[3002 tii]

Want to hardwire a dash cam and want the ability to record while parked (will use a discharger which will cut the power of voltage runs low). However I can't figure out which fuse (glove box or trunk) can be tapped.

[djrobx]

I had more trouble finding a fuse that was NOT always on. When I checked all the ones in the trunk behind the right cubby were constantly hot.

[nonot]

Use the fuse for lighter for ACC (it turns off after 15 to 20 minutes) and fuse for homelink for BATT. Both located under/behind glove box

[Radioactive]

Scratching my head a little bit. Let me see if I have this correct. You want to run a dash cam while the car is parked for perhaps an unlimited time or until the voltage drops to a certain amount? So you can't be constrained by the "power on" after shut off? If so, bypass the fuses altogether and wire directly to a battery connection and install your own fuse. If not, and you just want a limited on, I would agree with nonot. Just use ACC fuse. If you're not awhere of this, many owners seem to have electrical problems in the early F25's with voltage drops from the car sitting for a couple of weeks. Don't know if this applies to newer model, but thought I'd mention it since you're going to have a draw on battery.

[3002 tii]

Originally Posted by djrobx

I had more trouble finding a fuse that was NOT always on. When I checked all the ones in the trunk behind the right cubby were constantly hot.

Was that the case even after you locked the doors or pressed power 2x?

Originally Posted by nonot

Use the fuse for lighter for ACC (it turns off after 15 to 20 minutes) and fuse for homelink for BATT. Both located under/behind glove box

Excellent!

Originally Posted by Radioactive

Scratching my head a little bit. Let me see if I have this correct. You want to run a dash cam while the car is parked for perhaps an unlimited time or until the voltage drops to a certain amount? So you can't be constrained by the "power on" after shut off? If so, bypass the fuses altogether and wire directly to a battery connection and install your own fuse. If not, and you just want a limited on, I would agree with nonot. Just use ACC fuse. If you're not awhere of this, many owners seem to have electrical problems in the early F25's with voltage drops from the car sitting for a couple of weeks. Don't know if this applies to newer model, but thought I'd mention it since you're going to have a draw on battery.

You are correct. I want to tap the fuse box up front so I don't have to run wires for entire length of the car. The discharge prevention kit allows you to set voltage threshold so I would pick a conservative level. I did this on my 1 series previously and I was able to record 2-3 days before the discharge device kicked in.

[Radioactive]

Have to fix glovebox fascia yet again tomorrow. This means removing glove compartment exposing fuse box and wiring. I'll take a quick look with the volt ohm meter.

[Radioactive]

I'll take payment in beer! Sat in the car until ACC/Lighter no longer read a voltage. Then checked fuses for "hot". These still read a voltage after others did not. Outlined in red box

Edit-I did not test all fuses, just looked for the first few that showed voltage. Remember to verify on your own car before using!

[02420X3]

Nice! Thanks Radioactive.

There should also always be a "hot" pin in the ODB-II connector too. I would have expected Fuse 3 (Tan, 5A, right side, 3rd from the top) to be hot, but with nothing in the ODB-II socket then it may not have been drawing power. It may be easier to tap the power lead to the ODB-II socket than the fuse box.

Another alternative to the fuse box might be to use an inline fuse on your power lead and go to the jumpstart terminal in the engine compartment.

[3002 tii]

Originally Posted by Radioactive

I'll take payment in beer! Sat in the car until ACC/Lighter no longer read a voltage. Then checked fuses for "hot". These still read a voltage after others did not. Outlined in red box.

Thanks for spending the time to do this. Question - aren't 30/40amps too high for a small accessory like a dash cam or radar? Wouldn't I risk shorting the device?

[Jypsie]

Your cam will only require/ask max something like 1A of current, meaning it will require the source to deliver 1A. If your source is fused with 30 or 40A, you can connect 30 or 40 dashcams :-) before you loose the fuse. The other way around you will only loose the fuse (40A cam on a 1A fuse).

Voltage is something different, but that is normally all 12V in a car, but there if your cam would need only 5V and you connect it to a 12V source, it will burn out (and likely cause a shortage). To be sure check current and voltage requirements of the cam.

[Jypsie]

By the way, I wired to the back as this turned out to be a lot easier to work in the fuse box (and no hassle to take out the glove box). Wiring took maybe 10 mins (not even)....

What cam are you connecting?

[3002 tii]

Originally Posted by Jypsie

Your cam will only require/ask max something like 1A of current, meaning it will require the source to deliver 1A. If your source is fused with 30 or 40A, you can connect 30 or 40 dashcams :-) before you loose the fuse. The other way around you will only loose the fuse (40A cam on a 1A fuse).

Voltage is something different, but that is normally all 12V in a car, but there if your cam would need only 5V and you connect it to a 12V source, it will burn out (and likely cause a shortage). To be sure check current and voltage requirements of the cam.

Thanks! I just read that when hardwiring accessories you shouldn't use a fuse slot that's more than 5 or 10 amps.

I plan to use a 5v hardwire kit.

Originally Posted by Jypsie

By the way, I wired to the back as this turned out to be a lot easier to work in the fuse box (and no hassle to take out the glove box). Wiring took maybe 10 mins (not even)....

What cam are you connecting?

Maybe I'll try that. Which fuse in the rear did you go with?

Rexing V1 dash cam https://www.amazon.com/dp/B00X528FNE..._Cv4jwb5BENQHN

[Lotus99]

Originally Posted by 3002 tii

The discharge prevention kit allows you to set voltage threshold so I would pick a conservative level. I did this on my 1 series previously and I was able to record 2-3 days before the discharge device kicked in.

Repeatedly running down the voltage on your battery is not bad for it?

Originally Posted by Jypsie

Your cam will only require/ask max something like 1A of current, meaning it will require the source to deliver 1A. If your source is fused with 30 or 40A, you can connect 30 or 40 dashcams :-) before you loose the fuse. The other way around you will only loose the fuse (40A cam on a 1A fuse).

In that case, shouldn't he use a 1A fuse on the wire going to the cam, since the 40A fuse is way too high to blow in case of an issue? He'd risk frying his cam otherwise, no?

Originally Posted by Jypsie

By the way, I wired to the back as this turned out to be a lot easier to work in the fuse box (and no hassle to take out the glove box). Wiring took maybe 10 mins (not even)....

What route did you take for the wire?

[Jypsie]

Originally Posted by Lotus99

Repeatedly running down the voltage on your battery is not bad for it?

I would not do it....

Originally Posted by Lotus99

In that case, shouldn't he use a 1A fuse on the wire going to the cam, since the 40A fuse is way too high to blow in case of an issue? He'd risk frying his cam otherwise, no?

Agreed, but I would not use a 40A fuse to start, this was just to explain the situation. I would go for a 10 or 20A fuse and indeed you could added an additional 1 or 2 A fuse on your wire. I am planning to use a fuse tap (and a 2A fuse just to be sure), but for the moment I just connected to the 12V connection in the trunk, using the 12V adapter I had and that has a fuse too.

Originally Posted by Lotus99

What route did you take for the wire?

I have put my dashcam underneath the mirror in the center, then pushed the wire behind the mirror covers and went up toward the roof liner, via the roof liner to the front post (passenger side), then via the rubber seals to the bottom.

Then via the front door covers (you can just pull them out) to the center, and via the rear door cover (you can pull them out too) via the back seat to the trunk. There I have just put the original 12V adapter and inserted it into the 12V boot connection. I have my 12 to 5 converter to connect it to one of the fuses. I a not planning to have the cam always on, but will use a fuse that shuts down after 10 mins. Planning to use one of the following fuses (with a fuse tab), but still investigating


See also: http://x3.xbimmers.com/forums/showthread.php?t=727455
I only did it via the right side of the car, I end up on the fuse box side in the trunk that way and so need less wire in the trunk.

107 10 A
143 15 A
144 20 A
171 ?
176 15 A

Make sure you understand fuse tabs if you use them and put them in correctly.

[Jypsie]

When using fuse tabs, make sure you understand....See picture

[Jypsie]

See the picture, the 5A can be 1A or 2A as required.

If your source is 10A, if you connect your fuse tab correctly, you can split up in 5 and 10. (drawing 2).

If you do it wrong, your source is at risk (and unprotected) as it might have to handle 15A and not 10 with what it was protected to start.

I hope I explained it well enough.....

So in the drawings, the 5A (or 1A or 2A) goes to the dashcam), the 2nd drawing is what you should do. SO make sure you put the tab in correctly.

[Lotus99]

Thanks for explaining how you routed the wire to the back of the car.

You confirmed what I was thinking, which is you still need a fuse for whatever accessory you are connecting.

Yes, you should leave the original fuse in the bottom slot, so it still handles all the load. So in theory, if you use a tap at a 10A fuse, and you add a 5A accessory, if whatever was running on the original fuse draws 10A, and your accessory draws 5A, then you'd have a total of 15A drawn on that circuit, and the 10A fuse should blow.

I didn't realize there is a way to screw up installing a fuse tap though? How do you use it in parallel vs. serial? Isn't it by default in serial? If you reverse the fuses, then the lower fuse, which is 5A will just blow quickly, as soon as there's that much draw on it. You won't turn it from serial to parallel?

[Lotus99]

Originally Posted by Radioactive

You can make it a series circuit if you install the tap in reverse.

I'm confused by the above statement. How can you install the tap in reverse? You mean by installing it left to right or something? I didn't think with a DC setup it matters?

[Jypsie]

Post 15 is the wrong way of doing it (parallel), it needs (is better) to be serial. The original fuse (10A) stays the same (so no risk to overload), the new one comes after the original one and will blow first if your cam has a problem (as it has a lower value 5 or 2A). This will leave the original circuit unchanged.

A fuse tap is like a fuse, you can put it in with the wire sticking out to the left or to the right.

What is the battery side of the fuse? Remove the fuse, measure which side OF THE CONNECTION still has 12V: that is the hot side, goes to the battery. The other side should measure OV without the fuse, goes to the device.

Added an updated picture, hope it helps..... the red arrows are the fuses in the fuse tap.

Remark: Yes you can go the parallel way too, but then I recommend to lower the original fuse with the value you put in in parallel, that way you don't overload, but the original device will have to do with a lower fuse, which not always might be a good idea (could be ok if it is only a cigarette lighter).
So replace the original 10A with 8A if you add a 2A in parallel...

[Radioactive]

With no time to investigate; I'll delete some messages as not to cause any confusion.

Edit-Although as stated before I'm not an EE, my retired father is! Just happen to be going for a visit today. I'll ask him about it. But without tubes/valves......

[Radioactive]

Update-Going to make this fast since I really don't have the time to write a lot or discuss ampere physics. Ran this discussion past my father, who retired from a major American aircraft manufacture as a electrical engineer after 40 plus years of work. Worked on some of America's greatest military aircraft and commercial aircraft / Specialized in electronic circuit troubleshooting (perhaps the difficult in electronics) Back in the day was on airline flight that was being delay because electrical problems on a plane that he worked on when being manufactured, went to the cockpit and worked with the ground crew to fix the plane. / Built and installed his own electronic ignition system in the 1960's. Another words, I trust his judgement in electronics.

Both types of circuits would probably work in real world situations.

Best design practice: Parallel

http://x3.xbimmers.com/forums/attach...1&d=1445730196
Took one look at this and without me saying anything, he said "This is wrong".
http://x3.xbimmers.com/forums/attach...1&d=1445730294
As far as running on smaller circuit such as 5A, he chuckled. No need, 30A just fine.

[3002 tii]

Originally Posted by Radioactive

Update-Going to make this fast since I really don't have the time to write a lot or discuss ampere physics. Ran this discussion past my father, who retired from a major American aircraft manufacture as a electrical engineer after 40 plus years of work. Worked on some of America's greatest military aircraft and commercial aircraft / Specialized in electronic circuit troubleshooting (perhaps the difficult in electronics) Back in the day was on airline flight that was being delay because electrical problems on a plane that he worked on when being manufactured, went to the cockpit and worked with the ground crew to fix the plane. / Built and installed his own electronic ignition system in the 1960's. Another words, I trust his judgement in electronics.

Both types of circuits would probably work in real world situations.

Best design practice: Parallel

http://x3.xbimmers.com/forums/attach...1&d=1445730196
Took one look at this and without me saying anything, he said "This is wrong".
http://x3.xbimmers.com/forums/attach...1&d=1445730294
As far as running on smaller circuit such as 5A, he chuckled. No need, 30A just fine.

Appreciate you taking the time to investigate. Information overload but end of day got the info I needed and I'm sure plenty of others have benefited from your posts! Decided against the live fuse and just do a simple hardwire, major benefit being a clean install. Don't really need to record when the car is off as it's mostly parked in a secure garage.