stand-alone alternator

[Archangel]

Is that possible - have an alternator with a load, but no battery? I wanna install a second alternator in the rattler, as it turns out one ain't enough to power up all my lights and stuff at anything less than 1500 rpms engine speed. I cannot tie the new alternator with one of the factory batteries because I cannot isolate them from each other due to the huge current draw upon startup (150 amps per battery), and I have no place for a 3rd battery, nor do I want one. The new alternator will be running only lights, and maybe a trailer battery if one is present. To accomplish this I'm planning on installing a some SPDT (5-pole) relay before the lights that will allow me to switch between batteries and stand-alone alternator as a power source - with ignition off the lights are powered through the batteries, and when the engine is running they switch over to the alternator. At no time is the stand-alone alternator charging batteries or powering the cab or anything like that, all it will be doing is supplying power for the lights, so there will be no "fighting" with the regular alternator and trying to kill each other. Your thoughts on the subject?

[crown vic muscle]

i see no problem with that system, i thought about doing it for audio equipment myself. as long as the two alts never see each others current it shouldnt be a problem

[gadget73]

Probably need at least a capacitor to smooth out the output, and you need something to provide reference voltage from. Probably a small battery would be enough, even like an emergency light battery or something would fit the bill.

[crown vic muscle]

i was thinking along the lines of a sealed lawn tractor battery, it can be mounted in any position. im not sure a cap would do the trick, it would be drained before it was even charged.

[Archangel]

Mkay, so on the next trip to Harry's I'll grab the overflow tank from that '90s TC, then I can lose mine and install the lawn mower battery in its place on the inner fender. I just thought of where I can put 4 more lights on the front of the truck, so I'll really need this thing done soon Thanks for the info guys!

[87gtVIC]

oh god more lights!

[Archangel]

Well I already have four 3"x5" 55watt ones, might as well use them

[tim marks]

you should join the volunteer firemans squad....in case of an accident at night you can just respond with your flood lights. when not running with the fire company im sure there is a construction company that could use some lights for the night shift boys.......


geez...thats a lot of lights.

[Archangel]

Meh, not really - the two factory 55/65W headlights, four 100W auxiliaries, and soon another four 55W auxiliaries - total of only 750W. Of those the secondary alternator will be running two 100W ones and the four 55W ones, along with the two 100W rear floods and the two 55W ditch floods, so good 730W and about 60 amps. With no overheads I'll be totaling at slightly over 1kW of lights And yes, if I had a dog I'd put offroad lights on it too

[1987cp]

Need more pics with all the lights on!

Maybe you should put offroad lights on the cats ....