[E90SAR]

I want to replace the battery on my 2006 330xi since it's cranking weak in cold weather...2 questions:

1) Have any of you kept continuous power going through the car while changing the battery by hooking up a power source to the jumper terminals under the hood? This was recommended when I replaced the battery on my 01 X5 except the cig. lighters had continuous power so I just connected a battery maintainer there. The idea would be to prevent any computer codes from being triggered due to removing the battery.

2) What's the final consensus about this battery registration thing - is it critical? Would keeping continuous power going avoid the need for this?

Thanks

[carbo]

Bump.....mine is cranking slower it seems so I may need to do this also.......anybody?

[ledge76]

I just replaced my battery this past weekend and researched before hand and yes the battery needs to be registered to the computer using a software, I bought the Bavarian Technic enthusiast.

There was a guy on another forum that really went into detail but basically Yes. From what I can make of it the alternator thinks it has the old battery and overcharges, cooking the battery.

I ended up buying an Interstate made specific for my model and everything bolted up and snapped on like the factory battery but at half the cost.

As far as your first question not really sure, but there would be no reason to hook a charger to the connection under hood because you have to hook the software up to register it and the only other thing is to reset your clock.

[silkye90]

BTW, any one have the Battery part number and price listed??
Which one would be the best bet?? Dealer?

[kaigoss69]

Got mine at Wal-Mart for $75. Has 200 more CCA than stock. Did not keep power during the swap and the only thing I had to do was re-set the clock. I never heard of registering the new battery. Sounds like dealer scare tactics to me.

[raceyBMW]

I have heard that registering the new battery is highly recommended, but not absolutely necessary. It really depends on how bad your other one was, because the alternator will sense lower voltages and compensate accordingly. Now if you put in the new battery, the alternator will attempt to do the same, and could damage the new battery, shortening its life.

The car will eventually relearn the new battery voltage, but the damage may already be done. If you battery that you replaced wasn't that bad, there is probably not that much harm in not registering the new one, but why take that chance.

[stubenhocker]

Replaced the one in my E46 after 9years 10 mos of use and bought the replacement at WalMart for $75 and installed it myself no issues going forward. I've never heard that one about registering the new battery, but the shop manual on E46 doesn't mention it.

[kaigoss69]

I don't buy it, at all. Besides, these batteries are pretty robust so even if they get a little overcharged they will still last many many years. Last time I checked, you can buy three Walmart batteries for the price of one at the dealer so I am willing to roll the dice on this one. I like my odds.

[John 070]

Originally Posted by kaigoss69

Got mine at Wal-Mart for $75. Has 200 more CCA than stock. Did not keep power during the swap and the only thing I had to do was re-set the clock. I never heard of registering the new battery. Sounds like dealer scare tactics to me.

Curious....what is the group size that works???

My car has only 17k and the IBS sensor already failed, can't imagine how much the dealership would charge for that out of warranty. Kind of surprising how something so simple gets so complicated with BMW.

[E92-Lighting]

i got mine from AAA, no issues thus far