alternator voltage regulator

I have been searching and searching for weeks, and I cannot find a schematic. Pcb location and size is not a major problem, but function is. I need a voltage regulator for my alternator, my goal being to plug in the existing harness on the vehicle (I have an old regulator I can use for this, but the internals are bad, and I cannot remove the dernd silicone) and have a backup alt for use when I don't have a really good one. I want to make the regulator so the output voltage sits at 14.6-15v. My existing regulator, in the vehicle now, keeps the voltage at 14.2, which is a little low for my tastes. My preferred voltage is 14.7~14.8 (allowing for fluctuation of course) I am by no means an electronics expert, but I do have some rudimentary skills, and am still learning. If someone could find a schematic and/or data sheet with this circuit already built, and what to change to adjust it the way I need, that would be wonderful. Or a link to a company that builds custom regulators/alternators would be helpful.

If it is not a single wire (D+) alternator, just add a diode in series with the S (Sense) input. Any diode should do if it is a true Sense (ie, 50mA max). If its sensing is thru its Ignition terminal, then maybe a heavy diode (5A or more). And getting inside a D+ type to do the same is easier than building a regulator. The D+ type connects its Sense to its output (B, B+). BTW - the diode adds (say) ~0.6V to the alternator output. And please don't cook your battery.

Constant voltage level you require will burn out (filament) lighting bulbs within a few weeks.

Hence my battery cooking comment - that tends to happen above 14.5V for typical lead acids at standard temp (25C, ~75F), but at lower voltages at higher temperatures. Else get a 7-cell battery and run between 16.1V to 16.8V. I dread to ask why such a voltage is needed. (Oh no - not an amp!)

Sorry Peter, didn't look carefully enough.

Also in the case of what we're both wondering, the big 3 would be a better bet. The increased voltage wouldn't help because surely you'd get a slight drop in available current, anyway that's your department, I just do the diagnostics!

howie ll wrote: Sorry Peter, didn't look carefully enough.

It was a non-highlighted comment; easy to miss; and possibly independent of lamps anyhow - ie, if imtheman0313's comment "...keeps the voltage at 14.2, which is a little low for my tastes... meant that he had a higher voltage requirement for the battery. But imtheman0313's tastes may be to burn out lamps and explode batteries - hence why I queried why he wants the higher voltage. After all, 14.2V is a common setting for many modern alternators. But your (Howard's) point about the BIG-3 is excellent. IMO at times there is not much funnier than seeing things fry because the battery is 14.2-14.4V etc but the battery-voltage-sensing alternator is putting out 16V etc due to insufficient power & ground cabling (hence an advantage with single-wire D+ type alternators). The battery is fine at 14.4V, but other things getting (say) >16V get smoky and cause several $thousand damage (eg, audio & multimedia, EMS, lamps, ignitions). (I only blew my Alpine faceplate.)

The main reason for the preferred voltage is the voltage drop between sudden draw from the amp(S) and the time it takes the regulator to catch up and bump up the alt output current. I have 1/0 cable from the battery to the front fusebox, and 1/0 to my cap (helps to further stabilize the dc on small quick draws), plus the 4 ga. power from cap to amps (less than a foot between the cap and either amp) The amps draw enough power that the voltage drops to about 13.2, before the regulator bumps the output up enuf to bring the voltage back to 14.0. I would prefer to have 14.6, so that when those really hard notes hit, the voltage drops to 14.0 at the lowest. The psus in the amps are regulated, so it really does not matter either way, again it's just a comfort zone thing. And within the next, oh, i'd say 2 months, all my lights will be either LED or ARC (HID), all of which will be on circuits that supply only 12.4 volts to the clusters.

So how long does it take for the alternator to catch up? Sound like a crap alternator to me. What sort is it?

about .75 seconds, maybe 1.5 seconds on a bad day. Probably not noticeable by most drivers, but it is by me. My end goal is to have as smooth and even a ride and look as possible. I can modify the main fuse box to add a damping circuit so the lights and interior LEDs wont dim, but the voltage will still drop even if I do fix the "dimming" problem. By the time I get done, I want my 2 alts to provide enough current to run my stereo and all accessories at idle with no drop at all. I want zero drop with anything at all, full load, half load, watever the case may be. I understand that this is near impossible unless the alts are charging 100% full-time, which would be just stupid to do, so I want the closest thing possible. If I raise the charging voltage, I should be able to negate the effect to some extent. Even my interior lighting is susceptible to the .6v drop.