700BT loses settings - voltage drop?

[dylanc1]

About half the time I start my car, the 700BT forgets what song (on the SD card) it left off on, and starts at the same song over and over again. It also forgets that I have it set to "random".

 

At first I figured perhaps when the starter is cranking, the constant voltage was dropping low enough that it disrupted the volatile memory in the unit, which would store things like settings and last song played etc. However, my radio presets are never lost, so why would those save but not the other settings? I know that if you disconnect the cars battery you lose the radio presets, so the presets are stored in volatile memory as well. Is it possible they are in different types of memory and have different sensitivities to voltabe drops? Seems a little far fetched...

 

Is it possible it is software related? Its still weird that the problem only occurs about half the time. Any ideas on what to try? Anybody else have this problem? Im really trying to narrow this down scientifically but I cant even narrow down whats causing it the problem. Thanks!

[1loudls]

i thought that the SD would always start over when the unit shuts off then is turned back on

[dylanc1]

nope, about half the time it remembers everything - song it was playing, play settings (random, repeat, etc.) as well as what screen it was on last. Your probably have the same problem as me, just more severe so its 100% of the time.

 

Try this - play a song and then turn the car off. Then turn your car to on ar acc but dont crank the engine. Im willing to bet your unit will go to the screen and the song it was last on. If this is the case, its gotta be a voltage drop issue that happens when all the power goes to the starter

[csviegas]

I am having the exact same issues. When I start the car manually with the key, the SD card resumes from the last song it played. If I start my car using remote start, the SD card starts playing the music from the beginning. I was sitting in my car while turning on the remote start the other day to try to see what was being done differently that could be causing an issue. It seems like my car is putting in more effort when starting when I use remote start. So it may be that the voltage is dropping. Also, the illumi color doest save my custom color when I do a remote start, it goes back to the random color cycle; it will save a factory preset color though. But the color issue only started with firmware 3, it used to be fine on firmware 2.

[dylanc1]

After reading other posts with similar issues to kinda of get an idea of what was going on, I did some more fiddling. What I currently THINK is going on in my car is that when I put the key in and turn it to start, the key passes through 'ACC', through, 'ON' and finally to 'START'. So basically the unit gets power starting when the key is in ACC, which is a few milliseconds before the starter cranks. With most remote starts, this gap is much longer, as the remote start energizes things one by one - including any key bypass modules etc.

 

Anyways, what I think is going on is that the unit does not like the power drop when it is already on, even if its only been on for half a second. I dont think it requires much constant power to retain memory when it is off, but I think when it is booting up and experiences a voltage drop, weird stuff starts happening.

 

**Other posts suggest using a combination of a small rechargeable battery, battery charger, diode, and relay(s) and the idea would be that this setup would supplement the incoming voltage for the few seconds it drops during starter cranking. A capacitor in place of the battery would simplify things but there are arguments against that as well. Another advantage to this is that if you were hanging out in your car (car off) listening to music, then started the car, the stereo would be on the whole time. So you could stop for gas, turn the key to ACC, pump your gas, and restart the car without restarting the stereo.

 

**A simpler idea is to use a timer relay, such as the DEI 528T. Its around $20-30 and the idea is that you can use it to delay the stereo from turning on (until the engine is done cranking). The timer would basically start once it was energized by turning the key. The downside is that 1) for it to help with your extended remote start times you would have to increase the timer setting on the timer relay, and it would make your startup times when you use the key noticeably longer (sucks bc its already long).

 

**A third option for remote start induced problems would be similar to a timer relay, but to use on of the AUX outputs on your remote starter to control a relay. Most alarm systems can be programmed to turn the AUX output on with start etc. This would only work if you could program it to come on after the cranking. A cool plus side would be that you could turn your stereo on and off with your key fob.

 

**One last option is just something I came up with in my head, dont know if what im thinking of exists. What would be convenient would be if there was some kind of relay in which you could set the 'trip' voltage. In other words, maybe something that interrupts the circuit if incoming voltage drops below 10.5V, thus giving you only 0V or 12V and eliminating the situation where the stereo gets under powered and acts screwy

 

These are just my ideas, Im not positive on the problem or the solutions, so if anyone has anything to add, please do!

[1loudls]

oh yea, we covered a lot of that stuff for days in the remote start thread, i was convince why my idea of just a capacitor could have issues and not the best option, Joegr has designed a circuit that uses a small set of batteries, that looked to be the best option so far, sooner or later i will get around to building it but just haven't had the motivation yet.