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mk2 total power draw?
by
Smokey Eddy
on 19 Mar, 2011 13:17
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I'm curious how much work the alternator is doing at any given time. So like head lights +running lights+dash+maybe the cabin fan... that sort of thing.
Id like to put fog lights in the bumper and I don't want to try to draw too much from the alternator.
If anyone has some insight that would be great. I already have two 100 watt spot lights on the roof rck I rarely use.
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#1
by
RabbitJockey
on 19 Mar, 2011 13:50
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i think fog lights will be fine to add, many cars had them from the factory and mos tmk2s had the 90 amp alternator which would be 14x90 like 1200 watts, i can't imagine you would be using that much unless you have everything electronic on all at once, and even that i highly doubt
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#2
by
8v-of-fury
on 19 Mar, 2011 15:48
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On my bro's 84 right now with a 91 alt (I'm guessing 65a as it came from a non a/c car) he has 90w low beams, 35w driving lights, cabin fan, rear defroster there a little while ago, and stereo.. Obviously not boomin it out... But it didn't seem to struggle too too much. I mean the 90w lows pull 15a by themself! Lol
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#3
by
rabbitman
on 19 Mar, 2011 23:45
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Yeah just count everything up......headlights, running lights, heater fan and sound system. Running lights probably aren't worth worrying about. I know the heater fan draws a lot though.
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#4
by
Smokey Eddy
on 20 Mar, 2011 00:46
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Yeah I just don't know any numbers. 8v gave more than enough info.
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#5
by
8v-of-fury
on 20 Mar, 2011 10:35
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Well stock, the alt has to be able to deal with the possibility that EVERY electrical thing is gonna be on right?? And they probably gave it a bit of overkill.. So I'd say everything in the car on at full draw might come close to the 65a.. And even then I think they like to run at full efficiency, its when you ask 75a from a 65a system that you have troubles.. Lol
Also wait a while for the batt to charge from the start before loading up the alt.. Because re charging the batt will add a good chunk too.
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#6
by
bajacalal
on 20 Mar, 2011 10:39
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W = A * V so add up the wattage ratings of your lights and divide by the 12, the real voltage should be more but 12 is an easy number and gives you a higher amp result than 14, which is better than underestimating the amp draw and probably accounts for some of the electrical resistance in the wiring too.
I think the biggest draw would be the engine cooling fan, followed by the rear defroster and cabin fan.
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#7
by
theman53
on 20 Mar, 2011 12:15
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I vote starter for the most pull LOL, but yeah after that the rad fan, rear defrost, cabin fan, Head lights, glow plugs, 12v to the IP. There are a ton of little things but it shouldn't add up to much of anything to worry about.
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#8
by
Smokey Eddy
on 20 Mar, 2011 18:30
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Thanks for all the feedback.
I'm well aware of what draws power im more interested in numbers if anyone knows them?
like head lights, which Jeremy said were 80w each, im also wanting to add the running lights ect. i guess the running lights are 15 watts each, brake lights are 30? turn signals 30? i know they are brighter but i don't remember what the little package said when i bought new lights...
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#9
by
8v-of-fury
on 20 Mar, 2011 19:16
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well he has the uprated 90w H4 bulbs in his mk1. Stock are 55w i believe. sooo
9a for low beams
11-12a for highs
Cabin fan pulls through a 20a fuse? so its gotta be around 15-17a ??
I'd guess the rear de froster to be around 10-13a as well seeing as how it pulls through 15a fuse
Turn signals use like what 20w bulbs? so two at a time.. spikes of 3.5a on flashes.
Running lights are like 5w bulbs.. theres 6 outside? 2.5a plus maybe another 1.5a inside?
The rad fan pulls through a 30a fuse, so I'm guessing it to be around 300-360w max?
All that together your looking around 63-71 amps by my (probably higher than actual) best guesses.
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#10
by
R.O.R-2.0
on 21 Mar, 2011 09:08
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Thanks for all the feedback.
I'm well aware of what draws power im more interested in numbers if anyone knows them?
like head lights, which Jeremy said were 80w each, im also wanting to add the running lights ect. i guess the running lights are 15 watts each, brake lights are 30? turn signals 30? i know they are brighter but i don't remember what the little package said when i bought new lights...
a 65a alternator can keep up with a SoundStream 1600w mono-bloc amp... and the rest of the car, heater on, lights on bright.
Nuff said!
i imagine you could add 10 sets of fog lights safely, as long as there wired up good.
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#11
by
Rabbit79
on 21 Mar, 2011 10:01
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If you have access to an amp-meter that reads that high it would give you the most accurate results. Turn everything on with amp-meter hooked into the system and it would tell exactly how many amps you're drawing. I believe an amp gauge out of any car would do the trick also.
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#12
by
R.O.R-2.0
on 21 Mar, 2011 10:09
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dont you have to route the draw thru the gauge tho? you would need a pretty big ammeter..
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#13
by
Rabbit79
on 21 Mar, 2011 10:25
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Yes ammeters have to be connected in series. Kind of a PITA I know but I was just throwing that out there as the way to get the most accurate results. I know the amp gauge portion of my little multi-meter only goes up to 10 amps.... That's why I said "if you have access to one that reads that high". I have seen guys do this with an amp gauge out of a car though, they will usually read high enough.
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#14
by
R.O.R-2.0
on 21 Mar, 2011 10:54
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Yes ammeters have to be connected in series. Kind of a PITA I know but I was just throwing that out there as the way to get the most accurate results. I know the amp gauge portion of my little multi-meter only goes up to 10 amps.... That's why I said "if you have access to one that reads that high". I have seen guys do this with an amp gauge out of a car though, they will usually read high enough.
that would be the ideal way to get an accurate draw, but idk if he needs one that accurate, he just wants to add some more fog lights, prolly just 2 55w H3 or H4 lights.. the stock alt will do just fine for 2 more lights..
i used to run two 100w KC hi-lites, 4 driving lights, and 2 fog lights on my 4runner, it has a 60a alt.. and i cooked one alt, but that was from something else..
(that truck was blindingly bright with all the lights on, was like 22 million candle power comin down the road at you!)