8 volt regulator

Thu Jan 29, 2009 10:23 pm

Hi all...a couple years ago, I installed a group one 8 volt, yes 8 volt, battery in my farmall cub. Very knowledgable guy who sold me the battery said that a lot of guys with 6 volt systems on various cars, tractors, etc loved the 8 volt. He said you could increase regulator voltage by "tweaking" the 6 volt regulator..which I did. Got about 8.1 volts out. Charged good for the past couple years...Now no charge. grounded "field" on regulator, FULL charge on gauge. So now I am looking for another regulator...Is there an 8 volt regulator available, anyone else ever done this?? Did I burn out a good 6 volt regulator?? Are all 6 volt regulators designed for POS GND?? Thanks...Tom

Re: 8 volt regulator

Thu Jan 29, 2009 10:48 pm

Is there an 8 volt regulator available? Did I burn out a good 6 volt regulator?? Are all 6 volt regulators designed for POS GND?
Check with your local autoparts store - I didn't see an 8 volt regulators listed in my parts books.

You polarize the regulator upon installation - making the regulator match the battery/ground polarity. Instruction sheet for polarization is included in the regulator packaging.

Re: 8 volt regulator

Thu Jan 29, 2009 10:51 pm

Tom, I found an 8v regulator for Model T's, but it's negative ground - and $80. :o
Don't know if there are any others out there.
You might want to consider just getting a regular 6v battery.
They really work good on Cubs, and it would simplify things a lot.
I don't know about the other questions, but I'm sure others here will let you know.

Re: 8 volt regulator

Thu Jan 29, 2009 10:55 pm

if i remember right a lot of the amish use the 8v battery on their buggies,as to if there is a regulator you can get 9.6 volts from a 6volt regulator, i don't know how but with the 6 volt vw's they used to upgrade to the 8volt also to brighten the lights. :roll: :arrow: :idea: i'll stick to the 6

Re: 8 volt regulator

Thu Jan 29, 2009 11:36 pm

Tweaking regulators is touchy business. I'd go with a six volt battery and regulator. Or toss on a 10si alternator, a 12 volt battery, and call it done. 8.1 volts is normally not enough to charge an 8 volt battery.

Re: 8 volt regulator

Fri Jan 30, 2009 8:18 am

They do not make a 8 volt regulator.

You will need almost 10 volts to charge an 8 volt battery.

There are a lot of myths associated with an 8 volt battery and more starting power.

Go back to the 6 volt system, Rememeber it worked just fine when the tractor was new and will work just fine once repaired properly.

Go to the How To Forum and do a Voltage Drop Test to find your resistance in your battery circuit .

There is a lot of good info in the How to Forum that will get your starting and charging system in proper working order.

There are also plenty of help on this forum also

Good luck and keep us posted

Mark LaFollette

Re: 8 volt regulator

Fri Jan 30, 2009 12:46 pm

Sounds like the generator is working so just trace through the charging system looking for the obvious, loose or dirty connections. If you find none then I would open the regulator and clean the points, that may be all it needs.
A regulator does not need to be polarized, nothing inside is dependent on the polarity of the magnetic field. Regulators with coil springs are not hard to adjust to 9.4 volts or so to charge an 8 volt battery, regulators with flat springs may require a bit more work to adjust but it is possible.
If cleaning the wires and cleaning the regulartor points does not fix the problem then you may need to decide if it is worth the effort, it may be easier to go back to 6 volts. If you get a new regulator, just be sure you get the correct type, "A" Vs "B" circuit.

Re: 8 volt regulator

Fri Jan 30, 2009 1:04 pm

You can "convert" a 6 volt regulator into an 8 volt regulator by increasing the voltage it takes to close the contacts in the regulator. A 6 volt regulator will close at about 7.2 volts and a so-called 8 volt regulator should close at about 9.6 volts. With that being said, 6 volt batteries are much cheaper than 8 volt batteries. If a 60 cubic inch cub engine won't start on 6 volts, there is a voltage drop elsewhere in the circuit. I would check battery cables, starter switch or the starter itself. Increasing the voltage doesn't solve the problem, it only overcomes the problem.

Re: 8 volt regulator

Sat Jan 31, 2009 9:58 am

I tried an 8 volt battery before switching to 12 volt. I found an adjustable regulator and set it at 9.5 volts for charging my battery. I got it at the local electrical shop which rebuilds generators etc. He pulled it off a shelf in the back and said $10.

Re: 8 volt regulator

Sat Jan 31, 2009 2:17 pm

UPDATE..Before I posted, I did pull the regulator and clean the contacts inside...I thought. Last night I pulled it off again and checked it with an Ohm meter. The relay contacts associated with the "F" terminal were NOT making. I would get 20 ohms across contacts. Used a very fine jewelers file. BINGO...I'm charging again..Thanks to all who replied...Tom :D

Re: 8 volt regulator

Sat Jan 31, 2009 2:21 pm

Back in business, and didn't have to spend a dime.
Way to go, Tom! :{_}:

Re: 8 volt regulator

Sat Jan 31, 2009 2:31 pm

NICE diagnostic work Tom!!!!!

You deserve to be be proud of yourself and your efforts.

Keep us posted on your ongoing progress on your cub.

Mark LaFollette

Re: 8 volt regulator

Sat Jan 31, 2009 10:28 pm

Glad you got it going.... and also glad you posted the question, I learned from the replies (as usual! :D )