Single-to-dual field alternator help:

[Captain D]

Hello all,

On my 69' Charger (383), I'd 'really' like to get an electric fan installed. If it's a key-on style, that's fine as I'm grateful for what I can get. However, I'm unable to install an electric fan as of yet because: with currently having only a single field 65amp alternator, a 72V voltage regulator, & EFI set-up + electric fuel pump, & an electronic ignition distributor kit...I'm maxed out.

Everything runs as smooth as butter, but in order to upgrade & get an electric fan, I'm learning that I'd need a dual field alternator (75-80amp) & dual field voltage regulator. For someone, such as myself, who has limited knowledge about this conversion...would someone be willing to please provide a checklist of what all I'd need, any links to what works best based on your experiences, etc.?

I tried to go this route a number of years ago, but the shop couldn't get all of their ducks in a row. As such, they dang near fried my wiring. If I'm going to give it another shot, I'm looking for drop in & go if possible since I probably won't be trying it a 3rd time (too much time & money involved). And, I don't mind spending a few Xtra bucks to ensure that it's not only right, but also reliable upgrades that we're putting in too.

Thank you for any and all replies...

[b5blue]

https://www.qualitypowerauto.com/pages/ChryslerMegaAmp.php  Call these guys. (I've a Denso 120amp and will still be upgrading to this.) This came highly recommended for best cooling: https://speedcooling.com/26-Big-Block-Mopar-Radiator.html

[Captain D]

I called Summit & got some info.

Alternator:

https://www.summitracing.com/parts/sum-812117

VR:

https://www.autozone.com/batteries-starting-and-charging/voltage-regulator/duralast-voltage-regulator-vr733/130203_0?rrec=true

Pigtail connector:

https://www.autozone.com/electrical-and-lighting/voltage-regulator-connector/duralast-pigtail-connector-harness-249/342383_0?rrec=true

Possible fans:

https://www.summitracing.com/parts/sum-g4903

https://www.summitracing.com/parts/mar-m142k

The only thing that is throwing me off is that the Voltage Regulator doesn't indicate how much it can withstand (from the 80 amp alternator). I certainly wouldn't want to be pulling, say, 80 amps and the Voltage Regulator is only rated for 75 then poof, there it goes. I noticed that the alternator says 12V compatibility, which I'm assuming the Voltage Regulator is rated for. I just never want to push anything to the max though.

Also wondering about internally regulated alternators for the sake of ease & convenience to bypass much of this - is it worth it...?

[Nacho-RT74]

You don't need a dual field alt, you need an alt able to feed the fan no matter if dual or single field. Just it happens all the alts able to feed that ammount of load began to be available when the dual field system become standard, not earlier.

You can get also stock alts used on 80s Mopars rated 78 amps on $50-60 ( i.e. Rockauto ) these are a bit wider ( by a couple of mm ) and they are able to feed into 45 amps rate at iddle. But for a fan requiring a 15-20 amps load I would go higher than the stock 78 amps alt. Something in between 100-120 amps which should be able to be on 60 or more amps rate at iddle.

Myself I'm toward to the Tuff Stuff alts option, although I have know couple of guys having a defective one but they were returned and replaced without any other issue.

You don't need to become your charging system into dual field since grounding one of the alt brushes will be enough to match it to your wiring system, HOWEVER, is true the dual field with the stock electronic regulator is more efficient.

You can also upgrade your mech regulator to the aftermarket electronic regulator designed to replace the old mech reg into a plug and play job and keep the actual setup ( grounding one of the brushes on alt of course as mentioned ).

[b5blue]

  Your adding 30amp load or so and you need the fan at very low RPMs or idle. Alt output is not constant, it is lowest at idle and goes up with RPM. The REGULATOR sees voltage not amps, it turns on the Alt. to increase amps thereby bringing voltage up.
 If you have A/C a pusher fan starts at the condenser (Like mine) so you'll need a strong one that fits. This fits offset of center to clear bracing on my 70. https://www.flex-a-lite.com/electric-fans/12-volt-electric-fans/flex-wave.html   

[Captain D]

Thank you gents for the reply + info = much appreciated. I'll be sure to check out the links...

I did find this unit during the search, which seemed cool (but, I'll also check out the link b5blue sent as well for a higher amperage unit as well):

https://www.summitracing.com/parts/pwm-175191/make/dodge/year/1969#overview

Meant to add earlier that mine is a non A/C car. Thanks again for all of the info...

[b5blue]

If for now the only issue is cooling use something like this: https://www.summitracing.com/parts/sum-g4918?  I ran one many years only changing when I added A/C because it would not clear the compressor's clutch. It pulls so much air a shroud wasn't needed. Check max size/rotation and spacers for fitment and I bet your happy. 

[John_Kunkel]

I'm a big fan of the Quality Power alternators, fit in factory brackets and use the factory regulator.

https://www.qualitypowerauto.com/item_557/Chrysler-Mount-Mega-Amp-Alternator.htm

I would suggest running a #6 wire directly from the alternator output terminal, across the core support, to the battery positive terminal. Doing this makes the ammeter useless so I install a small digital volt meter.

https://www.ebay.com/itm/124443415876?hash=item1cf967d544:g:UWAAAOSwgY1fs01H

[Captain D]

Interesting...

If I got one of those, probably the 150 amp max - 120 amp idle (internally regulated with single belt pulley) would be all that I would need, I would imagine.

My 69' doesn't have a cooling issue, but without a fan, it naturally heats up at idle, long red lights, parades, etc. which is why I need to get a fan in there for sure. Thanks again for all the input, gents ..

[Nacho-RT74]

No need to bypass the ammeter, just be sure to feed everything from alt post. Parallel wire up to amm to save issues with bulkhead conections is way enough. But, well, this is a long therm discussion with diff opinions.

Alt output remains constant as far load requested is constant and alt is able to source it. If your car at iddle request for 65 amps and your alt feeds 55 at iddle, those 10 amps will be provided by the batt ( discharge at ammeter ). Then when revving up the alt will provide the 65 amps requested by the car plus whatever load the batt needs to get fully recharged back... 5, 8, 10 amps while is not fully charged ( charge reading ) , and this is added to the car request while rpms are up... 70, 72, 75, depending on how much and how long the batt was getting discharged.

Need to note, the ammeter will read JUST those extra amps running to the batt, not the full alt output. Bulkhead however will be getting part of those amps if being sourced from inside the cab. If accesories are sourced straight from the alt post, the bulkhead won't get those loads, just stock equipment which is sourced from the main splice into the cab. Except if engine is off or alt gets damaged, when all the loads will be running through the bulkhead ( and ammeter )

[Nacho-RT74]

On a side note... I THINK there is some manufacturer offering high output stock appearence single field alts

[Captain D]

Speaking of the ammeter, this is the area that makes me a lil' weary - I actually don't go through the bulkhead connectors. With much of the stock wiring still in place within the car I may not be able to run any of the bigger alternators (65+ amps) because of still having all stock dash gauges. Therefore, would I run the risk of totally pegging out the ammeter with anything greater than stock amperage...?