It is ok to recharge my Thelema Solo DNA 100C via Usb?

[FrancoS64]

Hi to all, first post here. I've just purchased a Thelema Solo DNA 100C, with a 21700 battery (4000 mAh) without an external batterry charger. It is ok to recharge my battery only via Usb? Someone tells me that could be some problems: specifically because the board hasn't a circut that cut off power when battery is fully charged, and also because it could be overheated.

Is that correct? It is better that I buy an external charger?

[Wayneo]

Yes, it is OK to use the USB to charge, especially with a single battery device. I charge mine at 1.5A, not 3A. 

In the grand scheme, using an external charger let's you see if you have any leaking into the battery area, and allows you to easily charge a spare battery.