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General Tech Current draw - various accessories

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Trevor Triumph

Jedi Knight
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I use a GPS when driving the Spitfires- the speedometer is more accurate. A friend says such a device draws 14 amps. I wonder how this could be since the fuse to the GPS is rated at 5 amps. Additionally I added halogen headlights and the current draw according to a website is less than five. My friend said the two lights will use 15 amps. I think the whole light system has a thirty amp fuse I think that includes the running lights too. Am I missing something?

T.T.
 
Your friend may be confusing watts with amps ... No GPS draws anywhere near 14 amps; more like 14 watts. Since watts is volts times amps, that would be just slightly over 1 amp.

Halogen headlights come in many different power ratings, so it depends heavily on which ones you have. But about 4.6 amps _per bulb_ is about the minimum you can expect (55 watt rating on low beam), maybe a bit more if you get good voltage to it. (Headlights are typically rated at 12.8 volts to allow for some voltage drop in the wiring. Nominal battery voltage while driving down the road is closer to 14.4 volts. A good relay setup will get close to 14 to the headlights, so the current draw will be a bit higher.)

To that you need to add the current for the tail lights, dash lights and any marker or license lights you have. Incandescent tail, marker and license lights are typically 0.6 amps or so each; dash lights on a Triumph are typically around 0.15 amps each. So the total draw for everything will be somewhere in the neighborhood of 15 amps.
 
Trevor Triumph said:
So it seems while a relay to the headlights may be a good idea, it is not a necessity?
Click to expand...

Not a necessity, but besides getting higher voltage to the headlights, it reduces the load on the light switch, since the switch will only carry the current needed to activate the relay, rather than the current used to operate the headlights.
 
Trevor Triumph said:
I guess I'll add that to my to do list.
Click to expand...
Just a thought : LED headlight conversions are getting close to being practical and pretty much remove the necessity for relays. They won't reduce the load on the switch as much, but will knock it down considerably; and since they are not voltage sensitive, the brightness will not change. The cost is higher of course, but installation was plug-n-play. And, they put out more light than even a 90/100 halogen.

Here's a photo that a friend sent to me today.
LED Headlights from Andrew Uprichard.jpg

And a shot of mine shining on the garage door (to show the light pattern) on low beam
 
And a shot of mine shining on the garage door (to show the light pattern) on low beam
Click to expand...

hey Randall, your headlight shining picture reminds me; since I've changed my lamps out, I've been hi-beamed by other drivers, apparently telling me mine are out of alignment. do you use a standard protocol to aim your headlights?

(apologizes for digressing on this thread)
BTW: your buddies small mouth looks incredible.

Guy
 
GTP1960 said:
hey Randall, your headlight shining picture reminds me; since I've changed my lamps out, I've been hi-beamed by other drivers, apparently telling me mine are out of alignment. do you use a standard protocol to aim your headlights?
Click to expand...
Not really. I just park the car about 20 feet behind another car, on a level street, and check where the light falls on the other car. By standing in front of each headlight in turn, I can get a good idea of the side-to-side positioning; and I make sure the cutoff line is below the edge of the rear window on low beam.

I actually feel that mine could come up just a bit higher, but due to some poorly repaired accident damage, the adjusters don't have enough range. (It just never occurred to me to check how vertical the headlight mounting surfaces were before mounting and painting the replacement front apron.) When time permits, I plan to add a wedge-shaped shim behind the headlight bucket.

Just out of curiosity, which lamps did you use? The Hellas from BusDepot or something else? The reflectors definitely make a big difference, and the reason I bought the Hellas was because I didn't care for the performance of the Bosch units that I got previously (from the same place).
 
Just out of curiosity, which lamps did you use? The Hellas from BusDepot or something else? The reflectors definitely make a big difference, and the reason I bought the Hellas was because I didn't care for the performance of the Bosch units that I got previously (from the same place).
Click to expand...

i got some eBay tripod knockoffs; they look nice, & may be I can adjust them down, but I haven't really gotten into it yet.
(one of those gradual awareness things, as I have been avoiding night driving). But I did order those LEDs you mentioned, so I'll probably really be off the alignment charts!
Thx for the advice.

GP
 
I've heard that some of the cheap tripod knockoffs are really badly focused. With that much more light coming out, you really have to control it or it will get in other driver's eyes, no matter where the headlights are aimed.
 
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