Hard wire dash cam to higher amperage?

[dazh123]

Hey guys,

First-time buyer of a dash cam here. I never "really" had to hardwire anything to my car - but now I am facing a problem.

My dash cam, Rexing V1LG (https://www.amazon.com/gp/B071LPV7G6), has a hardwire kit that uses a 15A fuse (https://www.amazon.com/gp/B074PBPPPN), I recently tried installing it, got everything set up and all - only to realize my car only has one 15A fuse in the passenger compartment.

My car is a 2003 C240 Mercedes, fuse box diagrams found here are what is shown in my car: http://www.autogenius.info/mercedes-c-class-w203-c240-automatic-2003-fuse-box-diagram/

Now, I tried these two fuses: #40 and #41. #41 is the only fuse in passenger compartment at 15A. It leaves the camera running when the car is off - I do not want this, although I could simply unplug the power cable on the unit every time I get in the car, this will become a nuisance for me. I tried #40 because it was 7.5 and seemed to have useless functions, but it was the same. The other fuses I avoided as I am trying to make sure I do not harm my cars systems as I am not an expert when it comes to cars, although I do have some knowledge of this stuff.

I am sure I could plug it into higher ampere fuses without creating too much of a problem, such as #34, which is only tied to the "Seat adjustment, passenger", together with fuses 1, 22, 38, (and 34), which I believe is not on when the car is off - but as I am hesitant to flat out try it, I thought I'd ask you guys on here if you have any advice on a good fuse to use in the passenger compartment, or any advice on the potential downfalls of using a different ampere than suggested (15A).

Hope you can help!

 

[dzal67]

 

[jeez123]

46, 47 and 64 should be what you need.

I would if possible try to avoid 46 but could be used as a last way out.

Don't ever put anything in the emergency-systems of a car, not the ABS, not the hazards, not anything related to the security of your car.. If your car has an e-call system that alerts the emergency central or insurance agency for road assistance it wouldn't be adviceable to goof around them because a fault in the electric system could either set it off or simply make it not working as intended.

You wrote you didn't wan't it on all the time.... Well, use the 64 for radio, and put a 5A fuse into the B-position of the Add-A-Fuse that came with your hardwire-kit. Leave the 10A on the A-position and you should be AOK.

 

[dzal67]

47 is your cigarette lighter and it is powered only when ignition is ON

 

[jeez123]

The reason i advice you against using #46 if avoidable is it's an 40A-fuse for the wipers. I think it's a LOT of power for that operation, i've driven cars that often only requires 20-30A for the wipers.

By sending 40A thru the housing of the add-a-fuse tap, you'll be sure to heat the plastic enough that it actually can melt and cause a open circuit to the other position of the tap, that leads to the camera.. You'd definately not wan't that...

The wire that is attached to be "B-position" that your camera is going to be connected to, is rated for 15A at maximum.

And by that, your best advice would be to pull off the power at the 47 or 64. My bet is that 64 shuts off with the car, when the key is removed.

 

[dazh123]

Jeez123, thank you so much for all the info. I do not think my hardwire kit came with an add-a-fuse though. Initially, I had wanted to use #47 as well, but the problem here is I had already wired everything up for the passenger fuse box - and had hoped for a solution that didn't require re-wiring it up to the front of the car. I am 90% sure that #47 shuts off with the car as my cigar lighter generally doesn't seem to work when my car is off. I avoided #46 because similarly to #47, it is in the front, but also because it has a much higher amperage. As for #64, in case the other one doesn't work out: Do you think 10A is enough to properly power both a front and rear camera combo?

Would there possibly be any in #21 to #42 that might look good to you? Because like I mentioned in the initial post, #34 really only seems to affect "Seat adjustment, passenger", which is just one seat, for a function I rarely use (only if I need to move seat to make room for heavy/big boxes or whatever). And it is 30A, so splitting the power at 15A between Dash Cam and seat adjustment shouldn't be too serious of an issue?

Also, you mentioned #46 which is 40A, and I wonder, like I did with #34 which is 30A, what will happen if I pop a 15A fuse into a housing that requires twice as much amperage? Worst case scenario?

 

[dzal67]

If diagram posted above is correct then you don't want use fuses 21 and 42. They control too many items. If you replace 30A fuse with 15A one there is a chance that at some point that fuse will blow because that specific circuit was designed for higher amperage.
I don't believe that your dash cam is high amperage device. Try to run it from small 5v phone battery pack. If is working properly then would indicate that is drawing about 2A or less on 5v. That would translate to around 1A on 12v. Considering efficiency it is probably closer to 1.5A.

 

[SawMaster]

I think there are some basic misunderstandings here. First I severely doubt that the cam draws 15A- all the cams I've seen specs on draw no more than 1.5A per cam. I looked on the Rexing site but could not find that spec. Regards the hardwire hit what I think this number means here is that the 'add-a-fuse' can carry up to a 15A load in the car fuse slot. This is how these are usually rated, and if that is the case here you'd not want a 30A draw through that 'add-a-fuse'

I would contact Rexing and ask what the exact amperage need of the cam is, and what the amperage rating of that hardwire kit means. Specifically whether you can safely draw 30A through it. Do heed the advice of never tapping into a safety or car-operational circuit. Always consider what the consequences will be if the fuse blows to that circuit as sometimes things do go wrong and we're all about enhancing safety here, not impairing it

Phil

 

[Ralph2]

If.. you can afford a Mercedes.. and don't understand electrical wiring and based on your concerns you don't.. Have it installed professionally.

 

[DashcamDPR]

If.. you can afford a Mercedes.. and don't understand electrical wiring and based on your concerns you don't.. Have it installed professionally.

unless he's had it the entire 14+ years, it might not have cost all that much to buy

 

[dazh123]

If.. you can afford a Mercedes.. and don't understand electrical wiring and based on your concerns you don't.. Have it installed professionally.

unless he's had it the entire 14+ years, it might not have cost all that much to buy

Bought my car almost 10 years ago, salvaged. I understand it enough to maintain it, but like I said I've never had to mess with the wiring more than a couple of times in those 10 years, and frankly just want to make sure I don't ruin my car/new $140 dash.

I think there are some basic misunderstandings here. First I severely doubt that the cam draws 15A- all the cams I've seen specs on draw no more than 1.5A per cam. I looked on the Rexing site but could not find that spec. Regards the hardwire hit what I think this number means here is that the 'add-a-fuse' can carry up to a 15A load in the car fuse slot. This is how these are usually rated, and if that is the case here you'd not want a 30A draw through that 'add-a-fuse'

I would contact Rexing and ask what the exact amperage need of the cam is, and what the amperage rating of that hardwire kit means. Specifically whether you can safely draw 30A through it. Do heed the advice of never tapping into a safety or car-operational circuit. Always consider what the consequences will be if the fuse blows to that circuit as sometimes things do go wrong and we're all about enhancing safety here, not impairing it

Phil

This was my basic understanding of it as well, but like I replied to the above: I was hoping for some experienced advice as my passenger compartment had only one 15A, two 7.5As, which are all on at all times - as well as being wired to a lot of things. I mistakenly wired my dash cam up before realizing this (we can credit this to never having to wire anything to my car) and was hoping someone could suggest something in that compartment so I do not have to rewire the whole thing. I might contact Rexing, but I'm gonna attempt just rewiring it up front instead for simplicity.

 

[Submariner Gold]

I would go for no 47.cigar lighter.
I managed to get through my mums C270CdI alongside the bonnet cable release, there was some space.
But then I am no expert!

 

[Nigel]

The hardwire kit you have linked to must be used in place of a 15 amp fuse, or placed in an empty slot.
If you put it in place of a larger fuse then it should blow when you use the original equipment, if you put it in place of a smaller fuse then it is dangerous.

I assume it has another in-line glass fuse in the round black connector type thing? If not then it doesn't look very safe...

Note that your dashcam probably only needs a maximum of 1 amp at 5 volts, which is half an amp at 12 volts - you are only going to add half an amp to the load on the original circuit.