3G Upgrade Important Information

[wayne marks]

I'll try to keep this short and simple. I believe most 3G upgrades are for sufficient ampacity at idle, not just for more ampacity in general. It upsets me to see the number of vendors that display 3Gs and right beside it will be a 100+ amp fuse and holder, implying that this is what you need for a 130 amp alternator. If you fall for this implication you will be putting your EB at great risk. The EB wiring harness was designed to carry 60 amps maximum. The 3G is capable of delivering 90 amps at idle...Great, but the short circuit protection for your wiring harness must not exceed 60 amps. If you install a 100+ amp fuse and develope a major short circuit your harness will melt, and probably set the vehicle on fire, before the fuse ever blows. I have a 3G on my EB but my fusable link to the black/yellow wire is 50 amps and that is sufficient. If you do have high amp equipment connect it directly to the battery (+), with the applicable fuse size, but do not connect the vehicle harness to a fuse larger than 60 amps or you may experience the great melt down.

 

[Old-Red]

What are your thoughts on the single wire 3g alternators on ebay? Would this be a way around the limit on the original wiring harness for a Bronco? http://cgi.ebay.com/ebaymotors/FORD...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Thanks

Kevin

 

[chuck]

I'll try to keep this short and simple. I believe most 3G upgrades are for sufficient ampacity at idle, not just for more ampacity in general. It upsets me to see the number of vendors that display 3Gs and right beside it will be a 100+ amp fuse and holder, implying that this is what you need for a 130 amp alternator. If you fall for this implication you will be putting your EB at great risk. The EB wiring harness was designed to carry 60 amps maximum. The 3G is capable of delivering 90 amps at idle...Great, but the short circuit protection for your wiring harness must not exceed 60 amps. If you install a 100+ amp fuse and develope a major short circuit your harness will melt, and probably set the vehicle on fire, before the fuse ever blows. I have a 3G on my EB but my fusible link to the black/yellow wire is 50 amps and that is sufficient. If you do have high amp equipment connect it directly to the battery (+), with the applicable fuse size, but do not connect the vehicle harness to a fuse larger than 60 amps or you may experience the great melt down.

My fuses are not next to the 3G so I guess you are not referring to my site. Anyway, the fuse I sell is 175A and the breaker is 150. As wired in my drawing (alt. to battery)the fuse/breaker only protects the Alt. The output of my alt. can go up to 167A so a lesser fuse will blow when the battery is very low. The battery is capable of putting out a lot more amps, maybe 400-800 amps depending on internal resistance so the EB load is protected by the fusible link which should blow if there is a short in the EB and doesn't matter if the amps are coming from the battery or the alternator. I guess it all comes down to where that fuse is.

 

[Viperwolf1]

Wire the alternator output directly to the battery and bypass the stock ammeter loop. Then you don't have to put the current limiter (fusible link/fuse) on the alternator.

 

[av bronco]

I understand your point, I hope that most people understand NOT to cut the stock fuseable link out when they do a 3g install and I think the fuse the vendors sell with the kit are supposed to go on the charging wire from the alt. to the batt. personally I dont run a fuse on my charging wire, it's short and very well insulated, my feeling is theres a chance of restance or failure with a fuse, connectors, and fuse holder vs a straght wire from the alt to batt.

 

[Viperwolf1]

Right. Always use a fusible link going to the accessories inside the cab. I clarified my response above.

 

[wayne marks]

You are all correct. As BCB said, "it all comes down to where the fuse is". I have seen people install the mega fuses upstream of the EB harness and this is what I was trying to prevent. Mega fuse between the 3G and the battery is a safe set up. The important thing is that people understand that short circuit protection for the vehicle harness should not exceed 60 amps.

Chuck, your excused from the afore mentioned.

 

[1sicbronconut]

I understand your point, I hope that most people understand NOT to cut the stock fuseable link out when they do a 3g install and I think the fuse the vendors sell with the kit are supposed to go on the charging wire from the alt. to the batt. personally I dont run a fuse on my charging wire, it's short and very well insulated, my feeling is theres a chance of restance or failure with a fuse, connectors, and fuse holder vs a straght wire from the alt to batt.

As a Ford tech for over 20 years I've seen quite a few alternators short internally and blow the mega fuse. I've seen it happen enough that I wanted protection on that circut for my rigs. If uyou don't want to go the mega fuse route and have acess to a junk yard get a alt power lead from a newer Ford lot's of them have built in fuseible links or mega fuses in them.

 

[chuck]

As a Ford tech for over 20 years I've seen quite a few alternators short internally and blow the mega fuse. I've seen it happen enough that I wanted protection on that circut for my rigs. If uyou don't want to go the mega fuse route and have acess to a junk yard get a alt power lead from a newer Ford lot's of them have built in fuseible links or mega fuses in them.

That's what I'm talkin bout

 

[1sicbronconut]

Cheap insurance when you think about a short with maybe 140 amps under your hood.

 

[chuck]

If the Alt. shorts you will have the full battery amps feeding the short and that would be 400+ amps, depending on resistance and battery. That is why when a alt. shorts you get fire. The only one that happened to me the battery cable insulation melted before the (+) post melted off saving my 65 chevy pick-up. Yes it did have a alt.

 

[methcat]

I have a 3G on my EB but my fusable link to the black/yellow wire is 50 amps and that is sufficient. If you do have high amp equipment connect it directly to the battery (+), with the applicable fuse size, but do not connect the vehicle harness to a fuse larger than 60 amps or you may experience the great melt down.

i noticed viperwolf and a few others suggest just bypassing the black/yellow wire (37), isn't this the same lead that supplies power to the fuse block and headlight switch? if it's bypassed, how are people getting power to the lighting switch? wouldn't whatever link that is, still need the 50amp fuse?


c

 

[TOFIC]

Interesting conversation, I wonder what RRRAAAYYY222 has to say about this whole issue?
TOFIC

 

[70_Steve]

i noticed viperwolf and a few others suggest just bypassing the black/yellow wire (37), isn't this the same lead that supplies power to the fuse block and headlight switch? if it's bypassed, how are people getting power to the lighting switch? wouldn't whatever link that is, still need the 50amp fuse?


c

The Black w/Yellow wire (37) and the Black wire (38) form a loop (Ammeter loop) from the output of the alternator, through the ammeter, and back thorugh the fuseable link to the BAT+ side of the starter solenoid. Yes, along that loop are connections to the fuse panel, headlights and other accessories. If you disconnect the alternator end of that loop, the loop is still fed through the fusable link.

My Bronco had the fusable link replaced by a circuit breaker. I tied both ends of "the loop" to one side of the circuit breaker, with the other tied to the BAT+ side of the solenoid.

 

[Viperwolf1]

i noticed viperwolf and a few others suggest just bypassing the black/yellow wire (37), isn't this the same lead that supplies power to the fuse block and headlight switch? if it's bypassed, how are people getting power to the lighting switch? wouldn't whatever link that is, still need the 50amp fuse?

Actually the black-yellow wire carries current from the alternator through the ammeter loop, inside accessories and out the black-red wire to the battery. The black-red wire has (or should) the fusible link. Keep the black-red wire in place and cut out the black-yellow and you'll have protected current to everything except the ammeter. The alternator will now need a large gauge (6 is good) wire from it's output directly to the battery. What this accomplishes is it eliminates all the alternator's output current (now 100+ amps) from passing through the black-yellow/black-red loop which was designed to handle a maximum of maybe 65 amps.

 

[Heus33]

Does anyone have some pics of their install for simple minded folk like myself? I'm getting a 3G delivered today and want to install it correct, the first time.

 

[Ryan]

Every Ford from 1997-up has a 175A fuse between the BATTERY and ALTERNATOR (some police cars and ambulances have even larger fuses). There is NO RISK using that setup on older vehicles.

The fuse is there to protect the battery and sensitive electronics from the alternator. If it shorts or goes to full field, it can boil the battery and fry the electronics.

The fuse is not there to protect the individual power circuits feeding the main fuse block.

 

[70_Steve]

Does anyone have some pics of their install for simple minded folk like myself? I'm getting a 3G delivered today and want to install it correct, the first time.

Did you get a harness with it?
The 3G wiring is pretty simple. The output of the alternator goes to BAT+ and it needs a hot-in-run. That would be the Green w/Red stripe wire that will be left over after you remove the voltage regulator and associated wiring.

 

[Heus33]

Did you get a harness with it?
The 3G wiring is pretty simple. The output of the alternator goes to BAT+ and it needs a hot-in-run. That would be the Green w/Red stripe wire that will be left over after you remove the voltage regulator and associated wiring.

Thanks Steve - yes I got a harness with it. I'll take a look at this diagram and line it up with the new alt when it comes in. Don't want to detract from this thread so I'll go back into lurk mode now...

 

[73stallion]

that diagram lists an optional charge light, is that referring to an idiot light?