[Nezil]

I'd been having issues getting my BlackVue DR750S-2CH dashcam to run longer than 6 hours with the power magic pro set to 12v cutoff, (extensive thread with analysis and discussion of this here, so comment there if you're interested in that point), so I decided to buy and install a Cellink B to overcome the issue. This is a thread to document my installation, in case anyone finds that interesting or valuable.

I opted to install the Cellink B with the PMP because I wanted to be able to control the length of time the dashcam runs for in parking mode; I'm not that bothered about the voltage protection of the PMP, but I do care about the timer aspect. I've not yet tested if the Cellink cuts power before the PMP, but I'd have thought it would be close knowing that 4 x LiFePO4 batteries in series has a nominal voltage of 12.8v, and will be almost totally flat at 12.0v.

The reason I want to be able to control the duration of parking mode is that we often use my wife's car (Honda Pilot) as the family car during the weekends, and my M2 can be sat in the garage for the whole time if that happens. In this situation, the Cellink would be completely drained before I leave for work on Monday morning, and it wouldn't fully charge during my 15 minute commute I wouldn't have thought. I'd then park at work for ~9 hours, and it would be depleted again, and during the course of the entire week, I'd keep running the battery down and probably rarely get it fully charged.

I do want the car to enter parking mode in the garage; not because I want it recording, but because I have a script that pulls the files off the dashcam automatically, and keeps 2 weeks of data on a drive in the house (see thread for this here). This can take quite a long time, perhaps as much as 6 hours, and this takes place each time I come home for the day.

So the best situation I think, would be to have the Cellink power the dashcam then the PMP shut it off after 12 hours, draining the Cellink about 50%. The journey to work will nearly fully charge the battery, so it will be more likely to be able to provide me with a reliable 12 hours whenever I need it, and more if I know I'm going to be away from the car for longer (by changing the DIP switches in the PMP). I've therefore got the Cellink input connected to an Accessory Add-a-Fuse, and the PMP connected to the output of the Cellink. Voltage set to 12.0v and timer set to 12 hours.

With all that said, this is how I did the installation:

I originally had the PMP connected to the fuse box with Add-A-Fuses; you can see the location, and the 5v DC-DC I use to power a WiFi hotspot also powered by the PMP below it.

I wanted to do the neatest job possible on the wiring, so I removed the trunk lining to give me more access. This exposed some plastic wire routing on either side of the trunk, with a useful external channel for extra wires that I made use of. On the driver's side, I routed the 5v USB power from the DC-DC convertor, and on the passenger's side, I planned to re-route the power wire to the dashcam.

I decided to mount the Cellink right next to the battery, next to the tire inflator and sealant. In order to do that, I put some double sided tape on the expansion battery wire to keep it out of the way:

Put Velcro on the Cellink, and then mounted it into place:

Next I had to think about wiring up the Cellink. I needed two sets of wires going from the Cellink to the fuse box area - one for power, connected to an Add-A-Fuse on accessory power to charge it, and the other supplying power from the Cellink to the PMP. I looked for a way to route this nicely, and found an additional channel in the guide for the 12v lines running to the front of the car:

I carefully measured the lengths needed, and made up the two cables. I then wrapped these in expandable sleeving to keep them neat and together. This took quite a while, but the results are nice, especially when installed. Here's the cable before installation:

And here's a couple of views with the cable installed; I added the self adhesive cable clips as well:

The only thing left after this was to re-route the power to the dashcam (and 5v DC-DC) out of the PMP. I made up a slightly longer cable for this, and again, wrapped it in expandable sleeving. This time, as planned, I routed it through the passenger's side cable guide:

Here's a couple of shots of the finished fuse box area from different directions:

And the Cellink installed and connected:

[Nezil]

As of now, the 5v DC output goes to a long micro USB cable that I have ending up at the tray on the driver's side of the trunk where I keep the WiFi hotspot. I'm toying with the idea of fitting a USB connector to the bottom of the 12v accessory socket plate in the trunk. This would look neater than the loose wire I currently have there, but I'm not sure if I want to cut into that piece... I should look at how much the part is if I mess it up or want to return it to stock!

[dtmurf]

Nice work! Is the WiFi hotspot used for downloading the dashcam files?

[Nezil]

Originally Posted by dtmurf

Nice work! Is the WiFi hotspot used for downloading the dashcam files?

No, it's for sending alerts if there are any impacts in parking mode, and for live viewing of the camera remotely - like when it's being serviced!

I turn the hotspot off when I'm at home and it connects to my home network.

[Nezil]

Originally Posted by Nezil

As of now, the 5v DC output goes to a long micro USB cable that I have ending up at the tray on the driver's side of the trunk where I keep the WiFi hotspot. I'm toying with the idea of fitting a USB connector to the bottom of the 12v accessory socket plate in the trunk. This would look neater than the loose wire I currently have there, but I'm not sure if I want to cut into that piece... I should look at how much the part is if I mess it up or want to return it to stock!

OK, so I did this tonight...

I haven't bought a replacement panel because I don't need to return it to stock any time soon; I just like to know that it's something I could do if I wanted to. I don't mind modifying my cars, but like the comfort of knowing it can all be put back to stock with fairly minimal effort.

With that being said, here are the installations shots:

I bought a panel mount USB socket for $3.16 (for some reason it's more expensive now) from Amazon, and then modified the plate to attach it just below the 12v outlet. Filing it out was kind of annoying, but it looks pretty good:

The end of the USB cable from the DC-DC convertor ended behind the trunk liner on the left side, so I removed the micro USB cable I had plugged into it, and cable tied it in place ready to connect up when the liner was re-installed. The cable for the power outlet is also right there; it's the red and yellow one that the USB socket is cable tied to.

Here's another view of the cable going through the cable guide just behind the back seat on the driver's side:

And here's the end result with the trunk liner re-fitted and the WiFi hot-spot plugged in. I'm going to put a much shorter Micro-USB cable in so that it's not all coiled up like in this photo, but at least it's not just a wire appearing out under the trunk liner any more... My OSD about it is relieved!

[DKX4///M]

why not a tiny sports battery under trunkmat with a battery isolater...bmw battery while huge tends to have strange drainage probs anyway (2016 at least)...just my $.02...

Otherwise way to get creative n worked out...looks clean

[Nezil]

Originally Posted by DKM2Power

why not a tiny sports battery under trunkmat with a battery isolater...

The main reason I didn't go this way is that a device that switches between batteries is very expensive, and there isn't that much space beside the battery for another one.

bmw battery while huge tends to have strange drainage probs anyway (2016 at least)...

Oh hell yes it does... this is what started this whole project off in the first place; I couldn't get more than 6 hours out of the car battery because the voltage dropped for an unknown reason at pretty much exactly 6 hours. See this thread: http://f87.bimmerpost.com/forums/sho...php?p=22615326

Otherwise way to get creative n worked out...looks clean

Thanks very much!

[Nezil]

I'm about due an update on this, especially now that I've been able to ascertain the full run-time of the Cellink B with my dashcam setup.

In summary, it's about 18 hours of parking mode. I suspect it would be slightly less, given the additional current drain I measured if there was a lot of writing to disk. I performed my test with the car in the garage and there was therefore almost no recording taking place.

I'd like to have a greater run-time if possible, and I'm therefore looking into a couple of options.

1) I've ordered an additional Power Magic Pro, which I'm going to use to connect ahead of the Cellink, with the intention of making sure that the Cellink is always fully charged after a drive. The PMP has a switch on it to bypass the function, which I'll probably leave in the off position if I'm not going to be leaving the car for extended periods.

Of course, I'll have to wire this through a relay to ensure that the Cellink is able to draw the full 7 ~ 8 Amps when charging.

The Cellink itself is only 6,000mAh, or 6 Ah, so if charging at 7 Amps, should be charged in less than an hour. My hope is that because I would usually drive for enough time for the Cellink to either be fully charged, or nearly fully charged, that the load on the lead-acid battery will be very low.

When setup like this, after stopping, the Cellink would continue to charge (if needed), and then once charged, the Dashcam would run under lead-acid power until the ~ 6 hours that the PMP would switch off at. At that point, the Cellink power would take over, running the camera for an additional 18 hours, bringing me to a total of ~24 hours of run time.

2) I'm looking to get hold of a Cellink B extended battery, which doubles the run-time of the Cellink B, bringing me to a combined total run time of ~42 hours. It's still not quite enough for the longest of my frequent trips to Southern California, but it's close.

The biggest issue with this is that the extended battery seems very difficult to get hold of in the US, so I'm going to try and source it in Korea, when I'm there later this month... wish me luck!

[Nezil]

Next update...

My second PMP arrived, and I quickly cobbled together the setup I described in my post above. Every time the ignition is turned off, the new PMP keeps power to the Cellink for 6 hours (or until the car battery drops below 12.0v) ensuring that it's charged. During this time, the dashcam is also powered by the car battery.

If the ignition isn't turned on before the 6 hour time ends, the Cellink will take over, providing power to the dashcam for either as long as it has the capacity to do so, or as long as the timer on the second PMP allows it to run for.

In practice, the Cellink ends up powering the dashcam overnight, and occasionally while I'm at work in the office. Usually though, the system is operating in the first 6 hour period, so the Cellink is fully charged most of the time. This is pretty much how I wanted the system to operate.

The only thing I'm not happy about currently, is that I have the Acc input to the second PMP coming from the Cellink. This means that the duration for how long the dashcam is going to operate for is currently a combination of the run time of the first PMP, and the second PMP, which isn't ideal. I can, and will, fix this, by connecting the Acc input to the second PMP to the fusebox location, therefore starting the timer based on ignition switch off, rather than Cellink switch on.

I also need to find a decent location for the second PMP and relay...

And, finally, I've also placed an order for the Cellink B extended battery that I'm going to pick up in Korea when I'm there in a couple of weeks. All in all, this should provide me with close to 48 hours of run-time!

[F87_LCI]

Jesus. My brain hurts after reading that. Tell me you're and electrical engineer or similar...

Nicely done. Great write up and pics. Glad you are getting close to the results you are looking for. I am considering adding a dash cam to my car...seen way too many YouTube video of people being stupid out there. Not sure I will go to this extent, but it's comforting to know there are guys like you Nezil that are great resources for the rest of us.

[Nezil]

Originally Posted by LSB --> LBB

Jesus. My brain hurts after reading that. Tell me you're and electrical engineer or similar...

Actually I'm a TV picture quality researcher / colour scientist / engineer. It's all about solving problems though, and that's really my definition of an engineer!

Nicely done. Great write up and pics. Glad you are getting close to the results you are looking for. I am considering adding a dash cam to my car...seen way too many YouTube video of people being stupid out there. Not sure I will go to this extent, but it's comforting to know there are guys like you Nezil that are great resources for the rest of us.

Thanks for the kind words. If you have any questions regarding the install / choice of cameras, feel free to reach out, I'd be happy to help if I can.

[Nezil]

I've been running the system with the two PMPs for just over a week now, and I've been very happy with how it's working. I therefore spent some time this evening tidying up the components and cabling.

To be totally honest, I've pretty much run out of room around the fuse box location, and I'm not 100% happy with the location of the second PMP (on the right) and the relay (on the left), but the cabling is neat, and the trunk insert fits in fine, clearing all the components easily.

I'm pretty happy with this now, but will need to move the Cellink slightly when the Extended Battery is installed. The ground wire from the battery is pressed against the Cellink now, which is fine, but it won't fit with the Extended Battery as well. I'm probably going to rotate the Cellink and Extended Battery 90 degrees to their current location, but we'll see in a couple of weeks when I'm back in the country and can install it.

[ZPrime]

Nezil, what fuse positions are you using for constant hot/battery and for accessory/switched power?

[Nezil]

Originally Posted by ZPrime

Nezil, what fuse positions are you using for constant hot/battery and for accessory/switched power?

Sorry, just seen this, and I'm not with my car right now. I'll look tonight if I remember... Feel free to PM me if I forget!

[Scrape]

I just picked up my car in November 2018 and will be hooking my PMP as well. I would like to know as well please? Thanks.

Originally Posted by ZPrime

Nezil, what fuse positions are you using for constant hot/battery and for accessory/switched power?

[cookiesowns]

Hi Nezil, any updates on the fuse & relay used?

I just picked up a 900s, PMP, and B124.

Thinking about doing the same thing you did. B124 hardwired ACC on -> PMP (timer) -> 900S

[Nezil]

Does this help at all:

[Nezil]

Sorry, a few people have PM'd me asking about first locations and I keep forgetting. Coincidentally, I'm flying out of town for a couple of days and want maximum recording time, so I changed some settings on my PMPs to achieve that once I parked up, and snapped a few photos while I was at it.

I'm not sure if everyone interested remembers, but I have a DR900S-2CH, Cellink B, Cellink Expansion battery, 2 PMPs and a FreedomPop hotspot powered through a 12v to 5v buck/boost in parallel with the dashcam.

Oh, I also have a relay switching the charge to the Cellink on because it can draw 7 Amps and the PMP isn't rated for that much.

Couple more photos:

[Scrape]

Thank you. I hope I can decipher from the photos.

[dtmurf]

I've been keeping on eye on your thread waiting for an update and while I don't need the file download capability, I'd like to have 24+ hours of parking mode.

What this thread needs in a wiring diagram! Any chance you've drawn up one up on the back of a napkin that you can take a photo of?

[Nezil]

Originally Posted by dtmurf

I've been keeping on eye on your thread waiting for an update and while I don't need the file download capability, I'd like to have 24+ hours of parking mode.

What this thread needs in a wiring diagram! Any chance you've drawn up one up on the back of a napkin that you can take a photo of?

Obviously I did... But I think I threw it away once I was done. Having said that, I need to re-do the USB part because I used a crappy tiny gauge wire that results in voltage drop under load to my WiFi hotspot. I'd like to run that without the battery, but it keeps powering off, so that needs some work.

Once I get round to fixing the USB, I'll make a wiring diagram. Keep pinging me... I'm forgetful, but not easily offended!

[jksgoh]

Hi Nezil,

great information.
I note that you are using fuses which relate to engine components or ECM.

Have you had any issues come up by doing this?
general advice about hard wiring dash cams is to try and avoid tapping fuses which are for "important" things.

However, i think these are the only fuses which turn off straight away.