Sounds like lightning is frying your boards. To much electricity going into the timer at once will cause damage. You will probably want to contact an electrician to install a lightning preventer or surge protector somewhere.

What's the model and is it hardwired or plugged into your outlet? Inside or outside?

First appreciate what your sprinkler system sees, Understand why four legged animals are also killed in storms when lightning is distant.

Lightning is a connection from a cloud maybe five miles to distant earthborne charges. A shortest electrical path is three miles down to earth. And four miles through earth to those charges.

Lightning strikes a tree. Some fifty feet away, a cow dies. Because a best path four miles to those charges is up a cow's hind legs and down its fore legs.

A distant lightning strike would be doing same to your controller. Incoming on wires to sprinkler valves. Outgoing to distant charges via the controller's AC power. In cow and controller, both an incoming and outgoing current path must exist.

Protection of a cow or controller is encircling all incoming paths (legs or wires) to a single point earth ground. For a cow, a buried ground wire encircles the cow. Then a best path is via that wire - not via the cow.

For your controller, every wire in each cable must connect to a same earth ground electrode either directly or via a protector. No, a protector does not do protection. Protector only does what a hardwire would do better. Some wires cannot connect directly to earth. So we do a next best thing - make that connection with a protector. Protector only does what a wire would do better. Then, like the cow, a surge current need not pass harmfully through that controller. Then protection already inside a controller is not overwhelmed.

Your answer starts by discussing how that current is incoming on one cable and outgoing on another cable via a controller. Farmer's cow is protected by discussing why current is incoming on fore legs and outgoing on hind legs. Same logic and solution applies to cow and controller.

Second new XC timer just 4 months old! Every time power is interrupted, it looses it's settings. Some times just the yr, sometimes more. I changed the battery twice. Same. I am not happy with the manual.

Do you have alot of power outages? If so, the timer would be living off of battery power a lot more rather than your power supply, draining the battery. This would be an electrical problem outside of the timer.

If you don't have alot of power outages, I would take it back for return as it could be something internal draining the batteries. Once you return it and hook the new one up, if you are still having the same problem you will know that the timer is not the problem.