Intended to test drive overdrive today, but battery was dead again after charging it all afternoon. I took it back to NAPA and they said it was so low, .058 cold cranking amps they could not test the battery. So the problem was either the charger, the alternator, or the battery. So, I purchased a new battery charger, charged and it all afternoon. It spun over nicely and started right up at 7:30. Checked the charging system and the voltage while idling was 14.75 volts. It was too cold by then to stand around to see if voltage would drop after a bit, but for now it looks OK. Unhooked the battery and closed things down. Obviously the old battery charger was not good. Eventually I want to get a nice battery tender that not only functions as a charger but will maintain the battery over the winter or any time the car sits.

Now I am wondering if there is a slow drain on the battery that ran it down since January as it sat. The BMW sat for 3 months and started right up this week. I think a battery cut off is a cheap stop gap for the moment. My only concern is I had one of these years ago, and it would sometimes fail to make a good connection when turned on. I used the kind that has a green knob that you turn to make and break the connection.

Thanks for any suggestions. Sam

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Sppedway Motors; They do have a few others, but I wouldn't want to trust them.

Roger

http://www.speedwaymotors.com/Moroso-74 ... 06748.html

http://www.speedwaymotors.com/Two-Post- ... ,2380.html

http://www.speedwaymotors.com/Four-Post ... ,6967.html

I have used the kind with the knob from the parts store and have had no problems with those.

Lou

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Home of Slant6-powered fun machines since 1988

I know you want suggestions on which battery disconnects to use. But as long and nothing is on (radio, dome light, security device) then nothing should drain the battery. I would check for a short or bad/corroded connection. I Just replaced my starter and got back 12.2 volts at the connection after i cleaned it. Compare that to the 12.025 i had before. It worked but not as well.......

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~Nic

I use what lou used.


The green knobs from the swap meet / parts strore work fine..


Nica,

Sam has a highly modified dart so there are tons of small electronics that could drain the battery.

In a pinch just disconnect the negative cable.... keep a small crescent in your pocket or on a key chain for this


Greg

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http://www.youtube.com/hyperpack

Thanks guys. The two most obvious drains are the aftermarket radio with its presets that go away when I disconnect the battery and the POS autogage analog clock, which you can hear ticking while sitting in the car with the engine turned off.

Have I damaged this battery by discharging it so completely? It is 2 years old from NAPA with a 72 month guarantee? It delivered 11.75 volts but no power. It went to 6 volts when cranking (clicking actually).

Sam

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Here ya go. Will also keep your radio presets.
http://www.classicindustries.com/produc ... 20309.html

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~Nic

You'll still drain the battery with that.........


Harbor Freight has those (minus the fuse).

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Sam,

I just use a cheep Wal-Mart cut-off with green knob which is installed on both old heaps. My thought was to have two old sleds unenergized when stored within the buildings, and a side benefit is a quick way to brake connection with battery during a wiring harness melt down when the Fire Gods become aggravated.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Great web site. Thanks. I will book mark that one.

Does anybody think I have damaged the battery by letting it get so low? Cannot interpret this new battery chargers LEDs. It never gets to where the fully charged LED lights up, however it will light the digital feedback LEDs so it says 100% IF I turn it off and on again. It will stop at 90 or 95% if left alone. The charger never seems to think the battery is charged enough to go into maintenance mode. I may take both the charger and battery back to NAPA for testing. Now that the battery is charged up, they should be able to put a load tester on it.

Sam

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Car batteries don't like to be deeply discharged but sometimes the survive OK; you will only know for sure if you charge it and test it for a while. I would run it and charge it for a few cycles and then put it on the charger for 8 hours. Then completely disconnect the battery and let it rest overnight and come back and measure it in the AM. It ought to read in the 12.6-12.7 volt range if it is good. Any lower than 12.6 and a cell likely weak. And it might be worthwhile to get a battery hydrometer and look at the acid in each cell if it is the type where you can access the acid, and see if they are all equal density.

As for disconnect switches, I use them on race cars, but prefer to not put them on a street vehicle. They can be problematic and cause electronic noise at times. I just disconnect a battery terminal if the car will set for a while.

I would expect the new charger to just look at voltage for it's decision making. If the battery is in-car with other electrical devices attached, it might not see the voltage peak enough to make it happy.

Thanks. When I got back from my test drive the VOM showed 13.1 volts. I will test it in the morning and see how it did. I guess I should disconnect it over night to know if a lower reading is a simple draw on it or losing its charge because it is bad.

Sam

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Yes, the 13.1v reading after charging is due to something call 'surface charge'. That needs to dissipate before you can take accurate cell or battery voltage readings. Once 'rested' (i.e., surface charge dissipated), a good battery with good charge should read 12.6-12.7 volts.

It reads 12.5 after a week of sitting unhooked in temps as low as 15 f. I guess its ok. Thanks.

Sam

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