@sailorman - Thought I'd get the 78mm ones. They don't say what mah they are but I know it isn't much. He doesn't want anything big and he doesn't want to push a button so I thought...six? I'm trying to keep this as simple as possible
I'll also get a USB chargers for the car... I just want him to be able to walk out of the house and not have to think about it. He tried this a few years ago and found the whole thing annoying.
Those 78mm "mega" batteries are 380mah. That's huge capacity for a mini. Each one should last him a good 3 hours at least. Six would be kind of overkill, IMO. That's how many little 180mah 510 Joye batteries I needed when I started. And I smoked 3 packs a day.
I'd say 3 or maybe 4 would be plenty. Even if he just rotated them, that's 1520mah altogether.
The thing about the Case is that he can just walk out of the house with it like a pack of smokes. It holds 2 batteries and 4 cartridges. One is charging at any one time. If he had on in his hand and two in the case, he'd be set for at least a day before he needed to charge the case back up.
I'd get an adapter to use in the car for the case. You can charge the case and the battery inside at the same time. He'd just plug the case, with a couple volt megas in it, into the car adapter.
It doesn't get any simpler than that.
The other thing is, if he has limited numbers of ports, he'd only be able to charge a certain number of them anyway because of the current draw on the USB.
I say get the case. It keeps everything together and he won't have to keep track of a bunch of chargers and loose batteries. One of the kits includes the mega case and adapters for the wall and maybe the car. Then he won't have to use a USB port at all. Get that and one or two extra batteries and he'll be set. Spend the extra money on cartridges.