Will your C7 last a month without a trickle charger?
12-11-2018, 12:39 AM
#61
Melting Slicks
I plugged in the factory trunk charger and left it for 3 months. I arrived back at Thanksgiving and noticed a funny color on the charger.....dead. I trouble shot it and found...... I forgot to plug it in the wall!!!!! 
Once plugged in, It was ready and fired right off the next day.
Once plugged in, It was ready and fired right off the next day.
12-11-2018, 01:06 AM
#62
Moderator
I agree that 05 should still be applicable, but if the article is correct then the draw will be higher when the fob is in range of the receiver because instead of just listening for the transmitter, the receiver wakes up in preparation for the next command. Now it seems to me Chevrolet has probably resolved the parasitic draw as it relates to this issue between 05 and present.
I'm not disputing what owc6 is saying. Theres a pretty good chance shes righ, because if she is wrong, then that would mean you could kill the battery solely by leaving the fob within range of the car, and i dont think that's the case.
Still, I want to see the data so I understand the system. Otherwise I'll be wrapping a fob in foil or some other crazy thing before I do a draw test on one of these cars.
I'm not disputing what owc6 is saying. Theres a pretty good chance shes righ, because if she is wrong, then that would mean you could kill the battery solely by leaving the fob within range of the car, and i dont think that's the case.
Still, I want to see the data so I understand the system. Otherwise I'll be wrapping a fob in foil or some other crazy thing before I do a draw test on one of these cars.
12-11-2018, 05:47 AM
#63
E-Ray, 3LZ, ZER, LIFT
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I will be going to Germany shortly for five weeks. After reading this post I will use my Battery Tender to support the C7's battery while gone. One problem through. The Battery Tender has alligator clips on the end and I want to install a lighter plug on it. It appears the center pin on the lighter plug is the positive and the side terminal is the ground. Is this correct?
FWIW, before I bought the equivalent to the Chevy Charger I used an arrangement I had made for my boat and the 2 amp slow charge tap on my large battery charger. I just used two bolts in a piece of heavy plastic and connected the charger clips to the bolts. Used a plug from an old usless car vacuum I cut off and put on ring terminals! I had an inline fuse so used it as well. Quick, safe way to do it if you don't want to permanently cut off the alligator clips or expose the battery to clip to the terminals.
Last edited by JerryU; 12-11-2018 at 05:54 AM.
12-11-2018, 08:30 AM
#64
Race Director
The receiver is frequently checking for a signal from the fob, but that signal only occurs when a button is pressed, not by being near the vehicle. The receiver wakes often enough that it does not miss a command signal from the fob (which is transmitted in 4 10ms data streams). Approaching your C7 with the fob does nothing until you press a button on the fob or the door button. Neither the fob nor the in car receiver transmit unless a button is pressed.
What happens when you are sitting in the car, door closed, not pushing any buttons on the fob, and you push the engine start button on the dash ?
The receiver has to know somehow that the fob is within proper proximity. This is the crux of my question. The article seems to imply that at that point, two way communication between the fob and car has already been established, but I don't think that's correct. It could be correct, but if it is, then it seems like having the fob within proximity of the car, would result in higher than normal draw on the car battery.
Last edited by PatternDayTrader; 12-11-2018 at 08:32 AM.
12-11-2018, 09:00 AM
#65
Race Director
The receiver is frequently checking for a signal from the fob, but that signal only occurs when a button is pressed, not by being near the vehicle. The receiver wakes often enough that it does not miss a command signal from the fob (which is transmitted in 4 10ms data streams). Approaching your C7 with the fob does nothing until you press a button on the fob or the door button. Neither the fob nor the in car receiver transmit unless a button is pressed.
The keyless smart fob is detected by one or more antennas located on the vehicle. The only difference is that the keyless push button start systems do more than just unlock the doors. Once the fob is used to unlock the door and/or is inside the vehicle, it’s the same as if the driver has inserted a key into the ignition switch and turned it to the “on” position. The smart fob transponder broadcasts its ID code to the keyless entry immobilizer module, which then authenticates the code.
^^ The point here is that a whole bunch of functions begin when the fob and the car are within certain proximity.
Last edited by PatternDayTrader; 12-11-2018 at 09:11 AM.
12-11-2018, 09:39 AM
#66
Safety Car
I have found that a small 8-10 watt Solar Photo-voltaic panel mounted on the roof of my garage does a wonderful job keeping the starting battery all charged up. When the car is outdoors I leave a small panel on the dashboard and it charges the battery up and keeps it full. These panels have a diode in their wiring to be sure not to discharge your battery when dark.
Beware of inexpensive battery chargers as they put out power all the time and do not have a cut-off voltage. I ruined a brand new battery using a 1 amp Battery Tender as it forced 1 amp into the battery all winter and I ended up with a battery with virtually no electrolyte and exposed "oxidized" plates inside the battery. The battery was not recoverable but was replaced under warranty.
Since these cars draw so much parasitic power why don't they incorporate a PV module into the body somewhere so the car stays charged? I would love to have a photo-voltaic system built into the sunroof.
Merry Christmas and a Happy New Year driving your Beautiful Corvette!
Beware of inexpensive battery chargers as they put out power all the time and do not have a cut-off voltage. I ruined a brand new battery using a 1 amp Battery Tender as it forced 1 amp into the battery all winter and I ended up with a battery with virtually no electrolyte and exposed "oxidized" plates inside the battery. The battery was not recoverable but was replaced under warranty.
Since these cars draw so much parasitic power why don't they incorporate a PV module into the body somewhere so the car stays charged? I would love to have a photo-voltaic system built into the sunroof.
Merry Christmas and a Happy New Year driving your Beautiful Corvette!
12-11-2018, 09:58 AM
#67
E-Ray, 3LZ, ZER, LIFT
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25 to max 40 milliamps is NOT "so much."
I designed and installed the electrical system in my Street Rod. Bought a high capacity alternator and have the minimum number of micros and few devices that draw any current when the car is off. The digital dash and the control/receiver for the electric doors and windows that communicates with the remote. Have a large sound wall BUT have a relay that only powers that system when the engine is running. I even put in a switch so the alarm system can be turned off.
When it was completed, I would drive a ~25 mile route several times a week, thinking I was charging the battery- NOT! Measured the current draw with nothing turned on and it was about 60 milliamps! Then estimated the power consumed starting the 502 cid BB and when I looked at charging rate and starting power required it was not maintaining a full charge. Since then have a charger always on when it's parked.
The C7 turns most power off in 10 minutes and only turns on things like OnStar for a very short time periodically than it's off. Leave a light on- no problem a microprocessor shuts it off. Just like the ones on the hatch if you leave it open. In about 5 minutes they turn off.
As I noted from the Service Manual, it indicates an 80% charged battery will be at 50% charge, ~12.3 volts, in 33 days which will start the car. (See my post #41 this Thread.) GM has done a great job on the C7, much better than prior Vettes or most cars, IMO.
I designed and installed the electrical system in my Street Rod. Bought a high capacity alternator and have the minimum number of micros and few devices that draw any current when the car is off. The digital dash and the control/receiver for the electric doors and windows that communicates with the remote. Have a large sound wall BUT have a relay that only powers that system when the engine is running. I even put in a switch so the alarm system can be turned off.
When it was completed, I would drive a ~25 mile route several times a week, thinking I was charging the battery- NOT! Measured the current draw with nothing turned on and it was about 60 milliamps! Then estimated the power consumed starting the 502 cid BB and when I looked at charging rate and starting power required it was not maintaining a full charge. Since then have a charger always on when it's parked.
The C7 turns most power off in 10 minutes and only turns on things like OnStar for a very short time periodically than it's off. Leave a light on- no problem a microprocessor shuts it off. Just like the ones on the hatch if you leave it open. In about 5 minutes they turn off.
As I noted from the Service Manual, it indicates an 80% charged battery will be at 50% charge, ~12.3 volts, in 33 days which will start the car. (See my post #41 this Thread.) GM has done a great job on the C7, much better than prior Vettes or most cars, IMO.
Last edited by JerryU; 12-11-2018 at 10:08 AM.
12-11-2018, 10:19 AM
#68
Le Mans Master
Thread Starter
Well, I'll certainly NOT drive it for a week, but WILL drive it in a month. That's the judgment call. Sure, the easy answer is "connect it every time you park" but that's dumb... it's a judgment call, and the more I know about the odds involved, the better I can make that judgment. That's all.
12-11-2018, 10:22 AM
#69
Le Mans Master
Thread Starter
The receiver is frequently checking for a signal from the fob, but that signal only occurs when a button is pressed, not by being near the vehicle. The receiver wakes often enough that it does not miss a command signal from the fob (which is transmitted in 4 10ms data streams). Approaching your C7 with the fob does nothing until you press a button on the fob or the door button. Neither the fob nor the in car receiver transmit unless a button is pressed.
In the 1994 model, the key had a motion detector in it and you could rock the car which would trigger the keys motion which would send a proximity signal that would open the car.
To duplicate that functionality you EITHER need a periodic broadcast from the fob on a regular basis or it must detect movement (which is cheap these days). But it can't just go to permasleep until a button is pressed or you lose that functionality.
Now the car could interrogate the fob of course but it'd still have to be awake and receiving for that to work too.
So how did they handle this, given your understanding of it?
12-11-2018, 01:13 PM
#70
Team Owner
"Will your C7 last a month without a trickle charger?"
To be honest I do not have a clue and no way would I try that. I had a new bought 05 Vert 6spdM and it was one that had the famous DBS problem. Hell you did not know if the battery would go dead overnight, a couple days later or hold for a long time. That was with the car shut down right (in reverse).
So do to my two year fight to get this problem straightened out, in disgust I traded it in for a 07 Z06.
Now my SOP is if the car is going to be parked for more that a week it goes on the tender.
It is now getting its 6 month sleep in my garage and rest assured the tender is on . The tender is in a place that I can see it every time I go in or out. . Seeing those two green lights on is very assuring!
To be honest I do not have a clue and no way would I try that. I had a new bought 05 Vert 6spdM and it was one that had the famous DBS problem. Hell you did not know if the battery would go dead overnight, a couple days later or hold for a long time. That was with the car shut down right (in reverse).
So do to my two year fight to get this problem straightened out, in disgust I traded it in for a 07 Z06.
Now my SOP is if the car is going to be parked for more that a week it goes on the tender.
It is now getting its 6 month sleep in my garage and rest assured the tender is on . The tender is in a place that I can see it every time I go in or out. . Seeing those two green lights on is very assuring!
12-11-2018, 01:39 PM
#71
Le Mans Master
I have ten cars in my garage, and the Z06 convertible is pretty low on the list of "things to drive today" on a rainy December in Seattle. It's my DD in June, not so much in the winter.
Never can understand the people that run up a ton of depreciating mileage by driving their convertible sports cars in rainy weather ;-)
Never can understand the people that run up a ton of depreciating mileage by driving their convertible sports cars in rainy weather ;-)
12-11-2018, 02:00 PM
#72
Moderator
Ok so that makes sense to me.
What happens when you are sitting in the car, door closed, not pushing any buttons on the fob, and you push the engine start button on the dash ?
The receiver has to know somehow that the fob is within proper proximity. This is the crux of my question. The article seems to imply that at that point, two way communication between the fob and car has already been established, but I don't think that's correct. It could be correct, but if it is, then it seems like having the fob within proximity of the car, would result in higher than normal draw on the car battery.
What happens when you are sitting in the car, door closed, not pushing any buttons on the fob, and you push the engine start button on the dash ?
The receiver has to know somehow that the fob is within proper proximity. This is the crux of my question. The article seems to imply that at that point, two way communication between the fob and car has already been established, but I don't think that's correct. It could be correct, but if it is, then it seems like having the fob within proximity of the car, would result in higher than normal draw on the car battery.
12-11-2018, 02:06 PM
#73
Race Director
Sitting in the car, door closed, not pushing any buttons and then you push the engine start button. Well, you just pushed a button. That causes the car module to transmit a "is there a fob out there?" message. Your fob responds, the in car module determines it is a matching fob and starts the car. Everything is started by a button push or some other event occurring (like shutting a door), NOT simply proximity.
12-11-2018, 02:11 PM
#74
Moderator
If that is the case, how does the car handle the keys locked inside?
In the 1994 model, the key had a motion detector in it and you could rock the car which would trigger the keys motion which would send a proximity signal that would open the car.
To duplicate that functionality you EITHER need a periodic broadcast from the fob on a regular basis or it must detect movement (which is cheap these days). But it can't just go to permasleep until a button is pressed or you lose that functionality.
Now the car could interrogate the fob of course but it'd still have to be awake and receiving for that to work too.
So how did they handle this, given your understanding of it?
In the 1994 model, the key had a motion detector in it and you could rock the car which would trigger the keys motion which would send a proximity signal that would open the car.
To duplicate that functionality you EITHER need a periodic broadcast from the fob on a regular basis or it must detect movement (which is cheap these days). But it can't just go to permasleep until a button is pressed or you lose that functionality.
Now the car could interrogate the fob of course but it'd still have to be awake and receiving for that to work too.
So how did they handle this, given your understanding of it?
Yes, as repeatedly mentioned, both the fob and the in car module are both "listening" periodically for the other one to transmit something. The referenced article states that it may listen for 1 ms at 20 ms intervals (so it is "off" for 95% of the time). "Listening" is a lower power operation that "transmitting", and transmitting is only caused by an event (fob button push, car door button push, engine start button, etc.). Otherwise they are listening, but not transmitting.
12-11-2018, 02:22 PM
#75
Drifting
The C6 electrical system design was a mess and had a high key off load. The C7 is electrical system is a new design and has much less key off load. My 2016 has sat for a month many times without being on a charger and has started with no issue
"Will your C7 last a month without a trickle charger?"
To be honest I do not have a clue and no way would I try that. I had a new bought 05 Vert 6spdM and it was one that had the famous DBS problem. Hell you did not know if the battery would go dead overnight, a couple days later or hold for a long time. That was with the car shut down right (in reverse).
So do to my two year fight to get this problem straightened out, in disgust I traded it in for a 07 Z06.
Now my SOP is if the car is going to be parked for more that a week it goes on the tender.
It is now getting its 6 month sleep in my garage and rest assured the tender is on . The tender is in a place that I can see it every time I go in or out. . Seeing those two green lights on is very assuring!
To be honest I do not have a clue and no way would I try that. I had a new bought 05 Vert 6spdM and it was one that had the famous DBS problem. Hell you did not know if the battery would go dead overnight, a couple days later or hold for a long time. That was with the car shut down right (in reverse).
So do to my two year fight to get this problem straightened out, in disgust I traded it in for a 07 Z06.
Now my SOP is if the car is going to be parked for more that a week it goes on the tender.
It is now getting its 6 month sleep in my garage and rest assured the tender is on . The tender is in a place that I can see it every time I go in or out. . Seeing those two green lights on is very assuring!
12-11-2018, 02:30 PM
#76
Team Owner
It takes only a few seconds to put on tender and I tend to think it allows me to sleep better!
12-11-2018, 06:03 PM
#77
Drifting
If that works for you and you sleep better knock yourself out. I understand why you would be concerned but it is really not an issue.
For me I don't put it on a charger unless the car is going to sit for more than a month. I'm sorry, but a bit of a pet peeve of mine is the reporting of previous generation issues or functionality in the C7 section. The vast majority of the previous generations issues get fixed in a redesign. Each generation tends to have it's own issues.
For me I don't put it on a charger unless the car is going to sit for more than a month. I'm sorry, but a bit of a pet peeve of mine is the reporting of previous generation issues or functionality in the C7 section. The vast majority of the previous generations issues get fixed in a redesign. Each generation tends to have it's own issues.
12-16-2018, 05:12 PM
#78
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The service manual says an 80% charged battery will be at ~50% charge in 30 days and will start the car
I would not push it more but some have. The trans issue was for an older Vette, C7 makes no difference. In fact the C7 shuts down about everything electrical in ~10 minutes even if you leave a light on.
The issue with the C7 is the computer controls charging rate to save enery. Hard to get it to 100% charge unless on a really long drive. I replaced my 2014 C7 battery in 3 years. Will do the same with the Grand Sport and get an AGM replacement. Real PIA to replace the C7 battery and would not want to do it when it might be needed in the winter or would never want a AAA person to jump or for sure they will rip the carpet. Reports that dealer techs have ripped it. Although not in the owners or service manuals I pop the rear clips on the passenger plastic wheel well cover before I pull out the unbound carpet!
12-17-2018, 09:38 AM
#79
Le Mans Master
Thread Starter
The C7 version fob does NOT have a motion sensor in it. If you "lock your key fob inside", there are 2 possibilities. One, shutting the door causes the in car module to seek any matching fobs in range. If it detects one (one responds back), it signals you (horn honk) that you left your fob in the vehicle). Two, you left the fob somewhere in the car (like in the rear cubby hole) where the in car module and fob cannot establish a connection and the car locks. At this point you are screwed. If you have OnStar active, they can unlock it for you or you'll need the other fob. Rocking the car will just set of the alarm, but it won't do anything for the fob inside.
Yes, as repeatedly mentioned, both the fob and the in car module are both "listening" periodically for the other one to transmit something. The referenced article states that it may listen for 1 ms at 20 ms intervals (so it is "off" for 95% of the time). "Listening" is a lower power operation that "transmitting", and transmitting is only caused by an event (fob button push, car door button push, engine start button, etc.). Otherwise they are listening, but not transmitting.
Yes, as repeatedly mentioned, both the fob and the in car module are both "listening" periodically for the other one to transmit something. The referenced article states that it may listen for 1 ms at 20 ms intervals (so it is "off" for 95% of the time). "Listening" is a lower power operation that "transmitting", and transmitting is only caused by an event (fob button push, car door button push, engine start button, etc.). Otherwise they are listening, but not transmitting.
12-17-2018, 10:12 AM
#80
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He's correct. No conjecture involved. Been discussed ad finitum on here by me, Lisa, and the other FOB geeks. I've even gone so far as to have communication with an engineer in Detroit discussing the RKE system and have reported it back here on the forum.
In a nut shell:
The FOB communicates to the car:
1) When you push a button on the FOB.
2) When you are standing within 3' of the door (P or D) and then press the Door Pad to open the door. The car talks to the FOB and the FOB answers back.
3) When you are within 3' of the trunk/hatch and press the open button under the trunk lip to open the trunk/hatch. The car talks to the FOB and the FOB answers back.
4) When you are sitting in the car ready to start the engine and press "Start". The car talks to the FOB and the FOB answers back.
5) When you leave the FOB in the car after shutting the engine off and you have the triple beep warning set to sound, the car talks to the FOB and the FOB answers back.
Otherwise, your FOB does not communicate with the car and is listening for the car and using a fantastically miniscule amount of power to "look" for a signal from the car.
Elmer
Last edited by eboggs_jkvl; 12-17-2018 at 10:31 AM.