I just received my military style battery from Bren-Tronics for the W1000. It's on the charger as I type. I also picked up the MaximalPower Li-ion 9v batteries and chargers off eBay and they're on chargers too. I'm thinking the 9v pack will be my backup. Like TLM said above, these rechargeable batteries are light.
Smitty
Smitty