Sony Battery Life

Just switched on my new SZ1XP/C which apart from the battery seems a really nice machine. Used it over the weekend and made sure the battery was fully charged. The machine was fully shutdown (not standby or hibernate) for around 48 hours, when I switched it on the battery meter showed 78%.

This machine replaced an S2VP which showed basically the same problem of battery drain. On the S2VP it lost around 20% per 24 hours. I once tested it by removing the battery and storing it separately, after putting it back 48 hours later it showed 97% when the system was booted. Suggesting that the machine even when fully shutdown managed to drain the battery.

My boss has a T1XP/L and I had that for a few days a while back whilst setting it up for him and it showed exactly the same problem. Fully shutdown it still managed to drain the battery.

Does anyone else have any experience of this? I wonder if the battery is really draining, or whether the software that shows the battery charge figure is faulty.

I don't believe that this can be a fault on these specific machines, it must be a more general problem. I'm going to fully charge the batteries on both the S2VP and the SZ1XP tonight and then remove them, replacing them exactly 24 hours later and record the battery figure. Then do the same thing but leave the batteries in the machines the second time. Will post the outcome of those 2 tests, but in the mean time I wonder if anyone else has a similar experience.

I'm not 100% positive but I believe it was plugged in to the mains first, I almost always do it that way. Do you think this would make a difference? I'll maybe try it both ways over the next few days.
I'll also get this software you linked to and see what that says.
Thanks.

OK I put the battery's in and after 24 hours out of the machines, both previously fully charged, the SZ1XP showed 97% and the S2VP showed 90%.
I Will fully charge the batteries again and this time leave them in the machines, will check the drain after 48 hours as I'm out tomorrow.

I used the Notebook Hardware Control program to check the charge and that said 100% as weel as the Windows Power Meter.

As an aside the SZ1XP comes with a 19V charger which is enormous. Absolutely criminal design on a smallish machine designed for portability.

I'm sort of annoyed at the charger. I like to carry my laptop around with me, and for my old Sony one had a Targus mains adaptor with the additional bit to charge both my phone and mp3 player. But for this one you need the 120W supply which Targus for some reason don't sell in the UK, so I'm stuck with the Sony brick, so frustrating to make a nice compact powerful machine with excellent thoughful design, and then supply that hideously oversized power supply.

I've always imagined Targus and Kensington are the same company, their products just seem too similar. The only 120W supply sold in the UK is a DC one for car and aeroplane power, it's not a mains adaptor. I know they sell a 120W mains product in the US, but not in the UK.