Re: 1951 Packard 288 dual 12V/6V cranking battery

Posted by DavidPackard On 2024/3/20 23:23:59

I don’t think I’ve ever seen a centered tapped 12 volt automotive battery, but the idea of using two Optima 6 volt units is definitely one way to make one. There is some advice in this site about using two batteries in series, that is; 1) the same type i.e. group number are used, and 2) the two batteries are roughly the same age. If the battery box in your ’51 is the same as used in a ’54 Cavalier, then two Optima’s will fit just fine. . . however you’ll need to fabricate a ‘custom’ hold-down.

The comments about 6 volt positive ground systems working adequately are well founded. Perhaps you can let us know what you are trying to accomplish by switching to 12 volt positive ground while retaining the 6 volt power to the starter motor . . . and perhaps other un-identified systems, such as the OEM radio. If the voltage swap is only to run an AC, then we’ve got at least one example (my ’54) that is a 6+ car that has an AC installed. I suggest you search this site on ‘air condition’, and review the thread titled ‘Aftermarket Air Conditioning’. So far, we’ve kicked-around mounting brackets, suitability of using a 12 volt clutch coil, but have left the subject of the evaporator fans alone . . . at least up to this point.

dp