I had a problem with my battery again, on Wednesday (two days ago) I drove down and up the other side of my drive, turned around and came back behind my house, and everything was OK until I hopped out, where I accidentally stood on the accelerator until it hit the limiter once, then the fuel needle dropped to 0 and the speed and fuel gauge needles started vibrating and shaking then went back to normal, I have put a new battery on my car now, (Varta B18 whereas my old one was from Motorcraft) and at low revs or even idle, the battery light is on, and even slight revs, maybe about 1500 makes the needles vibrate again, is it a battery/wiring problem or could it be alternator related? If its a battery, I'll see if I can get another Motorcraft battery like the one removed, if its alternator problems, then I'll have to get the garage to sort something out

Varta B18 whereas my old one was from Motorcraft

The B18 s a relatively low capacity battery. It will be suitable for some vehicles but not others.

...where I accidentally stood on the accelerator until it hit the limiter once, then the fuel needle dropped to 0 and the speed and fuel gauge needles started vibrating and shaking then went back to normal...

Well, that sounds like a reset and that should only happen if the battery voltage goes out of range. The likeliest explanations for that are either an alternator fault or a wiring fault (alternator charge circuit wiring or wiring and connections at the battery). Any chance of getting voltmeter readings off charge and when the battery should be charging?

The B18 s a relatively low capacity battery. It will be suitable for some vehicles but not others.

Well, that sounds like a reset and that should only happen if the battery voltage goes out of range. The likeliest explanations for that are either an alternator fault or a wiring fault (alternator charge circuit wiring or wiring and connections at the battery). Any chance of getting voltmeter readings off charge and when the battery should be charging?

Well, after I leave it running for about 30 mins or so, the battery has no problems afterwards, but if I revved it high again, of would probably do it again and go flat overnight then if I recharged it, it would start then after when I turn it straight off, it would probably be read again, so leaving it run for 30 mins stops it going flat when its turned off, I used this draper tester, which said the battery was fine, and when started, the other three lights came on, the top red one said 14V (High), so the regulator might have gone, I still done get how it could go flat with everything turned off (yes, lights, radio and everyone else off too)