Florida31623

Please forgive my lack of Ford technical expertise. I have a 2020 F-150 XLT, 3.5 EB. I was told that it’s alternator has a rated output of 200 watts. Since the “onboard generator” wasn’t offered in 2021, I asked and was told that it could not be retrofitted with an inverter as supplied as an option on the 2021 models. I only need 2,000 watt output on the inverter. Anyway, I found an alternative called a Car Generator. They make a 2,000/4,000 watt surge model but say to consistently provide power, it must have a high output alternator (165 watts at idle).
I asked the service manager at my local dealership if the alternator could be upgraded or if the software in the F-150’s would fail to function properly if the alternator were upgraded. I got the usual answer: I don’t know, we’ve never done that and Ford doesn’t allow…….
So does anyone know if the Ford software cares what size alternator is installed or will upgrading the alternator cause a problem?
I could perhaps purchase the Ford 2,400 watt inverter which mounts under the rear passenger seat (so I am told) and wire from the battery to it, and from it to the cargo bed and install an outlet in the wall of the bed, but it still is dependent on the alternators ability to supply adequate power.

Shane803

I replaced my 2020 Raptor's alternator with a Mechman370 due to my stereo system. It has a smaller pully as well which requires a 1" smaller belt. I also did the "big three" wiring upgrade which should also be done at the same time.

BareBonesXL

You might doublecheck your units. Amps or watts. 165 watts is only 13.75 amps at 12 volts. Pretty sure the Ford guys told you 200 amps, not watts, but not sure what the Car Generator guys told you.

Florida31623

Yes, I could be wrong about units. The Car Generator techs told me that I needed 165 amps output from the alternator to insure continuous 2,000 watt output from the Car Generator’s inverter. But he also told me that the alternator’s output at idle would be 1/2 it’s rated output. That would mean that my 200 amp (assuming I was told correctly at the dealership when they looked up the VIN) would be providing 100 amps at idle, not 165. But I am guessing from responses here that upgrading to a higher output alternator will not require a software upgrade, which Ford will apparently not allow its dealerships to do. The air conditioner in my travel trailer has a soft start and when running, pulls 9 amps according to the trailer’s electrical management system. Living in Florida, if I find myself without shore power and it is 90° at night, I would like to cool the trailer down so I can sleep. Since the A/C only pulls 9 amps, by my calculation the 2,000/4,000 surge inverter should be adequate for what I am hoping to do.

laterongc

what kind of differences did you notice after completing these upgrades?

and, if you did the big 3 first/separately, were there noticeable differences from that alone?

Shane803

I didn't do before and after voltage readings to be honest. I just knew I was gonna need them with the power I was running.

Florida31623

Yes, I wasn’t thinking when I said watts. My alternator output rating is 200 amps. Car generator has specifically stated that the 2,000 watt AC output model requires an alternator with 165 amp output at idle. I have been told the 200 amp alternator puts out 1/2, or 100 amps at idle.

Still, nobody has answered my most important question and that is will upsizing the alternator be compatible with the F-150’s module software?

I am a bit gun shy because my previous F-150 developed starting and other problems after a nearby lightning strike. It was in and out of the shop for 4-1/2 months and the parts changers couldn’t figure out how to fix it. It cost me a tidy sum to replace the vehicle and I do NOT want to play that game again, so I’m a bit concerned if an alternator upgrade will cause unforeseen problems.

mikeinatlanta

Do you have the need to run while driving? Best practice for an idle only system is a separate alternator on its own belt with an electromagnetic clutch (like a lawn mower clutch).

Florida31623

No. Will only need to idle when stopped. Don’t want a separate alternator when one will suffice if an upgrade to a higher output alternator won’t affect the truck’s so-called software controlled electronic brains. So far, no one has answered that question.

JaseBosto

You need a bigger alternator than 200 amps?
Do they even make an alternator that will produce 165 amps at idle? What are you trying to run off your inverter?