battery voltage question

[theplayer]

I have noticed that the voltage drops any time I roll down a window or press the brakes. It causes the lights to dim a little for about 2 seconds. Does anyone else notice this problem. It seems like the battery is too small for the electrical load required by the car. Will a larger battery help?

 

[silver98]

If you are noticing a voltage drop WHEN the car is running, its not the battery, The monitored voltage when the car is running is for the charging system and not the battery. You can check the battery voltage by turning the ignition switch to ON, but with the engine NOT started. I have not noticed this voltage drop on my 98, but on other vehicles I've had, as the window motor was 'dying', it would draw more current (hence a drop in Volts). The problem MAY be in a loose ground, dirty motor windings, dirt in the window track, etc that may cause a strain on the electric motor.

Does the window move slower than you're used to seeing? As for the brakes, you got me there. Do you have any codes on the DIC? If so, I have a 98 repair manual, and would be willing to check it out for you, but at best, it will give you only a very rough approximation as to the problem.

HTH,
Joe

 

[AZMike]

This is nomal. It takes a second for the charging system to adjust to the new load. A bigger battery may help a little - the stock one is pretty weak. I have several mysterious problems dissappear when I put in an optima red top.

 

[theplayer]

I have even noticed in my Toyota truck the voltage goes down when I put it in reverse or press the brakes but the lights don't go dim. In my car the lights go dim if I roll down a window, press the brakes, or the coolings fans come on. It seems that any sudden load addition is too much for the battery/alternator. Seems like it should be able to handle the normal load of the car but in mine the lights go dim for a few seconds. A better battery might be the fix. It has the stock battery in it now.

 

[AZMike]

Keep in mind that even with all the high tech gagetry in the vette, the charging system is still laregely based on state of the art 1970's technology. Fundemantally, there is very little difference between the electrical system in my 01 Vette and my 73 Bronco. The Vette, of course, has about 4 times the circuits, but the basic components are the same - alternator, battery, and voltage regulator.

I remember reading somewhere on the CAC about a DIC calibration that would help maintin the voltage, but I can't find the thread. I've simply learned to live with mine - which does not seem as noticable since I've put the new battery in.

 

[Ken]

This is nomal.

Agreed.