Battery Drain?

[Purplecty]

I parked the 4.6 in the garage Saturday afternoon and Tuesday at 130am the alarm started going off a bunch of times. The key would not turn it off due to the battery being so low. I somehow got the alarm to turn off and later that morning I opened the door to find the battery completely dead. I have had the X parked for way longer than this before but the temps have been a bit lower, but I am not sure what caused the battery drain. I had to throw the charger on just to get the trunk open. I left it like this while I had work for a few more hours and checked periodically to make sure the shifter light was off confirming she is properly going and staying asleep. I later proceeded to pull the battery to hook up the charger directly to it. I left it on a 10amp charge for around 8 hours and then set it to 2amp later in the evening. The battery is now fully charged and im wondering if it's worth having the battery tested to rule it out as being bad or maybe something else is causing the battery drain? I scanned the car with ISTA and did not have any new or sensor related errors (I was checking for the common hood sensor issue or anything else similar). Any ideas would be greatly appreciated...

[80stech]

The best way to test the battery is with a load tester. The best way to check for a drain is to do a drain test with multimeter and battery switch(optional but makes things easier and results more reliable.) Even if the drain turns out to be acceptable you'll have good knowledge and a base line for next time so no time wasted.

[Purplecty]

Originally Posted by 80stech

The best way to test the battery is with a load tester. The best way to check for a drain is to do a drain test with multimeter and battery switch(optional but makes things easier and results more reliable.) Even if the drain turns out to be acceptable you'll have good knowledge and a base line for next time so no time wasted.

Now that it is fully charged I will take it by advanced auto and have them test it since I do not own a battery load tested. I do have an aftermarket head unit with navi that came with the car and noticed the MK3 navigation unit is still installed in the trunk along with a Dietz multimedia interface which I believe is no longer being used. I think this Dietz interface is to work with the original 16:9 unit? Anyone familiar with this interface?

[c-bass]

How old is the battery? I my experience batteries nowadays are crap and don't last nearly as long as they used to.

First cold day is usually a good indicator of a battery that might be problematic soon.

[Purplecty]

Sorry forgot to post that the battery is from 2.19. I just removed all of the unnecessary modules from the driver side and the air pump(which wasn't connected but for easier access to the battery-I have coils that the PO installed in the rear in place of the airbags). I left the amp in there but it is already disconnected...

[puddinboo]

For our BMWs you would be lucky to get 5 yrs out a battery now a days. Especially if you live in the north where it goes down to -45c

Originally Posted by c-bass

How old is the battery? I my experience batteries nowadays are crap and don't last nearly as long as they used to.

First cold day is usually a good indicator of a battery that might be problematic soon.

Sent from my SM-G950W using Xoutpost.com mobile app

[puddinboo]

You would think the battery would be good,not even 2 yrs old yet. But you never know.

Originally Posted by Purplecty

Sorry forgot to post that the battery is from 2.19. I just removed all of the unnecessary modules from the driver side and the air pump(which wasn't connected but for easier access to the battery-I have coils that the PO installed in the rear in place of the airbags). I left the amp in there but it is already disconnected...

Sent from my SM-G950W using Xoutpost.com mobile app

[Purplecty]

Originally Posted by puddinboo

For our BMWs you would be lucky to get 5 yrs out a battery now a days. Especially if you live in the north where it goes down to -45c

Sent from my SM-G950W using Xoutpost.com mobile app

My 4.6 did spend the last 3 or so years in cold Wisconsin...

[c-bass]

Originally Posted by Purplecty

My 4.6 did spend the last 3 or so years in cold Wisconsin...

By the second winter my brand new Costco battery failed. It literally blew 2 of the covers off and spewed acid everywhere.

"They don't make 'em like they used to" might very well apply here

A few weeks ago I treated myself this battery tester from Amazon and tried it on the fleet.

https://www.amazon.ca/gp/product/B07...?ie=UTF8&psc=1

I had a few batteries ranging from few months old to a couple old long dead and I'm happy to say it was VERY accurate in my case.

This little tool also tells you the health of your battery and it seems about right. My brand new battery shows as 97% health and a battery I've had for several years in a car that's been sitting and gets a lap or two around the block every few weeks shows about 58% health.

It also will check your charging system/alternator while you're at it as well

[80stech]

@ c-bass, did you still have the vent plugs in ?? Or maybe your vent hose was plugged??
This is a better load tester https://www.amazon.ca/ATD-Tools-5489...324337&sr=8-25 Princess Auto sometimes has these on for $69!