Does anyone know if the Toslon 640 fishfinder has an inbuilt battery or does it need an external power supply?

In reply to Post #1
Both but if you put aa bats in they last 2 mins so we have small lithium batteries you do mean the handset?

In reply to Post #1
I have the 640. It can run off a set of AA batteries (duracell last at least a week) or you can get an external lithium ion battery that plugs into a port on the case

In reply to Post #1
No inbuilt battery but a battery unit for 8 AAs at back(removable obvs)

As said you can buy external lithium pack too which will last ages

In reply to Post #4
Thanks everyone. I will make an external power supply using an Sla battery