Voltage Issues with My Car

[Mini-itx]

I am driving an old 1992 Toyota and I am facing some wierd voltage issues for quite sometime already.

 

The battery reads 12.7V which is healthy.

 

When I start the car, the battery will rea around 13.8-13.9V (indicate charging from alternator).

 

However, when I start to on the aircon fan, voltage will drop by around 0.5V. Turn on head lights voltage drop another 0.5-0.6V. Its so much that I get only 12.xxV when car is running.

 

I tried to measure the output from the alternator and it says 14.15V, but I don't have an explaination why my batt only reads 12.5-12.6V. Does turning AC and headlights really consume that much power and cause that big of a voltage drop?

[Octopus]

I think older cars would benefit from installation of grounding wires, because the original ones may have deteriorated hence higher resistance for electrical flow.

[Yeobh]

What you need to do is a voltage drop test - from engine to chasis using a volt meter. Start the engine, select votlmeter to DC, place + probe on engine body and - probe on chasis and move - from location to location until uyou reach battery - terminal. Take not of the readings - should not be more than 0.5 volt dc. If more than 0.5 volt dc you need to place more cables from engine to chasis to improve return of current to battery - terminal.

 

PS Try cleaning cable connections from engine to chasis and battery terminal.Dirty, rusty connections can cause high resistance in current flow.

[Jilli8]

in old cars that types of came through many times but don't worry this problem can be solved

 

thanks

 

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