Power Options.

All Scitsu's are now Lithium battery power.

Standard Lithium
The tacho uses a user replaceable Lithium battery.

This battery does not need recharging. It will power the tacho all season. You can check its condition just by pressing the built-in battery test button. The tacho needle points to the level of charge in the battery.

Each year just replace by easily removing the back cover and fitting a new one.

These are CR-123 Lithium battery, available from large electrical shops and online cheaply and easily.

(Never try to recharge this type of battery)