rayy

my sister's 02' ES300 has been having alternator problems. she had it changed twice, and this morning, she couldn't start the car. had to jump start it again. went to the garage today and got the battery checked, i think with a multimeter(not sure) and they said that it was good. i personally dont know the ES300 very well because i'm mostly in the GS3 forum. any info would be very helpful. thanks.

vin 78

Have your battery checked at autozone or pepboys, I'm not too sure if a multimeter can check for a good or bad battery.

When your sister had the car jumped, how long did it last until the car stopped again? If your alternator is indeed bad, your battery probably powered the ES until it was entirely drained - which means that It would have died (depending on how long her trip was).

Now if your battery is dead, the jump start would have started the car, and the alternator would have driven the car, but if she turns off the ignition, she probably wouldn't be able to restart the car w/o another jump start.

Hope it helps.

Wassa786

You can actually check if the battery is good or bad by doing the following:
when the car is running, open the hood, and detach one of the battery plugs. if the car stops running, it's not the battery...and MAY BE the alternator, not sure, but thats one way of checking the battery...it was the alternator in my accord and I had a very similar situation.

CUMan

A multi-meter is a quick and easy way of checking a battery, but it does not give a true reading of the condition of the battery. All a multi-meter does is give you the total voltage of the six individual cells. You can have five good cells and one bad one, and the multi-meter can give you a reading of more than 12 volts. This can mislead one into thinking that the battery is okay.

A more accurate check is the battery checker where you draw acid from each cell and check its specific gravity on the indicator printed on the body of the checker. If you have one or more cells which show readings significantly different from the other cells, you have a failing battery. If the readings on all the cells are low but approximately equal, you might be able to get by with charging the battery.

Another accurate way of checking a battery is a load tester. These gadgets are hooked up to the positive and negative sides of the battery. They give you a total voltage reading like the multi-meter. However, they also have a switch you can activate to put a load on the battery. A display will indicate if the battery is bad when the load is put on it. These units can also be used to check the voltage output of the alternator when the car is running.

Load testers are available at very reasonable prices (around $30.00) at Harbor Freight stores.

wowo

I drive the ES300 rayy is talking about. 2 months ago I needed to jump the car. Went to mechanic and changed the alternator. The next day wouldn't start again, so I have changed the battery. 1 month later had to jump the car again, so they swapped out a "Bigger" alternator. the bigger alternator has more coils in it. Then like last week need to jump the car again, but it was a quick jump and working fine since... Don't know exactly what's going on although I may be thinking electrical problems?

Thanks for the info

CUMan

wowo, you can easily check the alternator output with an inexpensive multi-meter (preferably the digital type).

With the car not running, check the voltage of the battery by holding the positive and negative leads of the multi-meter against the positive and negative battery posts. You should get a reading in the area of 12.6 - 12.8 volts. Then, crank the car and check the voltage with the car running. The output should go up significantly because of the voltage being supplied to the battery from the alternator. My 94 ES has a reading of about 14.4 volts with the car running. This is a good level.

If the voltage does not increase when the car is cranked, there is either a problem with the alternator, the battery itself, or something involving the wiring.