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Discussion Topic:
40 charging question
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40fordor |
06-19-2010 @ 5:58 PM
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New Member
Posts: 116
Joined: Oct 2009
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My dash indicator has always been in the mid green range until very recently. Now it stays on the border line between yellow and green. When I check voltage at the battery with the rpm's above idle there is about 7.3 volts. The battery is very old and weak will this cause the ampmeter to show the lower current? I would think it should indicate a higher current for a weak battery.
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shogun1940 |
06-19-2010 @ 6:04 PM
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Posts: 464
Joined: Feb 2010
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bad batteries can cause all kinds of weird things. Take the battery to a place that can put load test on it and if there is any doubt, buy a new one.
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40guy |
06-20-2010 @ 6:30 AM
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Posts: 270
Joined: Oct 2009
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A 1940 battry guage is a voltmeter not an ampmeter. This is provided you don't have an after market guage. Therefore, the guage would indicate the battery voltage not amps.
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37RAGTOPMAN |
06-20-2010 @ 7:47 AM
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Posts: 1961
Joined: Oct 2009
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when the battery gets old it builds up a resistance, like it is charged already and it will not hold a full charge anymore, and will not allow it to charge fully, there for it is only alowing a little amount to charge CHANGE THE BATTERY,if it 3 years or older, it all depends who made and if it was good one or a cheap one,AUTOZONE makes a good 6v battery. I BUY all my batteries from them,have a good warrantee and a good retun policy,and a rewards program, and if and when I have a problem I know were I bought them, solves a lot of thinking were did I buy that battery 4 years ago, buy for my 31 2DR and 37CAB and well as my modern iron,
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alanwoodieman |
06-20-2010 @ 12:54 PM
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what is the voltage on the battery when the car is not running. local battery store told me it should be around 6.45 or 2.15 volts per cell, but they also said that to know for sure you need a hydrometer to test the specific gravity of each cell. I have been having a problem which was traced to a bad voltage regulator, took gen and bad voltage reg to a rebuilder, got new one from him and let him set it up, voltage running about 7.4 volts at running speed. took it home a put on, ran car ok, two days later battery was dead!!still looking for problem, must be a ground somewhere. with the car off-it shows a voltage drag on a meter between the battery and the frame of 4.5 volts-any answers>
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supereal |
06-20-2010 @ 2:33 PM
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I suspect you have a "parasitic" drain somewhere. You can put a test light between the battery port and the cable, and with everything shut off, see if the light is lit. If the drain is 4 volts, it shouldn't be that hard to find. The voltages you mention are about right, so follow a circuit diagram like a road map from the battery out into the car. If you don't have a circuit diagram, I can scan one for you. You said you installed a new generator and voltage regulator. Often, the cutout in a regulator sticks, but I think your problem wasn't with the regulator or generator, but elsewhere, and it is still there.
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alanwoodieman |
06-20-2010 @ 6:21 PM
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Supereal, I have disconnected everything from the circuit-horn relay, brake light swith, voltage regulator,heater switch, cigar lighter, radio, light switch even disconnected the starter relay-still got the drain--got any ideas?
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shogun1940 |
06-20-2010 @ 8:02 PM
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Posts: 464
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how about the brake lights going on in the middle of the night,, then find out if its draing through the gen. reg. what else is left
This message was edited by shogun1940 on 6-20-10 @ 8:08 PM
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Johns46coupe |
06-20-2010 @ 10:54 PM
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alanwoddieman, I had a slight drain as measured by the ammeter on my multimeter (didn't register on the car's ammeter because it was so slight). Chased it to an aftermarket turn signal switch. In this case, I would disconnect everything as close to the battery as possible. Then, with an ammeter, connect one thing and measure. If that's ok, add another and measure. When you find the connection that causes a draw, break that one down and disconnect all of it's branches. Then connect one at a time and measure. Eventually you'll find it. John
This message was edited by Johns46coupe on 6-20-10 @ 10:56 PM
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TomO |
06-21-2010 @ 7:33 AM
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Posts: 7253
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40fordor, the battery gauge shows the voltage in the charging circuit when the car is running. An old, sulfated battery will have a high surface charge causing the voltage regulator to react like the battery was fully charged. The battery gauge would then be on the border line between yellow and green or just into the green.
Tom
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