Hi this is continuation of "Re: Rhapsody/Symphony/Navi DX switched 12V current?" thread. I posted under a new topic to have the fix of the problem easily found for anyone else having that problem.

I'm taking my stereo out of my SUPERB tomorrow so I'll measure the current from the SUPERB to the stereo.

Well Bluefox, I am a little disappointed that you forgot to post the current value

Though it turned out that the value was not needed. I pulled out the radio last weekend and it does not have the "ignition sense" line connected at all - basically it gets orders from the ECU via CANbus.

So in summary, my problem with CD changer losing track position when the ignition is cycled remains. Solution - do not cycle ignition more rapidly than ~5sec between on and off. I can live with that, in fact I think it is better for the car not to cycle ignition too quickly.

The other problem of stereo losing CD number, track, and track position has been completely cured by adding a secondary battery, Yuasa NP0.8-12 (, 0.8Ah, 12V, 12A max)) It is a long life sealed lead acid type and quite safe to use inside car, it is even IATA certified.

Attached is the diagram of how to connect it (for future use )

The Schottky diodes I used are 3x 90SQ045 9A Schottkys connected in parallel. I used three so that they do not heat up so much, but even a single one is able to handle the max current of this unit (Rhapsody has 10A fuse). Basically any low voltage drop (Schottky) dode or diodes will do just fine.

The battery is so small it fits behind the radio, you can also put it on either side of the unit, behind the fascia. I fixed it with rubber ties.

So far (3 weeks+ now) the unit did not lose the track, even when starting up from a drained battery.

Hope it helps anyone with the same problem.

Cost of the mod - about stlg15 total and 30min time.

Original problem description:

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mentioned earlier that I have this annoying problem of CD changer "forgetting" track position, track number and CD number when the car is started and also when ignition key is quickly cycled. (The changer is actually the Solisto MP3 unit in my case).

Turned out to be 2 problems:

1. the constant 12V falls to a low value during starting and this resets the unit losing CD number, track number and track position. It needs diode isolation and battery backup (or a decent and always fully charged battery in the engine bay).

I solved this by putting in a Yuasa NP0.8-12 battery as backup and a Schottky diode to isolate the unit/battery from the car's installation when the voltage falls during startup.

2. The Rhapsody unit does not like the switched (ignition) 12V to be cycled quickly and also loses memory (usually just the track position, but not the track number / CD number) . This problem is not easily solvable, best solution is to avoid cycling ignition so much

Since I had this problem also in Octavia, with 2 different Blaupunkt units (CD only and CD/MP3), perhaps it'll help other people to know how to deal with it.

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Hi this is continuation of "Re: Rhapsody/Symphony/Navi DX switched 12V current?" thread. I posted under a new topic to have the fix of the problem easily found for anyone else having that problem.

Well Bluefox, I am a little disappointed that you forgot to post the current value

Hands up to that I'm afraid, I'm really sorry :(:(:(

It was a little more hectic than I'd planned when I chopped her in and I didn't have time to measure the current. Clearly I've not got the Superb any more either :(

It was only when I saw this that I remembered I'd forgotten to say... sorry dude.

Thanks for posting the fix

What made you decide to go for the battery option instead of a capacitor?

Basically, I worked out that I needed at least 1F capacitor, which would be bigger than the battery and several times more costly. Any you still need the diode to isolate the unit from the rest of the car.

The way I see it, even if this battery loses 98% of its charge capacity, it will still be good enough to keep the stereo going during cranking, so I do not foresse any problems in the next 6-10 years

Edited 1 April, 200917 yr by dieselV6

Basically, I worked out that I needed at least 1F capacitor, which would be bigger than the battery and several times more costly. Any you still need the diode to isolate the unit from the rest of the car.

Also, a 1F capacitior would be bigger than this small 0.8Ah battery.

The way I see it, even if this battery loses 98% of its charge capacity, it will still be good enough to keep the stereo going during cranking, so I do not foresse any problems in the next 6-10 years

Agreed, a 1F cap would be a fair size.

Thanks for clearing it up