Do I need to add inline fuses?

fronty

New Member
Joined
Jun 27, 2020
Messages
2
Reaction score
0
Location
florida
Country
United States
I bought the 3 wire hardwire kit from Viofo. I was planning on just soldering the connections at the ignition switch. Do I need to add fuses or are the ignition switch fuses fine? I know they will be high amp fuses.

I noticed a lot of people use the fuse taps. I don't have a fuse block under the dash, so I would have to run it to the hood fuse block. That is if I go the fuse tap route.
 
fuses are to protect the vehicle, not the device, would be advisable to fuse any third party device you add, could potentially affect your insurance policy if something were to go wrong and you hadn't fused it, something to keep in mind
 
You might find it a lot easier to run a cable to the fuse box, even if it is not in a convenient place.

The fuse is only needed to protect the cable after the fuse from short circuits which might cause a fire. Since the HK3 red cable is 7.5 amp rated, the fuse for the red cable should be 7.5A maximum, 5A normal, 2A minimum, the yellow and black do not need fuses. So technically you should not connect the red cable to a 30A fused cable without adding an inline 5A fuse. The only thing is is going to protect is the short length of red cable, so if you ensure that can't be damaged, cut by a sharp metal edge, etc., then the fuse is not necessary, you can make it safer by cutting the cable down to just a few inches in length and using tie wraps to secure it firmly, even with an inline fuse you have a short length of unprotected cable. The USB cable after the HK3 is not a concern since there is a current limiter in the HK3.

What car is it that doesn't have a fuse box?
 
I ended up just running the cables to the fuse box under the hood. I plan on just using fuse taps.

The vehicle is a Dodge truck.

Which fuses do you normally tap into for the constant 12v and ignition wires?
 
Using fuse taps make it much easier, as long as you get the right fuse type.

Don't have Dodge here so can't answer the other question properly. Most people just check which ones are on with a multimeter, the camera doesn't use enough power to cause problems, but it is sensible to avoid any safety system fuses such as airbags or anti-lock brakes.
 
Yes hard to say what fuses to tap into, i just procured a 5 dollar LED probe for installing hard wire for the first time in my own car.

But it can still be a bit tricky, some new cars keep some circuits live for a little while before finally turning it off, i ran into that issue putting a camera in my friends Mercedes, the fuse i ended up using i had deemed always live several times,,,,,, actually in his car it seemed like they was all live all the time.

So it could be a good idea to unlock and open doors, and then let the car sit there for a little while before you start probing fuses with a LED probe like mine or a cheap multi meter which you can also use.

you just need a 5 A fuse to protect your car from the dashcam.

I tap in to 10 A fuses if i can.

You of course want to steer clear of "mission critical" fuses like ABS / Airbags / engine manegement ASO, on the other hand Accessories - seat heat - defroster - cabin light ASO are fair targets.
 
In good engineering practice there will be a fuse located as close to a wire's power source as is practical. You can't get closer than a fuse-tap :p but if that isn't practical an inline fuse will also work fine as long as it's as close as is practical too. The fuse should be sized to the expected load, but to never exceed the capability of the wire itself. For reasons of reliability, rather than an exact load match going up one fuse size is usually best. No dashcams need more than 1.5A, so a 2A fuse is ideal. Those can be hard to find locally sometimes so you can also use a 5A fuse to equal effect- either will blow before wiring gets hot enough to do any damage :)

Now here is where some HWK's and some people make a simple mistake- the ACC or switched wire also needs to be fused similarly! It can short out too and without a fuse here that will blow the car fuse you're tapped into, which is what we're trying to avoid ;) It doesn't matter that it normally carries almost no current; we're protecting against the abnormal and not the normal. Again, any fuse less than the wire's capability will do fine, and if you can get one fuse for the BAT side you can get another of equal size for here at the same time :)

Best practice is to also fuse the ground wire at a rating equal to or less than the BAT fuse. Why? Because if the car ever loses ground somewhere else, the electricity will seek another path which can be right through the device you're installing which will destroy it :( But I don't do this with anything less than very expensive devices because the chances of experiencing this type of failure mode are extremely small, and most of today's cars have multiple redundant ground paths for high current loads already to protect the car's equipment reducing the chances of a failure like this to almost nothing. And if it happens to you, the cam is going to be the cheapest of all the things getting damaged :cry: I've only heard of two instances of this kind of failure causing collateral damage in over 40 years of working with cars and electronics.. Your car itself isn't wired this way so I say don't bother. Just be sure that what seems to be a good grounding point really is that way, and don't worry about it :cool:

Phil
 
Yep, worth doing, I place inline fuses almost obsessively. I like the weatherproof ones with a tight-fitting rubber cover.

You can use the smaller inline fuse holders (mini-ATM type) to save space and bulk.
 
Back
Top