runethechamp

After doing some searching here I didn't find any threads specific to the question/problem I have. One morning, the battery of my 94 4runner (manual transmission) was suddenly bad. Not completely dead, but low enough on capacity so it only cranked the starter for a couple of turns and it then just started clicking. Luckily, I was parked on a hill so I just roll-started the car. It runs fine, no problems at all, and the alternator seems to be charging the battery fine as well since the car starts like a dream after I've been driving it for a little while. The problem is, every morning (and now also after work), the battery is low again.

I used a multimeter to test if there was anything drawing current when everything was supposed to be off, and the only place I could find something was on the dome light curcuit. As far as I can see, the interior lights, the clock and the radio is on this circuit.

My first question is regarding the reading I get on the multimeter when I test this circuit. It reads 0.3-0.5A first, then drops down to about 5mA after about 10-12 seconds. Can this be due to loading whatever capacitors are connected in the clock/stereo to keep the time and memory going?

My second question is the battery. I suspect my battery is dying on me, but the little color ring/dot I can look at in the battery says it fine. Can it still be bad? Can I load test it myself or do I have to take it to a car store to do that?

Thanks for the help.

jimbo74

sounds lie kthe battery is no longer holding a charge.....

the little light are dummy guages... they do nothing than give you a false sense of security.....

surf4runner

if its the original battery, its time for a fresh one. try what has been said above first.

runethechamp

The battery has been in there since I got the car more than 5 years ago.

Btw, the voltage reading of the battery is 12.5 volts unloaded, and it's 14.5 volts with the car running, so the alternator seems to be fine that way. But I know that this really doesn't tell me how well it is holding the charge and how much current it is able to deliver.

I'll see if I can have it load tested for free somewhere.

mt_goat

What is the voltage across the battery posts right after you turn it off and after sitting overnight?

runethechamp

When I was doing my tests on Saturday, the car would not start, but the voltage was still 12.5 volts. I haven't tested when it is charged though.

jimrockford

I recently had a similar problem with a new Optima Red Top battery I bought. It wouldn't hold a charge for more than a day and was steadily getting worse. I did a little research and came upon the term "sulfation". This website has a really good explanation of what sulfation is, why it makes a battery go bad, and how you can sometimes remedy the problem.

In my case, I bought a Schumacher SC-6000A battery charger at WalMart that does battery desulfation. I ran it through a cycle overnight and haven't had a problem since.

Unfortunately, your battery sounds like it's just plain worn out.

89macrunner

yep sounds like the battery is just dying....The battery on my bike does that...i have to start it everyday or leave it on the battery tender (which is a great little gadget)

Ill just get a new battery eventually. but this works till i accualy ride the bike for more than 30min at a time

4Crawler

iTrader: (3)

You might simply have a problem with the wiring to the starter or in the starter solenoid (worn copper contacts), both of which can mimic a dead battery. Next time it acts up, check the battery and starter voltages:

http://www.4crawler.com/4x4/CheapTri...shtml#EasyTest

runethechamp

Update: Since the only current drawn was on the dome light curcuit, I pulled that fuse when I was at work yesterday and also overnight. ANd wouldn't you believe it, the car started fine both times. Does anyone know what kind of reading to expect on this circuit with the ignition off and the doors closed?

4Crawler

iTrader: (3)

Generally you want to be under 35 mA or so with everything "off". At that sort of draw, you are pulling under 1 AH out of the battery in a 24 hour period, maybe 12 AH in 2 weeks of sitting. If you are having the battery pulled down overnight, it would either have to me a much larger drain that that, or the battery is shot.

My old radio was pulling about that current when it was off, but I had it wired so that power and memory leads were hot all the time. If I switched it to have the main power switched off, the current drain fell dramatically.

runethechamp

From my first post:

My first question is regarding the reading I get on the multimeter when I test this circuit. It reads 0.3-0.5A first, then drops down to about 5mA after about 10-12 seconds. Can this be due to loading whatever capacitors are connected in the clock/stereo to keep the time and memory going?

runethechamp

Turns out it was the battery. Got a new one from the dealer for $90 with a 6 year warranty yesterday, and the car starts like a dream.