I use them and have done for some time,I am in the UK and I use a widely available adapter with the charger.They look pretty good.. pricey but good. Do you have some?
What about the charger (http://cgi.ebay.co.uk/iPowerUS-rechargeable-9-volt-battery-CHARGER_W0QQitemZ260326273799QQcmdZViewItemQQptZUK_ConsumerElectronics_Batteries_SM?hash=item260326273799&_trksid=p3911.c0.m14&_trkparms=72:1683|66:2|65:12|39:1|240:1318) Do you use that one? Is it good? And are you in the UK? (because they offer adapter for use in UK or US.)
They are also the ones supplied with the XSV v-locity hopper.