The Okin Battery Pack 1800 is designed for an inline back up. This means it connects between the power supply now and the chair. Power goes out, you wouldn’t even know it, even with the LED and USB connected. This battery pack is still the best option if you’r planning on using it a s standalone unit and would last up to 3 months before charging is required with NO LED.
Both are not suitable IF you’r planning on using them as  a standalone power source.
No battery is going to last long when the LED is glowing 24/7. Same as leaving your car lights on! You’d be charging it daily.