High output Alternator options for 6.9 idi

[Zeroluck]

I recently scored this sick 1976 1 ton econoline RV who some redneck engineer from Alberta has swapped a 6.9 and a t19 into at some point.

I fixed the glow plugs and clutch and it starts and runs great now, albeit slow and there’s some driveline bugs to be worked through.

I am planning to slap some solar panels and a lithium setup into it this spring but one piece of the puzzle I am missing is the alternator. It is a 6.9 and has a v belt setup and what I presume is a very small 60amp or so alternator.

I want to be able to charge a lithium bank at 50a at idle without overheating the alternator. I have a 145a ad244 on my Astro van and it overheats at idle with only a 40a constant load, especially if the electric radiator fan kicks on.

1. Is there anything out there I can bolt on? Maybe an IDI or powerstroke ambulance alternator with a pulley swap? I have seen some mention of a 160a unit online in the past. I did find a 1990s ford propane shuttlebus in the junkyard with a made in USA 100a unit in it, but I don’t think that will be enough and not sure if a 460 alternator will go on an idi.

2. Will the v belt be able to grip hard enough to push that much current or do I have to swap to a serpentine setup?

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[AlaskaLes]

I've read some posts about using a Ford Taurus alternator that makes good amps at low RPM. I'm thinking about going this route to keep up with the snowplow pump on my F-350. Sounds like it might be a good option for you too.

 

[FrozenMerc]

IF you have the room, why not add a 2nd alternator? Also, don't forget about the external voltage regulator. Not sure the stock 1st gen Ford units can handle much over 70 amps anyways, you may end up having to upgrade that system as well.

 

[rreegg]

I’m no expert but don’t the different battery chemistries between lithium and lead acid necessitate different charging voltages and protocols?
it makes sense to beef up the alternator for vehicle battery but if you install lithium for house usage should it be a separate charging circuit?

 

[IDIBRONCO]

Just remember that if you do use a Taurus (3G) alternator, you'll probably have to swap your V belt pulley onto it.

 

[ROCK HARVEY]

You want the long-eared 3g alternator. It’s a direct bolt-in, plus some minor wiring changes. Here’s the one on my Amazon wish list:

Amazon.com: OEG Parts New Alternator Compatible With Ford E350 Econoline V8 7.3L 1992 F2UU-10300-DC, F2UZ-10346-B, F2UZ-10346-BRM, F6PZ-10346-XARM2, F2UU-DC, 7756-3, 250-215, AFD0080, 20202, AFD0080, 40014012 : Automotive

Buy OEG Parts New Alternator Compatible With Ford E350 Econoline V8 7.3L 1992 F2UU-10300-DC, F2UZ-10346-B, F2UZ-10346-BRM, F6PZ-10346-XARM2, F2UU-DC, 7756-3, 250-215, AFD0080, 20202, AFD0080, 40014012: Alternators - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

a.co

You can get it out of many ford vehicles, but I like that this one comes with the correct pulley pre-installed. You will also need these two connectors:

Amazon.com: Standard Motor Products HP3910 handypack Voltage Regulator Connector : Automotive

Buy Standard Motor Products HP3910 handypack Voltage Regulator Connector: Voltage Regulators - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

a.co

https://a.co/d/0fcKzSqp

Lastly, you will need around 4 feet of 6 gauge wire and a 175ish amp fuse to replace the charge wire. If you look up “IDI 3g alternator swap” on YouTube you’ll get some great walkthroughs, it’s very straightforward.

 

[Zeroluck]

I’m no expert but don’t the different battery chemistries between lithium and lead acid necessitate different charging voltages and protocols?
it makes sense to beef up the alternator for vehicle battery but if you install lithium for house usage should it be a separate charging circuit?

You are correct. The solution to this is a DC-DC charger. They are basically buck-boost converters that take wide input voltage and output 14.6 (29.2 for a 24v lifepo4 bank).

Most of them shut off if input voltage goes below 13.8 so it doesn’t run when the truck is off.

 

[Clb]

Isn't there a 3g tech 101 here somewhere?
I thought I saw one once....

 

[Fredrickson]

I don't know if it would be more expensive, but is there an alternator/generator shop anywhere near you that you could check to see the cost of rebuilding one (the one you have or a "new-to-you" unit), and change the output profile for more amps at idle/lower RPM's, ramp up sooner and plateau quicker?

Given the RPM range of an IDI, match the power with the engine's sweet spot..

 

[Ruffnek7tree]

I have a mechman 240 amp alternator on mine, works like a wet dream.. lot of miles between 2 trucks over 8 years or so