Am wanting to hook up a Solar panel to a car battery to open a roller door at the moment am using a extension lead, now am looking at a system on ebay .
eBay item number:292369104640
and pairing it with this inverter
eBay item number:253655282304
will this work what size battery should i get
Thanks for any advice Jim.

I'm keen what someone else has to say as I want to do something similar.

It would depend of course on frequency of use. I would think a 12Ah battery would be enough. The only thing I would question is the ability for the inverter to draw the required power for the inverter to work properly. What current is it drawing and your battery needs to support that. Wouldn't mind others opinion.

Jim the easiest way to work out your requirements is to work backwards from the door motor, work in watts as this is the easiest to convert, A=W÷V therefore W=A×V so if your motor draws 10A @ 240v this is 2400w, 2400÷12=200 therefore a 10A 240 volt motor will draw 200A @ 12v plus current/power losses through an inverter (hope your still following ).

Once you have worked out you motor requirements it comes down to the amount of use, workout your general use then double it. If i was setting something like this up i would most likely go for a battery similar to what you would install into a 4x4, the inverters are rated at a duty cycle similar to a welder but generally displayed as 100% and surge eg 1000w with 2000w max, the 1000w is the 100% duty cycle rate of the inverter.

The solar power again is measured by you calculated usage, remembering that it only produces it's rated power @25°c, so a 50w panel will produce 4A ph for every hour of daylight over 25°c, just a note, solar panels require (usually supplied) a diode installed to stop the panel draing the battery at night.

Hope i haven't over explained it it is very simple maybe someone else on here might explain it better lol at any rate im only a phone call away