Radio 12V + shuts down after about 4 hours question
Discussion
Customers Mercedes 250SLK diesel, model year 2015. I have placed a GPS tracker with power taken from the stock radio 12V + permanent feed. But it appears this feed disappears after about 4 hours with car off and closed up and locked. Not sure if this is because the battery voltage / current sensor on the battery 12V + post is seeing an abnormal (if very modest) current draw on this feed, or if it's something that happens anyway. I have generally read things shut down with key out vehicle locked after a much shorter time scale. perhaps a matter of less than 15 minutes.
Feeding the tracker direct from battery 12V + post and therefore before the current sensor would make disconnecting the tracker pretty trivial if someone sees a none original feed direct from the 12V + post... Any point in the harness with a permanent 12V + but after the current sensor may suffer from shutdown though I am surmising? Any opinion as to whether the 12V + radio feed is shutting down due to a circa 30mA current draw, or if shutdown would occur anyway? Thanks!
Feeding the tracker direct from battery 12V + post and therefore before the current sensor would make disconnecting the tracker pretty trivial if someone sees a none original feed direct from the 12V + post... Any point in the harness with a permanent 12V + but after the current sensor may suffer from shutdown though I am surmising? Any opinion as to whether the 12V + radio feed is shutting down due to a circa 30mA current draw, or if shutdown would occur anyway? Thanks!
Hi Spare tyre thanks for the reply. I see where you are coming from, I also considered the glove box light, but what I do not know (and longer term access to the vehicle is difficult as it's in near constant use), is whether the CAN shuts down *all* circuits based on time once the vehicle is locked? I guess this cannot be the case, otherwise leaving a hazardously positioned vehicle locked whilst you summon help, with the hazard lights on, would see them shut down. I assume they would not shut down... So why does the radio "permanent" live feed seem to shut down, and why only after about 4 hours not in a much shorter time period? None of this seems well documented, but once the holiday season is over I will try asking some professional tracker installers. Maybe they shut the TRACKER down via the movement sensor BEFORE the CAN sees what it believes is an abnormal drain. Too damned clever by far these modern systems, they can work with or against you! 
All the best.
All the best.The 4 hours is probably to make it quicker to start up if you're in and out of the car a lot, switching on and off.
Cars can have loads of stages of sleep after different time periods so unless you pay for the official information (actually quite cheap for Merc and generally well detailed) there will always be some guess work.
Can you use the supply to the OBD port? These are always permanent live on pin 16, so if you can find the fuse or supply wire to tap off then that should work.
Cars can have loads of stages of sleep after different time periods so unless you pay for the official information (actually quite cheap for Merc and generally well detailed) there will always be some guess work.
Can you use the supply to the OBD port? These are always permanent live on pin 16, so if you can find the fuse or supply wire to tap off then that should work.
Out of interest what tracker are you installing ? Thought about a cheap DIY one myself.
I have a Mercedes c class of similar year, I have a dash cam in the USB slot for media and when I turn the engine off it turns on and off for about 15 minutes so behaves very differently to the accessory sockets
I have a Mercedes c class of similar year, I have a dash cam in the USB slot for media and when I turn the engine off it turns on and off for about 15 minutes so behaves very differently to the accessory sockets
OBD2 socket power source is a good call, thank you, I'll look in to that.
As to the tracker, the Ebay Chinese ones are a total lottery, I have loads! Even from the same vendor they can have different firmware. 2 *MAJOR* points to consider. What server do you want to use? Most Ebay ones have a suggested server in China listed in the pitiful Chinglish instructions. Now some will accept a different server and work indefinitely on that, but others time out after a few days and the GPRS signal to that other server is disabled. You can text "gprs" to it and it returns "gprson", but it is *NOT* on! It is hard coded in that particular firmware (that no one will give you the software to change or update). It then has to be reset by text to use the suggested server, (which CAN be adequate for most purposes) *BUT* the hidden caveat is most allow about 2 months free access then expect you to pay a fee for ongoing use of their server, and close down access from your tracker if you don't pay. Plus you are dealing with One Hung Lo, thousands of miles away, possibly a bandit... I have a few that this has not happened to and they will then work indefinitely on the (for example) excellent, free for 3 devices, "GPS_TRACE" server in Russia. It really is truly excellent!! But it's a lottery until you receive your Chinese device whether its firmware allows indefinite access to other servers.
The other big caveat is some Chinese Ebay devices will not allow an update time of less than ten minutes, which for many people is pretty useless. Again, a firmware lottery...5 or 10 seconds allows coherent tracks. 10 minutes does not, and if something is nicked it can go a long way in ten minutes, with you left oblivious. You need to set up a command to make them send a text if the vehicle moves.
I have now given up on the Chinese Ebay ones and recommend you find a source for genuine Teltonika devices and their FMB920 will do all and more most people could dream of. Setting them up is a bit of a nightmare until you have done a few as the instructions are from their Lithuanian company, and in some areas are rather obtuse. I have them sussed now and if I am not mad busy would do a config file for someone to get them going. I am sure there will be fake FMB920 devices, so be sure the suppler is a registered one.
DO NOT buy used, if they have been locked you have had it, as they'll never accept commands, and Teltonika want a receipt of purchase from a registered dealer to give you an unlock code. ONLY buy new!! Be sure it's a genuine device!!
Finally, you can run your own server on a PC at home or work, but you need a fixed IP address to make this anything but a severe headache, and you need to be pretty PC savvy to initially set it up without allowing all and sundry access to your PC / network with the expected serious risks of malware or ransomware. I am moderately savvy with this now and have my own server as well as using the "GPS-TRACE" one. Initial set up on a Windows PC is pretty trivial, on a Linux PC a nightmare unless you are a pro with that OS and like to waste your life doing things manually the Windows installation automates.
The FMB920 allows updates to 2 servers either if one goes down, or simultaneously.. Running 2 simultaneously uses twice the data... But it's an option, as are countless others, including Bluetooth access and reading and sending CAN BUS info from a suitable dongle. You can spend days playing
You can put them in sleep mode but unless you really study the huge instruction book and work out what it is REALLY trying to say, best to ask me, when it finally dawned on me what it really meant, it made some sense, until then I was adamant the thing was buggered and would not sleep <LOL>
You need to use a SIM card that will still do 2G for many trackers. I have found PAYG EE ones are hassle free as you need to know their server log on info which some providers try to hide, or even deny access to. BE SURE to remove the Voicemail option and any PIN, plus initialize the SIM in a none locked, or EE mobile phone before putting it in the tracker. Also set up an on line top up account for the card from a proper phone, none of this can be done via the trackers themselves.
All this probably sounds a right `mare, but if you make no typos and take your time sending SMS commands it isn't as bad as the above sounds. The nice thing about the genuine Teltonika ones are they can be programmed off line via a micro USB cable via freely available configuration software from Teltonika.
Any enough already, even the genuine Teltonika ones are amazing value (about £45), and if you strike lucky with the firmware on a £13 Chines Ebay one, even more remarkable value. I'd always buy genuine branded now though, I have a retirement home for recalcitrant Chinese trackers now. HTH.
As to the tracker, the Ebay Chinese ones are a total lottery, I have loads! Even from the same vendor they can have different firmware. 2 *MAJOR* points to consider. What server do you want to use? Most Ebay ones have a suggested server in China listed in the pitiful Chinglish instructions. Now some will accept a different server and work indefinitely on that, but others time out after a few days and the GPRS signal to that other server is disabled. You can text "gprs" to it and it returns "gprson", but it is *NOT* on! It is hard coded in that particular firmware (that no one will give you the software to change or update). It then has to be reset by text to use the suggested server, (which CAN be adequate for most purposes) *BUT* the hidden caveat is most allow about 2 months free access then expect you to pay a fee for ongoing use of their server, and close down access from your tracker if you don't pay. Plus you are dealing with One Hung Lo, thousands of miles away, possibly a bandit... I have a few that this has not happened to and they will then work indefinitely on the (for example) excellent, free for 3 devices, "GPS_TRACE" server in Russia. It really is truly excellent!! But it's a lottery until you receive your Chinese device whether its firmware allows indefinite access to other servers.
The other big caveat is some Chinese Ebay devices will not allow an update time of less than ten minutes, which for many people is pretty useless. Again, a firmware lottery...5 or 10 seconds allows coherent tracks. 10 minutes does not, and if something is nicked it can go a long way in ten minutes, with you left oblivious. You need to set up a command to make them send a text if the vehicle moves.
I have now given up on the Chinese Ebay ones and recommend you find a source for genuine Teltonika devices and their FMB920 will do all and more most people could dream of. Setting them up is a bit of a nightmare until you have done a few as the instructions are from their Lithuanian company, and in some areas are rather obtuse. I have them sussed now and if I am not mad busy would do a config file for someone to get them going. I am sure there will be fake FMB920 devices, so be sure the suppler is a registered one.
DO NOT buy used, if they have been locked you have had it, as they'll never accept commands, and Teltonika want a receipt of purchase from a registered dealer to give you an unlock code. ONLY buy new!! Be sure it's a genuine device!!
Finally, you can run your own server on a PC at home or work, but you need a fixed IP address to make this anything but a severe headache, and you need to be pretty PC savvy to initially set it up without allowing all and sundry access to your PC / network with the expected serious risks of malware or ransomware. I am moderately savvy with this now and have my own server as well as using the "GPS-TRACE" one. Initial set up on a Windows PC is pretty trivial, on a Linux PC a nightmare unless you are a pro with that OS and like to waste your life doing things manually the Windows installation automates.
The FMB920 allows updates to 2 servers either if one goes down, or simultaneously.. Running 2 simultaneously uses twice the data... But it's an option, as are countless others, including Bluetooth access and reading and sending CAN BUS info from a suitable dongle. You can spend days playing
You can put them in sleep mode but unless you really study the huge instruction book and work out what it is REALLY trying to say, best to ask me, when it finally dawned on me what it really meant, it made some sense, until then I was adamant the thing was buggered and would not sleep <LOL> You need to use a SIM card that will still do 2G for many trackers. I have found PAYG EE ones are hassle free as you need to know their server log on info which some providers try to hide, or even deny access to. BE SURE to remove the Voicemail option and any PIN, plus initialize the SIM in a none locked, or EE mobile phone before putting it in the tracker. Also set up an on line top up account for the card from a proper phone, none of this can be done via the trackers themselves.
All this probably sounds a right `mare, but if you make no typos and take your time sending SMS commands it isn't as bad as the above sounds. The nice thing about the genuine Teltonika ones are they can be programmed off line via a micro USB cable via freely available configuration software from Teltonika.
Any enough already, even the genuine Teltonika ones are amazing value (about £45), and if you strike lucky with the firmware on a £13 Chines Ebay one, even more remarkable value. I'd always buy genuine branded now though, I have a retirement home for recalcitrant Chinese trackers now. HTH.
Edited by Chris Wilson on Friday 27th December 12:49
Edited by Chris Wilson on Friday 27th December 12:55
Edited by Chris Wilson on Friday 27th December 12:58
Yes, that may be possible but I am still thinking this is on the "wrong" side of the battery current sensor, what I think I need to do is find out from someone totally familiar with the CAN BUS set up whether *ANY* current drain when the car is locked is seen as abnormal. But I don't suppose it will shut off the main starter feed... Things were oh so simple in the eighties <LOL> Thank you for your idea. If anyone knows how to get a full description of how and when this CAN BUS decides to shut modules down I would be most apprciative. For now the tracker itself is going to sleep and wakes on restoration of power (door unlocked), but a lift and transporter away situation would not be seen as no doors may be opened in such a scenario.
As you mention, it's very doubtful that the starter supply is shut down
Is there anything that can cut the starter supply? I doubt it
Going by what the following file contains.....(Does'nt mean the vehicle you're working on is of the same set-up but....)
If a rest current greater than 75 mA is measured 75
mins. after the vehicle is locked, the battery sensor
(B95) wakes the rear SAM control module (N10/2) and
a data record is created
See below PDF, it may be of some help to you
https://www.google.com/url?sa=t&rct=j&q=&a...
Is there anything that can cut the starter supply? I doubt it
Going by what the following file contains.....(Does'nt mean the vehicle you're working on is of the same set-up but....)
If a rest current greater than 75 mA is measured 75
mins. after the vehicle is locked, the battery sensor
(B95) wakes the rear SAM control module (N10/2) and
a data record is created
See below PDF, it may be of some help to you
https://www.google.com/url?sa=t&rct=j&q=&a...
Thanks for the continued replies. I need to source a wiring diagram for this car, not having access to it apart from short durations when it's not in use is a PITA! Someone mentioned if the battery might be tired. I think not as the customer says he often has to park it with sidelights on for hours at a tome and it's never struggled to start, plus it's quite new and a quality one, but thanks for the idea! I have made a poor choice of power source, I need to find a permanent live somewhere behind the centre of the dash....
24 hrs access to the Mercedes SPO website isn't ridiculously expensive.
https://service-parts.mercedes-benz.com/dcagportal...
You should be able to get wiring diagrams and a bit of explanation of shut down procedures, but probably not exactly what shuts down when as it will depend on a multitude of things.
https://service-parts.mercedes-benz.com/dcagportal...
You should be able to get wiring diagrams and a bit of explanation of shut down procedures, but probably not exactly what shuts down when as it will depend on a multitude of things.
:Late reply but the customer decided to leave it as is as when the car is not in use the tracker supply is shut down, any ignition event or just opening the door starts the supply again. So no permanent drain if the car is not used for weeks. has its downsides but everyone happy I got diagrams and found a none closing supply is the + 12V feed to the OBDII diagnosis socket. Thanks for the help everyone!
I got diagrams and found a none closing supply is the + 12V feed to the OBDII diagnosis socket. Thanks for the help everyone!Gassing Station | In-Car Electronics | Top of Page | What's New | My Stuff