Hi All. My 73 Roadster's battery is draining when sitting in the garage. I'm hooking up a quick disconnect for the battery since I'm not sure what's causing the drain. The only thing that should be running when the car is completely shut down is the settings on the stereo (not the original stereo) so I pulled the fuse to see if that would stop the draw. Does anyone know what else is running off of the "radio" fuse in the fuse box? I'm assuming the wiring is all original and nothing is tapped off of the radio line, but I'm not sure if there is anything else on the line. If not, I think I'm going to have to put a switch on the radio line to cut the power to the unit when the car is off. Of course, this means all my settings are gone every time I go for a ride, but that's better than it not starting due to a dead battery.

Thanks!

 

Best way to find a current draw is to monitor current at the battery and start to remove fuses one at a time 'til the current draw drops. Also check the fusible link if you don't find it by removing fuses. The radio "keep alive" draw shouldn't be enuf to drain your battery.

Check interior lites first. Since it's not the original radio, I'd check that wiring next unless you did the install.

 

Thanks for the info. Here's a little more background: I first thought it was the starter and replaced that. Then, thought it was the battery and replaced that. Then, the alternator. Then, the ground cable to the battery (which was down to about 3 strands). All of these things tested 'broken', but still had the power drain when sitting. I then pulled the battery cable and connected a voltage meter to the frame to test power as I pulled each fuse. I pulled every fuse and still had the meter show that something was being shorted. I gave up and brought it to an auto electrician who tested it by seeing the amp draw while the car was sitting (I was only testing voltage) and he showed me that there was a 'normal' draw of only (if I remember correctly) about .08 amps. He said that everything was running perfectly. However, I went away for 3 weeks and came back home to a completely dead battery again -- zero volts dead. So, thinking that the only thing that is drawing constant power is the stereo, I decided to pull that fuse and monitor the voltage drop every day. There was a significant difference in drop when the fuse was connected vs. disconnected. That's what made me think there may be something else connected on the radio fuse. The stereo is aftermarket and appears to be hooked up properly. So, my next steps were to add in a disconnect to the battery to cut all power. I am also thinking about a direct connection from the battery to the stereo with a switch to cut power to the radio as well. This is a bummer since my settings disappear every time the power is out. But I'd rather be able to start the car with the key instead of parking on a hill all the time...

Any suggestions?

 

Mike,you might have to put a battery maintainer on it. My C4 will kill a good battery in about 2 weeks,the C3 takes a little longer. Both have aftermarket radios. The $15 battery maintainer I picked up at wallyworld solved the problem. It's probably better for your battery to keep it fully charged. Make sure it's a "maintainer" a trickle charger will shorten the life of your battery. Also your battery may be on it's way out. They can check good and still be unable to hold a charge for a long time. Good Luck!
Ron

 

I had to Google a battery maintainer since I never heard of one and got tons of results. Is this like treating your car like an electric vehicle? Looks like you plug one end into the wall socket and the other to the battery or lighter and it will keep your battery charged. I'm not sure how this is different than the charger I connect every once in a while when it sits to re-charge the battery. I saw a solar one online and thought that would be a pretty cool way to keep it charged instead of the 'big charger'. I didn't see anything about the difference between a trickle charger and a maintainer though. I also had to Google wallyworld -- lol! I had no idea!

I don't feel so bad about what's been the trouble with my battery since you said that the same thing happens to your C3. My battery is new and had it tested to confirm so I'm pretty sure that's not the problem. Of course, I'm not sure what damage occurs from going from a dead battery to a charged battery using a battery charger all the time is doing.

Thanks!

 

What a charger will do to a battery depends a lot on the sophistication of the unit. Basically a trickle charger puts X number of amps into the battery as long as it's connected, so do most "big" chargers,they will overcharge a battery causing it to "gas" losing electrolyte and sulphation of the plates which will eventually ruin the battery. A "maintainer" is supposed to sense the level of charge and give the battery only what it needs charge-wise. The solar units seem kinda cool,but they cost quite a bit more and I'm not sure about the circuitry as to whether they "trickle" or actually "maintain".
I have both a Black and Decker and a Schumacher that I got at Wallyworld for under $20 and both seem to do what they are supposed to.
I know nothing about the solar units other than what I've read,mostly Harbor Freight and Northern Tool.
Ron

 

I had the same problem and discovered a loose wire up by the fire wall inside the engine compartment. It was a red wire over on the passenger side right above the heater fan. Tug on all the wires in that connection and see if one comes loose. I went to africa for 5 weeks (in the Navy) and it held a charge the whole time I was gone.

 

I can't imagine only 80 milliamps drawing down your new battery but as the others have said, here's your solution: http://batterytender.com/default.php?cPath=11_3

Never forget that you get what you pay for.

 

Thanks for the suggestions. I'll take a look for any loose wires. There is definitely 'something' on the radio fuse because when I take out the fuse, the charge stays (mostly). When I connect the fuse, it drains much quicker. The radio is pretty simple and is connected properly. That's why I was wondering if anything else is on the radio fuse. Thanks for the tender info. I'm ordering a solar one. I can't imagine that I can't get a solar one to work in SoCal with a convertible... (famous last words).

 

Should work as long as it's outside even if cloudy.