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Ok everyone, this is REALLY wild, but worth at least analyzing.

Reviewing my objectives (your might be different):

- I need 12 volt power for the air conditioning clutch & for things like a 12 volt auxiliary power outlet

- I'd prefer to keep as much of the existing voltage infrastructure as possible unchanged, since changing would cost money for each item and professional labor for some(parts and/or labor for: overdrive solenoid, possibly overdrive relay, horn relay, horns (eventually), all bulbs, flasher, potentially Runtz resistors for some instruments,starter motor solenoid)

- I need new wiring anyway (old and fossilized) so new wiring harness will happen regardless of anyhting else

- I want an alternator with its built-in solid state regulation and high output even at idle (MUCH better output at and near idle than a generator).

Given these, how about this scenario:

- New wiring harness

- 12 volt alternator

- 12 volt AC clutch

- 12 volt auxiliary power outlet(s)

- "12/6" battery from Antique Auto Battery

Let me explain:

The existing battery tray holds a battery that is 6 3/4 " wide x 10 1/8" long x 8" high plus 1" posts("GROUP 24".

Antique Auto Battery (1-800-426-7580 "Delores" x7)has:
(All batteries are 8" high standard plus 1" for posts)
12/6 Group 24 $210 with CCA = 400 to 425 "on each side", OR, if you can provide a larger battery tray (there is room):
12" L x 6 ?" W 12/6 battery with CCA = 450 "on each side" for $210.

The way Delores describes it, a 12/6 battery has 1 ground terminal and 2 voltage terminals. One of the voltage terminals at end of the battery opposite the ground terminal provides 12 volts. The other voltage terminal is between the 3rd and 4th cells on the battery and provides 6 volts. Loads can be connected to the "6 volt side" or the "12 volt side". This is what Delores means when she says "x" cold cranking amps available " on each side".

Delores says I would need to run a 12 volt alternator with this, but could tap off 6 volts for most loads (including lights, instruments, radio, overdrive solenoid). The 12 volt terminal would be used for 12 volt loads, like the AC and the auxiliary power outlets, and the STARTER. The starter SOLENOID would stay on 6 volts, so would not need to be replaced. The 12 volt power to the starter should greatly improve starting (even though it is excellent even now on 6 volts).

The advantages of this scenario? Cost and simplicity. The costs and changes required are:

- New wiring harness (which I want anyway)

- 12 volt / 60 amp alternator with built-in slid state regulation replaces 6 volt generator AND regulator - about $205 plus shipping at worst, and the power output is 33% higher than the generator made at its PEAK

- 12/6 battery for $210

There is one potential flaw: I'm not sure that "one side" of the battery, which means 400 to 425 CCA, is enough to reliably start a 288 cubic inch inline 8 under adverse conditions. I'm not sure that I understood Delores properly when she told me about this "one side" stuff, and they are now closed for the day so I need to clarify tomorrow.

The Packard service manual describes the original STOCK battery only as "17 plate, 100 amp hour". I'm not sure of the CCA capacity of my current 6 volt aftermarket battery.

I need to investigate a bit more . . .

Jim G

On another thread, Bob1951 has suggested that perhaps two separate 6 volt batteries could be used, and charged by having them in series.

The two "conventional" batteries would cost less than the one "12/6" battery, and would be easier to replace anywhere too.

Delores told me (I think, if I understood correctly), that with the 12/6 battery, you can indpendently charge each half of the battery with a 6 volt charger, if one side gets run down because of more use than the other. So, the answer COULD be "yes".

I don't have a clue on that. Bob is saying he might be able to find out.

Jim G

Jim,

A complete repro 6v harness will probably set you back over $1,000.

A universal GM style 12V harness with a modern fuse box and extra cicuits for the A/C, etc. can be had for less than $200. Also most of the wire colors on a GM harness are an exact match to the Packard harness (Packard Electic made both harnesses for Packard and GM)

You can't really use a 12v harness for 6v because the wires gauges will be smaller on the 12v harnes. Twice the voltage, but 1/2 the amperage.

The bulbs, horn relay, and runts are pretty cheap. The 12v replacement OD parts are where the costs are. I wonder if you can just use a high amp 'runt' to run the OD pieces, and leave the 6v versions in place?

Just something to keep in mind.

BigKev: Wow. I had no idea That getting a heavier 6-volt capable wiring harness would add THAT much cost over a typical universal GM 12 volt harness.

I knew that the ONE brand was very costly, but assumed that they are just very very high quality and feature laden.

Are you saying that there are no inexpensive universal 6-volt harnesses out there? THAT does put a real damper on choices of what to do.

Jim G

Thanks for the info. Read your last post re the 12 volt conversion. You have been doing a lot of research. I am interested in the 12 volt battery with the 6 volt tap in the middle. Maybe you could use a full sized 6 volt battery for the car and add a smaller 6 volt in series with it to supply the 12 volt accessories and then use the 12 volt alternator to charge them in series. I don't know if there would be a problem charging the two dissimilar batteries that way. I can probably find out.

Posted on: Yesterday 16:27:

I'm not sure who Delores is. Does she sell a system with a 6/12 battery as part of it. There may be some sort of an electronics box that senses the condition of each half of the battery separately and direct the charging of the two halfs separately. Does Delores's system utilize a 12 volt alternator or maintain the old 6 volt generator?

As far as finding out about charging two 6 volt batteries in series that are of different capacities I will talk to an engineering friend of mine about that and get back to you.

A side line to this is my father ( now deceased) was an electronics engineer and would have loved to have been able to work on designing a system that would do what you need. He was the one who taught me how to work on and adjust the old electro mechanical voltage regulators. I remember my Dad never wanted to wast time shaving before he left the house so he designed a power supply to run from the 6 volt system in his 1951 Studebaker that generated 120 volts DC to run his schick electric shaver. This was in 1951. Long before you could buy things like that. BTW if you're wondering why the 120 volts DC. The shaver had brushes in it and would run on AC or DC just as well and it was easier the make the DC. It had a vibrator power supply like the tube type radio in your Packard.

Boy I can rattle on can't I?

The 6/12 volt subject received much discussion a few years ago when I had my 1939 Cadillac 60 Special. You can probably go to the Cadillac La Salle club site and search for this subject. One item that got a lot of attention was a series-parallel device on a 12 volt battery that switched 12 volts for starting and then back to 6 volts for the operation of the rest of the electrical system. I believe this was only for starting and not for the operation of a mix 6 and 12 volt components at the same time.

The old Cadillac site DID have a lot of discussions on 6 volt / 12 volt / AC compressor topics, but it reached no wonderful conclusions on any of them, EXCEPT ONE:

There was ONE innovative, MAYBE practical solution, actually in use on a real old Cadillac, where the car had:
- its stock 6 volt generator charging system
- a 12 volt AC compressor driven mechanically from the balancer like normal EXCEPT with a dual-belt pulley on the compressor
- a 12 volt battery placed remotely in the car
- a 12 volt alternator driven off the second groove in the compressor pulley!

This way, the 12 volt battery provides power to the 12 volt compressor clutch, AND whenever the AC compressor is running, the alternator is also turning, providing power to the 12 volt battery to charge it! In addition, this minimizes total drag on the engine, as the 12 volt alternator is running ONLY when the AC compressor is running. Finally of course, the 12 volt alterator also powers the 12 volt fan in the HVAC ssystem, and any other 12 volt accessories desired. Pretty slick.

Jim G

Did they give any description of what type and how/where to mount the second pulley so it was independent of the driving pulley? Clutches I'm familiar with wouldn't have that provision built in without some kind of fabrication and an ordinary dual groove pulley wouldn't give that option.

HH56: No, you don't quite understand. The alternator pulley is INTENDED to NOT be independent of the compressor.

The pulley on the compressor is simply twin groove. One belt on it is the one from the balancer, that drives the compressor. The second belt is in the second groove, and simply drives the alternator. There is NO need to run the alternator anytime the compressor is not running, since the alternaotr can easily recharge the battery enough to replace the power used to simply engage the AC clutch, simply by running whenever the compressor is running.

I think 2-groove compressor pulleys are available, as some compressors use dual belts to drive them.

I've attached a photo.

Jim G

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