"industrial" digital 24/7 timer

[Mad Scientist]

There are a fair few of these on the market already however there are 2 main problems that i have with them which has prompted me to have a crack at designing one. the first problem is the reliability they tend to not like handling higher currents even though its well within its rating. ive had one mysteriously stay on no matter what the setting which caused havoc on the water pump system it was controlling. the second problem is very very limited settings the best one ive found has only 14 on/off times. the main use for this timer would be hydroponics applications so current spikes from multiple ballasts switching on (15mins of 2-3 amps then 1.75-2 amps running per ballast with a max of 10 amps but prefferably 30) and at least 24 on/off times at increments of 1 minute (can switch something on for 1 minute per hour throughout the day) hopefully i could just rip apart the current timers i have and modify them to be at least more reliable and handle more current i could live with the 14 on/off settings but i havent made a circuit for 5 years now and need a little help. the circuit runs on two AAA batteries (which is a pain also would be good if it made its own DC and just used those for backup) and round here power normally is 240V 10A but i have 30A lines installed.

HPM 7-Day Digital Timer D817/2 (M6598) | Dick Smith Online Store
the above timer is the one i use and the best they get and from talking to a fair few hydroponic shop owners they arent too happy with them either.

 

[mneary]

The product I see looks like it has a TRIAC output which often does not like an inductive or electronic ballast. I have had excellent results by placing a small (at 120V I use a 15W) incandescent bulb in parallel with the nasty load. The incandescent lamp provides the necessary starting and holding current to keep the TRIAC happy throughout the AC cycle.