I have 2 slots for alternators and want to add another high output alternator in the blank spot.

I have a FICM with low main power voltage (30 volts at start) and suspect that batteries and alternator may be the culprit(s). I want more charging power for the starting batteries to prevent the FICM from failing and add a second alternator to charge the house battery for my electronics.

Does anyone know how to add a second alternator to isolate a 3rd battery for house power? I have a battery isolator/charge controller ready to go.

My plans are to buy a high output alternator the for starting batteries. What if I buy the highest output alternator and use it to the charge 3 batteries?

We use the van for camping and run a small 12v fridge/freezer. I have a 180 amp hour AGM battery and plan on adding a 100w solar panel on the roof.

 

Well other than the belt and pulley parts you may also need the (at least on a truck you do) the CAC and HVAC
lines so that the alt has a pocket to sit in. You may not but be ready in case you do. Not sure how the PCM would feel
about a split system.It normally sees a signal from each alt to tell it that all is OK but if split not sure what would
happen. I'll see if I can find a diagram to post of the charging system.



Sean

6.0L Tech Folder

 

If you get al the components like Sean suggested, the cac tube, puleys and such then I do not see why you could not wire it up as a seperate charging system for a house battery. It may take some simple wiring but as long as the alternator turns you can make it charge a house battery.

If you want to have the dual alternator system to charge the engine batteries I do not think there would be any necessary pcm changes as the re is a connector, on the pass side inner fender, that has a green jumper wire, iirc. That would have to come out and the proper wiring installed.

As for adding a third battery to the dual battery system, it should work but I would advise against it. You would not want to drain your entire battery system while camping and not be able to start the truck. The house system should use a seperate battery bank.

 

I have an isolator so there is no worry about draining the starting batteries. I can use the fused auxiliary trailer battery relay and tie into it to charge the 3rd. This relay is a battery separator. I bought a CTEK D250 charging isolator. I have it tied into the auxiliary battery relay on my e150 van. My concern with the 6.0 is that it's more dependent on the starting the batteries and needs a high output alternator.

I like your idea about combining alternators. I have the shop manuals. I am no mechanic or ee, but I can copy other people's ideas.

If my OEM alternator tests bad I want to know if it would be.okay to install a high output alternator to charge both systems?

 

There are some threads around here about people installing 250 amp alternators as well as some G3 bodied alternators, I think I got that right. It mounts right up but has a higher output than the high ouput ford unit for the truck. There are many options. I think the easiest would be to just install a 250 amp aftermarket single alternator than to install multiple alternators unless you want to keep the 2 systems seperate.

 

Macrosill,

I find the PCM voltage readings through the port to be p*** poor. Yeah, you can have a full volt down from actual. If you want to know what the alternator(s) are doing you have to use a voltmeter at the battery terminal and ideally, also with an ammeter. As an alternate you can read voltage from a power port, but it will be down somewhat depending on how good the harness connections are.

If your seeing a good amount of variation, do this:

• Clean battery terminals including the bolt-on connections.
• Clean the negative cable connections at the lower pass engine block and pass frame rail.
• Pull the drivers air filter, battery, battery tray and clean the negative cable connection at the drivers frame rail. At this point I highly recommend also installing a 24" 1/0 cable between that frame rail connection and the engine block where there are bosses at the head.
• Clean the sheet metal ground connections by the passenger battery and drivers battery ( drivers is above the headlight. Also install an 8ga wire from that sheetmetal connection and the drivers battery negative terminal.
• With the drivers battery out pull the PCM three connections. If you have a contact cleaner like DeOxIt use it on those connections. If you don't connect and reconnect them three times to wipe the contacts clean.
• Pull and reinstall all fuses and relays your truck has for FICM and PCM power. This also wipes clean the contacts.

All of these will help clean up any system voltage drops and it's the most you can do without working on the contacts at the FICM itself, which for some can be fragile. And the other possibility is to change the FICM relay so that item has good contacts as others have recommended. I change mine every 100k.

I've seen the SG voltage drop at the start of a FICMs failure despite system voltage being fine. But if might just be the funkiness of the system rather then an impending FICM failure.

 

There is no need to back fit a second alternator when good high output single units are available. If you want to install a third isolated battery PM Bismic as he has done it.

 

I might be wrong but I think only the secondary alt. is commanded by the PCM. Correct me if wrong.

 

I'll look at it tonight. But I know that it does show the error status.
I'll take a photo of the active command screen and post it with the
right things marked.



Sean

6.0L Tech Folder

 

I plan on getting a 250 amp high output alternator that has enough current to charge all 3 batteries. The CTEK D250S functions as an isolator and charger.

Any suggestions for a high output alternator?

Too Many Toys recommended :"Pull the drivers air filter, battery, battery tray and clean the negative cable connection at the drivers frame rail. At this point I highly recommend also installing a 24" 1/0 cable between that frame rail connection and the engine block where there are bosses at the head." Is this for the frame mounted battery? I have 2 frame rail mounted batteries. It's a nice set up until one has remove, test, or modify them. I need to drop both batteries and inspect the cables.

I am still curious about the second alternator spot. If I can find a use for it, I will install the stock alternator there if the hole pattern is the same.

 

Should I test the FICM voltages with my volt meter before I send it back in for repair? I was trusting the ScanGauge II.

FICMrepair is going to load the Atlas 40 tune.

 

You have to get the lower ALT a top one won't fit there.

As for the FICM why test it if your sending it in?



Sean

6.0L Tech Folder

 

I feel like a dumb@$$ if I send it in and ask them to the test the voltage. I called FICM repair and they said they would test it before programming. If it's toast, I will get the premium repair service.

 

Coolfeet,

My response was to Brian with his F350 and seeing a voltage drop. E's are different, but let me take a look at what have in my files.

 

Coolfeet: You might want to take a different approach, or at least do the analysis: Do you guys watch TV at night, run lights for reading (if so switch them to LEDs), and other things besides run the small refer (likely your biggest draw)??

I'd first calculate your max theoretical overnight drain and see if you can't solve this just with solar/batteries/inverter, and skip the whole alternator thing, which by the way, is also an increased power drain on your engine (it takes HP to run bigger or more (working) alternators).

We've had 3 campers set up with solar now and recently got an older motor home, which I plan to put Major Solar on. I picked a specific type of panel as we do a lot of dry camping, but like your van: space is limited on a slide in camper. The type of panel is a layered Amorphous silicon made by a company now out of business (Uni-solar). I've used PWM charge controllers up until now but will go with a MPPT type unit on the MH (main advantage is I can run higher voltage panels and keep the wire size reasonable). The panel we have on our current camper is rated at 64 watts, which seems paltry, however in real-world use, it makes power even when the sun is not up yet, after sundown, in the clouds, under trees -- you get the idea. Down side of this type panel is foot print (larger), but upside of making power in almost any condition except night, and durability of tree branches, hail, you name it -- won out.

There has never been a day I can remember that our little group 24 Costco Marine/Deep cycle battery hasn't been fully charged by nightfall, and that includes whatever else we do during the day. Oh, and I never have the truck charge the camper anymore...

This is just a tangent for you to consider -- you may not need to replenish as many amp hours as you think, and while solar has a higher initial cost (but if you shop well can be minimized), then the power is "free".

You can find the peel and stick versions of Uni-solar panels still and those will have little to no aerodynamic downside.

And just to be fair: there are other thin film panels out you can stick on your roof, but I have yet to find one that can handle impact (think 16" falling pine cone) like the Uni-solars can. Pity they went out of business, but because of that the price of their panels is down...

well good luck and sorry if I put the rest of you to

Well probably not Jack