A 650mah mod is likely not going to get many of us through the day, I have a 1100mah one, also a no-name one, it's a passthrough ego device. One that can be plugged into a computer & even if the battery is spent, will work.
Until I got my Astro clone this past January, that was my only vaping device for about 2 months. It doesn't have the charge hold time that it once did, nor quite the hitting power, but it still lasts through the day.
The better ego devices will have a charger that plugs into where the tank screws in & it's not advised to use higher powered chargers on them, the warranty if any, will be gone. I'm getting a new 1300mah ego (I believe it's evod twist) next month, that's a brand name & won't be a passthrough. Many of 650mah devices are sold as starter kits, some over the counter in 2 packs at convenience stores & some tobacco outlets.
It's best to purchase one from someone that you can trust, if possible, develop a relationship with a local distributor whose primary business isn't in selling tobacco products. More & more vape shops are opening most everywhere, where legal.
Cat