jump starter battery

Why do they lose the codes / learnt settings when the power is removed? A I2C eeprom costs next to nothing and will store data indefinitely without power.

Radio no longer works if it gets stolen?

Because it's only the fine-tuning data that is stored in volatile memory, and that changes frequently each time the engine is started.

An eeprom would not withstand anything like the number writes that are made.

As an aside, a certain range of Rovers with Honda engines had all of their data in volatile memory. A completely flat battery, or a disconnection for maintenance, would result in a non-starting car until it had the base settings restored from a dealer's computer.

Now that was daft!

Chris

Wouldn't you *want* a radio to lose its codes when disconnected, to discourage theft? Otherwise what's the point of having to enter a code to make it work?

Yes its a mode that the average man in the street can't access though, most require direct access to the ECU at dealership level,

They don?t.

And that is why they don?t. Nothing happened when I changed the battery in my car, I only had to enter the code into the radio again because they are designed like that to discourage thieves.

The Astra H post 2006 MY doesn't have a radio code. Nothing written in the car pass on my 59-plate, just a printed radio type, a forward slash and a space for the code but left blank.

Does anyone steal car radios these days, or even your CD collection ?. Sat navs and in-car cameras are more saleable now I suspect.

When the alarm flattened my car battery, it required dealer attention to get the damned thing going again.

That's because security is provided by means of coding the radio to the ECU and possibly other bits of electronics.

All fine unless the radio needs replacing.

Well, I don't. ;-)

Chris

So that if nicked, they don't work

On a couple of my vehicles the cigar lighter is only powered with the ignition on, not in the accessory position. Agree with your other points.

Agree completely, I did the same in my "economy motoring" days. These days I don't *expect* to need to jump start my own vehicles, other than the Suzuki Carry van which has a tiny battery and no "lights" warning. Flattened that in the Wickes car park the other day. (I bought a warning kit for it, but the dog ate it).

But I do use my Li-Ions for other things. Just thought it was worth sharing the experience. They are so small and light they will rest on top of the air filter while jumping. I used to find with my larger one with relatively short leads that it was often difficult to manhandle it into a suitable position, especially if single handed.

Why do radios have codes at all, these days?

Many cars now have integrated sound systems. There's no DIN unit in the dash to easily pull, it's a multi-hour removal job to rip the dash apart to get at it. And most DIN units aren't worth nicking: anything that sets them apart (mega-amplifier with 99+9 surround sound) will be an extra box in the boot. Who would buy a nicked dash unit, when you can just get one from Argos for a few quid?

Maybe it's different in other countries, but seems to me the code should be an optional feature like on a phone - I suspect the pain caused by missing radio codes is much more than the pain caused by stolen radios.

Theo

That was my point - but I then realised that the comment also applied to the other functions. Those indeed should be non-volatile,

You want a radio that will only work in the car its fitted to. It needs to have a key exchange with the car so you can only pair it if you have the correct code for the car and the radio.

My aftermarket Blaupunkt radio takes a standard memory card, by hinging down the front plate. Under normal use you can record to this - handy if listening to a play on R4 etc - or use it for MP3s, etc. But it also takes the individual key card for the radio - needed to get it working if totally powered down.

No I don't, thank you.

Chris

Very loud speakers aside, a radio isn't going to work in a car it isn't fitted to :-)

No. I had the drive to my alternator fail, but it was still going round enough to prevent the warning light coming on. When power ran out I pulled into an emergency layby, phoned for help and got the van that arrived while I was still on the phone and had been sent for the other car in the same layby, also with alternator failure!