It's not really heavy. I am using a werker 6V 1.3Ah battery. It's only about 9 ozs and smaller than the router.
I have been testing it for the lat 4 hours and it hasn't put much of a dent in the charge. Best of all it's very inexpensive and rechargeable. For the price of one Trent 11000 I can buy 10 of these and a charger. Perfect if your worried about the urban assault mod being taken.
Depending on how long this one lasts I will go for the smaller one and report on it's run time as well.
The model I am currently testing is wka6-1.3f
UPDATE: I started powering an ALFA at 4:00PM and the Wireless radio shut off sometime between 1:30-3:30AM. It looks like the battery lasted about 9 or so hours. (that is without moving my clocks ahead, so it it 9 hours elapsed time).
After I recharge I am going to put it on my pineapple while it is running in it's normal forwarding environment and see how long it can maintain on battery power. Still not too bad for $8-$10 and smaller then the router itself.
I'll pick up some other capacities tomorrow(today) and see how they do.
Regards,
Cat