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7 Series - E65 / E66 (2002 - 2008)
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  #1  
Old 02-14-2014, 11:01 AM
thunderkyss thunderkyss is online now
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Register dead battery

While working on my car, I disconnected the battery for over a week. We had a couple of hard freezes during that time & it was cold overall on average.... highs in the 40s, lows in the mid 30s. When I hooked the battery back up, it was completely dead. I didn't expect that, but it's what it is.

So I jumped the car, it started & charged the battery. The car runs pretty rough, so I was going to hook up the 'ol computer & see what codes I've got, but while searching the forum for "rough idle" I came across several entries about replacing the battery & registering it.

I don't know that replacing the battery or registering it will help my idle, I doubt it. But, since I'll be hooking the computer up anyway, I was wondering if it would hurt any.
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  #2  
Old 02-14-2014, 12:43 PM
DriftGirl DriftGirl is offline
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u jumped the completely Dead battery without recharging it first?
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Last edited by DriftGirl; 02-15-2014 at 01:11 AM. Reason: spelling
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  #3  
Old 02-14-2014, 01:00 PM
thunderkyss thunderkyss is online now
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Correct
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  #4  
Old 02-14-2014, 02:28 PM
vichugo vichugo is offline
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Just because the car starts doesn't mean the battery is fully charged. Leave it on a charger until it reads 12.8V with the car asleep (motor off for at least an hour). That might make a difference.

If you have DIS software, check the battery history and see if your battery was registered. The age of the battery is usually stamped on the negative post.

You might also want to check the alternator's output from the secret menu on your dash.
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Old 02-14-2014, 03:45 PM
thunderkyss thunderkyss is online now
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Quote:
Originally Posted by vichugo View Post
You might also want to check the alternator's output from the secret menu on your dash.
Speaking of the secret menu.

I can't get it to work. I can get it to come up, & I can advance from the top of the list to the bottom of the list. If I want to go into one of the menus, nothing I do seem to work. Pressing the button "quickly" just goes from item 1 to item 2 & so on & so forth. Holding it for 3 seconds, does the same. Holding it for 5 seconds takes me out of the menu.
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Old 02-14-2014, 11:07 PM
vichugo vichugo is offline
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You need to unlock the menu with the sum of the last 5 digits in your VIN:

Get out of this thread, then go to the top of the 7-series forum page and click on "Search this forum". Enter "secret menu", click go, then scroll down the list of search results until you see a thread called "secret menu". In it Nygel describes how to unlock the secret menu. As soon as you have done it once, it's easy.

I use it a lot to check my alternator voltage and my coolant temperature.
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  #7  
Old 02-15-2014, 01:10 AM
DriftGirl DriftGirl is offline
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Quote:
Originally Posted by thunderkyss View Post
Correct
yeah, probably your problem.....as vichugo stated: FULLY Charge the battery first. An alternators job is to "maintain"...with what amounts to a surface charge.
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  #8  
Old 02-15-2014, 07:20 AM
thunderkyss thunderkyss is online now
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Quote:
Originally Posted by vichugo View Post
You need to unlock the menu with the sum of the last 5 digits in your VIN:

Get out of this thread, then go to the top of the 7-series forum page and click on "Search this forum". Enter "secret menu", click go, then scroll down the list of search results until you see a thread called "secret menu". In it Nygel describes how to unlock the secret menu. As soon as you have done it once, it's easy.

I use it a lot to check my alternator voltage and my coolant temperature.
Thanks. I'll give it a try.
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  #9  
Old 02-15-2014, 07:22 AM
thunderkyss thunderkyss is online now
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Quote:
Originally Posted by DriftGirl View Post
yeah, probably your problem.....as vichugo stated: FULLY Charge the battery first. An alternators job is to "maintain"...with what amounts to a surface charge.
So the question remains....... will "registering" a battery that's already been registered do more harm than good?
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  #10  
Old 02-15-2014, 10:23 AM
vichugo vichugo is offline
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Registering the battery lets the car know that you have just installed a new battery. My understanding is that the alternator will then charge the battery as a new battery and not overcharge it.

So if the battery was registered a while ago, you don't want to re-register it.

If you don't already know, you should find out what kind of battery you have and whether it was registered. It should be a 90 or 92Ah AGM battery and the DIS software will tell you if and when it was registered.

Getting the right battery and getting it registered cures a lot of problems.
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