the transistors are to use the cars ACC trigger to turn the radio on and off by using the power stored in the battery.
the dome light idea wouldnt work because it would reset when you go to start the car and you would still have the same problem, either makeing the battery device or geting a remote start would be a better option
the transistors are to use the cars ACC trigger to turn the radio on and off by using the power stored in the battery.the dome light idea wouldnt work because it would reset when you go to start the car and you would still have the same problem, either makeing the battery device or geting a remote start would be a better option
If I understand you correctly, transistors are so the ACC is powered from the supplemental battery (but still controlled by the ignition key). This prevents the cranking of the engine from dropping voltage on the ACC and causing the radio to shutoff. The transistors basically cause power to remain constant on both ACC and 12V. I'm not sure the drop in ACC would cause it to shut off. I thought it was just the main line that was the problem. Anyone tried it without the transistors? Why don't the transistors turn off, are they just more sensitive than the stereo?
I didn't mean the dome instead of the battery, I mean in addition to the battery. I think if I just wire the dome in with a diode, then when the dome goes on, the radio will start up. provided the ACC goes on before the dome goes out, the radio should stay booted (I guess I would have to start the car before closing the door), maybe there is another source for power that stays on up till start, like a door unlock line. Do I need a diode then on the ACC line too (I think I do to keep current from flowing from dome back into the battery)?
...If I understand you correctly, transistors are so the ACC is powered from the supplemental battery (but still controlled by the ignition key). This prevents the cranking of the engine from dropping voltage on the ACC and causing the radio to shutoff. The transistors basically cause power to remain constant on both ACC and 12V. I'm not sure the drop in ACC would cause it to shut off. I thought it was just the main line that was the problem. Anyone tried it without the transistors? Why don't the transistors turn off, are they just more sensitive than the stereo?...
Yes, I did some bench top testing. The AVIC would shut down if the continuous power input went below 10.5V, or if the switched (accessory) power input went below 10.5V. For that reason, I had to add the transistors. Of course, you could use a relay instead, but the transistors were smaller and simpler for me.
the transistors are to use the cars ACC trigger to turn the radio on and off by using the power stored in the battery.the dome light idea wouldnt work because it would reset when you go to start the car and you would still have the same problem, either makeing the battery device or geting a remote start would be a better option
My dome light stays on for about 30 seconds even after I start the car (Ford). It works the same for both driver and passenger doors, if you open the door from outside the vehicle(switch in the handle) or if you unlock the car with the remote. My vehicle has the Illuminated Entry Module which powers the dome lights and provides the delay. You would connect this output (pin 4, black/lt blue wire) to the AVIC ACC lead through a 1N4004 diode. The AVIC gets all of its power from the MEMORY lead, the ACC lead only carries 2.6 mA when the AVIC is powered up and playing music.
So with this idea in mind, you would not need the NiCAD batteries, nor the transistor circuitry or diodes, provided the domelight works in a similar fashion. Another thought here is that if the driver turned on his dome lights from the dash dimmer switch, you could keep the AVIC powered up while you ran into the bank or pumped gas thus eliminating the 528T delay relay and the external UPS battery(GELCEL) that I suggested in an earlier post. One drawback is that the alarm probably wont set with the dome light on and you have to remember to shut off the dash switch when parking over night! However the batteries would be necessary if your cranking voltage is low as previously discussed. I don't have a problem with this now, but in the winter I probably will have, since it gets mighty cold, and car batteries don't output as much juice.
I read the datasheet on the Schottky diode SDP10S30. It has a forward voltage drop of two silicon diodes thus putting the drop at 12.0 - 1.7(max) = 10.5v - 10.3 volts, somewhat low to be powering the AVIC. This may not be an issue once the vehicle is started and the alternator is suppling 13.4v, but under a heavy amp load such as headlights, A/C, heater or defroster on at the same time, the voltage power the AVIC could again drop to 10.3v at idle, depending on how beefy your alternator is. JoeGr you didn't find this to be a problem yet?
Thanks for the help, buying the componenets now. Will install on Monday.
A couple more questions:
1. Is it ok for the HD and XM modules to be hooked up to normal old acc? Will it mess up the AVIC if these powere up and down while the avic is on?
2. Should I install the bateries in a place like the glove compartment so I can change them out? How long will they last before they die from constantly being charged?
3. Do I need to hookup a relay to the battery so that it won't be charging while the car is off? I sometimes don't drive for weeks and I don't want the main battery dead ever. If I do this, how long will the cells keep enough juice to survive a crank? In my application would a SLA be better?
4. Could I rearange the diodes to eliminate the diode going back to the main battery. I think this would work because the resistor would limit the charge going to the main battery during crank. But the two diodes would allow current to flow to the AVIC as needed (main when not cranking, NICD when cranking):
main -----Diode>-----------------Avic
|....................|
R....................|
|....................|
|-------Diode>-------|
|
|
Backup
Thanks for the help
So how would you wire up the b28t to the avic since there is no pulsed trigger only constant 12volts?
1. I don't know.
2. Probably. I would expect them to last about three years.
3. No. Normal battery voltage will be too low to cause current to flow to the aux battery pack while the engine is off.
4. Yes, that will probably work. You may need to adjust the value of the current limit resistor, or add one more cell to the battery pack if you do this.
I mentioned this in a previous post about the diodes specified in the AVIC schematic using the NiCads. They have a forward voltage drop of 1.5v(each diode) as opposed to a diode of the 1N40xx,1N54xx series with only a .7v drop. There are 10 cells (1.2 volts per cell * 10 = 12) in the design, offering 12vdc. Subtract 1.5v from 12v and you get 10.5v, JoeGr said 10.5v powering the AVIC is a problem....so those diodes as specified, should not be used.
NiCads are known to be trickier to charge.
NiCads can be easily overcharged, shortening their life, thus requiring a 16 hour cutoff timer or shorter depending on the charge rate(amount of current flow into the battery). Which if you are only driving you car for less than 16 hours this maybe not a problem. But since they aren't being used but for a few seconds, I would think that if you drove your frequently for long periods you would end up overcharing the NICADs. Another thing, NICads require 1.41v per cel to properly charge, times ten cells is 14.1volts...My alternator puts out 14.1 v MAX so subtract the 1.5 diode drop = 12.6 volts, not enough to properly charge the NICADs so maybe they are not going to be overcharged, but will they be undercharged? NICads also have the highest self-discharge rate of any rechargable battery, so storing your car for weeks on end could result in a dead NiCAD, especially if it were not being charged properly.
Another idea is to replace the finicky NICADs with a 12v 2A(Atbatt.com AP-1220F1 $14.00 USD) sealed lead acid. It will charge just like your car battery, then you can eliminate D2 and R1 and replace with a 2 amp fuse, replace D1 with a 1N5408, and if you didnt want to deal with caps, transistors and resistors replace them all with a 12vdc SPST or SPDT relay. The relay contacts are wired to AVIC_ACC_PWR and AVIC_CONST_PWR, one side of the relay coil goes to ground and the other side goes to CAR_ACC_PWR.
So how would you wire up the b28t to the avic since there is no pulsed trigger only constant 12volts?
According to DEI, the 528T triggers from a pos or neg pulse or a pos /neg change of state.
Using this relay had a specific fix, in that using a certain remote start removed the ACC voltage from the AVIC for a few seconds as reported by one AVIC owner. The idea was for the 528T relay to trigger on for 30 seconds or so while the car cranked, bridging the AVIC_CONST_PWR and AVIC_ACC_PWR. When it timed out, presumably the car would have already started.
the 528T does not fix the problem of low cranking volts causing the AVIC to lock up during boot as reported by others, for this you need a 12v battery wired in to supplant the AVIC voltage during crank time.
OK so the 528 won't work for me because the acc voltage drops, it doesn't completly cut out. Somone mentioned about wiring a normal relay to the alarm so the radio only gets acc power when the alarm is disarmed. I kind of like this idea because then the radio will turn off if I leave the car running while running into the store. Anybody know what wire I would need to splice into on a viper 5701 to accomplish this?
the orange wire(on the main small gauge harness not the heavy guage harness) on any viper system is the "ground while armed" wire, so any time the alarm is armed it will send out a ground signal, and when you disarm it the ground signal will stop (some systems will keep the wire grounded if remote started until the key take over has been done)
Is this restart interruption a problem with everyone who has a remote start? I was planning on getting a remote starter but dont want to sacrifice my f90bt for it.
OK so the 528 won't work for me because the acc voltage drops, it doesn't completly cut out. Somone mentioned about wiring a normal relay to the alarm so the radio only gets acc power when the alarm is disarmed. I kind of like this idea because then the radio will turn off if I leave the car running while running into the store. Anybody know what wire I would need to splice into on a viper 5701 to accomplish this?
Are you sure you are going to like this feature, because it would be no different, than if you shut off your car and locked it. When you come back out of the store and deactivate yoour alarm, your AVIC will have to reboot with or without the car running. If you just want to turn off the radio portion, maybe you want to think about muting it.
Is this restart interruption a problem with everyone who has a remote start? I was planning on getting a remote starter but dont want to sacrifice my f90bt for it.
i have zero problems with my avic and my RS for the year that i have had them both, every car is slightly different however and some situations might need to be worked around as listed in this thread
OK so the 528 won't work for me because the acc voltage drops, it doesn't completly cut out. Somone mentioned about wiring a normal relay to the alarm so the radio only gets acc power when the alarm is disarmed. I kind of like this idea because then the radio will turn off if I leave the car running while running into the store. Anybody know what wire I would need to splice into on a viper 5701 to accomplish this?
Are you sure you are going to like this feature, because it would be no different, than if you shut off your car and locked it. When you come back out of the store and deactivate yoour alarm, your AVIC will have to reboot with or without the car running. If you just want to turn off the radio portion, maybe you want to think about muting it.
true this option will be very inconvient since the AVIC will not start booting up until your already in the car, and will reboot every time you lock the car and go in anywhere while the car is running, i only recomended this option as a possible solution to a remote starter problem, as it will fix the problem, it will make the system more inconvient to use.
hy,i'm new here,but i thinnk i can help.
u may had fixed the probleme wth you,re tundra,but if u haven't thiss may help
all you have to do is disconnect the wire from the alarm that powers up the acc,it should be a purple wire coming from the alarm brain, everything else will work just fine because in toyotas this wire only turns on the radio.
wiring the avic to the alarm should't be much of an inconvence because I usually unlock the car as we are walking up to it. The music starts playing after 30 seconds and is fully booted after a minute. Which terminal on the relay do I wire to the ground when disarmed wire?
run the ACC wire from the car to terminals 86 and 30, connect the "ground while armed" wire to terminal 85, connect terminal 87A to the AVIC's ACC wire, and then insulate terminal 87.
having 86 connected to ACC will keep the relay from energizing until the car is started and not all the time when the alarm is armed, therefore reducing the amount of power the car is using while armed and parked (not that its a big draw, but if the car ever sits for a while, the less the better)
if there is a diod on the relay, the coil polarity (85 & 86) may be reversed
if your alarm has AUX outputs and 98% do(for example mine has 2) you could use one to power the relay to turn on the AVIC. For example mine has the ability to provide a latched output(it will stay on) for up to 90 seconds. So i've used mine to power up my AVIC before i get into the car. I can also keep it running while cranking the vehicle using the same output
Is this restart interruption a problem with everyone who has a remote start? I was planning on getting a remote starter but dont want to sacrifice my f90bt for it.
i have zero problems with my avic and my RS for the year that i have had them both, every car is slightly different however and some situations might need to be worked around as listed in this thread
same here. I have the f700bt and a Aviator with factory remote start. No problems since install.
I wired mine last weekend to the alarm ground when armed wire like explained above, ever since then I've had no problem with my avic. I no longer need to enter the password everytime I remote start the car.
I have a compustar remote starter/alarm on my diesel truck. I don't have any issues with freezing bootups when remote starting. Alot of technical info in this thread!