAA Powersport white plus (55w=110W). The FF50 are the original lights coming with the kit, 55W each.

So I guess total is 110W for each circuit, ie total of 220W.

I don't plan to use both at the same time (I don't see why) but it's just in case a human error switches them both on inadvertantly...

 

[Wizard]

Each pair of lamps is drawing ITRO 10 amps, so you really need a cable that is spec'ed to at least 20 amps and a suitable fuse.

 

[Manni]

Thanks Wizard, I'll follow your combined advice and I'll run a separate cable from the battery to the second relay, with a 10A fuse. That way I don't have to touch the first circuit.

Wouldn't have been able to do it without the knowlegde availbable on this board (and without BTBR who pointed me in the right direction and provided the installation notes in the Nippy Norman pre-wired loom). So thanks all for the (hopefully not momentary ) success...