Hardwiring - Fuse Tap: Max value?

Unknown1

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After spending quite a few hours getting an unwanted back adjustment via the silly placement of my car's fuse box, I'm not sure where to go from here.

I'm installing a new A119 and moving the old A118C to the back. Instead of dealing with the annoyance of plugging and unplugging each time like I've been doing with just the A118C for the past couple years. I wanted to hardwire them to have the cameras power on when starting it up and power off when removing the key. I picked up 2 hardwire kits with 2 add-a-fuse's and started testing fuses under the dash on the driver's side (2002 Mustang GT).

Here's the problem, the mini ATM fuse tap is rated 2-10Amps and none of the 5 or 10 amp fuses behave like I need it to for desired performance.

I'm a little confused on this aspect of the tap rating. On the various online listings the new fuse rating is often listed, but the original fuse rating is often left out or in some cases listed as the same as the 'new fuse'. Can anyone clarify this? Can I tap into fuse slot that has a pre-existing fuse over 10Amps? Is there a max value?
Is there an ideal value (and source if possible) for the new fuse (Hardwire shows 'Output: 5.5V 1A')?

The two Taps I picked up from a local store are 'Bussman 2-10 Amp'
 

SawMaster

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You should tap into a circuit which has a higher rated fuse in it that what your added circuit is fused for. This ensures that the added fuse will blow in a short before the car's fuse blows, leaving the car fully functional.

For fuse taps, the rating indicates the maximum current you can draw through them. For the "add-a-fuse" piggyback type taps, the maximun rating applies to the car's fuse rating. So if these Bussman taps are unfused and just way to source power, they should work in any location rated at 10A or more. For the cam anything from a 2A to a 5A fuse is OK, and there does need to be a fuse downstream of the tap- this is usually already there in the hardwire kit's power lead. If it isn't then you need to add that.

And welcome to DCT :)
Phil
 
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Unknown1

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Thank you very much Phil!

I didn't know "Fuse Taps" were a separate device from the "Add a Fuse/Circuit" It seems they're used synonymously, frequently online.

The Bussman I have are the 'Add-A-Fuse' type (BP/HHH) that plugs into the original fuse and has two fuse slots, bottom for the original fuse and top for the new fuse with a wire attached on the side.

This is the hardwire I bought off Amazon: WheelWitness - Dash Cam Hardwire Installation Kit - 12V to 5V Mini USB
 

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They do make plain fuse taps, which are just a piece of metal you can clip a connector in or solder a wire to, then you slip the original fuse into place with it. the 'add-a-fuse' type are better. According to the Bussman site http://www.cooperindustries.com/content/public/en/bussmann/consumer/products/automotive_circuitprotectionprdandacc/fuse_holders_panelblockstaps/Blade_Fuse_Taps_ATM_ATC.html
the "HHH" series will handle up to a 30A car fuse circuit with an added 10A or less accessory. You should be able to find a suitable circuit within that range ;)

Many hardwire kits are poorly made and some have been known to fail and ruin cams Maybe @OCD Tronic can comment on yours as I know little about these.

Phil
 

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We don't currently stock any add-a-circuit / fuse taps but looking to stock something to sell in the future. The ones on Amazon are usually pretty good. Pull an existing fuse to see what size you need to match up.
 

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Asking about the hardwire kit here ;) Is the one he listed a good one? WheelWitness - Dash Cam Hardwire Installation Kit - 12V to 5V Mini USB
And thanks for the help (y)

Phil
 

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The Vico-Power PLUS is a great hard wire kit if you want "the best" :)
 

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The hardwire kit that I have used and supplied to more than 20 cars costs £2.53 but yet to have a failure, I just solder every connection then seal with LIQUID TAPE for 100% water tight flexible permanent seal.
Another easy way is "T" taps so you can add a wire/fuse holder etc, I always where possible try to join onto busbar in fusebox but so long as it is a heavy gauge circuit you should be fine
 

SawMaster

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It's always best to remember that a dashcam is just one part of a system where it can never be better than the worst part ;) If you use the cams, hardwire kits, and SD cards generally recommended here on DCT you will almost assuredly have the good experience you seek :) But if you go cheap on any part of your system that experience may not be so happy :(

You don't always have to buy the most expensive stuff, but it must always be good enough no matter the cost. Money spent on quality is always money well-spent :cool:
Phil
 
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You should tap into a circuit which has a higher rated fuse in it that what your added circuit is fused for. This ensures that the added fuse will blow in a short before the car's fuse blows, leaving the car fully functional.

For fuse taps, the rating indicates the maximum current you can draw through them. For the "add-a-fuse" piggyback type taps, the maximun rating applies to the car's fuse rating. So if these Bussman taps are unfused and just way to source power, they should work in any location rated at 10A or more. For the cam anything from a 2A to a 5A fuse is OK, and there does need to be a fuse downstream of the tap- this is usually already there in the hardwire kit's power lead. If it isn't then you need to add that.

And welcome to DCT :)
Phil
Old thread, but I tapped into a 5A fuse with my fuse tap having a 5A fuse in it. Is this fine? I see you said I should tap into a higher Amperage fuse so the camera fuse blows before the actual car fuse. After reading this comment and another comment over on reddit I was thinking of changing the fuse I tapped in to something else.
 

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It's probably OK as you're unlikely to have problems since dashcams draw so little power, but there's a risk of overloading that car circuit should the car and the cam call for maximum power at the same time. Better to find a fuse location with a higher rating if you can.

Phil
 
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It's probably OK as you're unlikely to have problems since dashcams draw so little power, but there's a risk of overloading that car circuit should the car and the cam call for maximum power at the same time. Better to find a fuse location with a higher rating if you can.

Phil

So tapping into my cig lighter (20A i think) for example and my windshield wipers (10A i think) would allow more breathing room for the fuse just in case the cam or car's device needs more power?
 
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So tapping into my cig lighter (20A i think) for example and my windshield wipers (10A i think) would allow more breathing room for the fuse just in case the cam or car's device needs more power?

So for the Acc tap i plugged into the cig lighter (bottom right). But for battery/always on power which fuse should i tap into? The washer ones only have like 0.20v in them while the OBD port has 12v and the stop lights have 12v. Is those two safe to tap into?

Edit: i just tapped into the S/roof which in assuming means sunroof even though my car doesnt have one. It was missing a fise so i bought the 20A one the fuse panel says needs to go into it
 

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SawMaster

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So tapping into my cig lighter (20A i think) for example and my windshield wipers (10A i think) would allow more breathing room for the fuse just in case the cam or car's device needs more power?
It makes it less likely that the car fuse or circuit will be overloaded, either blowing the car fuse or damaging it's wiring. Fuses are always rated higher than the load they are expected to carry, so that a slight excess current draw doesn't blow the fuse while a large overload or short does. The wiring supplyhing the fuse is also slightly oversized so that it doesn't get damaged before the fuse blows. So for a 4A device, you use at least a 5A fuse and wiring of the next size up from a 5A capacity. In theory, you could draw another amp without blowing the fuse, but in practice the fuse will then begin heating up, and in time will weaken from the hot/cold cycling, then will blow before 5A is reached. With a higher-rated circuit using this same 20% safety margin, you can draw an extra amp with less fuse heating, and therefore less chance of it experiencing heat-stress leading to it blowing. Just some added 'headroom', that's all. But as I said, for practical purposes your 5A car fuse circuit will likely carry a dashcam with no problem, even though using a larger capacity circuit would be a better choice.

Phil
 
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It makes it less likely that the car fuse or circuit will be overloaded, either blowing the car fuse or damaging it's wiring. Fuses are always rated higher than the load they are expected to carry, so that a slight excess current draw doesn't blow the fuse while a large overload or short does. The wiring supplyhing the fuse is also slightly oversized so that it doesn't get damaged before the fuse blows. So for a 4A device, you use at least a 5A fuse and wiring of the next size up from a 5A capacity. In theory, you could draw another amp without blowing the fuse, but in practice the fuse will then begin heating up, and in time will weaken from the hot/cold cycling, then will blow before 5A is reached. With a higher-rated circuit using this same 20% safety margin, you can draw an extra amp with less fuse heating, and therefore less chance of it experiencing heat-stress leading to it blowing. Just some added 'headroom', that's all. But as I said, for practical purposes your 5A car fuse circuit will likely carry a dashcam with no problem, even though using a larger capacity circuit would be a better choice.

Phil

Thanks for the detailed response! I did end up switching the fuse taps and i tapped into the cig lighter (15A, bottom right) and the s/roof (20A, 6th from the bottom left) which i assume is the sunroof even though my car doesnt have one the fuse was missing so i bought a 20A fuse for it according to the fuse panel. Tested and everything works as normal!

Thanks again for answering all my questions. Sorry for bumping an old thread!
 

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Not to muddy the waters... but if you are supplying your always on power to your dash cam with a 20 amp fuse.. That.. is potentially dangerous. The wire going from the fuse panel to your camera is not sized (it's really thin) to handle a 20 amp load.. if there were to be a "short" your wire would melt.

If.. you added an "add a fuse" that required placing 2 fuses (the original and lower value for the new load) no problem.. If you used a fuse tap that uses only the 20 amp to supply the new load.. change that fuse for a lower value that is sized to the wire size (5 amps). The bottom line here is that the camera wiring should not be supplied with anything over 5 amps.

Picking fuse sizes and sources seem to be a considerable problem.. when picking the size of the fuse.. one needs to consider both the load of the application "and" the size of the wires supplying that load.. Remember a fuse is nothing but a thin wire designed to melt in a controlled condition at a certain amperage.. Having the wire supplied by the manufacturer which is also as thin as they can make it.. melt first is not a good thing.
 
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Not to muddy the waters... but if you are supplying your always on power to your dash cam with a 20 amp fuse.. That.. is potentially dangerous. The wire going from the fuse panel to your camera is not sized (it's really thin) to handle a 20 amp load.. if there were to be a "short" your wire would melt.

If.. you added an "add a fuse" that required placing 2 fuses (the original and lower value for the new load) no problem.. If you used a fuse tap that uses only the 20 amp to supply the new load.. change that fuse for a lower value that is sized to the wire size (5 amps). The bottom line here is that the camera wiring should not be supplied with anything over 5 amps.

Picking fuse sizes and sources seem to be a considerable problem.. when picking the size of the fuse.. one needs to consider both the load of the application "and" the size of the wires supplying that load.. Remember a fuse is nothing but a thin wire designed to melt in a controlled condition at a certain amperage.. Having the wire supplied by the manufacturer which is also as thin as they can make it.. melt first is not a good thing.

Yea my add a fuse kit from the dashcam maker (viofo) includes the 5A fuse on the top for the cam, and i put the 20A fuse from the car on the bottom. Like the picture i attached except thats for the 15A cig lighter fuse.
 

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