Battery running flat even though disconnected at positive terminal, any ideas?

[Jac000001]

i have a 51 plate 1.1 saxo desire
and it seems to be eating batteries, ive had 3 brand new batteries in, in the last year and a half, and every time i get out of the car i disconnect the battery because it runs flat in around 14 hours if i leave it connected, but even when i take the positive terminal off as soon as i get out of the car in a couple of weeks (even when driven every day for at least 20mins) the battery is dead again. but the battery seems to be charging while in use, as i had a multimeter on it when running and i think it said 14V (might be wrong but it was definitely a healthy number) and when i stop the car and try to start it straight away again, it turns over very quickly like a fully charged battery, so then i disconnect it, and magicly it manages to run down :S
any help much appreciated.

[outrage_uk]

Needs to be posted in the > Saxo Problems & Queries (http://www.saxperience.com/forum/forumdisplay.php?f=13) > Forum...

Anyway, I think the problem lies with your alternater, just because it reads 14v with a multimeter at idle, doesn't mean it will supply enough charging current all the time. Your best bet would be to try testing it on a long drive with something like this; Draper Battery Charge Condition Analyser (http://www.autosave-scotland.co.uk/product/Battery_Charge_Condition_Analyser_2752_324_0_0.htm l) - see if voltage drops when your out and about. Also check the condition of the alternator belt. When you say you have had 3 new batteries, do you mean branded ones such as Bosch, Lucas, Varta... or are you using something like Halfords own brand? I find these to be quite weak and wont handle a full discharge very well.

[Tontsy]

Bad earth somewhere can still drain a battery.