What Size Alternator Can You Install?

[rlhedlund]

I have a LMM diesel with 125 amp alt. Gm sells a 125, 145 and 160 amp per my dealer. Have called 4 dealers and ACDELCO. No one will tell me if I can install a higher amp alt than the one in my truck.

[Mike Clay]

Now you have me looking for my sticker, I think I have a 125 amp in the LML also, I know I did in the LMM. Why do you want to go to a larger one?

[rlhedlund]

Faster recovery in the cold mornings after cranking the diesel. My accessory outlets are dead until driving down the road for several minutes.

They have no power until the system voltage recovers from a start. I just installed two new batteries that have higher CCA ratings than the OEM. recovery is better, but I would think a higher amp alternator would recover quicker.

I am disappointed the original batteries (one was bad) did not last longer.

[rlhedlund]

I also run a lot of extra lights. I also use juice sitting with engine off and was looking for faster recovery times. Or will that even happen?

[BMullins46]

I was looking at a Dodge window sticker today, the truck had the snow plow kit on it and part of that kit was a 180 amp alternator, so I would think you could add a larger alternator if you wanted.

[snoking]

My guess is that you have some other issue if you have dead outlets after starting the engine. You may want to leave it over night at a dealer so that they can look at the issue. Even in my old Dodge that continues to cycle the grind heaters after it starts, everything works. Voltage gauge goes up and down about 3 volts with the grind heaters.

Sounds like maybe the Alt you have has a voltage regulator problem.

Chris

[Mike Clay]

I agree with Chris my 08 and the 2011 the outlets work while the glow plugs and def heaters are running

[Diesel Dave 04]

you can go with the highest amp that they make for your truck. I went to a 205 on my 92 bronco that i plow with.

[rlhedlund]

Only the CENTER CONSOLE accessory outlet is dead until the voltage output reads over 12.5 volts. Everything else works to my knowledge. The accessory outlet on the DASH has power for my extra 12V heater.

I know the extra heater pulls a lot of power as it has a 20 amp fuse inline.

When I start up in the cold mornings with all the lights on, the scan gauge reads 11.6 volts or so.

I also notice my headlights and/or fog lights and/or extra driving lights brighten up at the same time the accessory outlets fires up.

Once I am down the road a ways, the voltage reads 14.2- 14.4 and stays there.

I would think I could go with a higher output alternator, but GM won't agree. They all say it is not recommended as it may blow something. I can't imagine why they would sell them, but they say only the factory can install them. ???????? The dealer will only install what came from the factory.

[Mike Clay]

If you start these trucks up on a cold morning and take off down the road it takes a while until the glow plugs shut off. My Dodge use to shut off the grid heater around 15 mph if i remember right but the Chevy (dont know about the Fords) with the glow plug setup takes awhile. The 14.4 V is normal and when you get on the road for a long trip it will drop down to the 13 ish range. If its a real cold morning you could put your truck on a timer and plug it in for four hours before you leave. I have the remote start on mine and if its cold the high idle comes on since the truck not only is running the glow plugs but the DEF heaters, mirror heaters, seat heaters and so on to make it nice and comfy for me .

[Rob & Cathy]

Once I am down the road a ways, the voltage reads 14.2- 14.4 and stays there.

I have a scan gauge too and mine will go to 14+ after startup but then returns to 13s after a little driving. Have you considered a bad battery(ies)?

Rob

[bigbunkhouse]

The fORD glowplugs stay on up to 2 minutes depending on the oil temp. the older trucks you could see the voltmeter drop and stay there till the glow plugs turned off. as far as 14.4 ish, that is perfectly normal and dependent on the settings of the voltage regulator, most will regulate somewhere in that range regardless of load, if all is well. my guess is that the power accessory outlet is somehow linked to voltage and turns on at a specific voltage, it is probably somehow regulated by a transformer or other device to protect anything that is pluged into it. The glow plugs or fuel heater or intake air heater are probably drawing enough current to keep the line voltage down enough to keep the power off. Somewhat like a fluorescent light, ever tru dimming a CFL? drop the voltage just 20% and it just shuts off.

As far as larger alternators, we have for years asked for the AMBULANCE package alternator at the local NAPA when we put accessories like electric hydraulic plows, dumps, etc and need more amperage. For example the 96 bronco we plow with now has 2 1085 AMP batteries and a 185amp alternator when the biggest they list is a 95 amp. It has a 5.8L gas and I just asked for a 96 E350 5.8L AMBULANCE package and voila more power. Your not gonna melt anything because the regulator controls what happens

[rlhedlund]

Once I am down the road a ways, the voltage reads 14.2- 14.4 and stays there.

I have a scan gauge too and mine will go to 14+ after startup but then returns to 13s after a little driving. Have you considered a bad battery(ies)?

Rob

Two brand new batteries. After the truck was dead in December. One battery looked like it had been hot.

[Rob & Cathy]

Two brand new batteries. After the truck was dead in December. One battery looked like it had been hot.

In a previous post you mentioned that your alternator is producing 14+ volts and staying there. I think that should be checked out. If your trailer convert was doing that you would eventually over heat your batteries.

Rob

[Mike Clay]

If you are only taking short hops in the winter it will pretty much stay there