Weak battery?

[Mr.Tom]

I've just upgraded from an Esc Escort to a GTi Mk3 2.0. When I start the engine with the radio on, it will turn the radio of for a second. I didn't get this with the Escort, so know it is not the radio doing it. Do I need a higher rated battery, or is it a "feature" of the car that the power is cut to everything but the starter?
Pretty sure the lights dim a little as well on starting.
Head unit is a JVC av-x2 if that helps.

If I do need an upgrade, what is the best battery for the money (of which I have little currently :/ )

Cheers.

[gtigolfthree]

Hi, welcome to the site, I wouldnt worry about the battery as long as the car is starting. It is perfectly normal for the radio to fade and the lights to dim while starting as the starter motor uses so much electricity.

[rubjonny]

strictly speaking it shouldnt do it as the radio live and key in ignition live should both still be on while the engine is cranking.  But as above its probably just that the starter drains a bit too much current for the switch to maintain enough power at the accessory live to keep the stereo on.
I found on my MK2 that it would sometimes do this, but not all the time!  Bit random.

[gtigolfthree]

Yes the battery voltage drops to around 9v when starting, some radios can handle that and some cant.

[Adam]

Mine does that, so does Shadys....both MK3s so wouldn't worry about it.

[th3_f15t]

Again, I have a Mk 2 with a Sony Xplode head unit and that turns off when I start the engine up.

[Mr.Tom]

Yeah, there was a Sony Xplod in there when I got it. That also did it.
Ah well, I guess I shall have to live with it then. Cheers.

[Wayne]

That is about normal, as starting a car takes a lot out of a battery.

[Mr.Tom]

I kept the battery from the Escort. Will see if it is compatible.