regulating voltage on an unregulated ride

I have a friend with a 55 Ford F-100. The truck has been converted from the stock 6volt system to an unregulated 12volt system. The ignition needs the extra power at high rpm (winds it to 8k+ rpm) Problem is now he wants a radio installed but cant with the electrical system the way it is. I will be metering it to see exactly what the voltage climbs to at redline, but until then what options are there for regulating the power source to 12volt for just the radio? Unless it raises the hair on the back of your neck, its only noise!

Install and external voltage regulator.  http://www.cpgenerator.com/voltageregulators.htmlSupport the12volt.com

So these external regulators are nothing more than a flood gate, keeping the output of power equal all the time. I assume these can handle anything an alternator can throw out? & if not, would wiring 2 inline work?Unless it raises the hair on the back of your neck, its only noise!

You need to use a regulator with at least equal current capacity to your alternator.  No, in general wiring dual regulators in parallel is not a good idea.Support the12volt.com

So I need to find out the specs on the alternator, then pic a regulator sized to match. From what I see there looks to be only 3 terminals on the external regulators, so can anyone tell me if this quick little diagram is correct? This "should" leave the ignition's coil getting the full output of the alternator as it is now, but the remaining electrical system will run off the regulated power flow. (radio included) Is this right?Unless it raises the hair on the back of your neck, its only noise!

Alright, took a look at the truck & found some interesting things. Alt is a 200amp HO. At idle the voltage sits at 16v & climbs with rpm. The truck has no tach (idiot) so I can only guess what the RPMs were, but I had it rev'd pretty high & got a peak reading of 19.8v. The alternator has 3 connections on the back, which only 2 are being used right now. He knows nothing about the alternator, and the wiring is sad at best. (10ga charge wire on a 200amp Alt?!) I am thinking because it has 3 connection points there is a voltage regulator built in & is either not hooked up right or at all because only 2 connections are being used. Nothing in the engine bay is original, and I have never played with old school V8 power. I will be rewiring the alt & bumping that charge wire up to a much bigger size, but I also want to know if I can just rewire the alt correctly & have the regulator start working. That & I have yet to find an aftermarket alternator that does not have a voltage regulator built in, so I am confident it has one. Anyone know what I should be looking for? (didnt see any markings on the alt)Unless it raises the hair on the back of your neck, its only noise!

with it it starting at 16v and climbing it sounds like a 16v setup instead of 12volt, it is often used in high performance vehicles for the increased voltage for the ignition systems. if you do some searching online you will see there is quite a bit of 16v stuff out there for the high performance market. You may need to keep it the way it is and just regulate the power you supply to the stereo. or setup the vehicle as 12v and get a step up converter to power the ignition with 16v which is also rather common. hope this helps

If all he needs is 12 volts regulated to a 12 volt stereo system, why cant you wire one 12v reg. in parallel from the alternator to the stereo. If its rated for the power consumption of the radio, why wouldnt that be enough?

jeffwhiteman wrote: If all he needs is 12 volts regulated to a 12 volt stereo system, why cant you wire one 12v reg. in parallel from the alternator to the stereo. If its rated for the power consumption of the radio, why wouldnt that be enough?

Thats what I thought first, but he said somebody tried that before & the radio kept shutting off anytime he rev'd the engine. I dont know if they hooked it up right, or if there is a specific way to get it right, which is why I am on here right now. It seems fairly easy, which is what worries me since it didnt work in the past. He keeps going through batteries in the truck, which I assume is because of the higher voltage. Ideally I want to regulate everything to 12volt in the truck but keep the ignition coil getting the excess power, that is the only performance part that benefits from the added juice anyway. Can anyone comment on the drawing I posted above? & thanks for the feedback so far.Unless it raises the hair on the back of your neck, its only noise!

reference my previous post, get the whole system regulated to 12 volts and get one of the converters to give 16 volts to the ignition