Battery Problems

[msfissel]

So, I am having an issue with Batteries going dead. I had a new battery in April, went dead, got a replacement in August. Somehow, the battery seems to be going dead just sitting here. Was fine a week ago when I drove the car, now it is not even showing 1 volt. Any idea what would not only drain the battery but cause the battery to go bad? I jumped started the car, cranked right up, checked voltage while running and it was around 14.5, seems the generator is working fine. Turn the car off and it immediately starts dropping voltage slowly.

The battery is a SuperStart Premium p/n 51PRM

Any thoughts?

[terribleted]

You likely have a short somewhere or something running in the car when it is shut down. Fully charge the battery and load test it. If it passes load test the battery is not the issue. Is there an aftermarket radio in the car? Is the memory wire hooked to constant power? I have seen these run the battery down in a matter of days to a week particularly if the unit maintains a standby voltage on the amps if not physically turned off when turning off the car. Eliminate things like aftermarket radio by disconnecting them to see if the issue goes away. After that, you need to test circuit by circuit to find the loss and fix it.

[msfissel]

Yes, the battery is definitely toast. I have a bad battery check on my battery charger. So that is 2 batteries in 5 months. No new radio, the original am radio is in the car. Not even sure where to start checking circuits, I'll consult the shop manual.

[bbodie52]

The video below is a guide to describe how to perform a parasitic draw test on your electrical system in your car. The basic process involves using a multimeter to measure the overall amount of electrical current that is being drawn from the battery when everything in the car is supposedly turned off. Obviously with everything turned off there should be essentially zero current being pulled from the battery. But if your battery is being drained quickly with the car just sitting and everything turned off, and if the battery is fully charged and has been load tested to confirm that there is no internal fault in the battery itself, it is likely that there is a faulty component, shorted wire, bad switch, etc. somewhere in the car that is draining the life from your battery. The test begins by measuring the amount of current being pulled from the battery when there shouldn't be any current being pulled from the battery. If you measure a significant amount of current (as described in the video) the next step would be to isolate one circuit at a time until you find the faulty circuit that is drawing current (the meter goes to zero when you pull the fuse or disconnect the circuit). If this process helps you to find the bad circuit you can then study the wiring diagram shown below to help you to figure out exactly what devices are wired to that circuit and how it is wired so that you can narrow the focus and continue troubleshooting and isolating components until you find the short or defective component that is draining your battery. However, in the Corvair there are a number of devices and circuits that are not fused! So if you do discover a significant current draw, and you are unable to eliminate the current draw by pulling any of the fuses, you will have to examine the schematic carefully to determine which devices get power from the battery that are not fused. If you trace the wires shown in the schematic diagram from the positive battery terminal, you will see that there is a direct connection to the starter motor and solenoid. There is also a direct connection to the voltage regulator and charging system. There is an additional wire that leads from the voltage regulator connection to the eight pin multi-connector in the engine compartment. That circuit passes through the multi-connector and continues on through the wiring harness to a junction point that is embedded in the wiring harness under the instrument panel.

The wiring junction point is a distribution point for power to all the electrical devices throughout the car (with the exception of the starter motor and solenoid and the charging system). Looking at the junction point and its feed line from the battery you can follow the other connections that surround the junction point to see where they go. Moving clockwise, the first connection is a wire that travels to a plastic multi-connector that passes through the body and into the trunk. This wire is unfused and terminates at the horn relay in the trunk. The next wire from the junction point is connected directly to the fuse block, where electrical power is distributed by the fuse block and through all of the fuses to the individual circuits. Continuing clockwise, the next wire in sequence is connected to the ignition switch. The next wire from the junction point is wired directly to the cigarette lighter. The last wire from the junction point is connected to the main light switch in the dashboard, where power is distributed to all of the lights throughout the car.

As you can see, there are quite a few devices and circuits in the Corvair that did not get power via the fuse block. If your initial test at the battery does show a significant current draw that is going somewhere in the car, your initial process would probably be to pull one fuse at a time to see if any of those fuses lead to the source of your problem. If none of the fuses point to a problem circuit, you must continue with your troubleshooting by isolating the remaining devices that are unfused. Some will be easier to access than others. You may have to unplug or disconnect each device to see which one is causing the current draw that's draining your battery. If you suspect the ignition switch or the light switch you can unplug each device one at a time to see if that corrects the problem. Both the ignition switch and the light switch support multiple circuits, which makes troubleshooting a problem with either of these a little more complicated. You must also be looking for a damaged wire that could be causing an electrical short. There could also conceivably be a short in one of the multi-connectors that is causing the problem. But electrical shorts that draw continuous unregulated electrical current will often cause physical damage and will show melted insulation or burnt wiring. Hopefully this troubleshooting process will eventually lead you to the source of your problem so that it can be corrected. I hope the material that I have provided here will help to guide you through the step-by-step process of fault isolation in your electrical system. Please let us know if you have any questions.

CORVAIR COMBINED WIRING SCHEMATIC DIAGRAMS
viewtopic.php?f=225&t=12968

Left-click the image to enlarge it for better viewing or "Pan & Scan"...

1963 Corvair Passenger Car Combined Schematic

[msfissel]

This is GREAT!!!

[joelsplace]

Draining a battery completely is very hard on it and can ruin it. Newer electronic chargers with a battery test will show a bad battery if it is discharged too far and they will not charge a dead battery. I keep plenty of transformer type chargers to charge dead batteries. The electronic ones will only charge a low battery.
Another tip - batteries that are discharged that far take a long time to charge. A 2 amp charger will take a couple of days.

[66vairguy]

Now batteries are typically paste/mat construction and once they discharge below 12VDC they can be ruined. About 12.2VDC is considered mostly discharged. At about 1VDC your battery is most likely ruined as others said.

Sorry but it's time for another battery and to find what in the car is draining it. Don't forget the alternator/regulator circuit could also be at fault. After all these decades and "creative" owners I find all kinds of wiring problems.

Meanwhile do disconnect the cable from the batter negative post when the car is not in use.

[msfissel]

So, I went and got another new battery, I have done the initial parasitic drain test. With my multi-meter set on 10 Amps I get a reading of .11, I am wondering if this is a intermittent issue that isn't always draining the power. Would .11 be enough to drain the battery over a couple week period?

[dave t]

bandaid
go to the local auto patrs store and get one of those green knob battery disconnects. the kind that mounts to the negative battery post and the negative cable mounts to that. this will allow you to quickly and easily disconnect the battery so you do not ruin your new battery when not testing.
of course, you will need to find and fix the device that is draining the battery.
bbodie52 has described a test procedure very well. follow that. in addition, start by testing for a drain to get a starting reference. then disconnect the engine harness at the firewall. test again. if the drain has stopped, the problem is forward of that connector. if you still have the drain, the problem is in the engine compartment. if not next unplug the multiconnector under the dash and test. if no drain, the front to rear harness is good. continue until you find the problem.
if the problem is found in the engine compartment, disconect the voltage regulator and test. if no change, re-connect and disconnect the generator/alternator and test. if it is a late model, also check the wires at the red plastic binding post on the frame by the battery.
write down each test so you can stay organized.
good luck and keep us posted.

Sent from my SM-G930V using Corvair Forum mobile app

[bbodie52]

As he states in the video, the most current you should read on a modern vehicle with everything switched off, doors closed, etc. is 50 mA. 1 ampere is equal to 1000 milliamps, so 50 mA = 0.05 amps. Modern vehicles contain a number of electronic devices that amount to small computers, and some of those devices (electronic stereo systems, alarm systems, and other monitoring devices or devices with a memory require a small amount of continuous current to keep them functioning, keep your radio settings, maintain your digital clock time, etc. 50 mA might be a reasonable continuous draw to keep these things going when the car is idle. But a Corvair is an ancient device that had none of these modern electronic components. So an original Corvair would be expected to have zero amps being drawn when it is shut down. If you have added a modern radio or a digital clock to your Corvair, the existence of those devices would explain a small current draw that would be less than 50 ma.

[msfissel]

The car is original except for this electric fuel pump the guy who owned the car prior added, I wonder if it could be the drain. Anyway, on to methodically checking things now.

[66vairguy]

Even when you find the amperage drain problem, a battery disconnect is still a good idea. Even though I rebuild/replace the electrical harness in my old cars I still use a battery disconnect on all of them. An electrical fire is rare, but easy to eliminate when the car is not being used by simply disconnecting the battery.

The average automotive battery should be charged ever two to four weeks to ensure long life even when disconnected. The Optima batteries will sit longer between charges, but they are not inexpensive.

BTW your battery has a rating of Amp Hours. That is the total rated amperage a battery can supply for an hour. While this value varies depending on actual current the average 45 Amp Hour battery will deliver 22.5 amps in two hours, etc. Two weeks would be about 0.13 Amps continuously so yes your 0.11 Amp could run the battery down in two weeks.

Good luck, and carry a fire extinguisher in the car.

[msfissel]

My Mooshimeter just arrived, looking forward to using it to try and debug the electrical issue. Wireless will be very handy for this while I am laying on my back disconnecting fuses not anywhere near the engine! :D

[joelsplace]

After you get the problem fixed buy a Battery Minder. It will keep the battery charged and desulphated. I've heard people claim to have batteries last over 10 years using them.

[66vairguy]

After you get the problem fixed buy a Battery Minder. It will keep the battery charged and desulphated. I've heard people claim to have batteries last over 10 years using them.

Agreed - but there is a lot of junk claiming to be battery tenders that are just cheap trickle chargers. Do the research and get a good one that works with the newer paste/mat batteries and has safety features. A good unit will monitor the battery and shut down at full charge and turn on when the battery charge drops. A full time trickle charge will shorten a batteries life.

[joelsplace]

Very true. I've heard the Harbor Freight ones will fry a battery in a hurry because they put out too much voltage. That's why I recommended a Battery Minder.