8 Volt Battery??

[OakhillOrchard]

Better to ask first. Can/should I use an 8-volt battery on my 62 Cub; its set up for 6 volt. I have a spare 8 volt on hand and thought it might work. Not opposed to buying a 6 volt, just trying to be frugal. Sometimes frugal means buying new.

Thanks.

[Jim Becker]

You can use it, unlikely to damage anything. The problem is your tractor may not do a good job of charging the battery unless you tweak the voltage regulator. I don't generally recommend trying to adjust a voltage regulator that is working. They are easy to mess up, new ones cost as much as a battery, and seem to be less reliable than the old ones.

Were it mine, I'd probably put the 8-volt battery in but not mess with the regulator.

[inairam]

The effort to get it to work is more than the effort to fix the charging system /battery issue you have. You can get a battery tester/ charging system tester on amazon or ebay for $20-30 making is very easy to troubleshoot.

[ajhbike]

We have a local collector who has about 20 farmalls and he told me the first thing he does is put in an 8V battery where they haven't been converted to get the crank.

[Scrivet]

The effort to get it to work is more than the effort to fix the charging system /battery issue you have.........

The OP doesn't say anywhere I see that he has a "charging system/battery issue", just that he has one on hand and wonders if it will work to save some money.

[inairam]

The OP doesn't say anywhere I see that he has a "charging system/battery issue", just that he has one on hand and wonders if it will work to save some money.

Re reading I see Thank you

I still think it is not worth the effort vs cost of the battery. The 6-volt regulators are iffy to begin with and messing with them to get more output seems risky to me and end up getting a new regulator..

At far as a standing practice to convert to 8 volts I have a lot of 6 volters and they crank fine. I can start all them in second gear on level ground and some I can start in 2-second gear with PTO to mott mower engaged.

The correct #2 cables and a good ground ( not to the sheet metal of the battery box but to the mount for the battery box) do the most of the cranking on 6 volts cub. I do run multi-weight oil as well.

[halftonstude]

the 8 volt battery will work until it has discharged to a point where the open terminal voltage is near to the 6 volt battery. There are many formulas that relate specific gravity of the electrolyte to open terminal voltage, but an 8 volt battery being charged at a 6 volt rate will guarantee you failure in the long term. Discharge of the battery will cause sulfatio:, its a natural process of the discharge reaction of both the positive and negative plates. There are a lot of snake oil salesmen out there telling you how to rid yourself of sulafation, but you're losing active material - which means capacity - and you'll lose your battery in the long run. I know i've cranked my cub with a 12 volt battery to get it started, and let the generator take over with the electrical system after it's running, but it's just the starter motor using the 12 at that point - short term cranking, no excessive heat, and the brushes have enough pressure to take the extra current. With the 8 volt battery and a 6 volt charging system that'll probably be putting out 7.2 the 8 volt battery will be severely undercharged, and fail shortly thereafter; so it won't work for a long term solution for very long. I'm not sure of the range of the 6 volt regulators, i've repaired many and tuned many up to perform quite well, even some of the new ones. they all require adjustment, and whether they're two or three relay versions, they're persnickety, but they perform pretty well. I just put a new regulator from steiner on my '52 cub and had to make many adjustments, and i know at charging voltage the points on the voltage relay are pretty close to closed all the way, so there's not much room for further voltage increases. The points on the voltage relay need to open and close to regulate the voltage that's charging the battery... .030? .025? I can't remember the gap at the top of my head but since it started at over 1/16" and is now close to being always closed, there' not much more room for increase. there are two windings on that relay that counter-act each other to cause it to do its job. it might be possible to take a 12v and open the points farther, but i'd have to read up on the range of those as well. They aren't that fussy, they need to match the current output of the generator, the field current of the generator, and voltage of the battery. it's quite possible to mix and match to get something to work...
c

[inairam]

I am not saying it is not possible I am saying, in my opinion, it is not worth the effort.

[John *.?-!.* cub owner]

I am an electronics technician by trade and antique machinery hobbyist by training as a youth and preference as I am older. An 8 volt battery in an older charging system that still has a cutout will give you a little higher starting voltage due to the fact the control is the HI-LO position of the light switch controls current, not the voltage as a regulator does. The lower current is due to the fact that each battery cell produces 2.2 volts, and to get an 8 volt battery in the same size housing the cells have to be smaller, so the current they can produce is less. An 8 volt battery in a system wit a voltage regulator will just be a partially charged 8 volt battery. The regulator can be adjusted for 8 volts, but my question is why bother?

[ShawnAgne]

My 300 was converted to 8volt when I got it. Didn't realize it until I converted them both. Assuming the regulator was adjusted.

[halftonstude]

100% John *.?-!.* Not worth it.
c

[Nelson 634]

Am understanding correctly, an eight volt battery may give you better starting capabilities (rolling the engine over) and can be sufficiently charged by an early year cub with a cut out. (Not a voltage relay.) I ask as I have a cub which came with an eight volt battery and has a cut out which I have had concerns about. Next question, will it harm or degraded the performance of other parts of the six volt system. Thanks for any and all answers, you guys and Gals are great. Walter

[Jim Becker]

Am understanding correctly, . . .

Yes Most components won't be bothered much by 8 volts. Bulb life will probably be shorter, but little enough that you might not notice it.

[inairam]

Am understanding correctly, . . .

Bulb life will probably be shorter, but little enough that you might not notice it.

You may be able to run 12v led bulbs at 8-9 volts charging range with the engine on. Most of the specs I have seen say they go that low.

Bach to a good tune-up, clean dry gas and a rebuilt carb will do more for power and starting than using "cough syrup" to get hid to the symptoms of hard starting.

[Nelson 634]

Good to Know. Thanks to all.