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Alternator boost?????

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Alternator boost?????

Postby Davem » Wed Feb 18, 2015 10:48 am

Hi Guys,

I'm considering installing a couple of very powerful (75/100w) driving lights onto my Mu and was wondering if anyone could give me useful advice on the most effective way to get the charging system to keep up with amperage that will be needed to not flatten the battery????? i.e. Can a bigger alternator be fitted to meet the current drain???? & if one can, which one????

Thanks.

Davem ( NZ )

Note: The spotlights are Night Stalker 180 Roo Lights( ex Fullers). I'm hoping that someone in OZ has already fitted some of these & has solved the problem.
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Re: Alternator boost?????

Postby geeves » Wed Feb 18, 2015 1:28 pm

200w is only 20 amps (16.6 to be accurate) so shouldnt be that much of a problem. Bigger alternators do exist but factory is 60a The big issue is space for the vacuum pump. You can hunt for a 80 a alternator or if willing to lose air con drop the compressor and wire whatever alternator you like in its place leaving the current alternator in place only to drive the vacuum.
Another option is hid or led driving lights Both give this output for under 50w power
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Alternator boost?????

Postby Davem » Thu Feb 19, 2015 7:52 am

Thanks Geeves, appreciated.

I was a bit concerned because recently I drove a one lane bush road into a hunting spot with just the headlights on FULL beam for 15k or so, to avoid a head on with loopy rally drivers!!! When I got back to go home there wasn't enough juice in the battery to turn the engine over & I had to get a wee tow from a fellow hunter after sitting for 2 hours chewing my cud!!! So I was thinking that 150/200 watts of driving lights would result in a sure fire flat battery????

Just as well I bought a manual Mu & not an auto, eh????
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Re: Alternator boost?????

Postby isuzurob » Thu Feb 19, 2015 4:22 pm

i have 120/160w headlights in my rodeo with spotlights and never get a flat battery with standard alternator, get your battery tested and make sure the alternator is charging correctly
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Re: Alternator boost?????

Postby geeves » Thu Feb 19, 2015 6:50 pm

If you really need extra lights hid and led are the way to go far more light for the same power and they dont crack when you cool them suddenly in a river. Ive always found the Hella plus 50 bulbs in standard headlights enough but I dont drive that agressivly on road at night.
Leds are more of a spread beam and hid more a spot in general but you can get good hid floods and led spots as well
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Alternator boost?????

Postby mattmannz » Fri Feb 20, 2015 3:40 am

Bosch make a 100amp alternator with vacuum pump which is a bolt in.

I have a light bar, two electric cooling fans and a winch with the stock 60 amp alternator. I do have dual batteries tho.
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Re: Alternator boost?????

Postby Davem » Fri Feb 20, 2015 8:05 am

Thanks guys. I think it might be the battery on the way out??? It is over 4 years old.!!!!!!
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Re: Alternator boost?????

Postby muzila » Fri Feb 20, 2015 10:27 am

Yea batterys only have a 5 year life span. Having said that I have one thats lasted nearly 10 years.. More than my moneys worth.

I run a single NS90 battery and a 80 amp alt. This runs my winch, 4x 130watt spottes and my 130/90 watt head lights. Have all the tech to do a dual battery setup just havnt gotten around to it. lol
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Re: Alternator boost?????

Postby Davem » Wed Feb 25, 2015 1:31 pm

Thanks very much for all the helpful info guys. Much appreciated. :D
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Re: Alternator boost?????

Postby Ricardo999 » Sat Nov 04, 2017 8:54 am

Other thing worth doing (maybe I have too much gear!!) is to add a second cable from the alternator to the battery to lower any possible voltage drops. I run lights, fridge, winch, etc, etc on a dual battery setup with a 120A Bosch alternator and a VSR - setup never gets below 13.5v (other than when winch is working hard) using a decent aftermarket digital voltmeter with everything turned on. Most of the time when above 1500rpm volts are over 14.
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Re: Alternator boost?????

Postby danz20 » Mon Sep 03, 2018 9:18 pm

mattmannz wrote:Bosch make a 100amp alternator with vacuum pump which is a bolt in.

I have a light bar, two electric cooling fans and a winch with the stock 60 amp alternator. I do have dual batteries tho.


You have a part number?+
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Re: Alternator boost?????

Postby DonaldNZ » Tue Apr 16, 2019 5:13 pm

On my alternator I wont be in a hurry to run a new thicker wire between the alternator and battery.

Most automotive alternators are rated at ~2/3 maximum output
manufacturers don't usually spend more than needed as standard equipment on a alternator.
extra batteries & loads have potential to increase the load on the alternator significantly.
the original wire between the alternator and battery acts as a resistor and as such limits the maximum energy drawn from the alternator, so making it thicker will ,make the alternator work harder and hotter and more inclined to let out smoke.

ways to get more grunt from an alternator; make the environment colder, duct cool air to it extract hot air from it , protect it from the heat of the exhaust and turbo, spin it faster.
My wizard air con pump is right beside an un shielded turbo with the alternator just under that.

I'll eventually shield the turbo from the ac pump and hoses,

around 6000 ~9000 rpm alternator rpm is a good place, faster = cooler due to more fan action, faster again = more likely to throw the rotor winding,

the Bosch load handler 200A 12v alternators alternators will handle a bit faster and have a lower cut in speed , so you may find they do make enough grunt at idle for 8 100 w headlights. 3 fans two beer fridges and a disco light for the missus

vacuum pump though

what is my alternator rpm ?

alternator rpm = crankshaft rpm x pulley diameter circumference difference.
so if crank pulley is 3 x alternator diameter then at 2000 rpm alternator will do 6000.
if crankshaft pulley is 280mm and alternator is 80mm at 2000 crankshaft rpm alternator will do 7000rpm

imagine the stress on the alternator and other devices in belt path when changing gears from say 2500 rpm to 800 back to 2000 made worse when heavier rotor higher output alternators high geared are fitted.
So will your belt handle the extra load ?

hence the development of the one way bearing in alternators, helps on the decellerate still got the accelerate stress. some alternator regulators have soft start where they ramp up the load over a minute to max output so it slowly warms up the belt to hot n grippy.

If you want hard out extra batteries and goodies buy a cheep temperature gauge and fit it to the alternator, I'd reduce loads so it never gets hotter than 90 degrees C, cooler equals long life

some regulators sense alternator temperature and reduce output if they exceed a certain temperature.
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