My owner's manual says battery should be 2900 watts. How does that convert to current practice of rating in amps, along with temp like 0 deg or 32 deg. Sometimes just saying cold amps of some amp amount. My current battery says 6oo amps @ O deg and 825 amps @ 32 deg? Think I need a little more power than what I have, sounds a little weak sometimes. Connections are fine.
Gee, that's the first time I ever heard of a rating like that. 2900w/12v = 241.66666 amps, you have plenty.
Assuming your battery is not more than 4 years old, it would seem more likely that your starter is aging, causing it to draw more power when under load. (like when the engine is hot). It could be time to have the starter freshened up by a good local rebuilder. Less likely, based on your comment, is that your battery cable is not delivering full power to the starter. If your battery is a tad older, you could 2X check by having the battery tested under load by a competent shop (they have portable testers) but otherwise 600 CCA should be plenty!
Thanks for response, should also have mentioned that it is a 72 skylark with basic 350 engine. Not a 455 for one thing which might take a little more oomph. Problem is after setting a couple of weeks needs to be jump started. So probably need to have battery tested as suggested. Hot starts are not a problem. Battery is not totally dead, interiors lights and head lights still light up pretty good. Starter is probably original and also may need attention as you suggest. Think most likely is short somewhere draining battery over time. Near as I can tell battery is fairly new, like a year old, got the car last winter and still getting it sorted out when I feel like it! Otherwise in pretty good shape, but as always with these old cars, always something!
Next time you let it sit for a week disconnect the battery. Reconnect it and see it that makes a different. If it does not make a difference you need a new battery. If it does, you have a short somewhere. Disconnect the battery and connect a volt meter between the cable and the battery. Start pulling fuses until the volts drop to zero. That's the circuit that's "leaking" - start looking for a short (low resistance) in that circuit.
Thanks Bill, Have decided as you suggest it is a short problem. Did disconnect for a time and it starts right up. And I think I know where the circuit leak is, will try your suggestion. Do have a meter, not real good with it but should confirm the trouble area anyway, as you suggest. I blew a fuse that has the Idle stop sol on it along with blinkers, TCS sol and seat belt warning buzzer on it. Reconnected the idle stop wire while trying to adjust and grounded it instead! OOPs. If I can't find it will take it to a local mech who is pretty good with a multi meter. Have other stuff for him to check out anyway.
Guess I need a little more detail. Disconnect the pos cable or neg or both? Where do I hook the meter leads ?
You disconnect one side of the battery but not both. You'll run the volt meter (set for DC current...amps..not volts) in series --ie in the middle --between the disconnected battery terminal and the battery cable. You can skip the first 2 minutes of this video for a tutorial . It's far easier if your volt meter has clips. One piece of advice --- don't get too aggressive removing fuses -- do it one at a time. You can quickly forget which size fuse is associated with which circuit...
Thanks, had figured out that I needed to check current not volts, which confused me. It's 90 deg today, will do some checking later! I'm betting on the 20 amp fuse that has the idle stop sol on it. Then the trick is where is the short?! Hopefully not someplace where the sun don't shine!
Roger - I have chased a few over the years on different cars -- I seem to find the same evils 1) A bad light socket 2) Someone's hack from 20 years ago (AKA black tape and crimper marks...) 3) A damaged connector 4) Mice
Good video! Yes - just one side of the battery. Your key should be off. Make sure you are using a digital multi-meter to check current. A meter with a needle needs to be checking voltage, basically it is on or off. A very small current draw is hard to detect but can drain your battery over a long period of time. Don't forget that your clock, if you have one, is always connected. Also, a modern radio may be always connected as well if it has an electronic memory.
Started some checking today. Used the pos connection just because easier. Got no light with all fuses in with my pocket current checker just like the one in the video. Thought "home free" but decided to see what my Sears Craftsman meter would say. It doesn't have a 10 amp position, only uA and mA. Got reading of 10 - 12 m amps. Is that milli amps I guess and too small to light the pocket tester? So removed 20 amp fuse for the circuit I suspected, same reading. Removed 10 amp fuse for radio since it is an aftermarket one with memory, same reading. So is that .10 - .12 amps or is mille amps a hundredth of an amp? Decided to call it a day, do get light when opening a door and of course key off. Thanks in advance for further comments.
Roger -- you need to use the meter. But 10 milliamps is only .01 amp --not exactly a huge drain. Someone smarter than I might know what latent drain is normal for an old timer...
My thinking now will be to look more into unswitched power items like the radio, courtesy lights, etc. Did check trunk light, lights as it should and off. One item this 72 has is the seat belt warning system with seat sensors and belt sensors, wonder if they are connected or on with the ignition switch. Have disconnected the buzzer as any annoyance already, warning light on inst cluster still works. I do use the belts! Will do some more checking tomorrow. Another suspect is the key warning buzzer which has not worked, it is an unswtiched item also I believe. Would 10 milli amps be .01 or .10 amps?
Checked milliamps conversion, 1 amp equals 1000 milliamps! Wow milliamps are teensy weeny. Did some more checking today and reading 1 milliamp, next to nothing! Will put the fuses back in and recheck. Have been doing some other things before I started this investigation, like removing the TCS valve that cuts off vac advance in first and second gear and bypassing direct to carb vac connection. That may have been offender, wiring looked shaky, but I'm not going to put it back to find out! But will let it set for a few days and see if it does OK.
You could also have leakage in 1 of the 6 diodes in the alternator. If you take the big red wire off of the alternator and the current drain goes to zero you found it. If you have a newer digital radio the memory will also draw a few mA.
