one of my ESP-GPS keeps switching off after being charged all night, set on beach go out and says go faster then 1.9 knots
i am doing over 20 knots it still says go faster then 1.9 knots, i switch it off start again, same thing happens
my other one after being charged all night says 100% but drops back to 50% within 10 minutes without being swiched on

Some questions :
Did the units ever worked as expected ?
Are the units hermetically sealed ? If not, can you replace parts (reed switch, battery, gps module...) ?
Which SW-version are you running ?
When connected to your home wifi network, do you have access to the webserver and configuration ?
Greetings, Jan.