with the extra draw on the eletrical system do I need to change the alternator to a higher amp one? I know I saw a thread about changing to a GM alternator, I haven't looked for it yet, but that could be a possibility if I need to go that route. The car is a 91 Loyale, automatic, 4 wheeler.

No. Now if you were adding three sets of lights then yes.

 

nipper

I'd say maybe...

 

You need to think about what you're normally running. If you normally blast the fan, use the rear window defroster, have the stereo cranked, and have your regular driving lights on, then I'd say you're pretty well loaded up.

 

What speed would you be running the fog lights at? On the highway (at 3500rpm) the alt won't have a problem punching out 40 or 50A, but if you're cruising around in town (low RPMs), the alt might have problems.

 

Also, what wattage of lights? A 55w set might be fine @ 8A, but a 100w set is 14A (at 14V).

 

Take a look at how you use the electrical system, and then decide based on that. If the lights will be for highway driving, and you're easy on the other electrics while you're driving, then you'd be fine.

 

Also, if you want to upgrade the stereo later, or add more lights, then you'd definitely want to look at doing the upgrade.

I'm gonna say no here, I've got two sets on my wagon, bumper and roof, most of the time I used them is for low speed off roading or when the car is off and I'm loading somethign into it. I have a stock alternator and cheapo battery, never in the time I've used them have I ever had a problem with the battery going dead or even turning over slow. Keep in mind you have to use some common sense, like don't leave them on for hours at a time with the car off, but I've left mine on for atleast 45min with the car shut off with no issues at all.

I'm gonna say no here, I've got two sets on my wagon, bumper and roof, most of the time I used them is for low speed off roading or when the car is off and I'm loading somethign into it. I have a stock alternator and cheapo battery, never in the time I've used them have I ever had a problem with the battery going dead or even turning over slow. Keep in mind you have to use some common sense, like don't leave them on for hours at a time with the car off, but I've left mine on for atleast 45min with the car shut off with no issues at all.

 

takes hardly any juice to turn a subaru motor over compared to most other cars, so you can drain the battery and still start. Usually when I need a lot of lights, I dont have my stereo blasting or a whole lot of other electronics, and I've run 5 55w lights and 1 100w spotlight along with my normal headlamps(and brights), and when I need that many lights pointing down the road, I'm usually going at good speed. Essentially, I've never had a problem with my alternator.

 

if you want though you can upgrade to a 100amp gm alternator, and the older hitatchi nissan truck alternators bolt right in, although they are only 60-70amps. Also theres a few others but I cant think of them off the top of my head.

 

The key to making an alternator work for you, and not have any excessive strain, is only use the electronics you need, only when you need them; versus crawling at less than 5mph but have your driving lights on that you use to see 500+ft down the road with.

not generally the battery that has issues.

 

have a set of 55w driving/fog lights on my wagon. used to use them a lot as daytime driving lights (other lights off) also used them at night in the country - speeds of 55 & up...have gone thru 3 stock 60 amp alternators in five years...

Its not required that you do so, however it doesnt hurt. Can never have too much juice.

 

Heres the thread: http://www.ultimatesubaru.org/forum/showthread.php?t=24227

And heres the USRM page: http://www.ultimatesubaru.org/forum/showthread.php?t=64613

 

Just remember to upgrade your harness while you're at it. It IS possible to put too much juice through too small a pipe. Ask me how I know.

 

Cheers!

Thanks everyone for the excellent suggestions. The car is mostly used at highway speeds of 35 and up. Looks like a set of good lights will work fine, just not go overboard in the wattage dept.