The Stovebolt Site Forums The Shop Area The Electrical Bay 8 volt battery in 6 volt

When I was much younger, our 6 volt tractor had been retrofitted with a 12v/6v battery. The battery was equipped with its own solenoid that would supply 12v only during the start and then revert to 6v during normal running. I recently saw an 8v battery available at Tractor Supply and am tempted to boost my starting rpm with that. Does anyone have experience with this in their 6 volt systems? Does it shorten the life of 6v gauges and bulbs? Is the 6v regulator and generator able to maintain charge on the battery. When you have an 8v installed and need to charge the battery, which voltage would you use 6v or 12? Application is 1946 PU.

I'd be inclined to clean your battery and ground connections thoroughly and double check that you have heavy enough cables, 2/0 is a good size.
With good connections and cables 6V systems start well. An 8V battery might just mask the underlying problem.

If you wanted more voltage I'd go ahead and swap to 12V, change bulbs, alternator/generator and regulator, and don't worry about the starter, they tolerate the higher voltage quite well.

My truck is one of the best original survivors in the country, I have maintained this truck in this condition for the past 43 years, so I refuse to swap out the 6v for a 12v system. My cables are rated for diesel, clean connections, starter rebuilt sometime in the near past. Just does not like to spin the engine when hot.
My current 6v battery is reaching the end of its life/reserve cranking capacity, looking at replacing in very near future and I want to use the forum to pose these questions. Thanks for your response, and I hope that I have clarified. So I will stand by waiting for other answers/experiences with 8 volt.

I know many here do not favor the 8 volt battery modification, however, back in the day it was quite common. You will need to tweek the voltage regulator to help keep the battery charged. As a side note I wouldn't buy a Tractor Supply battery if it were the last battery on earth. Seems that whatever the stated life span is you can count on it failing in about a year and a half. I did the 8 volt thing back in the early 60's and was very pleased with the results.

An 8v battery is a bandaid "fix" for dirty connections, small cables or failing equipment. You are asking opinions, mine is never use an 8v battery.

Could be the starter is getting tired is why it cranks slow when hot, and if you know the battery is getting old it may also be supplying less amps when hot.

I would keep the 6 volt. Have the starter checked out, cleaned, rebuilt if needed and make sure the 6 volt battery is doing its part.

The volt systems do work well when in good shape.

Also check the timing on the engine and points just in case there is some wear. Sometimes that will make one hard to start when hot.

Bandaid "fix"? You danged skippy it is, Tiny.
I did the 8 volt switcheroo 20-something years ago and had no problems whatsoever. I just tweaked the regulator up to around 9 volts read at the battery. I also cleaned all terminals and the frame for good connections.
I was very pleased to have a starter which did more than tell me, "I think I can, I think I can," before it may or may not start.
There is a concern about blowing 6 volt bulbs on an 8 volt battery, but if you measure the voltage at the bulbs, you will find a natural drop in voltage to begin with. (There have been posts on this site about using relays to correct this situation on the headlights.)
I have since gone with the 12 volt conversion with an alternator with internal regulator. I think that I could drive the truck down the road with just the 6 volt starter motor. Maybe not very far though.
I would like to have a bone stock AD one day with a fully functional 6 volt system. I just wouldn't want to depend on it as a daily driver.
Carl

There were some farm tractors in the 1940's and maybe early 50's that ran 8 volt batteries from the factory. Other than that application the best use for an 8 volt is a doorstop. Fix the 6 volt system right and stop looking for an easy way out. Adjusting the regulator to make it keep an 8 volt battery charged is an exercise in frustration. I've known 3 men who could do it, and two of them are dead now. I'm the third one!
Jerry

Hey Jerry, I did it at 16yoa and I'm not dead yet. Lucky? Maybe. Talented? Certainly not! But I did it. Just sayin!

Yep, that cob-job (low-cost) 8v battery fix was recommended to me when I bought my 48 panel at 19 years of age (29 years of age for the panel).

I do not think that Jerry was referring to the fix killing anyone - he was perhaps referring to the 8v fix being an old cooter solution for hard starting ?

I'm not so sure an 8 volt battery is a "low cost" solution any more. Batteries are getting obnoxious in price.

$84 at TSC

However, I'd spend the higher amount for a 6v Optima and clean/dress my connections (and get 00 cables, if I do not know what gauge cables I have)

I would go with Optima as well.

Precisely why I went away from the 8 volt battery deal after the first one finally wore out after three years of service. I was on a shoestring budget in bare feet back then.
Carl

My more expensive 6v Optimas have lasted 13 years and 8 years.

6 volt rules.

I would get 1 to 2 diameter size larger then the original battery cables.

Preferably 2 times. I have seen so many hard starting problems fixed this way.