Hardwiring Help on Merc C250

[a-aron22]

Hi all, I just ordered and should get the Thinkware F770 dashcam in the mail tomorrow and was hoping to set it up right away, but this is my first dashcam so I just want to make sure I'm not missing anything.

I ordered the hardwire kit but not the Cellink battery pack, and after reading some warnings on deep cycling a car battery I'm not sure I should hardwire it without the Cellink battery. Is that true, or does the F770 have a built in sensor to shut itself off if the battery gets too low?

I also will be running both the power and rear camera cable to the back of my car since the fuse box is in the trunk; should I run the cables on opposite sides of the car to avoid interference, or is that not an issue?

I'm thinking of picking up a multimeter and one of those 'add a fuse' tap adapters (hopefully a Autozone sells those, I'd hate to have to wait for that in the mail!)

Any other tips to help my install go as smoothly as possible?

 

[Dippy]

I ordered the hardwire kit but not the Cellink battery pack, and after reading some warnings on deep cycling a car battery I'm not sure I should hardwire it without the Cellink battery. Is that true, or does the F770 have a built in sensor to shut itself off if the battery gets too low?

Yes it does - I can't remember exactly but I think it can be set between about 11.8V and 12.6V in 0.1V steps. If your car is newer then it likely has a gel battery which handles partial discharge than older tech batteries, which is why they are used in cars with start/stop. So having the dashcam turn itself off at around 12.1V or so shouldn't reduce the lifetime of the battery too much. However if you are concerned then indeed something like the Cellink will protect it. However the Cellink won't last forever either and they're not cheap. When you set the threshold voltage you need to be confident that the car will still start, but you also want to maximise the length of recording in parking mode. The best way to find out is by testing, but I recommend 12.0V as the lowest. I have mine at 12.1V but I turn the dashcam off when I don't need it (e.g. when the car is parked in my garage at home) to avoid unnecessary draining of the battery.

I also will be running both the power and rear camera cable to the back of my car since the fuse box is in the trunk; should I run the cables on opposite sides of the car to avoid interference, or is that not an issue?

The USB cable which connects the front and rear camera already has power wires in it. So no, there will not be any interference and so no need for separate routing.
However the camera cable can cause interference to DAB, so I suggest doing a temporary hook up to check that the route does not cause problems in your car.

I'm thinking of picking up a multimeter and one of those 'add a fuse' tap adapters (hopefully a Autozone sells those, I'd hate to have to wait for that in the mail!)

You need two, plus two fuses rated 1A (but 2 or 3A will do). Have you checked the fuses sizes in your car? - Not the amp ratings but the physical size because you need to get the right size adapters.

Any other tips to help my install go as smoothly as possible?

If you don't have a soldering iron then you'll need adaptors with crimp connectors. If you haven't done these before then it is possible to crimp with pliers or grips instead of the proper tool, however there needs to be enough wire inside. Strip back plenty of insulation and fold over the wire, and then fold again.

 

[a-aron22]

I don't think my car has DAB, at least I don't listen to the radio enough to know, but I do have Sirius Satellite radio. As far as plugging into a fuse I plan on picking up a fuse tap; how does the F770 connect to that? My understanding is there will be an ACC wire that needs to be plugged into a fuse that is only on when the car is on, (so the F770 knows the car is powered up), and then there should be a BATT wire connecting to a fuse that always has power so the F770 can run in parking mode. Then a ground wire of course. So do I just take those two wires and wrap them around one leg of a fuse? With the two additional fuse taps and fuses I'm guessing I wrap the F770 cables around the new fuse plugged into the tap, then plug that whole tap into the fuse, (either for ACC or BATT). I'm also wondering what type of fuse the F770 needs to be connected to, 10? 15, 20?

Sorry for so many questions, I probably should have asked this before sending Amazon my order

If anybody who has installed an F770 in a Mercedes C class I'd be curious to know which fuses you used.

 

[Dippy]

I could not possibly advocate wrapping wire around the leg of a fuse. Some manufacturers are already designing cars to immolate themselves without owners adding to the fire risk! That is why the add-a-circuit fuse holders are such a great idea - easy to use and safe.

I really wouldn't worry about identifying which fuses to use if you buy a multimeter (which can be fairly cheap these days). My tip is to use circuits which you hope are least affected by the small extra drain on the battery. We know that BMWs can freak out about this. My Audi is OK, it just throws the occasional fault code which I clear when I do a diag check, but otherwise there is no effect. I don't know how Mercs respond. However I suggest using a lighting circuit for BATT. Because the lights are going on and off with doors, hopefully the power management will tolerate a bit of variation in current draw and not notice the dashcam. You need to check that the fuse is still powered after a few minutes - best to simulate parking, leaving the meter in a place you can see it, or maybe sitting in the car with everything off. For ACC its a matter of finding a fuse that is powered off as quickly as possible after parking and arming. The dashcam itself can take a while to go into parking mode. Whilst it stays in continuous mode until it switches so you'll get recording, I like to hear mine tell me that its switching before I'm ready to walk away from the car. I chose the fuse for the diag port on my car. But there are plenty of others such as the radio, aircon/climate etc.

 

[a-aron22]

I just got the F770 but have run into a bit of a snag. The hardware kit that came with it is about 9 feet, not nearly long enough to make it to my trunk's fuse box. Ironically the cable for the rear camera looks like it's almost twice the length even though it'll have a shorter run.

I really don't want to splice the cables, and if I do I'm going to have 3 unsheathed cables running through half the length of my car. Definitely not the clean install I want...

This came from Blackboxmycar.com and I have a feeling they swapped out the official Thinkware hardware kit, (which is supposed to be 16ft), with their own. I was wondering why they had two different hardware kits on their website.

 

[a-aron22]

Once I figure out the cable issue, what fuses should I tap into? Or more importantly, what fuses should I AVOID tapping into. Don't want to break anything!

 

[BlackboxMyCar]

I just got the F770 but have run into a bit of a snag. The hardware kit that came with it is about 9 feet, not nearly long enough to make it to my trunk's fuse box. Ironically the cable for the rear camera looks like it's almost twice the length even though it'll have a shorter run.

I really don't want to splice the cables, and if I do I'm going to have 3 unsheathed cables running through half the length of my car. Definitely not the clean install I want...

This came from Blackboxmycar.com and I have a feeling they swapped out the official Thinkware hardware kit, (which is supposed to be 16ft), with their own. I was wondering why they had two different hardware kits on their website.

The Thinkware TWA-SH is only about 10 feet long, but they've changed it a few times even since we carried it. The first ones we got came in a box and only had in-line fuses on the battery wire and not the ACC, whereas the latest ones do.
Our hardwire kit looks virtually identical with one distinction, for Thinkware's the ACC/Battery are indicated on a label that wraps around the wire, whereas our wires have tags that stick out

Typically with these hardwire kits the manufacturer only provide enough length for a front mounted fuse box, that being said on the current gen C300 we were able to find one ignition switched fuse on the front driver's side panel.

If you would like we can extend one for you with the coating so it's not just 3 loose wires, and you can return the old one
In terms of fuses, on my GLA there were a number of unused fuse slots intended for a trailer hitch accessory that my car doesn't have. There were both constant and acc fuses (I think there were more than 5 fuses for the trailer!)
I usually prefer using empty fuse slots rather than piggybacking off of existing fuses

 

[a-aron22]

In terms of fuses, on my GLA there were a number of unused fuse slots intended for a trailer hitch accessory that my car doesn't have. There were both constant and acc fuses (I think there were more than 5 fuses for the trailer!)
I usually prefer using empty fuse slots rather than piggybacking off of existing fuses

I have everything cabled up now and just need to plug in the fuse taps, if I use an empty fuse slot can any amp fuse be used? I don't have a fuse diagram and the only one I could find for my car online doesn't seem to match up exactly, and it doesn't say what amp rating to be used in the empty slots.

What is the lowest fuse amp rating that the F770 can be used with?

 

[flip9]

The hardwire kit already has an 2A inline glass fuse (the chunky black bits) so for the fuse tap id use a 2-5A blade fuse.

 

[a-aron22]

I'm not sure if this is an issue with my car turning fuses off or my record power settings, but when it goes to parking mode it shuts off pretty much right at 5 minutes. I've tried 3 different fuses for the battery connection:
#43 Rear blower motor - parking mode stops recording after about 5 minutes
#44 Passenger electric seat controls - parking mode stops after about 3 minutes
#46 Whole bunch of stuff; Alarm siren, tow away protection, Keyless-go antenna amplifier - parking mode stops recording after about 5 minutes

If I check these fuses with a multi-meter #43 and #46 both still have power after 5 minutes. I can't tell if simply opening the trunk is causing them to turn back on, but you would think something dealing with to-away protection and the alarm siren would always need power.

Adjusting the record settings so far doesn't seem to have changed much, but with that said I'm a bit confused. In my settings I have two power voltages; a setting for 12V and another setting for 24V, what is 24V for and what should I set it at? This isn't even in the Thinkware instruction manual. Currently I have both set in the middle, 12.0 and 24.0, which from what I've read should give me more than 5 minutes, which is why I'm wondering if the car 'goes to sleep' and drops power on those fuses.

One confusing part is if I watch the parking mode video it always shows the power hovering below 12 volts, usually bouncing from 11.9 to 11.3 throughout the video, until about 5 minutes, (or 19-20 seconds since this is a time lapse recording). Do I just have my record settings too high? Is it normal to work for 5 minutes below the set voltage threshold before shutting down?

 

[BlackboxMyCar]

You can ignore the 24V setting as your car runs on 12V.
Do you happen to know how old your battery is? Have you had a chance to drive around to charge up the battery after the install?

 

[a-aron22]

You can ignore the 24V setting as your car runs on 12V.
Do you happen to know how old your battery is? Have you had a chance to drive around to charge up the battery after the install?

I think that might be the issue, I'm not sure how old the battery is but I bought the car used from the dealer so it is highly likely this is the factory installed battery which would put it at about 4 years old. If I have the car parked and running the F770 live screen shows it hovering around 13V, driving it is around 11.8-12.2, except when braking it jumps to 13-14V. When it's parked and the F770 is in parking mode it never shows it above 12V.

I just changed the record settings to 11.9V and will check later to see if that did anything. I'm just curious if the 5 minute shut off is from the fuse I'm plugged into or part of the Thinkware firmware. Although if my battery is hovering around 11.8-11.9 when powered off that probably means I need a new car battery and shouldn't mess with the parking settings for now. My understanding is that below 11.7 there won't be enough juice to start the car.

 

[BlackboxMyCar]

Hmm it may be worth checking the ground and how the wire is connected into the fuse tap to ensure both are solid.
Even if the battery is older, while the alternator is running you should be seeing pretty consistent readings and it shouldn't fluctuate so much while braking.
It's tricky with the fuse taps as the wire gauge on the Thinkware hardwire kits is a much smaller size so they don't always have the best connection.
It should be easy to find the factory ground on this generation C class which is near the fuse box

 

[a-aron22]

I currently have my ground plugged into where a bunch of other ground wires are connected to near the fusebox. Previously I attached to a different bolt, but after your comment moved thinking maybe that was the issue. The power still seems to jump around a bit. In the picture the Thinkware's ground wire is plugged in on the right side where a bunch of other brown wires are grounded into.

But with that said, I'm probably going to buy the Cellink battery pack anyway. Do you have any instructions on how to install that with the Thinkware? I plan on adding it in the trunk since there is a lot of room and can just tap into the existing Thinkware wires, I just don't know how it'll need to be connected.

By the way the cam is pretty cool, but I'm a bit worried it's attracting crappy drivers. Almost had some guy in a truck back into me while waiting at a red light - I think dashcams might attract idiot drivers lol

 

[BlackboxMyCar]

To install the Cellink with the Thinkware hardwire kit, you'd need to cut the grounding terminal off of the Thinkware hardwire kit and splice them into the Cellink output.
This link might help explain what needs to be done: https://www.blackboxmycar.com/blogs/news/connecting-korean-dashcams-to-the-cellink-battery-b