12v to 6v Step Down converter.

[OUTFXD]

Okay, Been thinking on this. I'm not happy with Jacquilines wire harness and plan to upgrade it to 12v and a new loom but finances keep driving it down the priority pole.

 

My Generator is dead and needs to be replaced.   It is cheaper to buy a new alternator kit than it is to replace/rebuild the generator.  and I have found 30/40 amp 12v to 6v stepdown converters.

 

https://www.ebay.com/itm/282977212590

 

My thoughts are this.  I have to replace the generator but I am unable to do a full 12v conversion at this time.  What is stopping me from installing a 12v alternator,  and putting two 12v to 6v step down converters BEFORE the Fuse box (I have two power leads into the fuse box).

 

Also I see the fancier step downs have two grounds,  How would I wire those in? 

Edited March 27, 2023 by OUTFXD

[Sam Buchanan]

I would skip the Mickey Mouse approach and install a 6v alternator. When/if you decide to move to 12v you can sell the 6v alternator to someone on the forum who has gotten disgusted with trying to get their generator/regulator to work. 

[OUTFXD]

21 minutes ago, Sam Buchanan said:

I would skip the Mickey Mouse approach and install a 6v alternator.

That is my default solution.  I just dont want to buy something I know I am going to replace in the future. Lacking a good alternative Your plan is the one I am going with.

[OUTFXD]

Bit of a potentially alternate solution,  my buddy has a 6v Generator from a 52 Chev.  I lined them up and the brackets seem spot on,  but I will need to change the pully.   I took it out to the driveway and started to degrease it for playtime experimentation.

 

Any potholes or issues in the wiring I should be on the lookout for?

[Merle Coggins]

May also need to change the voltage regulator to match that Chev. gen. 

[OUTFXD]

After I posted, while I was cleaning up the Chevy Generator I got to thinking about Polarity.  I cant remember if my friends truck was Pos or Neg ground and he has gone to work so  I am putting the Chev Gen on the shelf till I can talk to him.

[Los_Control]

27 minutes ago, OUTFXD said:

my buddy has a 6v Generator from a 52 Chev.  I lined them up and the brackets seem spot on,  but I will need to change the pully.  

Were chebby ever + ground?

I've heard stories that while the normal for the day was + ground, most makers were using it ... chevrolet refused to use it.

Then by 55 when Chevrolet came out with the 265 V8 they were the top car sellers of the day .... everybody else just fell in line and went - ground also ..... Is it true?

 

If the pulley is narrow, you can use a narrow belt. Fits the generator fine & does work on the other wider pulleys, just sits deeper.

Not as sexy as the big wide belt .... works.    I destroyed a old generator trying to get the pulley off years ago ... obviously I did not have the right puller or knowledge.

 

[kencombs]

40 minutes ago, OUTFXD said:

After I posted, while I was cleaning up the Chevy Generator I got to thinking about Polarity.  I cant remember if my friends truck was Pos or Neg ground and he has gone to work so  I am putting the Chev Gen on the shelf till I can talk to him.

chevys are neg ground.  Interesting 'cause GMCs of the same year were +.   Both General Motors products!

[maok]

The step down converters won't charge your battery.

 

As mentioned, go the 6v alternator or the complete conversion to 12v.

[vintage6t]

I don't see that there is anything keeping you from converting to 12 volts with your existing harness. You can always replace the harness later.

 

A 6 volt harness will work fine with 12 volts but not vice-versa

Edited March 27, 2023 by vintage6t

[Young Ed]

47 minutes ago, vintage6t said:

I don't see that there is anything keeping you from converting to 12 volts with your existing harness. You can always replace the harness later.

 

A 6 volt harness will work fine with 12 volts but not vice-versa

Agree if the 6v harness is in good condition will handle 12v fine. If it's not you can get a generic wiring harness off eBay for about $40. If you already have the alternator I think the rest would just be bulbs. Maybe a step down for any accessories 

 

[OUTFXD]

51 minutes ago, vintage6t said:

I don't see that there is anything keeping you from converting to 12 volts with your existing harness.

Finances.  Its not as easy as just swapping out the Alternator.  I also need new bulbs, Step down converters, etc. and that I just cant afford at the moment.

[OUTFXD]

13 minutes ago, Young Ed said:

Agree if the 6v harness is in good condition

 

[vintage6t]

5 minutes ago, OUTFXD said:

Finances.  Its not as easy as just swapping out the Alternator.  I also need new bulbs, Step down converters, etc. and that I just cant afford at the moment.

 

We'll only you know what makes sense in terms of budget but that step down you originally posted is $119. I would think that's more than enough to buy all the 12 volt bulbs and the small voltage drop components for the gauges, wipers, and fan.  I'm not sure you even need to drop the gauges but if you do cheap buck converters will do. You can even skip the wipers and fan for the time being, they'll just run fast. Resistor type voltage drops will work if you don't want to skip those.

 

[Young Ed]

Not the prettiest harness but it doesn't look corroded or damaged. Any idea when it was redone as that's certainly not OEM

[D35 Torpedo]

Can't you just polarize the chevy gen to produce positive ground current?

[OUTFXD]

The clumps of flux on the soldering job where big enough to short to the firewall.  No idea when it was done,  I didnt do it and i am pretty sure the previous owner didnt do it.  I found the original regestration for the previous owner dated 1991.

[OUTFXD]

14 minutes ago, vintage6t said:

We'll only you know what makes sense in terms of budget but that step down you originally posted is $119.

When the though first crossed my mind,  I looked up a pair of step down converters for $12.  then I learned that I needed to match the amperage which brought up the price. But the seeds of the idea where already planted and I need to have the question answered or I will never sleep again!

[Dave72dt]

One of the questions that always come up in 12V conversions is "How do I convert the radio from 6V+ to 12V-?  Is it simple?  Is it expensive?  Is it worth the conversion to 12V?  I think the cheap step downs would work for some of the accessory circuits.  For example , would a 25 amp rated step down work on a circuit protected by a 20 amp fuse, using the step down to provide the power to the fuse?  What does the light switch have for a fse?  20?25?  Heater? 15?  But what do you do about the radio if it's polarity sensitive?

[OUTFXD]

37 minutes ago, Dave72dt said:

But what do you do about the radio if it's polarity sensitive?

Just wire it in Backwards.   EG Negative wired to HOT Pos Grounded to frame.    I did this with a Cigarette adapter to provide USB power to my offline GPS,  Has worked flawlessly for months.

 

<edit> ok wait.  I think I lost the plot.  What electrical system is IN the car and what electrical system is is the radio for?

 

Edited March 28, 2023 by OUTFXD

[Dave72dt]

I know next to nothing about those radios but if that works and the radio functions as it should, a separate step down to power it should also work.  If you can get confirmation the step downs will work as suggested, it would let you start your 12V conversion on the start, ignition and charge systems and swap over the remaing systems, removing step downs as you go and finances permit.

[LazyK]

I don't think the vibrator (power supply) in the radio is polarity specific. maybe some one else can confirm or debunk .

[Bryan G]

1) Like D35 Torpedo said, I'm pretty sure you can run that Chevy generator as positive ground. 

2) The old style vibrator doesn't care about polarity. There are modern solid-state replacements and you'll want to make sure it doesn't have one of those. (Should be pretty easy to tell; well labeled.) They'll burn up quick if connected backwards.

[D35 Torpedo]

On 3/27/2023 at 5:42 PM, Dave72dt said:

One of the questions that always come up in 12V conversions is "How do I convert the radio from 6V+ to 12V-?  Is it simple?  Is it expensive?  Is it worth the conversion to 12V?  I think the cheap step downs would work for some of the accessory circuits.  For example , would a 25 amp rated step down work on a circuit protected by a 20 amp fuse, using the step down to provide the power to the fuse?  What does the light switch have for a fse?  20?25?  Heater? 15?  But what do you do about the radio if it's polarity sensitive?

Fuses first, then step down. A high watt power resistor will work fine. Just keep in mind, they get hot. Most circuits never had fuses in these old cars. On my 50, the radio was 14amp i believe. So, 14 amps x 6 volts is 84 watts of power dissipation. 6 volts ÷ 14 amps is .429 ohms. So you need a 100 watt half ohm resistor or two 50 watt one ohm resistors connected in parallel. That should knock off 6.5 volts from your 12.6v. Fun stuff. Good luck.

[Sniper]

Other than the radio, there is nothing in the vehicle that is hard to convert to 12v operation.  Some items do not care, switches, some do care, light bulbs.

 

If you have electric wipers and a heater then you get into issues. 

 

The wipers will work at warp speed.  I used a current limiting circuit I built to slow that down, not 100% satisfied with that option though. 

 

For the heater blower, here is what I did.

 

http://www.yourolddad.com/blower-motor

 

For the gauges, the only one that might be affected is the fuel gauge, if your sender had two terminals it won't be, if it is a single one like my 51 it will be.  A "Runtz Resistor" on the fuel gauge + terminal fixes that.  The rest of the gauges, except the ammeter, are mechanical, change the bulbs and done.  The ammeter will need the two wires on the terminals swapped, otherwise it will read discharge when it's charging and charging when it is actually discharging (assuming 122 negative ground).

 

Finally, the battery will need replaced.

 

The only mandatory items initially are the bulbs, battery and alternator.  The rest can be done at your leisure.