Ok if i got it right 120w/12v=10a and 120w/24v=5a so i need 5-10a ,i choose 10a fuse,am i right ?

And i think i dont need more then 120 w cigarette splitter!

Thanks for the link.

As I said before, the choice of fuse is sized by the rating of smallest wire in the circuit. If you use the quoted plug, this already has a 2A fuse in it and this should be more than adequate for your needs. I assume you are using the 3 way sockets for convenience and not because you want to run maximum capacity from each.

 

Compare this to a domestic 6 way extension lead. In the UK this has typically 6 x 13A sockets and a single 13A plug on the cable. The cable is even often rated at less than 13A. The fuse in the socket strip is 5A, 10A or 13A to protect the (smaller rated) cable from overheating or fire risk.

 

On a slightly different tack, when using a piggy back tap connector on the car fuse panel you do not know what is behind the fuse on which you will piggy back. It could be wire or a substantial bus-bar so the same thoughts would apply in case it is a wire. My rule of thumb would be not to add more than 50% to the existing fuse location. The popular fuse 49 location has a 5A fuse in it so I would add no more than a 2A fuse. If you need more then find a location with a bigger fuse in it.

 

Edited typos

Edited 12 May, 201511 yr by pikpilot

the smallest sized in the circuit is on the kinivo (picture attached), i don't know if it has a fuse at all. so from what you are saying i need to treat this wire and put max of 50% is 7.5a or less 5a because the wire is thinnest among the other in the circuit.

yes i leave the main cigarette socket at his place in case i will need to connect something big and this 3 way socket cigarette i need onle for charging phone and tablet with the bluetooth receiver (kinivo).

 my only Confusion is if i will connect to devices in usb 2.1a ich (this is 4.2a allready) is the bluetooth receiver will work with the 0.8a that left ,if i use 5a fuse and will left 3.3a if i will choose the 7.5 a.

 

thank you for your help

i am sorry if my questions are not so brilliant, electronics isn't my specialty that why i ask so many questions.

Ok if i got it right 120w/12v=10a and 120w/24v=5a so i need 5-10a ,i choose 10a fuse,am i right ?

And i think i dont need more then 120 w cigarette splitter!

Thanks for the link.

 

Do you intend to draw 120w?

 

As I said, look at what you intend to power & add some overhead.  You don't have to fuse it for the maximum rating of the power splitter device.

hello

i calculate  the 2 usb 4.2a need -(12vx4.2a=) 50watt, but i dont know how much the bluetooth receiver (kinivo btc 455) needs.

so i guess i will use if everything is plugged, max 120 watt,

correct me if i am wrong ?

Isn't the output voltage of USB 5v and 2.1amp max?  

 

The kinovo is 5v 1.0 amp.  It's in the manual which is readily available online - it took me 5 seconds to find the info for both the BT and the USB.  It's better than "I guess".

 

I'd fit a 5amp fuse & see what happens - the worst is that it will blow on overload.  Over spec the fuse & something else will melt.

hello

i calculate  the 2 usb 4.2a need -(12vx4.2a=) 50watts

correct me if i am wrong ?

Yes, you are wrong. Each USB output has a switched mode dc to dc converter with an efficiency of at least 80% (some are better than 95%). So worst case is (5 x 4.2)/0.8 = 26.25W. Translated to the current draw at 12V, this is just under 2.2 A.

thanks for all, i just sow the details about the kinivo in there manual,

i will go with 5a fuse like you all suggested,

i will cut off the plug from the unit ( http://www.ebay.com/itm/371200960018?var=640339698094 )and connect to( http://www.ebay.com/itm/191468796990?var=490555151290) 

and from there to the rear wiper location fuse.

 

one more thing - do i need to put another fuse between the fuse holder and the unit (close to the unit ) Instead of the plug that i cut of (in the plug there is a fuse ) ?

 

thanks.

thanks for all, i just sow the details about the kinivo in there manual,

i will go with 5a fuse like you all suggested,

i will cut off the plug from the unit ( http://www.ebay.com/itm/371200960018?var=640339698094 )and connect to( http://www.ebay.com/itm/191468796990?var=490555151290) 

and from there to the rear wiper location fuse.

 

one more thing - do i need to put another fuse between the fuse holder and the unit (close to the unit ) Instead of the plug that i cut of (in the plug there is a fuse ) ?

 

thanks.

 

I do but I'm a bit anal about these things and I have several spare inline fuse holders in the shed. - it's probably unnecessary

ok thanks,

i will do like pikpilot did without the extra fuse , only one in fuse holder 5a.

i got my kinivo today so i will wait for other stuff to arrive,

and if anybody will want after install i will upload some pics.

 

thanks to everybody who answer my questions,

you helped me alot.

 

eddie

Great post, I will be doing the same on my Mk2 VRS CR TDi next week as I hate having the wire of my DOD LS460W, phone charger and sat nav all over the place.

Thanks for the guide, finally managed to get a round to doing it. However :(

 

What would cause a dash cam to (i'm guessing) become overloaded?

 

I followed the guide, plugged in the cam and switched the ignition on. All good!  For a couple of seconds then the screen went white and it started smoking!

Thanks for the guide, finally managed to get a round to doing it. However :(

 

What would cause a dash cam to (i'm guessing) become overloaded?

 

I followed the guide, plugged in the cam and switched the ignition on. All good!  For a couple of seconds then the screen went white and it started smoking!

 

Did camera work before this directly off a 12v socket with no dramas? Have you removed the 12v plug from camera and wired it directly in? Reverse polarity is also a possibility if the device is not protected against this. Which camera is it btw?  My first ever dash cam died in this way, just as I turned key to leave moving to Holland car loaded down, was going to make a sped up video of the journey, but camera decided to start smoking heavily :( it was launched and I had to make one of my only ever journeys without one. 

Yes the camera was working fine 10 mins before.  Didn't wire it directly just plugged into the 3 way adapter. Cheap cam so not too worried (maybe it was just its time to go) about it as its a good excuse to upgrade

 

Plugged in an old phone to charge (not using my new one ) and it worked fine.  

this is was i did.

this what i did second chapter

i cannot upload any more files, if any one whant i will send directly.

Anyone used a cable that connects to the OBD port?

 

I've seen a cable which is OBD to micro USB so you'd think it supplied 5v at the end....

 

Anyone used a cable that connects to the OBD port?

 

I've seen a cable which is OBD to micro USB so you'd think it supplied 5v at the end....

 

Not used one, but I wouldn't personally feel happy piggy backing off the cars ECU in any way. 

Not used one, but I wouldn't personally feel happy piggy backing off the cars ECU in any way. 

That's my concern.....

Just ordered one of these and the piggy back fuse thingy.....

 

http://www.ebay.co.uk/itm/12V-to-5V-Hard-Wire-Power-Adapter-Cable-Cord-Jack-For-Car-DVR-Dash-Camera-Black-/381347786691?var=&hash=item58ca196fc3

Just ordered one of these and the piggy back fuse thingy.....

 

http://www.ebay.co.uk/itm/12V-to-5V-Hard-Wire-Power-Adapter-Cable-Cord-Jack-For-Car-DVR-Dash-Camera-Black-/381347786691?var=&hash=item58ca196fc3

Should do the job nicely. It's strange that they don't tell you how long the cable is though? Might need to extend the cables and hide the wee box bit on it somewhere if it's too short. Be good to know how long it is when it arrives though. 

 

Anyone used a cable that connects to the OBD port?

 

I've seen a cable which is OBD to micro USB so you'd think it supplied 5v at the end....

 

 

Would definitely avoid this method. You're just asking for trouble requesting this via the OBD port. That's not what it's designed for, and it would likely end up being very expensive trouble too :(

 

Follow the well-proven piggy-back fuse method.....

I think I need to move mine and run it up the driver side A pillar instead of the passenger as I am sure it is interfering with my radio reception at times :( 

Excellent article. Thanks for the post. I successfully installed the extra power socket in the glovebox of my Vauxhall astra. 

 

I have a query though

 

I used a fuse slot which belonged to rear wiper. The weird thing which happens is;

 

When the ignition key is;

* ON - Wiper & Dash Camera (accessory connected to the new power source) WORKS. 

* OFF - Wiper is OFF, but Dash Camera is still ON ? Any reason why ? As now both the Wiper Blade and new Power source is connected to the same fuse, I would have expected both to stay ON or OFF together with the Ignition in sync. 

 

Any ideas ?