Dashcam question

[rh71]

UPDATE: resolved. Thx.

I'm an electrical noob and just need to understand a few things before I install this dashcam. I have an ACN type add-a-fuse that came with a 5A fuse in the top (right) slot. The car's fusebox under the dash doesn't offer a spare fuse (or any fuse) lower than 7.5A and I read that ideally I want the two fuses on the add-a-fuse to match. Even if they don't, I understand the top (right) slot needs to be an equal or higher amperage for it to work properly - is this correct?

1) Can I simply move the 5A to the bottom and use the car's 7.5A for the top slot? Asking because after plugging the add-a-fuse in like that, wouldn't this fuse setup make it a lower amp than originally in the fusebox slot?
2) These cams use so little power - would this 7.5A/5A fuse even do what it's intended to - to catch a short/prevent a fire?
3) How do I know which direction to plug in the add-a-fuse considering only one side of the fuse slot is the lead?

(part of this item I bought: https://www.amazon.com/gp/product/B072J3L2JN/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1)

 

[Paperdoc]

It's easier than you fear. The whole idea behind thus is that you must select in your car's fuse box a fuse with power supplied the "right" way. For this purpose the size of the original fuse in the box is not important.What is important is whether the car's device fed through that fuse is always on, or only gets power when the key is turned on. If you choose an "always on" thing like the headlights, then that new added dash can will always get power and USE it, potentially draining your battery. The kit's black box has a circuit to limit that. But even better is to use the fuse for something that does NOT get any power until you turn on the ignition key, like may accessories do. Maybe the heater fan, or the radio. Then your new camera will always be shut off and using NO battery power when your car is not in use.

Now, what needs to be done is to tap into the end of the existing fuse that gets power directly from the battery, so the new added item is not getting its power though the existing fuse. Then the new added (camera) device also gets power from that source, but limited only by its own new fuse. To make that process easy, the kit comes with four different red wires (for different types of fuses and fuse contact spacing) and you choose the one that matches your fuse box parts. Identifying the end of the original fuse 's socket that comes from the battery is best done after you have removed that original fuse. You can use a simple voltmeter, or even a small 12 V light bulb with wires. Clip the voltmeter (-) lead to the car chassis ground, then touch the meter's (+) lead to either end of the empty fuse socket. If you find NO voltage at either point, then you probably have a circuit that is turned off when the key is off, which is what you want. Turn the key on to "ACC" (you do not need the engine running) and probe again. You should have 12 v on only ONE end of the socket. So now you can insert the correct adapter into that empty fuse socket, and insert the old original fuse into the proper side of the adapter. Now do three checks to be sure, First, test the original device (fan? radio?) to be sure it is getting power just like it did before. Next, test with your voltmeter the shielded output end of the adapter's red wire and it should have NO voltage on it. Then insert into the adapter's other socket the red fuse (the one that fits) that came with the adapter kit and test with your voltmeter again the output end of the adapter's red wire. This time with the red fuse in place you should find 12 VDC there. So now you know you have the adapter installed correctly.

This connects BOTH devices in parallel to the same power source from the battery, each with its own separate fuse. One of them just restores the normal fuse supply line to the original thing. The other establishes a new power line for the new device. Finally, the kit includes an in-line mounting case for a tubular glass fuse that comes with your new device (the camera). This has just the right rating for that device, and is the real thing that limits current flow from the source to the camera. The original fuse that you re-installed in the adapter back in the fuse box has NOTHING to do with the camera power supply.

One thing to note. Once you have installed in the adapter the second (red) fuse from the kit, the output is "live". It is shielded, but don't let anything stick into it and cause a short circuit to ground.

You can then finish installing the rest of the wires to the location of your dash cam. The kit output wires have a common USB2 Type A connector, and it comes with two adapters to convert that to either a mini USB or a micro USB, whatever your dash cam needs to fit it. I suggest that, once you connect these items together, you wrap them with tape to ensure they do not shake loose and disconnect.

Have fun!

 

[Fritzo]

Just an alternative method I did- I got an OBD2 power adapter for my cam and it works REALLY well. The port already has a fuse, it only uses the power pins so there's no contact with the car's computer, and it shuts off automatically if the battery gets below 11.8v. https://www.amazon.com/gp/product/B07J3BLFBN/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

 

[highland145]

Do your cars not have dash plug ins? My Tacoma has a lighter and a separate one.

 

[rh71]

...

Thanks for the informative post. I don't need always-on so it's simpler and now it's installed and working. With your instruction, I tested which side of the fuse slot was live so I was able to set that as the opposite side of the add-a-fuse wire so it goes through the entire fuse first. I hope that's right. Someone elsewhere said since it's DC system, it didn't matter how I plug it in, so I'm still a bit confused on why it wouldn't if I want it to trip the fuse by going through the one side first then through the trip wire.

Just an alternative method I did- I got an OBD2 power adapter for my cam and it works REALLY well. The port already has a fuse, it only uses the power pins so there's no contact with the car's computer, and it shuts off automatically if the battery gets below 11.8v. https://www.amazon.com/gp/product/B07J3BLFBN/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

That's interesting but if you're in a public parking lot I'd wager you'd get constant motion detection.

Do your cars not have dash plug ins? My Tacoma has a lighter and a separate one.

I wanted the entire cable hidden except for it coming out of the roof liner. I had already done my other car through its fusebox but was very fuzzy on what's right or wrong hence the thread.

 

[Fritzo]

That's interesting but if you're in a public parking lot I'd wager you'd get constant motion detection.

It depends on the camera settings. You can get them without the motion sensor too.

 

[Paperdoc]

OP, there is no need for the power to the camera to go through the original fuse first, and then through the camera fuse. Almost anything fed normally from the car's fuse box will have a higher power draw (and hence a much higher fuse rating) than the camera does. You can check that. Look at the original fuse for whatever car circuit you tapped into and find its amperage rating. Now look at the small fuse (tubular glass?) that came with the camera. That should be the one you installed in the glass fuse holder built into the wire feeding to the adapter kit's black box. I bet that camera-specific fuse it rated much lower than the one in the auto fuse box. When a circuit is set up that way (in series), any overload will cause the SMALLER fuse to pop immediately, and the higher-rated fuse will no nothing. So it never helps in the protection of the camera at all.

That is why the intent of the adpater kit is to have the added device (in this case the camera) tap into the power source from the battery AHEAD of the "normal" fuse, because that old "normal" fuse for some other car component has no use in the camera circuit. However, even if you have connected that part "backwards" that will not really affect anything, so I'm sure you can just leave it as it is. Glad to hear you got it working well.