Re: 8 volt batteries?

Posted by Jim McDermaid On 2013/1/4 16:55:10

I use a 6 volt battery in my 1954 Packard Cavalier as well as my 1922 model T Ford.

I use an Optima 1000 cranking Amp battery in the Packard and regular old 6 volt checker auto type in the T.

Over the years people have talked about using an 8 volt but I personally see absolutely no reason.

Some problems are slow cranking with 6 volt which is usually do to using too light of gauge battery cables.

The Optima is probably as good at cranking as the original battery and if you need more juice, two of them could be paralleled and sit on the battery shelf.

I just got through rebuilding my 6 volt generator and replacing the regulator and it will run the headlights and radio and heater fan and maintain just under 7 volts at idle. I regulates around 7.2 volts when warm but higher when the car is ice cold.

I run the original 6 volt system so I can keep the original lights, tube radio, and other electrical stuff these cars come with.

I live in Phoenix AZ and it rarely gets below 30 degrees but it has been in the low 30's the past few weeks and my Packard and Model T start right up.

An 8 volt battery would require higher charging voltage from a 6 volt generator. The system in my 54 is rated at 45 Amps, which when delivering 7.5 volts = 337.5 Watts.

If you jack that voltage up to 10 volts to charge an 8 volt battery you will need 450 Watts from the generator. Watts = heat in the armature windings and regulator contacts.

Jim