What size fuses to protect "Batt" and "ACC" lines for A129 Plus Duo?

[fjparks]

Hi All,
Looking at the manufacture site I only see spec of 3.1A for the supply voltage but it is not broken out for Batt Vs ACC lines
As far as I can tell the HK3ACC hardwire kit is not fused.
I could just go with "150% rule" and SWAG it as say a 5A in the one and 3A in the other, but maybe someone has a better answer...
Thanks

With the two camera system and using HK3ACC hardwire kit
What size fuse should be used to protect "Battery +" (red)?
What size fuse should be used to protect "ACC" (yel) ?

 

[Nigel]

The HK3 contains a current limit to protect the USB cable and camera, so it is only the coloured 12V wires that the fuse protects. Those wires are probably labeled 20AWG and you should use a fuse suitable for protecting 20AWG automotive cable. Exactly what size fuse that is is debatable, but a 5A fuse should be fine. Yellow and red wires are rated the same, so the same fuse size can be used, even though the yellow uses close to 0A.

The 3.1A will be for the USB cable at 5V, so at 12V the maximum current is not going to be more than 2A, so a 2A or 3A fuse would also work fine.

 

[fjparks]

The HK3 contains a current limit to protect the USB cable and camera, so it is only the coloured 12V wires that the fuse protects. Those wires are probably labeled 20AWG and you should use a fuse suitable for protecting 20AWG automotive cable. Exactly what size fuse that is is debatable, but a 5A fuse should be fine. Yellow and red wires are rated the same, so the same fuse size can be used, even though the yellow uses close to 0A.

The 3.1A will be for the USB cable at 5V, so at 12V the maximum current is not going to be more than 2A, so a 2A or 3A fuse would also work fine.

Ahhh, the HK3 does have over current protection.
Thanks

 

[joe384]

I have run the HK3 with 2A fuses fine, in fact I pretty much use 2A for all dashcams I've hardwired, unless there is a specific reason not to

 

[fjparks]

I have run the HK3 with 2A fuses fine, in fact I pretty much use 2A for all dashcams I've hardwired, unless there is a specific reason not to

Thanks for the reply Joe.

 

[SawMaster]

Standard car fuses are rated for continuous loads, so they can handle more than their rating for short times like during a cam start-up cycle. Since in our usage they're in place to protect the car, it's best to fuse both wires on the HWK but at the very least the full-time power lead must be fused; the switched or ACC wire draws almost no current but it can also accidentally short out too, so two fuses are best. 2A to 5A fuses should protect everything adequately and provide all the power needed, but go no larger

Phil

 

[Nigel]

it's best to fuse both wires on the HWK but at the very least the full-time power lead must be fused; the switched or ACC wire draws almost no current but it can also accidentally short out too,

Since the fuse is only protecting the cable, and the red and yellow cables have the same rating (20AWG), the risk is exactly the same for the two coloured cables, both should be fused the same. The only real risk is that the insulation on the cables gets worn through by rubbing or rattling against a sharp edge, if it is an earthed piece of metal then you get a short and that can start a car fire, and cars are not self extinguishing. It is a genuine risk, so the fuse should be got right. Using tie wrap to avoid rattling cables also reduces the risk and keeps things tidy.

(I think that is more or less what you said last time I accidently suggested that the fuse on the red cable is more important!)

 

[fjparks]

Standard car fuses are rated for continuous loads, so they can handle more than their rating for short times like during a cam start-up cycle. Since in our usage they're in place to protect the car, it's best to fuse both wires on the HWK but at the very least the full-time power lead must be fused; the switched or ACC wire draws almost no current but it can also accidentally short out too, so two fuses are best. 2A to 5A fuses should protect everything adequately and provide all the power needed, but go no larger

Phil

Thanks for the reply Phil