Akumulator Proverka

7/23/2019 Akumulator Proverka

http://slidepdf.com/reader/full/akumulator-proverka 1/14

pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API

lead connects to the car chassis, and negative meter lead to the negative post of the battery.

A good electrical system battery drain

http://pdfcrowd.com/

http://pdfcrowd.com/redirect/?url=http%3a%2f%2fwww.w8ji.com%2fbattery_and_charging_system.htm&id=ma-150609010415-4f160127

http://pdfcrowd.com/customize/

http://pdfcrowd.com/html-to-pdf-api/?ref=pdf




This is measured on the 20mA scale. The mA scale reads in thousandths of an ampere. My 1989 Mustang LX, after I changed a bad alternator diode, now has about

1.73 mA of battery drain. This drain is all from the EEC-IV computer memory. Different radios and different computers might have different standby drains, as mightaccessories like clocks, but in no case should "overnight off" leakage exceed 25 mA or so. 100 mA is like leaving a small interior dome light on!

My Kenwood stereo draws 1.5 mA when connected. If you have a digital clock that stays on, an alarm, or some other load this current will be higher. At 75 mA,

leakage could compromise battery life of infrequently driven vehicles. mA is milliamperes, or one 1000th's of an ampere.








The meter above is on the 20 mA scale, and is reading 1.73 mA. That is nothing. The battery charge would probably last for months of sitting.

Bad battery parasitic Drain

If the test light lit, you will want to locate the wire loading the battery. First make sure all lights are off. You can do this by having someone open and shut things with

lights, like the trunk, and watching for a define large load change. You should see a definite load change when shutting doors with lights, like the glove compartment.

Connect the test light in series with the negative post, and start pulling feed wires. The first to check is the heavy charging wire from the alternator. A bad or leaky

diode in an alternator is a very common source of overnight battery drain.










Connect wires one at a time to see what lead is drawing current. In my case it was the alternator lead! Even though the alternator was charging fine, it was also draining

the battery. My problem was a bad alternator diode. There could be a variety of other problems, like a bad voltage regulator or a stuck relay contact.

Download a wiring diagram








I downloaded this from T. Moss's website, which I find much more useful than other sources. Tom Moss goes out of his way to help people, and is a genuinely

nice fellow. AutoZone and others have some free schematics up also.

T.Moss's diagram (linked above) showed me the heavy dark green wire from my starter relay causing my "drain problem" went directly to my car's alternator output.

In my case one of the diodes (the little black "arrows") in my car's alternator was bad. This current loss also made my alternator slightly warm to the touch, even when





http://www.veryuseful.com/mustang/tech/engine/




sitting off for several hours.

Other Helpful Voltages

Battery voltage can be higher than 12.6 volts immediately after charging.

Open Circuit Voltage of 12V batteryafter car is off for one hour

Relativecharge

12.6 V 100%

12.4 V 75%

12.2 V 50%

12.1 V 25%

Less than 12 volts Dead

Any open terminal voltage below 12 volts is considered full discharge or a dead battery.

Testing Starters

Starters sometimes can test good out of the car, but can be bad. One common problem with cheaply built or defective starters is starting torque loss when hot. This

usually happens because the iron loses ability to hold magnetic flux (starter current skyrockets when hot), or because the wire is undersized and goes up in resistance

(starter current drops when hot), or the starter seizes up (also causing high current).

The best way to test a starter is by measuring voltage and current.

To test a starter and wiring with a simple meter:

Clip the meter positive lead to the starter feed wire going into the starter

Clip the meter's black negative lead to the ENGINE BLOCK

Make sure the meter is on volts, and set to the lowest voltage scale possible that reads at least 15 volts. In other words if your meter has 2.5-volt, 25-volt

scale, and 250-volt scales, use the 25-volt scale. The 25-volt scale is the closest scale to 15 volts, but is not under 15 volts.








With the meter clipped across the starter, watch the meter while cranking the engine.

Make sure the battery is good. There is a voltage table above for battery charge. The no load (everything off) battery post voltage should be at least 12.6 volts and as

high as 13.8 volts.

If the starter cranking voltage goes below 9-10 volts, you have a problem with starter current, engine grounding, or battery.

Measure across the battery by probing directly into the battery posts (NOT the terminals that clamp to the posts, but poke directly into the lead posts coming out of

the battery), and see how much the battery drops when cranking. If it drops and you are sure the alternator is working, take the battery to an automotive parts store

that tests batteries. Unlike starters, testing batteries is VERY easy and very reliable.

If the battery stays up on the posts and the starter voltage sagged down, you probably have a bad starter wire, ground wire, or some other wiring problem. If the

battery post voltage tests good but sags abnormally with your starter, you probably have a starter problem. You need to have starter current checked.

Cheap or poorly manufactured starters show up mostly when the starter is very hot. Starters very often cannot be tested accurately on a bench, because they often can

fail only when very hot. I see very few tractors, cars, and trucks that crank OK when cold and do not crank when hot that have problems other than a starter! My

diesel tractor was a bitch to start when hot, but cranked like a dream when cold, and it was the starter. My tractor does not have headers, either. Just the block heat

was enough to make the starter quit. I've had the same experience with cars. When cold, the starters work and test good! Marginal starters can have enough oomph to

start properly when the system is cold, but fail when hot.

Bad alternators or batteries show up mostly when the car is very cold, but both alternators and batteries can be tested reliably to see if they are good.

Installing a larger alternator will not fix a bad starter, bad battery, or bad wiring.

















Documents

Akumulator Proverka