Automated Farm Gates Project

[Menicus]

Hello EEVBlog Forum!  This is my first post but I've been a fan of EEVBlog on Youtube for years.  Shout out from Canada!!

I have an interesting little home project I could use some help on to save money.

My Father has a sheep farm with a bunch of gates between fields that he would like to automate to open and close at specific times of the day rather than have to go out and do it himself.  It would also mean better pasture management.  I'm designing a solution for him and it goes like this...

I have a winch motor, one designed to be bolted onto an ATV, truck etc and runs off the 12V starter battery.  Along with a spring, a regular switch and a pair of timers controlling the circuit I can safely open and close the gates at whatever times he wants.  The motor only needs to run for ~15 seconds twice a day ( I calculated 1.5 Wh total per day if I recall correctly, a tiny amount of energy because of the short run times).  I am currently using a lawn tractor battery and a 4-Watt solar panel to power my test setup.  The lawn tractor battery costs ~80 bucks but because the motor runs for such a short amount of time I don't need remotely all the charge stored in the thing.  Canadian Tire sells these 12V 3Ah (30$) general purpose lead acid batteries that would do just fine but they only give a max 0.3A current.  I checked the winch on load and it was drawing 13.5A, not a problem for the lawn tractor battery but the little 3Ah won't cut it. 

My question concerns capacitors.  Is there any way I can use a capacitor in this setup to allow me to use the 30$ 3Ah instead of the 80$ lawn tractor battery.  The solar panel is designed to charge a 12V car battery and it has overcharge protection built in.  Will it safely charge the PBS general purpose battery I have? (links below)

I know a well stocked electronics store with a huge range of capacitor sizes so I can get whichever one I need.  There are a total of 10 gates on the farm that he would like to automate so were talking 500$ in battery savings and the gates are far from each other or any power source.  If an appropriate capacitor is going to cost 50$ or more then I might as well keep the setup I currently have.  I know what a capacitor does but I don't know enough to select one or if this is going to cause problems or damage to the winch.

 These are big, heavy gates btw and there are sometimes going to be sheep (a whole flock) pushing against them so I want to keep the powerful winch in the setup, it needs to be robust and strong.  The sheep arrange themselves in the appropriate places because they are motivated by corn in the evening and grass in the morning so these gates are fine to just open and close themselves at their designated time.


The winch in question:
http://www.canadiantire.ca/en/pdp/tundra-tested-electric-winch-3000lb-12v-0996118p.html#.Vxt7WFUrK70

And the 3Ah battery:
http://www.canadiantire.ca/en/pdp/12-volt-3ah-sla-battery-0102034p.html#.Vxt7KlUrK70

Thank you for your time and knowledge.

- Adam

[Menicus]

 :-DMMI've looked at those driveway gate setups and I'm afraid they are not going to be reliably tough.  They are designed to operate in a safe environment where there is nothing touching or pressing on the gate or getting in the way.  The farm gate setup needs to be able to handle a sheep scratching itself on the gate while it's trying to open and push the sheep out of the way, hence why I need the powerful winch motor.


EDIT:   NVM, it turns out the 0.3A rating was the maximum charging current, not the max current the battery could supply.  Drove up to my dad's Farm today and hooked it up, worked beautifully.  Thanks anyways to those who took the time to read.