Two alternators

[dangerranger83]

Well as the title says and Im about to ask, has anybody done this to there truck? I know it can be done but wondering how? Im looking at it being cheaper to run 2 instead of one since I can go to the JY and get one for $25 or so bucks and was thinking about putting it in the place of where the AC compressor would be . I wouldnt need to make it move due to my power steering pump is the thing that adjusts my belt tightness. I know thjat this takes my OBA idea out of the idead but there are other ways around that unless I mount it to where the smog pump use to be.

I plan on putting more lights on my truck and was wondering how to hook it all up so that the alternators dont fight eachother but instead charge the battery but not over loading it and whatnot. As you can see Im still doing my truck build on a budget and this would be the cheapest way to go plus if I do have an alternator go out on me for some reason, I still have a backup one.

My engine is a 2.8 Durasparked. Any and all ideas are welcome.

 

[shane96ranger]

Are you planning on doing a 2nd battery as well? Are you just wanting more output from your alternator? What amperage is your goal?

 

[doorgunner]

yeahhh.....get a second battry while you're at the J,Y. & run all your xtra lites off the 2nd alt./2nd battry.........

 

[shane96ranger]

yeahhh.....get a second battry while you're at the J,Y. & run all your xtra lites off the 2nd alt./2nd battry.........

This is what I was thinking he might be wanting to do.

If you were doing 2 alternators to the same battery, you would have to run them alternators in parallel, and I believe they would have to have a matched output. Matching outputs would be a difficult task if it's a JY unit.

 

[Original_Ranger84]

You can get dual battery and dual alternator kits that do exactly what you need them to do. They make sure both batteries get charged and both alternators will not be fighting eachother but I think the dual battery and alternator with one going to each one would be the best bet. but seeing as you probably have the 40amp alternator and v belt you can probably do the chevy alternator and pick it up in the JY for the same price which would give you over twice the potential amp output.

 

[Will]

You can get enough power out of a single alternator. Adding a second one is a mechanical issue. Mechanical issues are always more expensive. Use the compressor spot for air or hydraulics.

 

[shane96ranger]

You can get enough power out of a single alternator. Adding a second one is a mechanical issue. Mechanical issues are always more expensive. Use the compressor spot for air or hydraulics.

I agree. There are few places around here that will beef up your current alternator, and it would probably be cheaper by the time you throw all of your time into a dual setup.

EDIT: Does anyone know how close the brackets are to a Fox Body/SN-95 Mustang? They look close.

 

[gwaii]

running two alternators is not a problem.

and no,they don't need to be matched...they will not 'fight' each other.
in this instance amperage is not a factor,except as your goal.voltage is what determines how they'll charge.even if the regulators are set to slightly different voltages,it just means the lower one will ramp down it's charge rate first as the battery reaches it's full charge.

i've done exactly this modification,with several reasons behind it.the main one is that an alternator failure miles out into the bush will leave you walking.a bigger alternator will give more charge,but it's still just one alternator failure away from a bad day.a spare is a nice insurance policy.an insurance policy i've had to collect on before.
higher amperage was a secondary reason,with the added bonus that since the load is split between two alternators heat loading is significantly reduced compared to one overpowered unit.so you've not only got a spare,the chances of failure are significantly reduced on either alternator.

i ran mine with seperate belts,so a belt failure will not take out both.
i ran two batteries,but had switch gear so that both alternators could work on either battery(together or one at a time) or both batteries could be coupled.

from a mechanical standpoint,this is just a little more complicated than changing spark plugs.
but not that much.

 

[dangerranger83]

I want to run a single battery with this setup but have it so that both charge the single battery. Running a single large one will cost me more money to buy it or running a dual battery setup will cost more too. As said above by gwaii, its just good insurance too. Its nothing luike away from home in some back woods and your alternator go out. As far as it being another mechanical issue that could go wrong, thats a chance that I am willing to take and doesnt seem all that risky. Running all the lights I plan on running off a second battery doesnt seem like I would be getting ahead to well for myself. That would be 2 batteries that the factory alternator would have to charge and could potentaly over load it causing more issues while all the lights I plan on running are going.

I plan on running four 55watt fog lights on my headdache rack along with my current factory head lights, 55watts, and my two 100watt fog lights on my brush gaurd. My truck has 2 belts and I will run the second one off the other belt so that if one snaps, Im still good.

Yes I plan on turning the night into day.

gwaii how did you end up running the two i.e. wire wise and whatnot. Your kind of responce was the one that I was looking for and would love to learn more.

 

[AllanD]

If you want a rediculous amount of electrical power look for a junkyard that has some retired ambulances.

I snagged a 200Amp Lesse-Neville Alternator out of one that uses the later "three bolt" style mounting.

Frankly I'd be running that alternator on my 4.0 except for one "small issue"
The alternator will only go onto the factory bracket if I remove the passenger
side Valve cover AND rockershaft from my 4.0 engine...

So I guess I have to just struggle through life with a 135Amp alternator... Boo Hoo...


On another note I just finished retrofitting a 95Amp later style alternator
to a friend's '89 Bronco2 (look in the junkyard for a 1992-93 F-150 wih a 4.0 engine).

But be aware that you will need to modify the pulley on the old alternator to swap it over.

AD

 

[4.0B2]

i have 2 deep cycle batteries.. i know for a fact i can drive for 3 days w/ my alternator out... lol. so another alternator...and whatever, is not really insurance IMO. i'd do dual batteries instead. that all i have and i run my headlights, 2 hella's, over 1500 watts of amps (2 amps), an invertor.. and its nothing for my bass to pull me down into negative amps when running 2000 rpms down the road.. and i survive just fine w/ dual batteries.

however, dual alts would be cool and would work great... just make it happen. all you need is a way to mount it, and that's just fab work. so its easy... then measure for a belt, or find a pulley that's a double you can put on a different thing, and use a separate belt on it.

what output is your alt? is the 2.9 not stronger? maybe just do a swap... lol. idk, just tossing out ideas

 

[gwaii]

gwaii how did you end up running the two i.e. wire wise and whatnot. Your kind of responce was the one that I was looking for and would love to learn more.

the way i wired mine was a bit more complicated than what you're after,so i'll tell you how to do it the easy way instead.

get the factory alternator harness with your new alternator.

hook the output wire to the starter relay just like the original one.

tie the green/red wire from your original alternator to the new one's green/red wire.

you're done.

seperate charge lights can be hooked to each one,but that's a little bit more involved.

 

[Original_Ranger84]

I ran 2 100w long rang lights, 2 100w flood lights and 2 55w driving lights plus a 500w sub and a 300wamp for my speakers on my old 84 with a 40 amp alternator and I would notice a definate dimming when I put in the clutch but other then that the setup worked just fine. no need for an extra battery or alternator.

 

[dangerranger83]

I already have dim lights with my current setup and thats without running anything but my headlights, put he fog lights on and you can see it more and thats running at 800rpm warmed up. Driving down the road Im fine.

With this all I want to do is just hook the alternator in with the battery/current charging system and be fine. Fabbing up a braket wont be a problem.

Now heres something I just thought about and have another question. I have an 87 alternator sitting in my garage off my old 2.3 and it has the serpentine belt pulley on it and was wondering if I can switch out the serpetine belt pulley for a v-belt one and also it has the built in voltage regulator on it and if it is okay to just took hook it to my battery because of that.

If all that can happen, I can do this for almost nothing and I think have another alternator on mine for little cost. I know alot of people will say switch out the 84 for the 87 but I still want to fun dual alternators, I will say it cant hurt to run two.

Mounting it wont be to much of a problem, theres a nice spot where the AC unit should be that it can go.

Remember trying to keep this on the cheap side but not affraid to do custom/hands on work to make this happen either.

 

[gwaii]

Now heres something I just thought about and have another question. I have an 87 alternator sitting in my garage off my old 2.3 and it has the serpentine belt pulley on it and was wondering if I can switch out the serpetine belt pulley for a v-belt one and also it has the built in voltage regulator on it and if it is okay to just took hook it to my battery because of that.

i didn't even notice you were running an '83 with the seperate reg,but that won't change much.

the pulley can be easilly swapped from serpentine to v-belt,you just need to get a pulley from another alternator.
on the '87 alternator,do you have the harness for it?if not,these are common at the wrecker.hook the output to the solonoid as before,but run a jumper from a switched positive,such as the ignition coil to the green/red wire.if there's a white/black wire or a smaller yellow/white wire don't worry about them,you don't need them.

while you don't need to,i'd recommend changing out your old alternator for a newer internally regulated one at some point.as you stated earlier,they can be had cheap and are more reliable than the externally regulated ones.