Weird electrical gremlins

[Chucklez]

Originally Posted by bcredliner

Even though you have fairly new battery and alternator. Load test the battery, most chain type auto parts stores will do it free. Charging voltage is easy to read with a multimeter at the battery connection under the hood though I think the easiest way is to unlock the cluster and go to test 9. https://www.youtube.com/watch?v=z4Kk3Q5co5c

Thank you! Okay so I did the test twice. First time I did it the battery showed 11.2V then when I switched it to accessory it went to 10.9V then starting the car took it down to 10.2V but then quickly shot up to 13.9V after the alternator kicked in. Definitely not good though so I let the car sit for a few minutes and did the test again JUST to be sure ya know? This time the voltage started at 10.4V then in accessory it dropped to 10.2V then when starting it dropped all the way to 9.1V then once again after the alternator kicked on it jumped up to 13.8-13.9V.

So I'm going to make an assumption that the problem is the battery? Thankfully mine has a 4 year warranty on it from Sams Club but here's the other thing my battery is not a AGM battery, does this matter? This is the exact battery I bought. Should I get a AGM battery instead? Does it make THAT big of a difference? Also if it matters last time I had my X5 into my personal mechanic (which was to replace the alternator and the alternator bracket) he said something about the programming of the car thinking it had a AGM battery in it so he switched it to think it has a normal battery in it.

[wpoll]

Originally Posted by Chucklez

Also if it matters last time I had my X5 into my personal mechanic (which was to replace the alternator and the alternator bracket) he said something about the programming of the car thinking it had a AGM battery in it so he switched it to think it has a normal battery in it.

Most newer BMW cars need programming when changing the battery but the E53 X5 is NOT one of them. If your mechanic said he re-programmed the car for the battery, I'm left wondering what it was he actually programmed - or thought he programmed.

*edit* Unless your mechanic meant he somehow adjusted the alternator output to suit the new battery.

AGM batteries require slightly less charging voltages than flooded cell batteries and a standard charge voltage of 2.4v per cell (14.4v total) as most cars charge at will overcharge an AGM battery in the long term. AGM is better of at 13.5v -13.8v for long term charging but the vehicle normal 14.4v is ok most of the time.

Most folk seem to have no trouble when fitting an AGM battery to a car designed for flooded cell batteries (such as the E53 X5) but in a few cases where long driving is common, the life of the AGM battery may be shortened by overcharging.

[Chucklez]

Originally Posted by wpoll

Most newer BMW cars need programming when changing the battery but the E53 X5 is NOT one of them. If your mechanic said he re-programmed the car for the battery, I'm left wondering what it was he actually programmed - or thought he programmed.

That's a good question. I mean he didn't charge me for it so in the end it doesn't really matter to me if you get what I mean that way its not like he popped it on there for a additional charge.

Safe bet is the battery is bad though? Should I switch it back to whats recommended aka a AGM battery?

[wpoll]

Originally Posted by Chucklez

That's a good question. I mean he didn't charge me for it so in the end it doesn't really matter to me if you get what I mean that way its not like he popped it on there for a additional charge.

Safe bet is the battery is bad though? Should I switch it back to whats recommended aka a AGM battery?

Get the battery load tested - then you aren't guessing but yeah, it seems like it's not holding up like it should. And an AGM is not the recommended battery for the E53 X5 but it will work ok .