Submariner Gold
Active Member
- Joined
- Jan 8, 2018
- Messages
- 198
- Reaction score
- 27
- Location
- Berkshire United Kingdom
- Country
- United Kingdom
- Dash Cam
- Vicovation MF3
Bought this 12V USB dual Charger to hardwired into the car
It says it Outputs 5V 3.1 Amps per port , specifically highlights, that both are rated at 6.2A total.
When it comes to calculating the fuse on my Piggy back fuse holder.
Does it work like
6.2A x 5 V = 31 Watts output.
Therefore 31 watts / 12 volts = 2.588 A so a 3A would be fine.
As this rear cigar fuse only comes on when the engine is running is technically the calculation
31 watts / 14.3 V = 2.167A
I happen to have a 4A Fuse and a 3A so thought that either would be Fine. But would prefer to use the lower i.e. 3A
Is that the way you work it out?
I assume the conversion from 12V to 5V would consume some power
Note the other part of the piggyback has been filled with the original specified 15A fuse.
In real terms it might power one battery with a max input of 2.1 A
And one dash cam 0.6A = total Amps 2.7A
so 5V x 2.7A = 13.5 watts.
So on the 12V side , 13.5 / 12 = 1.1A.
I am trying to reduce the Amps as much as possible because the piggyback will only go in the wrong way around, thanks to a physicaly high relay block. Thus the piggy back is in parralell, where I would have prefered it to be in series.
However as its an S Class Coupe it actually doesnt actually have a rear cigar lighter, so there should be no load on this circuit, other than the wiring loom. ( note fuse diagram says for S Class and S Class Coupe.)
I did think of lowering the std. fuse to 10A and putting a 3A in here, as thats lower than the 15A in total as per theFuse diagram.
But I just wonder if it does secretly power anything else? Nothing on the fusebox diagram uses No. 117.
(The front Cigar lighter, and the boot power supply lighter socket both have individual fuses)
Other reason I didn't down grade to original fuse, is the fuse holder next to it says its for the fuel pump, and that should be 30A but its actually 15A. So I wondered if undocumented for the Coupe they Loaded some of that load on this empty circuit.
It says it Outputs 5V 3.1 Amps per port , specifically highlights, that both are rated at 6.2A total.
When it comes to calculating the fuse on my Piggy back fuse holder.
Does it work like
6.2A x 5 V = 31 Watts output.
Therefore 31 watts / 12 volts = 2.588 A so a 3A would be fine.
As this rear cigar fuse only comes on when the engine is running is technically the calculation
31 watts / 14.3 V = 2.167A
I happen to have a 4A Fuse and a 3A so thought that either would be Fine. But would prefer to use the lower i.e. 3A
Is that the way you work it out?
I assume the conversion from 12V to 5V would consume some power
Note the other part of the piggyback has been filled with the original specified 15A fuse.
In real terms it might power one battery with a max input of 2.1 A
And one dash cam 0.6A = total Amps 2.7A
so 5V x 2.7A = 13.5 watts.
So on the 12V side , 13.5 / 12 = 1.1A.
I am trying to reduce the Amps as much as possible because the piggyback will only go in the wrong way around, thanks to a physicaly high relay block. Thus the piggy back is in parralell, where I would have prefered it to be in series.
However as its an S Class Coupe it actually doesnt actually have a rear cigar lighter, so there should be no load on this circuit, other than the wiring loom. ( note fuse diagram says for S Class and S Class Coupe.)
I did think of lowering the std. fuse to 10A and putting a 3A in here, as thats lower than the 15A in total as per theFuse diagram.
But I just wonder if it does secretly power anything else? Nothing on the fusebox diagram uses No. 117.
(The front Cigar lighter, and the boot power supply lighter socket both have individual fuses)
Other reason I didn't down grade to original fuse, is the fuse holder next to it says its for the fuel pump, and that should be 30A but its actually 15A. So I wondered if undocumented for the Coupe they Loaded some of that load on this empty circuit.