Which fuse is live only when switched on or running?

[plankton99]

On my M4 at the rear trunk fuse box, does anyone know which fuse number is only on when the car is switched on or running (NOT when I open door)

[Cooltones]

Hey Op,
Check out my post below, re: my Dash Cam install:
http://f80.bimmerpost.com/forums/sho...&postcount=197

Basically only 2 types of fuse slots in the rear trunk fuse box: MAIN type, where the power is always on, regardless of whether or not the car is running, and ACC-Ignition type, where the power is on when the ignition is on.

Not sure there's the type of power source you refer to where the fuse slot, intended to be an Ignition type, is not affected by the doors being opened.

Also, a number of fuse slots where they are typically turned on when the ignition is on, and/or when a door is open, will usually stay on for about 20 minutes after the car ignition is turned off or when a door/trunk is left open constantly for about 20 minutes.

The fuse slot I used, for ACC/ignition, was fuse slot 125 (refer to my post pictures).
A quick way for me to confirm that the slot 125 did NOT have power was when the trunk light would turn off (when leaving the trunk open for about 20 minutes).

So, I'm curious as to why you're asking. What's the project you have in mind?

Hope this helps.
-Tony

[plankton99]

Originally Posted by Cooltones

Hey Op,
Check out my post below, re: my Dash Cam install:
http://f80.bimmerpost.com/forums/sho...&postcount=197

Basically only 2 types of fuse slots in the rear trunk fuse box: MAIN type, where the power is always on, regardless of whether or not the car is running, and ACC-Ignition type, where the power is on when the ignition is on.

Not sure there's the type of power source you refer to where the fuse slot, intended to be an Ignition type, is not affected by the doors being opened.

Also, a number of fuse slots where they are typically turned on when the ignition is on, and/or when a door is open, will usually stay on for about 20 minutes after the car ignition is turned off or when a door/trunk is left open constantly for about 20 minutes.

The fuse slot I used, for ACC/ignition, was fuse slot 125 (refer to my post pictures).
A quick way for me to confirm that the slot 125 did NOT have power was when the trunk light would turn off (when leaving the trunk open for about 20 minutes).

So, I'm curious as to why you're asking. What's the project you have in mind?

Hope this helps.
-Tony

I am adding a LUKAS Dashcam Battery backup to my Blackvue dashcam.

The Battery charges when the power is live and when the power is cut off the dashcam uses the battery backup while parked. I wanted to have the battery charge only while the car was either running or switch ON and NOT when the car is on the 20 minute mode supplying power. The load on the battery I fear will be too great and possibly drain the car battery while charging the backup battery for 20 minutes. (does this make sense?)

Here is the backup battery in case you are interested.

http://www.amazon.com/LUKAS-LK-570-L...ilpage_o09_s00

[Cooltones]

Originally Posted by plankton99

I am adding a LUKAS Dashcam Battery backup to my Blackvue dashcam.

The Battery charges when the power is live and when the power is cut off the dashcam uses the battery backup while parked. I wanted to have the battery charge only while the car was either running or switch ON and NOT when the car is on the 20 minute mode supplying power. The load on the battery I fear will be too great and possibly drain the car battery while charging the backup battery for 20 minutes. (does this make sense?)

Here is the backup battery in case you are interested.

http://www.amazon.com/LUKAS-LK-570-L...ilpage_o09_s00

You've clarified things here, regarding what you're looking for - Thanks.

FWIW, Here's my "daily/weekly drive" activity:
Monday - Thursday: I'll drive my M4 to work (about 35 minute drive one-way), it sits in the parking garage for about 8 hours, then I drive home into the garage. A few times I've taken a look at the Cellink Battery as soon as I parked in my garage to see the green light confirming it's fully charged. The next morning the BlackVue is still operating.

From Thursday night to Saturday morning my M4 typically sits in the garage, with me occasionally going to the trunk to put in/get out something. Sometimes I just jump in the driver's seat, not starting the car, but just to be in an environment that helps me think and makes me smile...

Saturday morning arrives and when I start up the M4 I don't get any "battery drained" notifications or comfort access not working (which appears to happen when our F8x's have battery draining events...).

Just wanted to share my experience thus far. No "visible" battery concerns; HOWEVER, I totally agree with you -- It would be GREAT to find a fuse slot that only turns on when the ignition turns on, AND NOT when the doors/trunk opens...

Let's be sure to share notes if one of us finds such a fuse slot...

Cheers,
-Tony

[Mandi90TT]

Originally Posted by Cooltones

HOWEVER, I totally agree with you -- It would be GREAT to find a fuse slot that only turns on when the ignition turns on, AND NOT when the doors/trunk opens...

Agreed. I tried to find one for my amp install, but didn't have any luck at all.

[heckyeahbro69]

F146 controls one of the exhaust flaps and the parking aid and it's switched on, not hot all the time. You could try that one.

[plankton99]

Originally Posted by heckyeahbro69

F146 controls one of the exhaust flaps and the parking aid and it's switched on, not hot all the time. You could try that one.

thanks, I'll try it

[SLF80]

I need to bump this.

Has anyone managed to find a reliable 12V and ACC set of fuses tested over time to work with the PowerMagic Pro for the BlackVue?

Also how did you handle the ground wire? I can't find a way to attach it to the chassis reliably.


Thanks.

[Frode D]

I know this is an old thread but I spent some time searching for info as I needed a power source which is not powered on every time I open the door, and shuts down when I turn off ignition. And I found the correct fuse. In my car (2018 M3) that is fuse 146.

I opened the chart with all the fuses and found the ignition symbol - I guess any one of these are good, but 146 was the first one I tried.


Fuse 146 location - on the way out.


Properly wired:


Hope this helps whoever need an ignition source in the trunk which isn't powered on when you open the door and for 20 minutes after locking the car.

[fackamato]

Originally Posted by Frode D

I know this is an old thread but I spent some time searching for info as I needed a power source which is not powered on every time I open the door, and shuts down when I turn off ignition. And I found the correct fuse. In my car (2018 M3) that is fuse 146.

I opened the chart with all the fuses and found the ignition symbol - I guess any one of these are good, but 146 was the first one I tried.


Fuse 146 location - on the way out.


Properly wired:


Hope this helps whoever need an ignition source in the trunk which isn't powered on when you open the door and for 20 minutes after locking the car.

So this is an ignition on only fuse?

[djpeetur]

10 amp for battery backup
5 amp for radar

It will turn off when u turn off car immediately.
Make sure on the wire tap you put the stock fuse amperage on the bottom. And whatever amp you need for your hardware you stack on top. If you put the wrong fuse amperage you will blow 10 fuses like I did

[The_One]

Try No. 46 in the trunk, it's HomeLink, that powers the inner rear view mirror and only on when the power is On.

[frankzlin79]

Originally Posted by djpeetur

10 amp for battery backup
5 amp for radar

It will turn off when u turn off car immediately.
Make sure on the wire tap you put the stock fuse amperage on the bottom. And whatever amp you need for your hardware you stack on top. If you put the wrong fuse amperage you will blow 10 fuses like I did

I just tried wiring a Blackvue B-124 battery to Fuse 146. I put the stock 5 Amp fuse in the fuse tap nearest the prongs. I placed the 20 Amp fuse that came with the battery furthest set from the prongs.

I start the car and get an iDrive error saying that the Parking Aid is disabled. I go check the 5 Amp fuse on the fuse tap, and sure enough, it was blown. What have I done wrong?

I can confirm that when you kill ignition on Fuse 146, power is cut immediately (no stupid 20 min of residual power).

[jmciver]

Originally Posted by frankzlin79

I just tried wiring a Blackvue B-124 battery to Fuse 146. I put the stock 5 Amp fuse in the fuse tap nearest the prongs. I placed the 20 Amp fuse that came with the battery furthest set from the prongs.

I start the car and get an iDrive error saying that the Parking Aid is disabled. I go check the 5 Amp fuse on the fuse tap, and sure enough, it was blown. What have I done wrong?

I can confirm that when you kill ignition on Fuse 146, power is cut immediately (no stupid 20 min of residual power).

Well, assuming the add-a-fuse itself is not faulty, it sounds like the fuse may have just blown sporadically, which does happen occasionally when you remove/install fuses under load (even though that fuse should be dead with the ignition off). So you could try installing a new 5A fuse to see if it blows again. If it blows again, then you may have a faulty add-a-fuse. Also, you should verify that the add-a-fuse is completely seated in the fuse box. A loose connection could cause a small arc, which could also cause a fuse to blow.

This is one of the reasons I plan to use the OEM fuse tap method .

[frankzlin79]

Originally Posted by jmciver

Well, assuming the add-a-fuse itself is not faulty, it sounds like the fuse may have just blown sporadically, which does happen occasionally when you remove/install fuses under load (even though that fuse should be dead with the ignition off). So you could try installing a new 5A fuse to see if it blows again. If it blows again, then you may have a faulty add-a-fuse. Also, you should verify that the add-a-fuse is completely seated in the fuse box. A loose connection could cause a small arc, which could also cause a fuse to blow.

This is one of the reasons I plan to use the OEM fuse tap method .

I went to Autozone and got a 5 Amp fuse to replace the blown one. It fixed the problem of "Parking Aid" being disabled.

I don't believe my fuse tap is faulty. Because I used the same fuse tap and tapped into Fuse 145 (which ordinarily holds a 15 Amp from the factory) to hard wire the B-124 battery. My volt meter showed that Fuse 145, like Fuse 146, shuts off immediately when ignition is killed.

Everything works perfect now. No errors reported by car.

I doubt I had a faulty 5 amp fuse from factory. Maybe what happened is that 5 amp factory and the 20 amp that came with my B-124 are too far apart and my B-124 draws 9 amps. That 9 amps was too much current for the factory 5 amp fuse. I think that if you use a fuse tap with the B-124, you must choose fuses that occupy 10 amp or higher. This, Fuse 145 is a no go since it is rated for only 5 amp. But Fuse 146, which is rated for 15 amp from factory, is sufficient to power the B-124 (draws 9 amp).

So using the B-124 20 amp fuse in the fuse tap with the factory 15 amp fuse in Fuse 145 works perfect!

[jmciver]

Interesting.... My basic understanding of how they worked was that the size of the fuses used did not matter as long as the factory fuse and the aftermarket accessory fuse were installed in the correct position in the add-a-fuse tap, everything would work. Your experience is very weird - makes me wonder if that is something unique to BMW (and the F8X/F3X platform)...

[frankzlin79]

Originally Posted by jmciver

Interesting.... My basic understanding of how they worked was that the size of the fuses used did not matter as long as the factory fuse and the aftermarket accessory fuse were installed in the correct position in the add-a-fuse tap, everything would work. Your experience is very weird - makes me wonder if that is something unique to BMW (and the F8X/F3X platform)...

Definitely no. The rating of the fuses do matter. If they did not matter, then wouldn't BMW just use say, a 20 amp fuse in all locations? The fuse ratings are matched to the electronic devices of the car that need to be powered. Some Devices like headlights require a lot of amp, versus something that doesn't require a lot of amp (door locks for example).

Check out my comprehensive thread I just wrote here:
Which Fuse in Trunk for Blackvue B-124 / Cellink Neo?
https://f80.bimmerpost.com/forums/sh....php?t=1568426

[jmciver]

Originally Posted by frankzlin79

Definitely no. The rating of the fuses do matter. If they did not matter, then wouldn't BMW just use say, a 20 amp fuse in all locations? The fuse ratings are matched to the electronic devices of the car that need to be powered. Some Devices like headlights require a lot of amp, versus something that doesn't require a lot of amp (door locks for example).

Check out my comprehensive thread I just wrote here:
Which Fuse in Trunk for Blackvue B-124 / Cellink Neo?
https://f80.bimmerpost.com/forums/sh....php?t=1568426

I agree that the rating of the fuse is based on the equipment attached to the circuit, but if the add-a-fuse is used correctly (and not faulty) the factory circuit should be separate from the new accessory circuit, both of them protected by their individual fuses.

[pmooiweer]

Originally Posted by frankzlin79

I just tried wiring a Blackvue B-124 battery to Fuse 146. I put the stock 5 Amp fuse in the fuse tap nearest the prongs. I placed the 20 Amp fuse that came with the battery furthest set from the prongs.

I start the car and get an iDrive error saying that the Parking Aid is disabled. I go check the 5 Amp fuse on the fuse tap, and sure enough, it was blown. What have I done wrong?

I can confirm that when you kill ignition on Fuse 146, power is cut immediately (no stupid 20 min of residual power).

When using an add-a-fuse adapter make sure that it's oriented the correct way. The side with the wire/pigtail should be AWAY from the hot side. If you put it in backwards the current will flow through both fuses (in serial). If you're adding a higher amperage circuit to a low amp circuit and put the adapter in backwards it will blow the original lower amp (bottom) fuse. For fuse 146 the hot side is on the passenger side, so the add-a-fuse pigtail should be on the driver side.