[Slick_FThirty]

Hello,

My battery just recently went flat (I was doing some coding on the car). I witnessed the car losing all power, which involved a humming/ticking sound that seems to have come from the front and back right side (passenger side), until it went silent from losing all power. The humming/ticking occurred for about 10 minutes.
I bought a charger and connected it to the charging and jumping terminals under the hood. When I powered on the charger, the humming/ticking as above resumed and decreased in loudness with time over about 30 minutes. My battery charger was charging at 4.5V and continued to do so over 3 hours without changing. If I tried to turn on a light in the car, for example, the ticking/humming would start from the rear passenger side area, until I turned the light off ( the light would just be flickering).

I now removed the battery from the car and have connected it directly to the battery charger. The voltage started at 10.7V and is now at 11.5V after two hours at 2A.

What is the cause of the humming/ticking and low voltage with the ports under the hood?

[IK6SPEED]

Originally Posted by TechiGamer

Hello,

My battery just recently went flat (I was doing some coding on the car). I witnessed the car losing all power, which involved a humming/ticking sound that seems to have come from the front and back right side (passenger side), until it went silent from losing all power. The humming/ticking occurred for about 10 minutes.
I bought a charger and connected it to the charging and jumping terminals under the hood. When I powered on the charger, the humming/ticking as above resumed and decreased in loudness with time over about 30 minutes. My battery charger was charging at 4.5V and continued to do so over 3 hours without changing. If I tried to turn on a light in the car, for example, the ticking/humming would start from the rear passenger side area, until I turned the light off ( the light would just be flickering).

I now removed the battery from the car and have connected it directly to the battery charger. The voltage started at 10.7V and is now at 11.5V after two hours at 2A.

What is the cause of the humming/ticking and low voltage with the ports under the hood?

There is a reason why Dealership connect up to a charger when updating code in cars.

[rak299]

Bad ground cable?

[Slick_FThirty]

Update: so I've been charging my battery externally from the car, and it charged up enough to barely turn the engine over. I then drove it for about 30 minutes. Connected up my charger to the terminals under the hood and now it is charging it fine. It's giving 8A at 12.7V with 60% charge.

I'd still be curious why I wasn't able to charge the battery when it was flat through the engine bay terminals, and what the source of those noises were, and why my charger was detecting 4.5V as the appropriate charge voltage.

[dmaxdmax]

Sounds like maybe it's time for a new battery? (I'd expect that you'd need more time charging the flatter a battery is...and coming from the hood, you've got a lot of cable to put power through.) My shop owner says bmw says to put a new battery in every few years.

I drove my 80k mile battery for an hour on the turnpike. An hour after shutting down it's at 12V. Should be 12.5. Alt is putting out 14.5. Tired, old battery. These cars apparently use a lot of electricity!

Getting a new one this a.m. Good luck with yours.

[Billfitz]

The noises and the inability to charge using the posts were caused by all the devices in the car that were attempting to power up but couldn't because the voltage was too low. You didn't state if you had the engine running or if you had it on the charger when coding. If you didn't that's what drove the last nail in the battery's coffin, but at seven years old it was likely ready to give up the ghost at a moments notice anyway.

These cars apparently use a lot of electricity!

The problem is how much they use when the engine is off. That's especially problematic when it gets cold. Mine goes on the maintainer every night that the temperature goes below 25F, or when it goes below 32F and I'm not driving the next day. A constant drain on the battery in cold conditions shortens its life. A maintainer keeps the charge topped off, and takes the load off it, extending battery life.