pusher_sr

background: new alternator, new battery, new voltage regulator, new a/c work (switched to r134a last winter). my problem: when i turn on the a/c now the battery jumps up to 3/4 on the overcharge, and just a bit more when i turn on the blower. it was working fine a month ago. where should i start my search on this new "electrical problem". thanks for any help or advice. ted

63C2splitter

Not sure what you mean when you say "over charge". My amp meter centers on 0, then the needle can go to + or - 40 amps. When my AC is on, the needle will go up on the + to indicate the alternator is providing additional charge to the battery / electrical system. Will see some jump if I turn on other electrical draw on the system (ie. headlights).

Dave

pusher_sr

yes, that's what i meant (to the right on the positive side). i noticed a slight increase before, but now it jumps up far too much (past the 3/4 marker). my new alternator & voltage regulator are only 4 months old and was hoping to eliminate those two as my problem. could i possibly have a defective alternator or voltage regulator?

67435animal

Check your battery cables and grounds. Make sure they are corrosion free and tight. At your regulator, make sure that the connector is snug for each terminal. There is a very important ground that must be connected to the base of the regulator.

If everything is snug and clean, you should be fine. I'd worry if the regulator showed it was charging all the time with the AC off.

ffas23

I'm not sure you really have an electrical problem.

First of all if you were to have your lights on plus the a/c and blower on this uses a lot of power and you cars charging system needs to put power back into your battery. The needle on your amp meter is going to move up on the right while these items are being used. With these items shut off the needle on your amp meter will usually be just about center on the dial showing a normal running system. If you don't trust your amp meter and really want to be able to check your system I recommend you get yourself one of those hand held Battery and Charging system testers. Milton makes the best one part number 1260. You can get a cheap Chinese copy from harbor freight for under $20 where the Milton will cost you probably around $60 or higher. This way you can just pop your hood with engine running, attach the 2 cables from the tester to your battery and check how your charging system is and compare it to your cars amp meter reading at the same time if you want. The scale on the Milton tester and copy tester have colored zones as well as numerals showing charging voltage. This testor will show overcharging and undercharging to no charging at all pointing out a problem your car could have. Believe me the tool is worth the money and will pay for itself a hundred times saving you from buying a new battery when it is not necessary to do so plus tell you if your alternator or regulator or both are bad on any car you own. The tool also checks a car battery to see if it is good or bad by doing a 10 second load test on it. This needs to be done on a fully charged battery to test properly though so having a battery charger is needed also to do this test. If you are going to work on your own car it is almost a necessity to own both these tools.

magicv8

Put a $5 voltmeter on the battery, alternator, and horn relay, before you say the battery is being overcharged. The battery meter reads the voltage difference between the horn relay and the starter solenoid, based on the shunt value of the engine bay harness lines (that connect the solenoid to the horn relay). If the shunt value is too high due to poor connections or wire gauge size, the battery meter will read high.

Only voltmeter readings will tell you what the alternator is doing. If the alternator is putting out 14.5 volts or less and is rated for at lest 61amps (for A-C cars), it's normal. In that case, adding a big red wire between the the horn relay and the solenoid will suppress the high battery meter reading, but I would put a 30 to 60 amp fuse in the line and a 1 or 2 amp fuse on the battery meter terminal.

PS: The factory battery meter does not read in amps.

63C2splitter

It could be something as simple as a faulty Ammeter (battery gauge). In the service manual for my 63, they provide little info on trouble shooting. There are only 4 lines of info in the section titled "Ammeter or Oil Pressure Gauge". In the 63 Service manual it is located in Section 12, page 14. Good luck getting the problem resolved.

Dave

pusher_sr

i just re-read my post and i forgot to state that when idling i don't have a problem with the ammeter jumping up on the positive side when the a/c gets turned on. it's fine when idling but takes a huge jump (past the 3/4 line towards + ) when i rev up the motor to 1500 rpm or better. does this maybe narrow down my problem? sorry for the original misinformation (or should i say omission). thanks for all the responses.

ffas23

Reading this post it sounds like a faulty regulator to me but not having the car right in front of me with my Milton Tester I can't really tell you by just reading what is written here on the forum. Do you know what type of regulator is on the car? Is it the old point setup or is it electronic? You could do the process of elimination and just plug another regulator into the system to see if the same thing happens with the test regulator. They are not that expensive. Just make sure you get an allegator test lead to ground the test regulator if you are going to use another to test the system. I would also use the same test lead as another ground to use for the current regulator on the car in case you have a bad ground causing your problem. If there is no difference I would suspect the amp meter but before I would look to replace it I would invest some money and pick up the Milton or Harbor Freight copy tester out there to see what the meter shows on the tester and compare it with what is showing up on your amp meter at idle and while giving the engine some gas.

magicv8

I don't want to hijack the thread, but a small explanation may help.

The Battery gauge is a sturdy galvanometer, not an ammeter (read the label). It has a winding inside the can/cover that either works or is burned through. Where it is connected in the harness, it only responds to voltage differences between the battery terminal of the horn relay and the battery terminal of the starter. Its wiring stradles an engine bay harness wire that acts as a shunt - that is a connection that takes most of the current while the meter gets just enough to show which way current is flowing without melting the fine wire in the meter. If the harness shunt wire is burned or disconnected, the battery meter will burn out, since it can't take the load. I protected my original battery meter with a 1 amp fuse. I would not allow more than 2 or 3 amps through the meter if I were you.

C1 cars have ammeters. c2 cars have galvenometers labeled "BATTERY".

PS Since PUSHERSR said he had replaced the voltage regulator, I assumed the first one had the same problem. Assumptions are tricky. Pusher - why was the regulator replaced??

63C2splitter

As for resolving your problem, I think Magicv8 and ffas23 are correct in thinking it may be a regulator problem. Need to get a meter on it to trouble-shoot. If you have the old regulator, that is the first thing I would try.

As for the gauge discussion, an ammeter and galvenometer are basically the same thing. If you do need to order a new "battery" gauge, it will be identified as an ammeter in the parts list (costs about $70 to $80).

Dave

http://en.wikipedia.org/wiki/Ammeter