Alternator

how many amps can i expect from the stock alternator?

and if i am going to fall short of the amps i hope to acheive does anyone have any ideas/suggestions of either a second battery or an upgrade alternator

Depends on the year truck. On the Bronco early to mid 80s usually around 65 amps, mid 80s to early 90s usually 95 amps, and later either a 95 or 130 amp 3G alternator. You can identify the 95 from the 130 by the hole pattern in the front.

What problem are you experiencing? A second battery is not a solution to a under powered alternator. If you have added a lot of new stuff like high powered amplifier, lights, etc. you most likely need to upgrade the alternator. The battery is not supposed to be supplying power after the engine is started. It's sole function is to start the engine and from then on the alternator should be supplying the electrical demand. If it doesn't, then you will be discharging the battery not keeping it charged. There are good reasons to add a second battery, but not to supply the load when the engine is running. If you add a second battery to run things when the truck is parked and not running, you need to add an isolation relay between the two battery connections and feed the stuff that is being run with the truck engine off from a separate fuse box.

Good luck,

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Well this probably isn't a viable option for ya but let me throw it out just as food for thought. Back in the Day when I had my 78/79's and did a lot of trail riding I had one of those ubuquitous pick-up bed-trailers. I purchased an F250 bed from a boneyatd complete with the frame section from under the cab, heated & bent the framerails in then welded everything up and attached a hitch to it. I painted it to match the truck and then with a well-concieved spare-carrier I had pretty much a complete set of spares for both front & rear axles that I could drag around with me on trail rides. To help out along the way I had a pair of deep-cell marine batteries mounted in the trailer and I removed the yoke from the rear-end and installed a V-belt pulley instead. I mounted an extra allternator high on the frame of the trailer and ran it with a belt off the rear-end pulley. Just driving up to the trailhead would charge the spare batteries and a modified jumper quick-connect hooked everything up. Always had 2 completely charged spare batteries and while my truck never needed them they DID come in handy a few times. Not really applicable to what you're doing but I figured I'd mention it.

Also, while I've never done it I've given a LOT of thought to mounting a second alternator in place of the AC compressor and using it to charge a second under-hood battery. Never needed to do it once I built the trailer and I haven't done enuf trail-riding since then to justify it but I always kicked it around.

IF YOU'VE DONE THE SAME THING I HAVE BY PUTTING AN AMP IN THE THE TRUCK,LIKE SEABRONC SAID YOUR BEST BET WOULD BE UPGRADE YOUR ALT..BEST THING I'VE DONE SINCE I UPGRADED MY HEADLAMPS FROM SEALED BEAM TO COMPOSIT ALONG WITH HEAVYDUTY HARNESS...WENT FROM A 65 AMP TO 100 AMP ALT.WORKS GREAT...

Broncobill78 said:

Also, while I've never done it I've given a LOT of thought to mounting a second alternator in place of the AC compressor and using it to charge a second under-hood battery. Never needed to do it once I built the trailer and I haven't done enuf trail-riding since then to justify it but I always kicked it around.

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That was a pretty neat ides you had there / . My father in law runs an alternator at his hunting camp from water power and uses 12V lights in the cabin.

I've heard of that being done, but never have seen it. It is a good idea, for a second battery that gets discharged during, say a camp out as you really shouldn't us your primary alternator as a battery charger on a regular basis, it is ******* it and if done repeatedly it will drastically reduce the life of the alternator. The Bronco did have a second battery option for just such usage with things like camping trailers.

Good luck,

yea basically amps and lights...i hope to be running 3 amps very soon and i am all ready seeing problems running everything at night with the headlights on and pulling a trailer

so what are some bolt on upgraded alternators i can use in a 88 bronco

Your 88 has a 2G alternator. Outwardly the appearance is quite different, the 2G has a fan attached to the pulley in front of the alternator while a 3G does not have an external fan, it is on the inside. As far as wiring goes there will be very little difference. I would go with a 3G alternator and you can find them either bran new on the net or go to an Auto Recyclers and get one out of something like a mid 90's Mercury, Taurus, etc. You will need a new wire harness for the alternator which has the right plugs on it. Make sure you get a 130 amp alternator not a 95 amp, they look similar but can be identified by the hole pattern in the front end, (last picture), that is a 130A the 95 has a group of 4 holes where you see the two. Also, the case styles vary, this one fits older trucks like mine, the one that fits yours has shorter ears on it.

Here are some pictures, like they say, worth a 1000 words

Hope that helps.

Good luck,

>-

Seabronc said:

That was a pretty neat ides you had there / . My father in law runs an alternator at his hunting camp from water power and uses 12V lights in the cabin.
I've heard of that being done, but never have seen it. It is a good idea, for a second battery that gets discharged during, say a camp out as you really shouldn't us your primary alternator as a battery charger on a regular basis, it is ******* it and if done repeatedly it will drastically reduce the life of the alternator. The Bronco did have a second battery option for just such usage with things like camping trailers.

Good luck,

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Well, like I said I never got around to it after mounting the spare alt & dual-deep cells in the trailer but now that I have this 88' to goof around with (Don't really think my oldest will care *what's* under the hood as long as the windows roll down so he can chat with the girls) I'm getting a little more anxious to experiment. I had always figured thw way to go with it would be to make the 2nd alt a completely seperate system. Run it to a second Deep-cell and use THAT battery to run the lights & winch so those hi-draw items were isolated from the primary system. I really don't see any dealbreakers or anything that's very difficult to isolate or wire. Seems like it should be fairly straightforward.

SeaBronc, funny you should mention that. My old Chief had a hunting cabin powered with 3 alternators. 2 on the roof attached to windmill type props and a 3rd in the stream that fed the lake. He had 15 or so deep-cell batteries he'd accumulated over the years in a box under the back porch. He had a nightmare of wiring in a closet nearby but I recall him saying he paid an average of $3-$5 a month in electric bills and that kept the refridge going all the time and lights whenever he needed them. We'd go down there most mornings after our shifts & do what off-duty P/O's do off-duty for a few hrs before going home to sleep and I know for sure that the 'fridge was always cold and the stereo always worked.

I had a Canadian Bronco that came with a Factory dual battery setup, I replaced the secondary with a deep-cell and the whole gig always worked just fine for me. I honestly wondered why it wasn't a more popular option.

bronco graveyard has a 170 amp alt, that's what I got when I changed mine.