I have sold quite a few of the a100li and they have trouble just like everthing else in the world
It's not often that the charger is defective, but most times its lightning, rea coop surge, components getting wet( in all weather case ???)
Surge ptotection on the electric plug in on rural electric line is a big help
Ground it just as the instruction say
Try to keep them out of direct rain
Lightning/Surge Protection
Lightning is one of the main causes of fence controller failure. If a storm is forecast, disconnect your fence controller from the fence in advance, and unplug if it is an AC-powered unit. Using a Zareba Cut-Off Switch (part no. COS1) is a simple way to quickly disconnect your fence controller. If you are in an area with frequent electrical storms, be sure to keep a spare fence controller for backup.
Storm Guard (part no. 01667-92) –(comes with a100li)
Helps protect fence controllers rated at 1 joule of energy output or greater from lightning strikes.
Spring Gate Kit (part no. SG1) – Spring coil helps to dissipate lightning surges.
AC Surge Suppressor (part no. 1549-96) – Protects AC-powered fence controllers from power surges up to 6,000 volts.
Tip: While lightning protection devices can reduce damage by up to 75%, no device provides 100% protection from lightning .