Battery tender

[tmntmn]

Originally Posted by 哇靠M3

Thanks for the info. I hooked it up for 6hrs the first time... The lights didn't change and it was still solid red. Thought the charger was broken. I put it back on the tender this morning and will keep it on longer to see what happens. Getting sick of the stupid clock problem.



How did you hook it up? I would like to see pics... also any problems with keeping it on the battery all the time?

from my understanding we can keep it hooked up as long as we want/need to without damaging anything.

[aussiem3]

Originally Posted by ///M Power-Belgium

I have the CTEC Multi XS 7000 and works perfect,in the kit is a cable with 2- O- rings they go direct on - pole and + pole of the battery in the trunk and stay there, this cable has a central connector and with one click... takes 5 sec. i charge the battery >http://www.horsepowerinabox.com/HPIAB2/prod515.htm

Hi Phillippe

I was looking up TIS and found this ..

"On vehicles with Intelligent Battery Sensor (IBS), recharging the battery is directly at the battery terminals could lead to a misinterpretation of the battery condition and even unwanted Check-Control messages or fault-memory entries. If the battery is recharged while it is installed, it must be recharged using the jump-starting points, whenever jump-starting points are provided in the engine compartment (all vehicles except R55, R56). Only then can you be sure that recharging is correctly recognised by the vehicle electronics on vehicles with intelligent battery sensor (IBS)

I take that the E92 is equipped with IBS so we need to be careful when charging at the battery rather than at the engine bay point. Anyone like to chip in?

[Richbot]

I use the tender at the battery with no issues. I believe that warning is for serious charging at relatively high amps, the battery tender rarely pushes more than about an amp even with a significantly discharged battery. For a jump start or a jump pack, yeah, use the underhood stuff, it's easier to access anyway

[///M Power-Belgium]

Originally Posted by aussiem3

Hi Phillippe

I was looking up TIS and found this ..

"On vehicles with Intelligent Battery Sensor (IBS), recharging the battery is directly at the battery terminals could lead to a misinterpretation of the battery condition and even unwanted Check-Control messages or fault-memory entries. If the battery is recharged while it is installed, it must be recharged using the jump-starting points, whenever jump-starting points are provided in the engine compartment (all vehicles except R55, R56). Only then can you be sure that recharging is correctly recognised by the vehicle electronics on vehicles with intelligent battery sensor (IBS)

I take that the E92 is equipped with IBS so we need to be careful when charging at the battery rather than at the engine bay point. Anyone like to chip in?

Just took some pictures of my CTEK in action .....
I use the CTEK now for more than 2 years with 0 problems,in winter time'(hibernation) it was for more than 4 months connected to my battery, works great,and super easy to charge the battery,you can see the O rings mounted on - & + pole of the battery,and with the cover on the battery,you can see only the very small central connector, and when i want to charge my battery i open the trunk,one click and 5 sec. later i charge....so easy and practical,this is actualy the best thing to do
The pics............

[1MOREMOD]

I don't see anything happening! Is it working?

[jqsmooth]

Just got one today and hooked it up. Spent last two winters driving the car at least once a week, and thought that was enough. This winter's been horrific and haven't touched the car in 3 weeks. Should've gotten it sooner. Read somewhere that using it regularly throughout the year helps extend the life of battery a couple of years.

[///M Power-Belgium]

Originally Posted by jqsmooth

Just got one today and hooked it up. Spent last two winters driving the car at least once a week, and thought that was enough. This winter's been horrific and haven't touched the car in 3 weeks. Should've gotten it sooner. Read somewhere that using it regularly throughout the year helps extend the life of battery a couple of years.

Spot on ! no doubt

[jqsmooth]

Originally Posted by ///M Power-Belgium

Spot on ! no doubt

I like your setup(very easy to plug in and take out). I just hooked it up to the engine bay, it was close to the outlet as well.

Still learning lots from this forum. Appreciate the pictures.

[///M Power-Belgium]

Originally Posted by jqsmooth

I like your setup(very easy to plug in and take out). I just hooked it up to the engine bay, it was close to the outlet as well.

Still learning lots from this forum. Appreciate the pictures.

Great to hear that the pics are useful ! THX
For further questions feel free to shoot me PM....anytime

[G80indy]

If you buy a CTEK put it on the snowflake/AGM battery mode for best results

[///M Power-Belgium]

Originally Posted by 330indy

If you buy a CTEK put it on the snowflake/AGM battery mode for best results

In my garage i'm using recond mode, it's about 15° Celsius in my garage so no need for the snowflake !
With freeze temps i'm agreed and thats the intention of the snowflake

[G80indy]

Originally Posted by ///M Power-Belgium

In my garage i'm using recond mode, it's about 15 Celsius in my garage so no need for the snowflake !
With freeze temps i'm agreed and thats the intention of the snowflake

It is also the AGM mode, which I use all year.

[jqsmooth]

Originally Posted by ///M Power-Belgium

Great to hear that the pics are useful ! THX
For further questions feel free to shoot me PM....anytime

Thanks man! Much appreciate it!

[Semi-Poor]

Clear and dry yesterday, drove the M for first time in a month (winter ). Hook up the BT for full charge cycle weekly if no trips.

[ezndo]

For those using the trunk option, is there anyway to close the trunk while charging or do you have to leave it open?

[glockz]

Any recommendations on where to purchase the batter tender?

[kawasaki00]

Originally Posted by glockz

Any recommendations on where to purchase the batter tender?

http://www.amazon.com/Battery-Tender...battery+tender

I have 2 of these and they work great

[Richbot]

Originally Posted by ezndo

For those using the trunk option, is there anyway to close the trunk while charging or do you have to leave it open?

I close the trunk, the flat BT cable and weather strip allow this without pinching the cable.

[wrecklessfool]

I am by no means an expert here, but this thread prompted me to see exactly how an AGM battery differed from the traditional acid filled batteries I am familiar with. I came across this paragraph and it makes me question whether a charger made for "universal" or "standard" batteries is good over the long-term for use with our AGM batteries found in the M3. Here is the quote:

"As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive."

I have no idea what voltage these chargers run at for recharge or float charge, but it may be worth looking into for those who use the Battery Tender.

[G80indy]

Originally Posted by wrecklessfool

I am by no means an expert here, but this thread prompted me to see exactly how an AGM battery differed from the traditional acid filled batteries I am familiar with. I came across this paragraph and it makes me question whether a charger made for "universal" or "standard" batteries is good over the long-term for use with our AGM batteries found in the M3. Here is the quote:

"As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive."

I have no idea what voltage these chargers run at for recharge or float charge, but it may be worth looking into for those who use the Battery Tender.

With AGM batteries they should not see 14.8v and the CTEK senses this automatically. However ... They do require more robust float charge, 14.7v (in spite of a closely managed peak voltage because they are a bit of a deeper cycle type battery) than the 14.4 float charge of a lead acid wet cell battery to keep them fully topped off. Hence the AGM /snowflake mode is 14.7. Another feature I love about the 7002 is the pulse charge in deep sleep (after a ten day period in uninterrupted float charge mode) -- exercises the battery a bit for long term hibernation, which works well for the deep Midwestern snooze. Keeps my battery fresh.
Also a reason I will not use the BMW aka/Deltran maintainer on the E92. I cannot confirm it auto-adjusts to an AGM.

[wrecklessfool]

Was at Advance Auto today to buy oil and filter for my girlfriend's car and saw the BT on the shelf and figured I'd give it a go since my car doesn't get driven much in the winter. Hooked it up under the hood per BMW's recommendation. Took all of 5 minutes and puts my mind at ease about coming out to a dead battery.

EDIT: Tried to attach pics from mobile app but failed as usual. Pics below.

[wrecklessfool]

Under hood connection points