Thank you I read the whole thing that pretty much confirms the accessory rack is the same between LA and Magnum engines if I'm not mistaken. The powertech is a completely different alternator/rack though right?

I will hunt down the 150A I plan on running a car-PC soon so it sounds to be in my best interest.

 

Do you have a capacitor for your system? If so how many farad?

 

Nope, a cap is a last resort in an electrical system I want to fix it the right way. It's not a fix nor a bandaid and will create an even greater current demand on my already compromised alternator, I'm sure it will smoothen peaks and make my lights dim less but while beating on my battery and alternator since its not always topped-off it's constantly sulfating; shortening the battery life.

If I had an 150A alternator (or aftermarket 250A) paired with an AGM battery which takes a charge faster and more efficiently it would be a rock solid power grid for future electronics like a PC for music.

 

Well, the cap will not put extra strain on the system it just helps clean up the signal so your computer does not pick up as much noise from the amp and the electrical system can work properly.

You could always put in another battery with an isolator when you put a 150 amp alternator and not have to worry about it hahaha. Oh well, I'm sure you will figure it out... Happy Hunting

 

yeah but MOUNTING that Ford alternator and converting your wiring to run it wont be worth it the alt you show was available in more than 1 amperage. and with any alternator, electrical demand determines output more than "rated" capacity. Will a 65A unit put out 200A? No of course not. but if your electrical demand is only 40A at the moment that 200A unit will only put out 40A not 200. Same 40A that the 65A unit would put out under the same conditions.


You do have to be careful though; I know these trucks have volt gauges rather than amp gauges but when I had my 79 Ramcharger I used as a quasi "rescue" vehicle; in the sense of jump starts pulling out stuck cars from snow etc.... I put a 100A alternator on on place of the 65 that was stock, (100A was a factory option that year but took different brackets and such to mount which I'd saved from a previous vehicle I had owned)
100A equipped vehicles came with a "shunt" on the amp gage because if you have an amp gauge all the amperage has to pass thru it for it to sense amperage. My truck, originally with the 65 amp unit, did not have this shunt on teh amp gauge. It did fine with the 100A until the 1st time I went to jump a dead car with it; the alt went to full output (demand from dead car) and my amp gauge in the dash amoked. that is why they would tell you with the older Dodges to bypass the amp meter in the dash and install an add on volt meter because the next time I shut the key off it wouldnt even crank over... I had to jump the starter terminals w/a screwdriver and run a wire from the battery to the coil to start it; I could remove the jumper once started; until I connected the wires from each side of the amp meter together on teh same post... never had an issue again. and I jumped more cars with it than I care to try and remember.
I did wind up buying an aftermarket Stewart Warner amp meter and putting it in the hole in the dash where the original had been...

Your truck does not have an amp meter so you don't have to necessarily worry about that "exact" issue but there may be something else in the system that may fry (not sayng "it will") if there is ever cause to make the alternator produce its max rated amperage.... just something to think about; its an '88 which is (yikes/already?) 25 years old wiring and terminals aren't new and shiney any more if you know what I mean....

in my case, they made a 78A alternator in the same size case as my 65A with no bracket change needed and still more amps than my original alternator (that particular alternator put out as little as 37A back in the 60s/early 70s and was made in several versions up to 78A) Now had I just gotten me a 78A version instead of the 100A I would have probably been fine and not fried anything... that truck was carbureted with no computer and didnt have the electrical needs of newer fuel injected computerized vehicles loaded with power amenities...
and your 88 doesnt need as much as newer vehicles that have as many as 7 computers that all need power to make some of these newer vehicles run. I didnt think the alt you showed was "out" yet in 88, it looks like the one on my 93 Dakota nd both my 97 Jeeps... which incidentally I believe to be teh same alternator as each other

but to answer your original question? I dont see the harm in a junkyard alternator; but given that DON'T get crazy here and try to adapt aomething from a different kind of car or truck (besides another Mopar as alot of them used teh same unit as each other)
Sometimes they are stamped or have a sticker to tell their output; but if it looks lie a rebuilt sometimes they upgrade the smaller amp rated units to the larger amperage of the same size alternator internally during the rebuild process no way to tell; but if you have the 90A version and can find the 120A version (same case just diifferent innards) it will directly bolt on and wire up the same I dont think I would try to go any larger capacity than that;
your battery has as much to do with powering accessories as the alternator, now there it don't hurt a bit to get the largest cranking amp capacity battery that will fit the tray this is a place to gain extra reserve too. if you put a huge capacity alternator in and not have a good battery that's no good either This does NOT mean you gotta go buy an Optima;
but if the standard is a 60 month and theres a 72 or even 78 month available, not only is the warranty better, the longer rated batteries almost always have more amperage capacity than the cheaper version of the same size; and $10-15 difference in one grade of battery vs the next one better may mean the difference between starting or not in the dead of winter. cheaper than calling for a jump....
and me, I always swap batteries when I buy a different vehicle so spending the extra on a better one doesnt bother me.

 

Actually a cap stands for capacitor which charges and discharges has nothing to do directly with a noise ground loop, I would think a single Optima D35 will do the trick at the time of the 150A alternator swap.


"yeah but MOUNTING that Ford alternator and converting your wiring to run it wont be worth it the alt you show was available in more than 1 amperage. and with any alternator, electrical demand determines output more than "rated" capacity. Will a 65A unit put out 200A? No of course not. but if your electrical demand is only 40A at the moment that 200A unit will only put out 40A not 200. Same 40A that the 65A unit would put out under the same conditions."
We have already passed this idea onto strictly Chrysler alternators (56041-394AA). Yes and no, if I am listening to my stereo with the engine off a 200A will recover a deep cell battery much faster while continuing to draw the same load once the engine is started.

I assume my volt gauge will be fine then, I did plan on adding an amperage gauge though at a future date. According to that article all sounds good for the swap although it IS regulated in my ECU which will not be changed...I will be upgrading the ground and battery + from the alternator to 1/0AWG when I do the 150A.

87+ used the same alternator configuration according to an article I read up till the early 2000's.


"but if you have the 90A version and can find the 120A version (same case just diifferent innards) it will directly bolt on and wire up the same I dont think I would try to go any larger capacity than that"
I have a 65-75A and I know for a fact a 136A will fit perfectly fine and came standard in some Dakotas (minus the ecu regulating question) I really want to use the 150A read here: http://members.shaw.ca/j_e_e_p/Altupgrades.htm


"If you put a huge capacity alternator in and not have a good battery that's no good either This does NOT mean you gotta go buy an Optima;
but if the standard is a 60 month and theres a 72 or even 78 month available, not only is the warranty better, the longer rated batteries almost always have more amperage capacity than the cheaper version of the same size; and $10-15 difference in one grade of battery vs the next one better may mean the difference between starting or not in the dead of winter. cheaper than calling for a jump...."
I know, it drains from the battery before the alternator because there is a "switch-on" delay but that is not the only reason I want a yellow top Optima...if you read it's description its a muti-purpose battery. Maybe it does not have as high of a capacity as others in the same price range but if I wish to crank the stereo with the engine off it will not sulfate the battery like a higher capacity battery in the same price range that is not intended to be drained this way. With a future stereo addition and a computer system on the way now is the time to lay a solid power grid, I even laid 1/0AWG from the battery post all the way to the amp for only 400W but at least the grid is back there for more amps and processing. I figure $350 will get me an Optima and used 150A alternator...as long as my ECU likes it I will have rock solid power for multiple intended uses.

 

Here is my alternator in the Grand Cherokee 5.9 Limited sitting in my driveway:


This cross references to a 150A:


Notice all the same wires; two field wires, a ground and battery +


My current 65-75A:

 

I have heard bad things about Optimas not being worth the excess coin; what they used to offer as a truck/RV battery is more like a deep cycle marine battery that is designed to be drained/recharged often... I have run marine batteries in my vehicles as a matter of necessity. needed a battery and used what i had laying around I have run these batteries in some of my former vehicles for a couple years at a time and never had a bit of an issue.

and BTW how much stereo power do you really need in a (puny) Dakota reg cab??? Certainly not near as much as it sounds like you are wanting to run! My 93 had some kind of "system" in it that was literally "ripped" out by the PO... no radio at all no speakers (even stockers) though the factory wire plugs were still there for speakers in those locations; I did have to resolder pigtails onto what wires were lefta nd just dangling in the hole in the dash to be able to put any kind of radio back into it when I got it; I love my classic rock especially when they play stuff like my favorite station did earlier tonite from 1974 (every day they do a different year) as I was working out in the garage.. but man... I can crank my Pioneer up overpoweringly loud with no additional boosters/amps. and even at the volumes that I listen to, have been complained to about being "too loud" No caps, no amps, no "super alternator" required.....

 

The only reason I was looking at the Optima was because I stop my engine for 5-15min at a time while listening to the stereo sometimes longer, then start the vehicle and take a short trip up the road (back home). I was going to get a deep cycle but most don't have the cranking amps needed for a healthy starter, also the Optima claimed to take a charge faster and more efficiently which is the idea behind a 150A alternator; to bounce back a discharged battery faster after an engine start.

I need a LOT of stereo power trust me, a rolling studio almost a live concert feeling focusing more on punchy mids than bass but the woofer does hit very low frequency's just not "SPL" however it's nice to have some power behind a sound quality system. I did not think I would need to do this with only 400W to the front stage not including the woofer but the high power mids take a lot of amps and if the voltage drops at all the PSU in my amp pulls more amps to compensate but will kill your batt/alt if not setup like I'm trying to do. Also this amp has two cooling fans from hell; if I shut the ignition off while the system is turned up after the music cuts out you can hear the fans wind-down.

The only thing I'm worried about is using the old voltage regulator in the ECU with the new 150A what if something goes wrong and it does not stop charging the battery? I mean...you COULD get up to a 136A in the Dakotas anyway so all the ECUs should be universal in this area but if not KABOOMIE!

 

The yellow top (Deep cycle) Optimas are great. Long deep cycle so you can run electronics for a while with no problem, with a good CCA rating. The next great deep cycle battery is the Odyssey batteries.

Again you probably don't NEED more than a 120 amp alt. But of course the more the better. You won't fry the voltage regulator due to a higher amp rating altenator. Most likely you will have the truck idling while running your equipment, at which the alt will not put out 100% amp output. At idle I'm guessing it would do a max of 60% and only if it is needed since the PCM will determine when it is needed. To get closer tot he 100% amp value you will need to be 2,000-3,000 RPM continuously.

What stereo system are you using and what wattage size is the amps?