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help on battery tender

11K views 39 replies 21 participants last post by  BossM6 
#1 ·
just bought a battery tender, here is my question. do i close the hood and if so how? tried many diffrent ways to close the hood but i cant because the clips is in the way? or do i just leave the hood open?
 
#3 ·
I was able to close the hood with the clips setup as shown in my photo, but it was not very stable (and only used the clips a few times).

The solution is to hardwire the Battery Tender connections. A hardwire harness is included with the Battery Tender, but I made my own to look OEM :biggrinbounce:
 

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#5 ·
Why do you feel the need to close the hood?
The last thing you want to do is drive off with it connected.

Similar to TampaMark I leave my hood open so that I wont forget its connected before I start the engine and drive off with the car.

Mark Carson is correct. I always like my battery fully charged so when I wont be using my car for a few days I always hook up my batter tender.

I vote you leave your hood open when battery tender is connected.
 
#9 ·
I can't remember the details, but somewhere there is a thread regarding NOT connecting a charger directly to the battery in the trunk. I think something in OM as well. Something to do with the car actually knowing a charger is connected and regulating charge of battery. Not saying I'm right just something I vaguely recall around this topic. Cheers!
 
#11 · (Edited)
You are correct, the BMW TIS specifically calls out charging at the front connectors. Supposedly allows for the charging system to monitor the charge.

I use a quick connect permanent mount wire for my motorcycle, but the battery is buried and requires tools to access. The car has quick connects, open the hood and connect!

Like Dan says, also makes sure myself, or more likely my Wife, would not drive off while connected.
 
#13 ·
Attached are a few interesting documents about batteries.

On vehicles with 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).
 

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#14 ·
Just a little caution, if you attach the battery tender to the engine terminals just make sure the clips will not short each other if you decide to close the hood.

The hood is conductive so just be careful as if the batter tender alligator clips touch the hood it will short out not only the battery tender but the battery as well and you now have a risk of fire.
 
#16 ·
Just leave the hood open...what's the problem:thumbsup:
 
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#17 ·
If you leave the hood up, will the car still shut completely off? Or, will there be some draw on the battery? There is a pressure switch next to the passenger cabin filter, and what if you put a weight on that switch to fool it into thinking the hood is closed?
 
#18 ·
Leaving the hood up will still enable the auto shut down of power consuming electronics. No issue.

No need to do anything else.

Folks, I hook up my battery tender every time I travel on business or wont be driving the car for a few days and there is Zero issue.

Like I said and everyone said, just leave the hood up so that you or your wife wont drive off with the battery tender still connected.
 
#21 ·
Thanks for the advice/information/tips! So, while waiting for the replys, I connected the tender, left the hood up, put a weight (small can of paint) on the pressure switch and locked car with the fob. Confirmed all dash/shifter lights went out. A couple hours later, I'm watching TV and I hear the car alarm wailing and my wife runs in from the garage holding her ears! She lifted the can of paint from the pressure switch setting off the alarm. Classic.
 
#22 ·
At least on my e60, I can leave all the doors, trunk, hood open, and not worry about battery drain. After awhile, the car will turn everything off and go into service mode. It assumes, with everything open, you are servicing the car.
 
#27 · (Edited)
Make sure that if you are going to close your hood that everything below is out of the way...On my previous 645 it appeared that something was in the way when someone closed the hood becuase there was a sharp dimple in the hood like something tried to poke through it! What an eyesore it was....from the day I bought it! The alum is very easy to dent....

I also did not know about charging from the accy post under the hood instead of the battery in the trunk....I bought a charger and was going to connect it to the battery posts in the trunk but did not...I will connect the quick connetor to the accy post when I return home in a few weeks!
 
#31 ·
I have the ctek and leave it on my car 24/7 on the jump points with the hood up while in the garage. Confirm you have an AGM battery with the black battery case if it's OEM. All M's should come with it, but if you're not the original owner, I'd check to make sure someone didn't put a lead acid battery (white) if it's a BMW battery in there. I select the snow flake option on the ctek which is for AGM.
 
#34 ·
This is directed to everyone with a ctek cahrger that leaves it in the garage.

1) Do you guys leave the garage door open for ventilation?

2) Anyone tried the cigarette lighter connection?
 
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