Ambulance dual alternators? keep or toss?

[rubberduck]

Have any ambo guys that gut all the power hogging stuff removed the second alternator? Trying to decide if going to the single truck style would be easier to find parts in the future.

 

[java]

It should still be a pretty standard alternator as far as I'm aware. I would not remove it personally. You have lots of built-in charging capacity, why get rid of it?

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[rubberduck]

Never really looked into availability of the alternators. We had a fairly tough time finding a belt when the vacuum pump ate the last one. Just pondering the ease of finding emergency parts.

 

[java]

Never really looked into availability of the alternators. We had a fairly tough time finding a belt when the vacuum pump ate the last one. Just pondering the ease of finding emergency parts.

Interesting, I figured as a factory option parts would be easy. I guess I should buy a spare belt....

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[rubberduck]

Napa had one in stock. But a good idea to have a spare to save all the searching.

 

[Brewdiak]

i think i'd take it off - most of the stuff i'd use on my truck isn't when the engine is running anyway, and the drag of the extra alternator = ?mpg? loss?

if it's cause for concern, extra repairs, etc then i don't think it's worth having imo

 

[rubberduck]

i think i'd take it off - most of the stuff i'd use on my truck isn't when the engine is running anyway, and the drag of the extra alternator = ?mpg? loss?

if it's cause for concern, extra repairs, etc then i don't think it's worth having imo

Those are my thoughts as well. Hoping someone had already done it.

 

[luthj]

Not an ambo guy. However, there is a good reason to keep the second alternator. You can isolate the second alternator from the engines electrical system. Then connect an external regulator for the alternator. Then use the second unit as a dedicated charger for your Aux battery bank. By using an external regulator, you basically turn the second alt into a temperature compensate 4 stage smart charger. This can really boost your charge rates, especially over long wire runs, and you don't have to worry about high voltages that might cause issues with the engine/drivetrain electrics.

This is a pretty common approach on boats. On some van RV conversions, and even larger RVs/expo rigs, a second alternator like this is the preferred method. In some cases your alternator can be replaced or rewound for mega amps (200A+), which allows running beefy AC units etc directly from the engine if needed.

 

[rubberduck]

Not an ambo guy. However, there is a good reason to keep the second alternator. You can isolate the second alternator from the engines electrical system. Then connect an external regulator for the alternator. Then use the second unit as a dedicated charger for your Aux battery bank. By using an external regulator, you basically turn the second alt into a temperature compensate 4 stage smart charger. This can really boost your charge rates, especially over long distances, and you don't have to worry about high voltages that might cause issues with the engine/drivetrain electrics.

This is a pretty common approach on boats. On some van RV conversions, and even larger RVs/expo rigs, a second alternator like this is the preferred method. In some cases your alternator can be replaced or rewound for mega amps (200A+), which allows running beefy AC units etc directly from the engine if needed.

Hmmmm, now I have more research to do.

 

[Brewdiak]

Not an ambo guy. However, there is a good reason to keep the second alternator. You can isolate the second alternator from the engines electrical system. Then connect an external regulator for the alternator. Then use the second unit as a dedicated charger for your Aux battery bank. By using an external regulator, you basically turn the second alt into a temperature compensate 4 stage smart charger. This can really boost your charge rates, especially over long wire runs, and you don't have to worry about high voltages that might cause issues with the engine/drivetrain electrics.

This is a pretty common approach on boats. On some van RV conversions, and even larger RVs/expo rigs, a second alternator like this is the preferred method. In some cases your alternator can be replaced or rewound for mega amps (200A+), which allows running beefy AC units etc directly from the engine if needed.

hadn't thought of that - definitely a consideration though, i have no idea on my rig how long/rpm's etc it would take to recharge the batteries. i don't 'intend' to use a ton of house battery power, and i also don't have any idea what the 'parasitic' loss of the 2nd alt would be on the engine. good points though ... if there's already a 2nd alt it may be worth doing this mod to take advantage of it.

i wonder how many newer ambos have 2 alternators now that lights are LED? way back in the day of revolving halogen/flashing halogen the power draw to keep everything running was horrible - i can recall having to turn off my old smith/wesson lightbar on a 89 crown vic so i could actually get it up to speed before turning the 'grinder' back on (it sounded horrible like i was mixing pina coladas up there)

 

[eporter]

My ‘97 ambo had the huge 215 amp Mitsubishi alternator. I had it rebuilt when it went bad. Those things aren’t cheap to buy new! It might be easier to find one or two smaller alternators if needed on a road trip. Can you get a smaller belt that lets you just run one? Then you could do the main/house charging setup, and swap the good house alt over if needed.

 

[luthj]

Another option to reduce alternator drag is to swap in an under-drive pulley. This will reduce the alts output at idle, but overall drag (due to bearings/fans) will be reduced. You would need to adjust your belt size slightly, but thats a pretty simple calculation.

 

[SpeedHighway46]

Rubber duck: if you could see me now you would see me all green . . . with envy! The one last mod I want to make to my rig is to add a second alternator!

A trip to the local Caterpillar Dealer to check if they make a kit to add to my model engine; and if they do, can I afford it. Otherwise, perhaps I can fab one.

Plan is for one alt to feed the stock electrical system, and the second one to feed the house system. And of course, having complete redundancy in case one fails.

Heavy electrical demands and having a second alternator would be more than worth the added drag and slight reduction of mpg.

I would make the second alternator exactly like the first one; same capacity and same mounting style. That way, one can be substitutef out when failure occurs by using the old fan belt.

I have not seen your installation, but I would advise you to keep it! The one failure I had when 350 miles from home was my alternator; barely made it. The replacement unit was only abt $150. A lot cheaper than a tow job ($1000).

Two alternators- awesome! I’m jealous as hell.

Good luck with your ambo project!

 

[Bikersmurf]

Keep... I’ve only got one... 215A, 30 lb one. The plus side for you is you’ve got a couple of $200 alternators available anywhere vs one $1000 alternator that Ford doesn’t have stock of anywhere in North America!

 

[dwh]

Keep.

Drag is a non-issue...

With no electrical load (resistance), the only drag it puts on the engine is whatever it takes to overcome the resistance of the bearings (almost nothing) and for its fan to blow some air - i.e., not much drag.

If you apply a 1,000 watt load, the drag on the engine will be basically the same whether it's one alt servicing 1,000w or two servicing 500w each...

But split between two, they'll run cooler and last longer.