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2005 Optima/Magentis 2.0L 4 cyl 4 speed auto 2WD
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2005 Optima/Magentis 2.0L 4 cyl 4 speed auto 2WD

My friends car battery went dead during lock-down. Here in the tropics, they don’t last more than a few years.
So, a new battery installed by a great battery shop. System tested … all good.
After a month, the car sat for another 5 days. Again, dead.
Brought it back to the shop thinking, maybe a bad battery?
They gave her a loaner while they recharged the battery for a proper load test.
Same thing happened with the loaner battery.

Obvious things were checked like the truck light. No accessories plugged in.

I spent 2 days doing all sorts of tests. It is amazing the current loads that come on and go off in a timed sequence simply by turning the key to on and then off. I have an industrial duty Fluke meter and connected it in-line with the battery … in series with the negative cable.

If you do this, do NOT attempt to start the engine with the meter connected. I think starter motors draw about 200 amps.

What I discovered was, when I connected the meter and everything was off, the current draw was 0.02 amps. However, if I turned the ignition switch on and then off, it only dropped down to 0.25 amps and never went lower.

I repeated this test multiple times and the results were the same.

With the 0.25 amp load, I unplugged every fuse in the engine compartment.

The 50 amp fuse marked I/P B+2 was the only one that interrupted the current.
That supplies the fuse block inside the car, so I did the same there. There sure are a LOT of fuses.
The one that had an effect was a group of two held by a clip so they can be withdrawn for car storage.
The two are marked Memory and Audio.

The audio was the one that was causing the problem.

I had noted when I took the car, the radio display said “CODE _ _ _ _ “
It is a theft feature. The radio will not work if you do not enter the correct code.
So what. I wasn’t listening to the radio.

I located the code card and entered it just because I was trying everything.

The problem disappeared.

How strange. Regardless if the radio is on or off when you turn off the key, it draws more current if the code has not been correctly entered.

BTW ….. 0.25 amps x 13.2 volts = 3.3 watts That will discharge a battery over time.

The radio …. Kia XCD-222/XCD-232
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2019 Kia Sportage. SX with AWD. 2.0L Direct Injected Turbocharged & Intercooled Gas.
1,099 Posts
Excellent write up! Thank you for sharing!
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