Mr12volt wired connection / charging?....

AnubisZed

Veteran
 Lincolnshire, UK
So I've had an idea regarding using my phone with the Mr12volt mmi box (would be the same for any other MMI box).

Firstly some background....
MMI boxes have the choice of either a wired or wireless connection, and most seem to like the wireless connection. And to be honest this is preferred simply because it's convenient, you get in the car, leave your phone in your pocket (or wherever you have it) and it just works. Now there's nothing wrong with this, except on long journeys where your phones battery is running out of charge a lot faster than normal due to the constant connection. Now I'm sure some are thinking that you'd put your phone on charge, either a wired charge or a wireless charger. The problem with this though is heat build up, especially with a wireless charger even more so, and in the summer months this can be quite troublesome if too much heat was building up.
Now a solution is that if you are going to plug a phone charger in anyway then you might as well just plug into the USB lead from the mmi box, and this is a good solution, no problems with signal drop and no excess heat build up. BUT, the charging capacity of the MMI box isn't all that good. It'll keep it charged, but wont really put much extra into it.
So all of this will work but there is a downside to all of them in one way or another. So what we want is a way to charge our phone properly while on the go and a good connection to the box all at the same time :unsure:

Well I think I've got the solution, one of these....

USB1.jpg

Now firstly you're probably thinking, "well that's not going to fit our cars!", and you'd be right. What it needs is a little fabrication and a small bit of wiring.
So looking from the back of it there are two sockets

USB2.jpg

The one on the left is a 4 pin connection that has 12v+, negative and lighting. The other is for a Fakra plug that has the USB control. So you then connect the USB of the Mr12volt box with a USB to Fakra cable to this socket, something like this...

USB3.jpg

This then carries the data signal to/from the Mr12volt box for the new USB-C socket, and the 4 pin power plug supplies the better charge rate, you simply just use a USB-C to USB-C charge cable for your Android phone (USB-C to Lightning for Apple devices). This can still work for just charging any USB-C device.
For the 4 pin power plug you could simply tap into the cigar lighter socket wiring as it has all three wires already (+, - and lighting) and the circuit is rated for three sockets (ashtray, inside centre armrest and one in the passenger footwell), of which most UK cars have only two anyway so you'd not be overloading the circuit.

DISCLAIMER** This is only theory at the moment, as I've not actually tried it, but I'm in the process of doing so.

I've ordered the parts and will be assembling a test rig soon, then, if successful, I'll fully install it. I've bought my socket attached to the mounting plate of a G20, which gives me the chance to do a bit of fabrication and have it at an angle to assist inserting the cable (chop off the angled socket section), as I'll place it in the passenger footwell somewhere in the location that the OE 12v socket would have gone. This should give it a nice OE look but keeping it out of the way.


USB-C(2).jpg

Hope you like the idea :):driving::thumbsup:
I'll update this as I go
 
Nice idea..I guess the neatness of the fit will be important to us with cable OCD..

As you say if you start with a fully charged phone and use the wired connection then a long day on the road is ok..

I was under the impression that data for charging rates and capabilities was embedded on some of the wires in some fashion?
 
Nice idea..I guess the neatness of the fit will be important to us with cable OCD..

As you say if you start with a fully charged phone and use the wired connection then a long day on the road is ok..

I was under the impression that data for charging rates and capabilities was embedded on some of the wires in some fashion?

Now these new USB-C ports are a different kettle of fish altogether. They receive 12v, of which on the G20 is fed by a 10amp fuse for the two sockets on that car (well the one I've looked at anyway). Now I'm told that USB-C can give out up to 20v, depending on the equipment that is being fed. Upon reading BMW's own information then I believe these USB-C sockets are feeding 5v at 25watt, so a decent supply for modern phones (source... https://www.newtis.info/tisv2/a/en/g20-330i-lim/1VndHx1sR2)

As for cable neatness, it'll be no worse than charging your phone in any other way, although I will be trying my best to make sure it's as neat as possible ;) :driving:
 
The usb c chargers seem to very powerful but with auto throttling to avoid cooking things that can’t take the faster charge rates..

I’ve got everything that needs a cable in the central cubby..

I’m happy..

Look forward to another foray into the unknown…

As usual knowing what / if / how the bmw s/w firmware manages things is the great unknown..
 
This is what I'm currently using.
It's a desktop phone charger that's been cut down and mounted on a plastic sheet, fitted in place and the USB runs to meet up with the USB from my Mr12volt. I made it a few years ago and on the whole it works OK. BUT there are two problems with it, one is that sometimes it randomly disconnects from the mmi, and previously this was because the cable where the plug meets the phone wears out. I've replaced that part once before and recently it's started to do it again. It's a good idea let down by shoddy parts. The other issue is that, in summer, if I'm using it for music and nav then the phone tends to overheat and shut down or disconnects from AA.
So I've been looking for a better solution for where to have the phone. As I have the ashtray cup holder replacement I've got a phone mount that sits in one of the holes and has an extension arm to lift it clear of the gear stick (so I don't hit it with my hand). This should be a good location with this new charger cable idea. Hopefully it'll all work well.
I did consider 3D printing a OE console side cup holder (reversing all the dimensions of a LHD version) and then have a phone mount in there, but that may be just a little too challenging, especially as I don't have a 3D printer :ROFLMAO:
There is a company called KUDA who make a panel to fit on the dash so you can mount any phone mount on it, unfortunately though they only make it in LHD.
 

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This is what I'm currently using.
It's a desktop phone charger that's been cut down and mounted on a plastic sheet, fitted in place and the USB runs to meet up with the USB from my Mr12volt. I made it a few years ago and on the whole it works OK. BUT there are two problems with it, one is that sometimes it randomly disconnects from the mmi, and previously this was because the cable where the plug meets the phone wears out. I've replaced that part once before and recently it's started to do it again. It's a good idea let down by shoddy parts. The other issue is that, in summer, if I'm using it for music and nav then the phone tends to overheat and shut down or disconnects from AA.
So I've been looking for a better solution for where to have the phone. As I have the ashtray cup holder replacement I've got a phone mount that sits in one of the holes and has an extension arm to lift it clear of the gear stick (so I don't hit it with my hand). This should be a good location with this new charger cable idea. Hopefully it'll all work well.
I did consider 3D printing a OE console side cup holder (reversing all the dimensions of a LHD version) and then have a phone mount in there, but that may be just a little too challenging, especially as I don't have a 3D printer :ROFLMAO:
There is a company called KUDA who make a panel to fit on the dash so you can mount any phone mount on it, unfortunately though they only make it in LHD.
Yes I saw that..wireless charging ...work of the devil..can't beat copper wire..
 
I’ve have seen active cooled wireless chargers for what it’s worth, but this is a pretty cool idea!
 
Thought I’d add a response so this, as I much prefer fast charging with a wired CarPlay connection, rather than wireless.

I simply used one of these to split the data between the Mr12volt unit and a dedicated hard wired fast charger.


All components are hard wired and tucked inside the centre console, beneath the handbrake and idrive controller trim.

At the moment I have a flying lead from this board to my iPhone. Charging is extremely quick, even when using CarPlay. Why these MMI units don’t have a high current USB output as standard is beyond me.

It is important to note that you cannot go splicing cables together to achieve this outcome. The USB power distribution standard relies on resistance values to determine maximum charge rates. This is why the splitter board is required.

I plan to modify the existing USB socket under the armrest and wiring into this, removing my flying lead. It needs to be modified to remove current limiting resistors that block the ability to fast charge though it.

Happy to answer any questions or share details on other components in the setup.
 
@Matt.rowley.1990 Matt
I like that, didn't know it was a thing.
It's probably a similar circuit as used in the BMW USB-C socket I'll be working with as its the same idea.
Will have to wait and see if mine works though as time to do these things is always limited especially at this time of year.
 
Thought I’d add a response so this, as I much prefer fast charging with a wired CarPlay connection, rather than wireless.

I simply used one of these to split the data between the Mr12volt unit and a dedicated hard wired fast charger.


All components are hard wired and tucked inside the centre console, beneath the handbrake and idrive controller trim.

At the moment I have a flying lead from this board to my iPhone. Charging is extremely quick, even when using CarPlay. Why these MMI units don’t have a high current USB output as standard is beyond me.

It is important to note that you cannot go splicing cables together to achieve this outcome. The USB power distribution standard relies on resistance values to determine maximum charge rates. This is why the splitter board is required.

I plan to modify the existing USB socket under the armrest and wiring into this, removing my flying lead. It needs to be modified to remove current limiting resistors that block the ability to fast charge though it.

Happy to answer any questions or share details on other components in the setup.
USB B 2/0 defines a maximum charging current of 0.5A ...that's why its fixed..
 
USB B 2/0 defines a maximum charging current of 0.5A ...that's why its fixed..
Yes, the official standard does but many devices deviate from this to facilitate faster charging. Most OEM head units with CarPlay are a prime example.

Also take for example the devices themselves. The iPhone (until the very latest) is USB 2.0 and have supported charging beyond 500mA for as far as I can remember.
 
@Matt.rowley.1990 Matt
I like that, didn't know it was a thing.
It's probably a similar circuit as used in the BMW USB-C socket I'll be working with as its the same idea.
Will have to wait and see if mine works though as time to do these things is always limited especially at this time of year.
I’m looking forward to seeing how you get on, as I’ve been eyeing up the dual USB version of this to fit in my E89 for some time. I even contemplated using it as a front face for the solution I documented above.
 
Yes, the official standard does but many devices deviate from this to facilitate faster charging. Most OEM head units with CarPlay are a prime example.

Also take for example the devices themselves. The iPhone (until the very latest) is USB 2.0 and have supported charging beyond 500mA for as far as I can remember.
I don't like deviants..!-:)

Of course if you're using an iphone and want faster charging whilst connected wired to carplay mmi I guess you could use this..?

 
I don't like deviants..!-:)

Of course if you're using an iphone and want faster charging whilst connected wired to carplay mmi I guess you could use this..?

In theory yes but in reality, no. Those devices put the iPhone into host mode. You’ll also notice that the USB B connection is female to denote this. You can add power in but the socket is purely for a storage device, keyboard/mouse etc.

For what I’ve achieved, there really isn’t much of a commonplace and neat consumer solution.
 
Those dual OEM USB-C sockets have a 5 pin FAKRA connection, not the 4 pin as standard like all others, so you'd need to find one of those.
You'd also need to find somewhere to put it, as it wont fit in the standard location in the armrest, due to a lack of space behind.
 
Those dual OEM USB-C sockets have a 5 pin FAKRA connection, not the 4 pin as standard like all others, so you'd need to find one of those.
You'd also need to find somewhere to put it, as it wont fit in the standard location in the armrest, due to a lack of space behind.
Good point on the space.

I suspect I’d be hacking the thing up anyway to interface into the connectors themselves, so depth could be reduced, especially given they only mount by clipping in at the front. All theoretical at this stage anyway! I’ll wait and see how you get on :)
 
In theory yes but in reality, no. Those devices put the iPhone into host mode. You’ll also notice that the USB B connection is female to denote this. You can add power in but the socket is purely for a storage device, keyboard/mouse etc.

For what I’ve achieved, there really isn’t much of a commonplace and neat consumer solution.
Not true in all cases..

I've just yesterday used one to allow an iphone to charge whilst feeding iphone lightning usb data to a Audiotec Fischer USB card in my Match 10 DSP that only supports data and no charging.


 
Not true in all cases..

I've just yesterday used one to allow an iphone to charge whilst feeding iphone lightning usb data to a Audiotec Fischer USB card in my Match 10 DSP that only supports data and no charging.


I suspect that’s because the iPhone was treating the interface as a sound output device. In other worlds, still in host mode :)
 
I suspect that’s because the iPhone was treating the interface as a sound output device. In other worlds, still in host mode :)
iphones treat the world in a Trump like fashion..no consistency in their behaviour..

My earlier iphones work ok either direct or with this bodge.later ones refuse to talk to the HEC USB come what may..its enough to think about using Android..
 
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