1948 dodge keeps draining the battery

[Guest glarizza]

i have a 1948 dodge custom all original except for the fact it has an alternator... it goes to an 8v converter and out.... i disconnected every wire in the car with the exception of hooking up the ignition, still the battery drains out on it. i jump the car it starts and runs great will even run without any battery attached to it.... if i start it right back up it will start, but if i wait a bit the battery will be discharged. i changed the ignition, the points seem to open and close fine, and the battery was new, but now has had to be charged several times because of being drawn down. i am totally clueless. i do find that there is a voltage drop when i turn the key on, but it does regain that lost voltage after a min or so. is there something missing or???? any ideas would truly be appreciated.....

also i did have the battery tested by the auto parts store they said it was ok.... i did also notice the points are in a closed position when the vehicle is off, but do open and close fine when car turns over. Scratching my head here, this whole positive ground thing and old 6v wiring system is new to me, im a 32 year old guy with a car twice as old as me, but its a beauty! hopefully will post some pics on here soon

thanks again

[JACK M]

Could be a diode in that alternator.

[Guest glarizza]

the alternator puts out a little over 9v , i dont get any voltage drop until i turn the ignition on, then i get a 1 to 2 v drop, but it regains the voltage back but slowly

[1936 D2]

6 volt systems are plenty capable to run your car efficiently especially if setup correctly. Sounds like you will need to start looking around for places of current drain. Could be at any "device" connected in the system, like a faulty/dirty ignition switch, poor connection to amp meter, a short to ground on the fuel gauge system, lighting switch faulty/dirty, etc. Try disconnecting a battery cable and with ALL switches off see if there is a current flow using a volt meter inline. If there is, start disconnecting things one at a time to see which one is allowing current flow. (Start with the coil as that most likely will show draw particularly if there is a problem at the ignition switch). Decide in your mind if an item is supposed to allow current to flow with the ignition switch off. (A wiring diagram will help here). Then try "Jack M"s notion by disconnecting the alternator. That would indicate a possible problem with the diodes if a leak disappears. Consider a grounded automatic choke issue, or possibly a grounding of some type in the starter.

Also, eventually, be sure ALL grounds are clean and tight to all devices needing one. These 6 volt systems are especially needy of clean, tight grounds and will show odd symptoms if there are faulty ones.

And a safety idea, once you have this all figured out, is to install a battery cut off switch. I use one ALWAYS when parked.

Edited August 8, 2012 by 1936 D2 (see edit history)