Newbie Here - What Can I Run With This Setup?

[DenverGuy]

I live in Colorado. I have a detached 2-car garage that I share with my neighbor. Plenty of sun and no trees. We found out that she pays for the electric use for both sides, so I have just installed a solar system for my side. Here is what it's made up of: One 100W solar panel, 100AH battery, 1500W inverter.
The purpose is for the garage door opener an a few lights. There are three AC outlets on the inverter, and I thought it would be fun to run a shop vac, leaf blower, etc., from them. Three questions:
How do you calculate what devices can be run? Is it only watts? If so, do I base it on the battery, the inverter, or both? Also, if I try to run something that draws too much, will it blow an inline fuse?
Thanks.

[SunEagle]

A basic way to understand what a load will consume is by multiplying the wattage rating by the hours expected. Watt hours totals will help determine the battery size. A better way to know what you consume would be to use a Kill A Watt meter which will track the actual usage for a 115V load over any period of time you desire.

And yes if your load draws more amps then your system can handle it could blow a fuse or worse melt a wire.

Finally a 100Ah 12V battery usually wants about 10 amps of charging. I do not know of any 100watt panels that can delivery that amount of amps.

[bcroe]

I live in Colorado. I have a detached 2-car garage that I share with my neighbor. Plenty of sun and no trees. We found out that she pays for the electric use for both sides, so I have just installed a solar system for my side. Here is what it's made up of: One 100W solar panel, 100AH battery, 1500W inverter.
The purpose is for the garage door opener an a few lights. There are three AC outlets on the inverter, and I thought it would be fun to run a shop vac, leaf blower, etc., from them.

I would imagine, unless you have a serious shop out there, your electric use amounts
to a few pennies a year. Even that could be scaled way down with LED lights. The door
opener electricity is such a small duty cycle as to be lost in the noise. I also have a lot
of outdoor motion detector lights, same for them.

Others more experienced with batteries, will be saying you are grossly under paneled to
maintain a battery. That inverter standby current 24/365 is gong to wipe out your battery,
but if you turn it off, the door opener will not work. Likely a battery powered door opener
and some LED lights could be set up with adequate panels to get your garage off grid.
Some battery powered tools could also be charged or operated.

The practical solution usually is just run house power out to the building. Really
the cost of stand alone solar would probably exceed just paying the neighbor for
a century of her power. good luck, Bruce Roe

[oregon_phil]

I live in Colorado. I have a detached 2-car garage that I share with my neighbor. Plenty of sun and no trees. We found out that she pays for the electric use for both sides, so I have just installed a solar system for my side. Here is what it's made up of: One 100W solar panel, 100AH battery, 1500W inverter.
The purpose is for the garage door opener an a few lights. There are three AC outlets on the inverter, and I thought it would be fun to run a shop vac, leaf blower, etc., from them. Three questions:
How do you calculate what devices can be run? Is it only watts? If so, do I base it on the battery, the inverter, or both? Also, if I try to run something that draws too much, will it blow an inline fuse?
Thanks.

In your other post, said you wanted to run a garage door opener (that had a backup battery) a couple of times a day and a couple of LED lights. If that is truly your goal, then I would like to offer an alternate solution. 1) Find out if the garage door opener backup battery is 12 VDC. 2) If yes, then I would unplug it from the wall, remove the ~5ah battery from the garage door opener and run my own wiring from the garage door opener battery connector to the 12VDC 100AH battery. 3) You can run your 100 watt solar panel through some battery maintainer to the battery.

I have a liftmaster garage door opener with battery backup. It works fine on battery backup only at half speed.

This takes the inverter standby load out of the equation, but also eliminates use of any AC appliances.

[chrisski]

You already have the system installed I take it. So, go to PV watts and see how much solar you get per day. Can be 1.5 hours in winter and 5 hours on the summer. All depends on where your at in the world latitude wise, and the weather, and the time of year.

THat’s how much power you will make.

Please keep in mind, your inverter likely burns 1 amp per hour idling. Your solar panel probably maxes out at five or six amps. But keep in mind, in the winter, there’s 14 to 16 hours where I live between useful sunshine. So that’s 14 or 16 amps negative. If I’m in an area that makes 1.5 hours of sunshine, my battery dies a slow death every day. I need at least 2.5 hours to 3 hours just to keep the inverter on 24 hours.

A couple ways this can go, is some sort of low voltage cutoff. This means you get out and open the garage door when the batteries are low. Or, you can Add more panels so that your batteries get charged properly. Bad thing is your lead acid battery may like being charged at around 10 amps per hour, so now that makes the calculations a bit harder. Two panels will exceed that, so there has to be a current limiter on the SCC. My MPPT has a max amp output. My PWM SCC does not.

While your doing that, It’d be worth a call to Home Depot to see what a trencher rents for, or if you’re up to it, a pick and shovel, or just call an electrician to find how much it would take to run a 15 amp circuit to the garage. I do like the idea of paying for a centuries worth of electricity to your neighbor.

You can also just run the system you have and hope for he best. Maybe it will work. Is it really all that bad if you kill your 100 AH battery? If it dies you know you need to do something different, if it doesn’t die, it means you’re fine.

[DenverGuy]

Thanks for your suggestions. I will read them over. The only thing that concerns me is that I hear the fan in the inverter starting up every 25 seconds and immediately stopping. Very strange. I wrote to the company. I should add that the opener draws 100-120 watts when it opens. Not much.

I found out that I can turn the inverter off when not needed and the battery will still charge. That will save some power,