# How to calculate the number of cycles my linear actuators can run

I've recently bought a set of linear actuators for a personal project of mine and I was wondering how many times can this linear actuator run before my battery runs out. (My battery is rated 12V, 8000mAh)

Here is the link for the linear actuators ive purchase, its rated power is 20W. Is it possible to calculate the number of times it will take to drain my battery?

• A proper data sheet for the actuators and the average duration for each actuator cycle is required. – Andy aka Mar 31 '20 at 12:58

According to the description

Rated power: 20W, maximum 30W. Push bar Each side contains a travel limit switch. When the telescopic bar runs to the top or to the top, it will automatically disconnect the electricity. The motor will not idle. Cut off the power, it can be stop at any position, with self-locking function.

if the motor is operational at all times, it means:

$$t\approx \frac{12V\cdot 8Ah}{(20W ... 30W)}=4.8h...3.2h$$

However, this assumes that during the whole battery level, you are going to provide a clean and stable 12V, which probably is not the case (Output voltage will drop eventually). Based on that, you can say that the above calculated value will be slightly lower.

This question has already addressed how to design a driver for a linear actuator. You can refer to it and along with some additional logic, design a small circuit to turn on the actuator only when you need it.

• This is the ideal conditions isnt it? So if the motor is in idle state at most times, does that mean it will be able to last a long time? – Axois Mar 31 '20 at 13:08
• @Axois yes, if you disable or cut-off the power, the battery will last longer. – vtolentino Mar 31 '20 at 13:10

keep the input 12 volt constant. Use a 12volts - 60 watts DC adapter. The speed is provided in the manual. It's 20 mm/sec. I've used these many times. Speed doesn't vary if the input voltage is constant. But use feedback. The current will drop as soon as it reaches maximum or minimum length. You will hear a sound as soon as it reaches the maximum or minimum position. It's due to the auto shut down process of the motor. And so current will drop drastically.

If you use a battery, use a buck-boost regulator.

• Thanks for the answer, but i feel this is more of a comment than an answer, thanks though! – Axois Apr 4 '20 at 3:10