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Truck alternators

mt-ed
Explorer
Explorer
I've noticed that truck manufactures offer alternators with different outputs. Can anyone please explain to me why a truck owner might want, or have the need, for an alternator that has these higher outputs? I'm assuming there is some need for it, but exactly what might these needs be?
Thank you very much for your help.
21 REPLIES 21

Kayteg1
Explorer II
Explorer II
time2roll wrote:


Dad had a lifetime battery.... replaced 3 times free before the car was stolen.


I had coworker who had 1 back in 1970's.
In his case the 4th battery got stolen.
There is company FCPEuro who sells everything with lifetime warranty, what include wears. They will send you new oil when you send them used one. I only wish they would sell toilet paper.
Ponzi scheme if you ask me, but since they charge $10 more for AGM battery than other places, I bought 1 from them, hoping that since batteries die in 2-3 years, I will get 2nd before they close the door.

time2roll
Nomad
Nomad
Eric&Lisa wrote:
bwlyon wrote:
...The thing to remember is that the battery in the car is a power reservoir used to start the car not run other electronics. The alternator is what runs the electrical components in any vehicle, and top of the battery after it has been used to start the engine. When you start running aftermarket accessories you can easily use all the alternator’s capacity and drain the battery, hence the need for an alternator with a larger output.


On a related note.... Had to replace a battery a few months back. I have always paid the premium for the "100 month" battery. I could not find them. Started asking around. With modern vehicles relying more & more on electrical/electronic systems and high power demands, the battery manufacturers were having a tough time meeting the 100 month warranty commitment.
Also I think people are keeping vehicles longer so the warranty has started to actually cost something.

Dad had a lifetime battery.... replaced 3 times free before the car was stolen.

Kayteg1
Explorer II
Explorer II
Eric&Lisa wrote:
Look at these golf-cart style cars that shut the engine off at every stoplight (stupid, IMHO). The car will then draw all its electrical load off the battery - radio, wipers, lights, HVAC, etc. A quick stab of the gas pedal and the starter hits it too. Then it gets 30-45 seconds of charge time before the next stop light. Yeah, that has got to beat the snot out of battery longevity.

-Eric


I actually love ECO stops as quite often we seat for 1.5 minute on red light, when in rush hr we need 3 changes to pass the intersection.
but in my Mercedes the "smart charging" is also recouping braking energy, so the battery is never fully charged to be able to take extra energy when available.
Not only car has 2 batteries for the system, but constant charging/recharging shortens the battery life. (isn't it working the same way in electric cars and hybrids?)
Still if I can save $100 + every year on fuel, I don't mind to spend $150 every 3-4 years on new battery.
2-tons Car makes 30-35 mpg in city driving.

Eric_Lisa
Explorer II
Explorer II
bwlyon wrote:
...The thing to remember is that the battery in the car is a power reservoir used to start the car not run other electronics. The alternator is what runs the electrical components in any vehicle, and top of the battery after it has been used to start the engine. When you start running aftermarket accessories you can easily use all the alternator’s capacity and drain the battery, hence the need for an alternator with a larger output.


On a related note.... Had to replace a battery a few months back. I have always paid the premium for the "100 month" battery. I could not find them. Started asking around. With modern vehicles relying more & more on electrical/electronic systems and high power demands, the battery manufacturers were having a tough time meeting the 100 month warranty commitment.

I guess it makes sense. Look at these golf-cart style cars that shut the engine off at every stoplight (stupid, IMHO). The car will then draw all its electrical load off the battery - radio, wipers, lights, HVAC, etc. A quick stab of the gas pedal and the starter hits it too. Then it gets 30-45 seconds of charge time before the next stop light. Yeah, that has got to beat the snot out of battery longevity.

-Eric
Eric & Lisa - Oregon
'97 Silverado K2500, New HT383 motor!, Airbags, anti-sway bar
'03 Lance model 1030, generator, solar,

Grit_dog
Navigator
Navigator
Similar to your gear ratio post, any OE alternator in any newer pickup (and for the most part older trucks as well) will sufficiently support and "charge" your camper batteries. Although realize the OE charging circuit is very low amp draw/capability.

If you get serious about on the road charging or install or employ a large converter, then greater capacity than some trucks offer may be needed.

If you're just plopping a TC on a truck, virtually all the components are sufficient to haul it save for suspension and tires, depending on the weight of the camper and the truck it's going on.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Grit_dog
Navigator
Navigator
^Wow! Hold my beer and watch this!
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Kayteg1
Explorer II
Explorer II
You definitely don't need more alternator for winch.
Don't know what rating my 1999 F450 had, but I had 8000lb winch on it and I was pulling 10,000lb equipment with it on high flatbed without starting the engine.
The dual batteries would drag the forklift with front plate scraping the concrete at the approach and still have enough reserve for engine starting.
And that was 7.3 powerstroke who on cold start would run on batteries for few minutes to protect glow plugs from high charging voltage.

time2roll
Nomad
Nomad
TxGearhead wrote:
I ordered my Ram with the highest single alternator, I think 180 or 200amps. Thinking I might someday get a winch. Someday...
Consider a MileMarker hydraulic. Uses power steering pump and maybe 2 amps from the battery to activate the controls.

TxGearhead
Explorer II
Explorer II
I ordered my Ram with the highest single alternator, I think 180 or 200amps. Thinking I might someday get a winch. Someday...
2018 Ram 3500 CC LB DRW 4X4 Cummins Aisin Laramie Pearl White
2018 Landmark Oshkosh
2008 Bigfoot 25C9.4
2014 NauticStar 21 ShallowBay 150HP Yamaha
2016 GoDevil 18X44 35HP Surface Drive

time2roll
Nomad
Nomad
deltabravo wrote:
time2roll wrote:
Put 200 watts solar on your truck camper and any base OEM alternator is fine.


I have 300 watts on my AF811

More often than not, I will travel with my inverter powering the AC function of my fridge. The solar and high output charging cables I did make that possible.

Solar and OEM charging wires from truck to camper would not support the load on an all day drive.
Although do you have the stock alternator?

deltabravo
Nomad
Nomad
time2roll wrote:
Put 200 watts solar on your truck camper and any base OEM alternator is fine.


I have 300 watts on my AF811

More often than not, I will travel with my inverter powering the AC function of my fridge. The solar and high output charging cables I did make that possible.

Solar and OEM charging wires from truck to camper would not support the load on an all day drive.
2009 Silverado 3500HD Dually, D/A, CCLB 4x4 (bought new 8/30/09)
2018 Arctic Fox 992 with an Onan 2500i "quiet" model generator

time2roll
Nomad
Nomad
Get the optional large or dual alternator if you are an outfitter building ambulances, tow trucks, Fire or police support vehicles, or some other commercial application.

Put 200 watts solar on your truck camper and any base OEM alternator is fine.

Kayteg1
Explorer II
Explorer II
Per my experience no winches and no inverters will run on alternator power alone.
They have high spikes and when alternator helps in recharging the battery, the power for high draw device has to come from battery.
Heck even my camper jacks will not operate on alternator. That's due the 30 amp charging wire, but still I need battery in camper to raise or lower 4 jacks.
Bottom line, it takes some calculation to make right call.
I was using 1500 W inverter for oven power -with single battery on my boat having 30 amp alternator. But boat did not have any other power draw, so the 30 amp was used for recharging in 99% and boat run at high rpm most of the trip.
Now if you have battery bank to power your AC and want to recharge it in 20 minutes, you need 200 amp alternator.
Actually I am thinking about doing such setup on my Sprinter.
120V AC on the roof, 2 house batteries with 1800 W inverter and the van 250 A alternator should keep the system running.
The 4-cylinder diesel in van probably sips less fuel than most RV generators.

deltabravo
Nomad
Nomad
mt-ed wrote:
Can anyone please explain to me why a truck owner might want, or have the need, for an alternator that has these higher outputs? I'm assuming there is some need for it, but exactly what might these needs be?


Higher output = more charging amperage.

There's also trucks with DUAL alternators, which my truck has
2009 Silverado 3500HD Dually, D/A, CCLB 4x4 (bought new 8/30/09)
2018 Arctic Fox 992 with an Onan 2500i "quiet" model generator