Silly idea
Submitted: Thursday, Feb 19, 2004 at 22:25
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Member Eric
Was wondering how i was going to power 4 x 240 blitz lights on my roof rack . I think I will need heavy dutie cable to handle at least 30 or 40 amps , is this correct ? Now for my silly idea , i was wondering if a battery on the roof rack (in a battery box ) would run the lights , with only a standard wire around 10 or 15 amps from the altinator to keep it charged .
No laughter , just answers lol
Venus Bay
Reply By: Wayne (NSW) - Thursday, Feb 19, 2004 at 23:38
Thursday, Feb 19, 2004 at 23:38
I once fitted 6 cibie lights to a roof bar of a Hummer. 6x100 watts. The Hummer was used for some promotional work.
Battery on roof, hope it does not leak
Battery isolater between main battery and the one on the roof
Relay x4
Switch in cabin for lights
Cable
Fuses
If you still want to go ahead with the project, run a cable up the "a" pillar and do all the other wiring under the bonnet and forget about the battery on the roof.
WayneAlways Out'N About
AnswerID:
47405
Follow Up By: V8troopie - Friday, Feb 20, 2004 at 01:49
Friday, Feb 20, 2004 at 01:49
Yes, silly idea indeed. Once you start drawing the 30 or 40 amps from the rooftop battery, the alternator will try to keep the battery fully charged and - guess what? - pumps 30 to 40 amps up to the rooftop battery.
If you run a flimsy 15 amp cable to supply that current it might get a little warm, it might develop a noticeable voltage drop and your rooftop battery might not get fully charged.
I'm glad I'm not the only one with silly ideas from time to time :-0
Klaus
FollowupID:
309386
Reply By: Member - Dragan T (VIC) - Friday, Feb 20, 2004 at 09:57
Friday, Feb 20, 2004 at 09:57
Well,Eric, dunno about all this cop related stuff. But you can't just wack in a battery between your lights and alternator and hope that it will take the load off. If your lights are gonna draw 30-40 amps it will draw it from alternator, if you have battery connected to the circuit it doesn't matter. It will just make matters worse (weight on the roof, leaking, etc.) Since batterieas are heavy, I reccomend that you put it somewhere closer to ground. You still have to use wire able to handle 30-40AMP, no matter if you have battery and where it is positioned. Good solution will be, to install soleniod that will charge your battery only when your lights are off, and when you turh them on soleniod automatically disconnects alternator from your battery/lights circuitry. Down side of it is of course, you'll be able to run lights only until go go juice from the battery is drained. Exapmle - if you wack 200 Ah battery in there, you'll get about 5 hours of your lights if they draw 40 Amps. Then you'll have to switch them off for battery to recharge. Maybe you can use 2 batteries, so one i running lights while other one is charging. But I guess, we are getting in to to many batteries here. Anyway, there are many solutions, it just depends what suits you. Or maybe, has anyone taught about installing twin alternators Ha? Anyway, let me know if you want more details on electrics!
Cheers!!!When I grow up, I want to be PATROL TDI - Dragan's Terrano
TAR SUCKS!!!
AnswerID:
47421
Reply By: Member - Bradley- Friday, Feb 20, 2004 at 09:58
Friday, Feb 20, 2004 at 09:58
Ok buddy, i love a crazy idea like this, Go down to your local supplier of car stereo gear and grab your self some 8 guage power and 8 guage ground wire, some crimp on eye connectors, an inline 8 guage fuse to go at the battery, run both the power and ground wires direct from the battery, up to the rack in some flex conduit and terminate to an anderson plug. Go to the auto elec and grab a high current 12v relay like a battery isolator job, and put this inline on the power cable and control by whatever means you desire. Mount your lights on a removeable rack fitting with the corresponding anderson connector. You will have more than ample current supply with no voltage drop. and will be bulletproof to boot.. Cops might not like it , but i reckon it will look MAP (Mean As P...) Wont cost the earth either ( apart from the lights) CheersJust killin time till
easter...............go and play in the dirt, instead of workin in it......
AnswerID:
47423
Reply By: Willem - Friday, Feb 20, 2004 at 12:28
Friday, Feb 20, 2004 at 12:28
Eric,
Don't listen to the doom and gloom posters...they have their own agenda.
I think it is a great idea. I will go one further. Put all the lights on a hydraulic ram so that the lights lie down when you are driving. Just flick the switch and the light come up into position. (The traffic police in Arizona have some vehicles with ram fitted flashing lights on unmarked cars...I know....I got caught!!!)
I wouldn't bother with an extra battery. Just upgrade your main battery to a really powerful one and maybe the alternator as
well.
There are lots of ways to skin a cat.....................:-)
Hope you have them on by LD.
Cheers,Willem
Out on the Gibber
AnswerID:
47436
Follow Up By: V8troopie - Saturday, Feb 21, 2004 at 00:45
Saturday, Feb 21, 2004 at 00:45
Great Idea Willem. you could rig the hydraulic ram so it also can tilt the lights forward for a gradual dipping for oncoming traffic.
Klaus
FollowupID:
309493
Reply By: Member - JohnR - Friday, Feb 20, 2004 at 17:28
Friday, Feb 20, 2004 at 17:28
Eric, bearing in mind you will be expected to douse the mean lookers at the time the road train coming the other way does, what will be the point if you have to drive on dip for such a long time before it has passed?
The other option he may have is to drive over the top...... I was warned of that once when a relay locked on.
Whenever I have seen European vehicles with six or so big lights across the roof they have been low wattage and blue tint for some reason, just like trucks here use width or height lights.
I have driven with highmounted lights on tractors and while they may be good for some uses I have never tried them on a road. They can throw up a lot of glare of anything like a bonnet.Regards
JohnR - Not enough of the right travelling, some here..... some over there.......
AnswerID:
47457