Hardwiring Direct to car battery?

[Chris Hunt]

Hi All,

Need some advice please. Got a guy who has wired his hardwire kit directly to his car battery, not via his fuse box. I am definitely not an expert in this area, but this seems to me to be a bad idea. Can anybody with more knowledge in this area offer any advice?

 

[jokiin]

Euro car by any chance?

 

[petepete]

As long as he has used a suitable fuse there is no difference than wiring to a fuse box permanent live...

Saying that, it might be beneficial as he might get less voltage drop.

 

[Nigel]

Hi All,

Need some advice please. Got a guy who has wired his hardwire kit directly to his car battery, not via his fuse box. I am definitely not an expert in this area, but this seems to me to be a bad idea. Can anybody with more knowledge in this area offer any advice?

It will work fine, the problem is that when the loose cables he has left lying around in the engine compartment rattling against pieces of sharp metal wear through their insulation in a years time and short out, without a fuse to cut the power his cable will vaporise possibly burning the car to its shell in the process.

He should add in a 2 amp fuse as close to the battery as reasonably possible to protect the cables in the event of a short circuit. Car fires do happen, are dangerous and are very often caused by short circuits. There is no need to go through the fuse box but you should have a fuse.

 

[Chris Hunt]

Euro car by any chance?

Old school Aussie guy. Turns out he's driving a 2015 Mazda 3 SP25. Says he's no expert so i thought i'd get him some advice. Sounds like as long as he checks his install he should be okay.

 

[Chris Hunt]

It will work fine, the problem is that when the loose cables he has left lying around in the engine compartment rattling against pieces of sharp metal wear through their insulation in a years time and short out, without a fuse to cut the power his cable will vaporise possibly burning the car to its shell in the process.

He should add in a 2 amp fuse as close to the battery as reasonably possible to protect the cables in the event of a short circuit. Car fires do happen, are dangerous and are very often caused by short circuits. There is no need to go through the fuse box but you should have a fuse.

Thanks for your advice Nigel ..and others i will pass on the words of wisdom so he is better informed of what his best options are.

 

[dash riposki]

Is the camera running 24/7?
Always on? May be some battery drain issues if it is, and the car sits unused for a few days, and there is no low voltage cut off device inline.

 

[SawMaster]

Ditto the good advice so far. Must be fused at the battery, with wires ran where there will not be heat or chafing problems, and where they will not possibly interfere with anything which moves.

It can be as safe and as solid as factory wiring or better when done right. DC line losses happen quickly, so go at least one wire gauge larger than you need by usual spec, use wire rated for the heat and chemical-fume laden under-hood environment, then fuse for the original power level to ensure the fuse will always be the weakest link.

Phil

 

[Chris Hunt]

Is the camera running 24/7?
Always on? May be some battery drain issues if it is, and the car sits unused for a few days, and there is no low voltage cut off device inline.

He's using a Vico Power Plus Hardwire kit, so he can set the Voltage drop to whatever setting suits or have it time out after 6, 12, 24 hours etc. Depends on how he runs his setting but with trial an error i think he will be safe from flat battery.

 

[pirasa]

That is all right, because it will do the work. But regarding safety, it is an unsafe practice. The device connected may have its own safety features but it will not protect the wire connecting it to the battery. Connecting a fuse will solve this concern. For the wiring installation as long as it follows the existing automotive wiring harness of the car it will be fine. Just be sure that the wires are securely bundled to the wiring harness.

circuit board assembly

 

[max789]

Hi, all

I hope it's alright to resurrect this old thread.

I've the same dilemma in battery vs fuse box hardwiring.
https://dashcamtalk.com/forum/threads/hardwiring-directly-to-battery.28818/

I note that the original poster Chris Hunt is still active and would appreciate his feedback as well as others' views.

I note that Nigel mentions using a 2A fuse for protection. Could a 5A fuse be suitable, depending on the type of cable connecting to the car battery?

Thanks in advance!

 

[RojoLibertario]

Hi max,
It depends on what you are using it for. I'll use my dash cam as an example. My cam consumes 370mA while my car is on, that would be 0.370A. I use a 3A fuse, because that's what was provided to me.
Now let's say the wire that's feeding the camera gets cut and causes it to short. The Amperage will go up, and this can cause further damage to the wire, making it worse, damage to the camera, damage to nearby wires which it can basically damage your whole car (this depends upon where you run the wires).
Now in my case once the amperage gets to 3A the fuse breaks (that's what they do and so you have to replace them) and this breaks the circuit, stopping all of the stuff that i said from happening. But it can still damage things just not as much.
Now if I place a 5A fuse to protect my dash cam, it might protect it but you want to try to have something that will stop it sooner than later, in case something were to happen.

I have never wire anything directly from the car's battery, because I believe to be unsafe. And so I can't say how well it works.

Sent from my SM-N920P using Tapatalk

 

[Nigel]

Hi, all

I hope it's alright to resurrect this old thread.

I've the same dilemma in battery vs fuse box hardwiring.
https://dashcamtalk.com/forum/threads/hardwiring-directly-to-battery.28818/

I note that the original poster Chris Hunt is still active and would appreciate his feedback as well as others' views.

I note that Nigel mentions using a 2A fuse for protection. Could a 5A fuse be suitable, depending on the type of cable connecting to the car battery?

Thanks in advance!

A 5A fuse is fine, but then you must use 5A cable so that if the cable is damaged and there is a short, the fuse will blow before the cable catches fire and burns your car and everyone in it to the metal shell.

The fuse is not for protecting the camera, it doesn't need to have the same power rating as the camera, the fuse is there to protect the cable from catching fire.

 

[SawMaster]

Wiring directly to the battery can be safe but only if all is done correctly. I have a 30A (no typo) circuit going all the way to the back of my van. It is routed where it shouldn't get hurt, generally alongside factory wiring. The wire is rated to 40A and heavily insulated with grommets where it passes through metal. The one thing which makes this safe is the 30A fuse mere inches from the battery Branch circuits taken from here have lower-amperage fuses protecting them individually, again placed as close to the 30A 'bus' as is practical, so a branch circuit failure will not kill the 30A 'bus' but only that one device

tldr:
1- Fuse as close as practical to the power source. Be certain any unfused section is absolutely safe.
2- Fuse rating never exceeds wire rating, and it's best to use an under-rated fuse or over-rated wire for a larger safety margin
3- Route wires carefully thinking about all possibilities (even a crash). Running with factory wires is generally safe as they are engineered for placement safety.

Phil

 

[max789]

Thanks, all, for your feedback. Most helpful and very educational!

 

[Ralph2]

Wiring directly to the battery is generally done to provide power for electrical brakes on a trailer..or.. for those that have large audio requirements.