Fuse taps using the hot side aka wrong side

Discussion in 'Power Magic Pro' started by Pbets, Jan 17, 2016.

  1. Nigel

    Nigel Well-Known Member

    Messages:
    5,614
    Likes Received:
    2,517
    Location:
    Devon
    Country:
    United Kingdom
    Dash Cam:
    Gitup Git3, Mini 0806
  2. Rajagra

    Rajagra Well-Known Member

    Messages:
    2,525
    Likes Received:
    1,896
    Country:
    United Kingdom
    Dash Cam:
    Mini0806
    I'm sorry but one of your own diagrams illustrates the problem, with a 30A fuse leading to the original load and a 5 A fuse leading to the PMP. Meaning the combined current could be 35A from the hot feed.
    You could rely on the wiring being higher spec than needed, but it would be an assumption.

    Depending what way round the fuse tap goes, the current going to the new accessory can go through either both fuses (lower value blows first) or just the new fuse.
    Yes, the original devices are protected as before. But some of the wire leading to the fuse box is less protected than before, if the fuse tap is fitted a certain way.
     
  3. jokiin

    jokiin Well-Known Member Manufacturer

    Messages:
    36,965
    Likes Received:
    18,894
    Location:
    Shenzhen, China - Sydney, Australia
    Country:
    China
    Dash Cam:
    Too many ¯\_(ツ)_/¯
    if you overload a circuit of course you could damage it, unlikely with just a camera and providing the correct size fuses are used, but still something to keep in mind
     
  4. Nigel

    Nigel Well-Known Member

    Messages:
    5,614
    Likes Received:
    2,517
    Location:
    Devon
    Country:
    United Kingdom
    Dash Cam:
    Gitup Git3, Mini 0806
    Fuses are there for when things go wrong, not for when things are working as planned. If you tap into a 10A fuse then it is quite likely to be supplied by 10A wire, car manufactures don't put unnecessary copper in the cars as it reduces profits, use a 10A fuse for your new circuit with the tap the wrong way around then it is possible to draw 20A down the 10A wire. Just needs your lithium battery to short out internally while you are using the thing the circuit was intended for and you might have smoke and maybe flames.

    The consequences of a car fire can be very nasty, why take any chance, however small, when you can very easily put the tap in the correct and safe way around? It doesn't cost any extra to put it the correct way around, it is not difficult, but it is safer.
     
  5. jokiin

    jokiin Well-Known Member Manufacturer

    Messages:
    36,965
    Likes Received:
    18,894
    Location:
    Shenzhen, China - Sydney, Australia
    Country:
    China
    Dash Cam:
    Too many ¯\_(ツ)_/¯
    if nothing else you've finally admitted lithium batteries aren't safe
     
    Dashmellow likes this.
  6. Nigel

    Nigel Well-Known Member

    Messages:
    5,614
    Likes Received:
    2,517
    Location:
    Devon
    Country:
    United Kingdom
    Dash Cam:
    Gitup Git3, Mini 0806
    They are very safe if used with a correctly installed and rated fuse!
     
  7. jokiin

    jokiin Well-Known Member Manufacturer

    Messages:
    36,965
    Likes Received:
    18,894
    Location:
    Shenzhen, China - Sydney, Australia
    Country:
    China
    Dash Cam:
    Too many ¯\_(ツ)_/¯
    Keep digging
     
    Dashmellow and Gabacho like this.
  8. Gabacho

    Gabacho Well-Known Member

    Messages:
    5,250
    Likes Received:
    2,353
    Country:
    United States
    Dash Cam:
    SG9663DC
    How many add-a-circuits can you safely use in the fusebox?
     
  9. jokiin

    jokiin Well-Known Member Manufacturer

    Messages:
    36,965
    Likes Received:
    18,894
    Location:
    Shenzhen, China - Sydney, Australia
    Country:
    China
    Dash Cam:
    Too many ¯\_(ツ)_/¯
    would depend what you wanted to add but I can't see people really adding too much extra equipment for that to become a problem
     
  10. Gabacho

    Gabacho Well-Known Member

    Messages:
    5,250
    Likes Received:
    2,353
    Country:
    United States
    Dash Cam:
    SG9663DC
    Thanks for the response. We are working on temporary solutions for rear cameras, and our installer advises to put them on separate circuits and not to exceed three. He does not enjoy my complete confidence so I am looking for other opinions.
     
  11. jokiin

    jokiin Well-Known Member Manufacturer

    Messages:
    36,965
    Likes Received:
    18,894
    Location:
    Shenzhen, China - Sydney, Australia
    Country:
    China
    Dash Cam:
    Too many ¯\_(ツ)_/¯
    depends on the camera and how much it draws I guess, they certainly draw a lot less power than some other accessories you could add that people wouldn't think twice about, CB radios, car fridges etc, you could add 10 of our cameras and they still wouldn't pull the same current as a single car fridge would, I certainly wouldn't suggest overloading any single circuit though regardless
     
    Gabacho likes this.
  12. Nigel

    Nigel Well-Known Member

    Messages:
    5,614
    Likes Received:
    2,517
    Location:
    Devon
    Country:
    United Kingdom
    Dash Cam:
    Gitup Git3, Mini 0806
    My suggestion would be to use 1 fuse tap on the accessory fuse and use it to power 1 decent quality multi way USB converter such as:

    [​IMG]

    If you install that above the roof liner next to the interior light then you can power the cameras with reasonably short standard USB to micro USB cables and all the wiring is neat.
     
    Gabacho likes this.
  13. Ralph2

    Ralph2 Active Member

    Messages:
    644
    Likes Received:
    176
    Location:
    Edmonton AB
    Country:
    Canada
    Dash Cam:
    BlackVue 650GW in 2011 Highlander
    You could add as many as you can fit. Providing you keep the hot side common to all you could even stack one on top of another. Each subsequent fuse tap would be limited to the size of fuse under it.. The draw of one camera is very low, using 10 amp fuses you could easily stack and run 7 cameras.
     
    Gabacho likes this.
  14. jokiin

    jokiin Well-Known Member Manufacturer

    Messages:
    36,965
    Likes Received:
    18,894
    Location:
    Shenzhen, China - Sydney, Australia
    Country:
    China
    Dash Cam:
    Too many ¯\_(ツ)_/¯
    first thing that came to mind

    power.jpg
     
    spaceballsrules, Ralph2 and Gabacho like this.
  15. Gabacho

    Gabacho Well-Known Member

    Messages:
    5,250
    Likes Received:
    2,353
    Country:
    United States
    Dash Cam:
    SG9663DC
    Things do get out hand sometimes :p
     
    jokiin likes this.
  16. Ralph2

    Ralph2 Active Member

    Messages:
    644
    Likes Received:
    176
    Location:
    Edmonton AB
    Country:
    Canada
    Dash Cam:
    BlackVue 650GW in 2011 Highlander
    :) Me too but did not know how / where to find such a fine example. Well done..:)
     
    Gabacho likes this.
  17. Rajagra

    Rajagra Well-Known Member

    Messages:
    2,525
    Likes Received:
    1,896
    Country:
    United Kingdom
    Dash Cam:
    Mini0806
    You might need to alternate the orientation of the fuse taps. I.e. the 'output' of one fuse has to feed the 'input' of the one above to get the effect you describe.
    It would depend on the construction of the fuse tap. If one was built as shown in the green box of Nigel's diagram that would be great, both for safety and tidiness.

    You wouldn't get that effect if you kept the hot side common to all. (As in the red part of the diagram.) That would have the fuses working in parallel, not in series. Each would work independently, and the potential total current would be the sum of the fuse ratings.

     
    Nigel likes this.
  18. Ralph2

    Ralph2 Active Member

    Messages:
    644
    Likes Received:
    176
    Location:
    Edmonton AB
    Country:
    Canada
    Dash Cam:
    BlackVue 650GW in 2011 Highlander
    I give up on the orientation of fuse taps..:).. Just.. because you have found a colored image does not make it correct.
     
    CDNinHH likes this.
  19. Nigel

    Nigel Well-Known Member

    Messages:
    5,614
    Likes Received:
    2,517
    Location:
    Devon
    Country:
    United Kingdom
    Dash Cam:
    Gitup Git3, Mini 0806
    Since in most fuse taps, the fuses go at 90 degrees to the originals, you will have to alternate them or they will not physically fit!

    They will also build up in a staircase instead of vertical making it difficult to use taps in the adjacent fuses and the stack will probably become rather unstable!
     
  20. Ralph2

    Ralph2 Active Member

    Messages:
    644
    Likes Received:
    176
    Location:
    Edmonton AB
    Country:
    Canada
    Dash Cam:
    BlackVue 650GW in 2011 Highlander
    The whole concept of adding multiple fuse taps is silly :rolleyes:. Use ONE.. and add as many outputs as you like from that ONE pigtail. Add an inline fuse on each leg if you want extra safety.. but it would not be necessary.
     
    Rajagra likes this.
Loading...

Share This Page