[MTCB Android Head Units Q&A] kaween:
Yeah, I aree : the ELK-960 is a nice piece of kit.

Somewhat related to this issue :

When I checked the behavior of the JY unit on my testbench, I noted a couple of very non-typical electronic characteristics for this type of unit which may have an influence on anyone having "boot problems during crank" ect ect.

Short version : my JY makes life a lot easier compared to all other 2din headunits I've toyed with so far.

Long versions :

When replacing a stock radio with a JY (this may be true for all of these RK units, but I only had my own JY to torture like this) some people will complain about their units rebooting during the crank-process of their cars.

So, it's safe to asume that if you're having this issue, the unit does loose power during crank, resulting in a temporary shutdown.

In my experience when dealing with this issue in the past, there have been 2 major reasons for this behavior :

1) car battery power goes below critical treshhold of the unit's "stable voltage" level to ensure operation during crank. Do not be fooled : even on a good battery this will be a problem depending on your headunit. A Pioneer AVIC for example has a treshhold somewhere like 11.5V . In less-then-ideal batteryconditions (short start/stop cycles, very cold weather), your battery power WILL go below that value, by a big margin even. I've seen and measured certain cars (Honda for example) where the crank of the engine did cause a spike of below 9V (!) for a couple of miliseconds during the crank process on a new battery.

2) some cars will use the ignition mechanics to electrically disconnect every non-essential power path to ensure full battery power is available during the engine start process. On such cars, the factory used headunits come with a "keep alive" internal circuit to bridge short periods of power loss. Of course, if you use an aftermarket unit, that internal circuit will not be there.

Anyhow, up until now, I used a small, dedicated secondary power circuit with its own battery to deal with these issues and so far, ALL head units I've ever used were affected by both points 1 and 2. So even if I hooked up the headunit "badly" and straight to the battery, the negative spike in the cars battery level was enough to reboot any headunit connected to it. So when I installed the JY, I took over the existing solution, especially as the shutdown-delay didn't exist for my specific unit at that time.

Today, I've tried to exclude the secondary battery circuit based upon the measurements I did and indeed ... the JY does work without the secondary battery support system during crank. I still have the Powertamer which essentially does what the ELK960 does, but the quite extraordinary behavior of the JY makes the 2nd battery redundant.

What I mean with this is best illustrated by this :

Pioneer AVIC : shuts down when power goes below 11.5V -for what ever reason-. Major pain in the *ss.

S150 : when power goes below 9.5V, a shutdown is initiated. In plain English : even when connected directly to the main battery, the unit will shut down 2 out of 3 cranks.

AN21-U : once below 9.0V, same behavior as with the S150.

JY unit : this one behaves ODD or sturborn if you will. It will continue to play music till about 9.2V But when the voltage drops even further, it won't simply shut down : first it stops soundoutput (at 9.2V), indepenant of line or speaker output -the fact it doesn't make a difference says something about the units clumsy hardware design-, but the android part keeps functioning without any issues.

It's only when the voltage breaks down to a terrifying 6.9V the JY will shut down, but even then it will not loose memory data (like for example radio presets like you'd have when you cut the constant Vbat+ completly).

So basically, the JY will -in worst case- cut the sound of the unit during crank, but providing you don't have a car that has the "complete power cut during crank" in point 2, it should not reboot during crank.

An odd little beast this is.

[MENTION=255279]Reptile-X[/MENTION] : Always nice to see a clean and propper installation. Nice work !