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Battery maintenance over the winter

4K views 27 replies 12 participants last post by  Verts4Ever 
#1 ·
Hello everyone,
I am about to store my 2011 335I and was wondering which would be the best trickle charger to purchase and is there any special instructions to follow.

thanks,
 
#12 ·
Funny, I just ordered this 10 minutes ago, before reading this thread :)

I don't store my car for winter, but I just got back from vacation after a few weeks and my battery was so low my CA didn't work. After driving a while it charged up and started working again. I went through this with battery #1 and eventually the battery would never charge back up. It may be overkill, but I think from now on I'm going to use a BT when the car will be sitting for a couple weeks or more. These cars really seem to suck the life out of batteries.
 
#6 ·
You would probably be perfectly fine with all of the above suggestions, but you did ask for "the best", and that could possibly be the CTEK chargers. OEM for MB, Porsche, Ferrari, Bentley and others I have read. They look quite sleek, and are lightweight, diminutive, a sealed system, shock proof, water resistant, blah blah (there's a video where a girl is hosing the charger while in the engine bay, and then it's run over with a car, yeah who knows if it's all marketing bs, but still . . . ) and they cost only a little more than the BT, maybe $10-15 (at least for the 3300, but I wonder if the 800 is perfectly adequate at $39). I wonder if the BMW charger is simply the BT rebadged at a higher price; I think Deltran makes the BT.

They are extremely simple to use. Simply cycle the mode button past the motorcycle icon, past the car icon, to the one with the snowflake (this is the proper mode for AGM batteries). The half full battery will be lit in red when charging, and the green full battery is well you get the idea. I've seen it go from green to red as soon as I opened the door, recently. Yep, there is only one button you can press, the "mode" button, and it can only cycle through 4 modes.

Remember to overinflate tires, possibly use fuel stabilizer, perhaps stuff the tailpipes with steel wool . . . maybe don't use the parking brake so that it won't lock into place, but your car is quite new so maybe I wouldn't worry about that.

 
#11 ·
It depends on how you want to do this. I run my connections under the hood and then run the cable that hooks them up under the space in the front headlight and close the hood. Works perfectly for the past 4 years. If you look on the passenger side headlight you can see where there are openings. Very clean and I just disconnect the connector there and leave everything intact until I hook it up again when out of town...
 
#14 ·
I have the BMW branded battery charger. I plug it in all winter and it keeps it charged perfectly! I use the clips under the hood to connect it... they are very convenient!

When spring comes I just push the start button and them vroom vroom!!
 
#19 ·
Thanks for the replies!

This is the first time I've used one of these so I wasn't sure what to expect. I'm going to be traveling soon for a couple weeks, so that will be the test. It is amazing how fast these drain. I drive around 20 miles to/from the office so the figured that was enough to keep it fully charged. Maybe not...
 
#22 ·
Personally, I would charge it before you leave, if only to see how long it takes to charge. Wouldn't that be of interest to you? If you charge it only when you are away for a while, you won't get to know. Anyway, it would just be one data point for you. Otherwise, it will pass the "test" and be fully charged, waiting for you to come home.

I usually don't use DRLs, I roll my car out in neutral (without starting) to wash it, I immediately lock (sleep) my car upon exiting, and I try to take at least one medium length drive per week, but it still took 24 hours the first time.
 
#26 · (Edited)
I just got the CTEK 3300 today, i ordered it yesterday with free shipping, it was at my door today, total was around $60

the terminals at the jumper posts in the engine bay make it really convenient.
I removed the plastic cover from the terminal connection for the + post. Removed the 10mm nut, put the ring terminal on it, then buttoned it back up.
For the negative lead, i used the designated - post on the inside of the fender. I found a metric machine bolt that fit inside the threaded post and used a lock washer, installed the ring terminal onto the bolt and tightened into the - post.

I was hoping for a solution that would put the car side of the connection at the grill where i would not have to open the hood to make the connection. but snaking the lead to the grill looked like a PITA, i might do it later down the road. also the esthetics of having the plug behind the grill might bug me.


i ended up spinning the connection 180 degrees after i took this photo







great thread, thanks for all the ideas here :thumbup:
 
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