Topic: Battery


silverchief    -- 09-22-2017 @ 12:46 PM
  I'm on my second Optima battery in 12 months. For the first few weeks when new they work fine. Then after sitting a week they will not turn engine over enough to start. Voltmeter shows 10 volts, dropped down from original twelve. I would think ten would be enough to turn the engine over, but no. Will then will accept a charge, but not full which I understand is normal for Optima with a home charger. Disconnect negative cable, put a test light between the cable and battery post. No sign of a drain. Seems to me the big question is could a drain be so minute it would not show on the test light? I have used two to be sure they are good. With a charged battery, the starter works fine. I would like to solve this headache. Also they show good at the vendor, but he has been good enough to replace both.

This message was edited by silverchief on 9-22-17 @ 12:48 PM


supereal    -- 09-22-2017 @ 2:25 PM
  Go to the Optima website for charging information. While these batteries are better for the old car hobby where our cars sit for extended periods, they require special care when being charged. I keep a "Battery Tender" connected to my battery when it isn't depending on the car's charging system. The Optimas have lasted 6-7 years using this method for me. As for parasitic drains, some are very hard to measure. A while back we had a Cadillac Escalade in our shop because the battery kept running down. The dealer had already replaced the battery and alternator, and was about to swap out the ECM. What we found was that the rear dome light (this was the Suburban version) was at fault. It was designed with a built in device to fade the light out when the doors were all shut. It did fade out the bulb, but not all the way, so it didn't show, but was enough drain to lower the battery so the starter wouldn't work after a couple of days. We recommend a master battery cutoff switch for safety reasons, but it will also prevent accidental discharge. Electrically wound dash clocks will do it. That is why so many pull the fuse.


shogun1940    -- 09-22-2017 @ 4:57 PM
  I have two 6 volt Optimus wired in series and they sit all winter for almost 6 months , the car starts up fine with out charging them. That's one car, my stock 48 will drain the battery, optima or lead acid , in three days . It also shows no drain even in milliamperes . I basically disconnect the positive ground cable or keep a charger on it.


silverchief    -- 09-23-2017 @ 8:12 AM
  Thanks guys - I have a disconnect switch, and guess I am just going to have use it after every ride.
My clock did an obvious drain, so I pulled the fuse long ago. My parking lights work fine, but only if you go to headlights first, then push the switch forward to parking lights. They don't work if you just go to parking lights on the switch. This happened after installation of new wiring harness. Must be connected wrong somewhere. If I can find the reason for this oddity, it might help.


TomO    -- 09-23-2017 @ 8:38 AM
  Bill, Your parking light problem sounds like a bad light switch. I have no idea why it would fail after replacing a wiring harness.

Sometime a drain can be so small that it will not have enough current to make the light glow. If you have a multi-meter with an AMP setting, you can use that in place of the test light.

10 volts will not operate a 12 volt starter. Is this your 46 Coupe? Did you change it to 12Volts?

Tom


silverchief    -- 09-23-2017 @ 4:54 PM
  Sorry Tom - senior moment. I was using a "range doubler" meter, so it was actually indicating 5 volts.
Yes - it's my 46 coupe.

Would never change to 12 volts. Double checked using Rhode Island schematic today to be sure the light switch is wired correctly. I never considered it might be faulty. Also I should have mentioned it is only the front parking lights that require first switching to headlights, then to parking lights for operation. The rear parking lights come on with the correct position on the headlight switch.

Three other electrical units do not work correctly on my car- and despite repeated efforts following Forum suggestions, a I have not had have the electrical moxie to fix them. Making sure each has a good ground is about the extent of my expertise, and any one could be the source of other problems.

A heater motor that if it decides to turn, you can stop with one finger.
A gas guage that works excepting that after five gallons used - it still registers over full.
A clock that keeps great time, but lights up a drain test light like the sun. I pulled the fuse long ago.

I will look out for a new headlight switch. The others I have pretty much decided to live with.

Thanks for your help.




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