That's strange, the internal battery should only come into play when the unit is unplugged so it keeps its settings. Sounds like a software issue. You could try contacting the place you bought it from and see if they're willing to help.
Or try contacting Renee at evergrow and let her know your issue, she may be able to help
Renee Chen:
sales15@evergrowlighting.com
Skype:evergrow-renee
WhatsApp: +8613509681786
www.evergrowlighting.com
Tel: +86-755-23212781
Good luck
