This is my experience.
I have several GL-MIFI’s. There are 2 versions. Version 1 has a 2 pin internal battery and can power an external drive and charge a phone. Version 2 has a 6 pin battery and is only capable of giving a few hundred milliamps before it trips. It can only power a USB stick. It will not power an external hard drive and will only charge a phone if the phone is switched off. And even then the charge will take a long time.