weak alternator voltage and 10 burnt fuses... !! ??

[theoldwizard1]

With the engine off, turn your headlights on for about 10-15 minutes. Start the car and check the voltage at the battery with known good DVM. It will be over 14V but will come down to that 13.8V mark after a few minute.

This is how the "smart charging" system works.

Blown fuses are not related to this behavior.

 

[stamp11127]

You don't have to drain the battery prior to starting. The initial crank load is in the neighborhood of 400+ amps before the engine starts turning. This is enough for the voltage regulator to start charging the battery.

Once running you can put a good load on the electrical system by turning on the ac and high beams. This will put at least a 45amp load on the system in addition to what is already on.

Mohammed, clean the wire plugs and contacts on the alternator with contact cleaner also. Disconnect the negative battery cable at the battery first though. Reconnect when finished.

 

[mohammed]

With the engine off, turn your headlights on for about 10-15 minutes. Start the car and check the voltage at the battery with known good DVM. It will be over 14V but will come down to that 13.8V mark after a few minute.

This is how the "smart charging" system works.

Blown fuses are not related to this behavior.

OK, I'll try it and get back with results

I didn't know about smart charging, but is it normal even if I notice the instrument panel light some how dim no as I remember them ? is it related ?

the fuses were not blown, I just rechecked them after words when vehicle when engine on and took of some of them and were fine.

You don't have to drain the battery prior to starting. The initial crank load is in the neighborhood of 400+ amps before the engine starts turning. This is enough for the voltage regulator to start charging the battery.

Once running you can put a good load on the electrical system by turning on the ac and high beams. This will put at least a 45amp load on the system in addition to what is already on.

Mohammed, clean the wire plugs and contacts on the alternator with contact cleaner also. Disconnect the negative battery cable at the battery first though. Reconnect when finished.

in all my test scenarios it involved testing the vehicle with A/C on headlight and fog lights, the voltages are as discussed earlier.. so yah its head scratcher.

 

[stamp11127]

Disconnect the battery and clean the output stud and wire terminal on the alternator and cable. Also clean the connector for the other wire to the alternator and battery posts and terminals using contact cleaner.

Reconnect the battery positive first then negative last.

Start engine and read charging voltage.

Let engine warm up some then place a load on the electrical system by turning on ac with blower motor on high and the high beams. Rev engine to at least 1500 rpms and read charging voltage again.
If not within spec of 13.5 to 14.5 volts, using a volt meter or multimeter read voltage from alternator output stud (+) to negative battery post.

Be careful to avoid shorting the output stud to alternator case with the probe.

Let us know what the voltages are.

 

[mohammed]

Disconnect the battery and clean the output stud and wire terminal on the alternator and cable. Also clean the connector for the other wire to the alternator and battery posts and terminals using contact cleaner.

Reconnect the battery positive first then negative last.

Start engine and read charging voltage.

Let engine warm up some then place a load on the electrical system by turning on ac with blower motor on high and the high beams. Rev engine to at least 1500 rpms and read charging voltage again.
If not within spec of 13.5 to 14.5 volts, using a volt meter or multimeter read voltage from alternator output stud (+) to negative battery post.

Be careful to avoid shorting the output stud to alternator case with the probe.

Let us know what the voltages are.

I just cleaned off the battery terminals until I exposed the copper and sanded the battery posts,

The starting voltage is 13.6 after engine start
Underload voltage 13.8 v

Reving the engine didn't make any noticable difference

I also checked the voltage from the alternator, I didn't notice any voltage drop from to the battery.

Does it mean any thing, is it smart charge as "theoldwizard1" said ?

 

[stamp11127]

The charging voltage is within spec but on the low side.

The next step would be to electrically drain the battery a good amount. You can do this as stated in an earlier post by turning the head lights on and monitoring the battery voltage until it drops to 12.2 volts.

With the meter still attached to the battery start the engine and increase rpms to 1500. Note the charging voltage with the meter. It should be above 14 volts but drop as the battery charges back up.

If it is still low then you need to determine why.