Question on Alternator Charging

**Hibiki** · February 4th, 2007 07:19 PM

Kapag naka-idle ba ang sasakyan, bukas ang headlight, bukas ang aircon, at bukas ang radio dapat nagcha-charge pa rin ang alternator?

Ilang volts dapat ang magre-register sa voltmeter kung nagcha-charge ito?

Yung isuzu pickup ko kasi nasa 12v lang ang naga-appear sa dashboard voltmeter. Iniisip baka nade-drain ang battery.

Salamat sa replies.

**alwayz_yummy** · February 4th, 2007 07:46 PM

norammly dapat 12.5(full-load)- 14.1v lang yan. above that, sisirain na baterya at electricals mo, lower than 12 didiscargahin baterya mo.

**JiggeR671** · February 4th, 2007 08:13 PM

^
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true that

**lhandzs** · February 5th, 2007 03:43 AM

Here's what you need share ko na rin sa lahat from ASE TECHNICIAN...ooooppss hindi po ako un

[SIZE="3"][SIZE="3"][SIZE="3"][SIZE="4"]Step 6: Measure Charging Voltage at Battery Terminals - Engine Cold ( engine cold running test).[/SIZE][/SIZE]
[/SIZE][/SIZE]
DO THIS:
Start the engine. Place the DVOM test leads on the battery terminals (red on positive and black on negative) with engine running at about 1500 rpm to verify correct charging voltage. The voltage that actually charges the battery is the amount of charging voltage that appears at the battery terminals.

EXPECT THIS:
The charging voltage should be approximately two volts above battery voltage. For example, 12.66V + 2V = 14.66V. Charging voltage varies between 13.8V -15.1V depending on ambient temperature [higher in cold weather, lower in hot weather]. Allow for changes in charging voltage due to ambient temperature variations, as well as, differences in car makes. Practical experience checking several vehicles will help you determine actual normal charging voltage values for any given car make and vehicle condition.

TIP:
Do not check charging voltage at the back of the alternator nor rely totally on charging voltage value displayed on a diagnostic machine. The actual charging voltage, the voltage that charges the battery, can only be measured at the battery terminals with a DVOM.

[SIZE="3"][SIZE="3"][SIZE="3"]Step 14: Measure Final Charging Voltage for Undercharge.
[/SIZE][/SIZE][/SIZE]
DO THIS:
This is a quick check to test the charging system for undercharging. Place DVOM test leads on the battery terminals with warm engine running at about 1500 rpm. The idea is to check the charging system under a normal but heavy electrical load.

Turn on these electrical loads:
1. high beam headlights
2. a/c (or heater) high blower
3. electrical windshield wipers
4. radio

EXPECT THIS:
A lower charging voltage under electrical load. Charging voltage under load at the battery terminals should be in the range of 13.0-13.5V for a healthy charging system. It should not be lower than 13.0V unless the ambient temperature is very hot. If lower than 13.0V it indicates a weak charging system due to these possibilities: a loose alternator belt: weak regulator: bad alternator diode or defective rotor winding in the alternator. However, in hot weather a charging voltage lower than 13.0V maybe normal for some vehicles under normal but heavy electrical load. Practical experience in running these tests will show you what is normal for a given vehicle.

TIPS:
#1. If you suspect a bad alternator hold this test condition for about 5 minutes and watch for a drop in charging voltage. If charging voltage drops too low the alternator may be breaking down under load when hot.
#2. If the cause of a lower charging voltage is due to a bad connection between the alternator and the battery it would have been revealed by higher than normal readings in steps 11 and 12.