Ugggh! Before throwing away your 8 volt battery, try this..
1) loosen the negative cable at the battery. Suggestion... put one of those on/off battery pole switches on it so you never have to do it by hand again.
2) start the truck, then remove the negative cable at the battery. (trying to keep sparks down by doing it this way)
3) LEAVE the cable off no matter what happens until you turn off the ignition switch. Then put the cable back on.
NOTE: This isn't something you want to make a habit out of without that switch since any sparks near the battery can cause an explosion.
4 and most importantly) Leave the 8 volt battery in and enjoy the benefits of a little peppier start, a little brighter lights, a little stronger everything without changing anything.
My 2 year battery is an 8 volt, been in my truck for 3 years and shows 8.37 volts. Do I care if the storage battery is only 85-90% charged? No. No I don't. That's the small price you pay for not having a properly engineered system (8v in a 6v system)
I can hear it now especially as a Kansas farm boy back in the day... Hey Earl, Trucks not starting again.. go out to the shed and get the tractor battery. AGAIN. Because anyone in north America in the wintertime knows a 6 volt truck is very iffy when it gets below freezing. I agree its not a perfect solution. As a electrical engineer I get all of that. I do most of my trucks with 12 volts to stop the madness completely. Its called common sense and fulfilling a need with what you already have.
Besides this is a universally known trick that has been used for a million years on all makes of the old 6 volt vehicles. Show cars/trucks have 8v to give the presentation just a little better flavor. Open mindedness and helping people with what they already got.. no need to rain on anyones parade with the top down.
