Solar power to a detached garage for only a garage door opener

SilentP

Time wounds all heels.
I realize that there are posts that address this question, but let's just say that as far as experience and understanding goes, I look up to newbies because their knowledge and experience greatly exceeds mine....That said...

I am aware of DC, battery-backed-up openers that have their own lighting - maybe 1/4 to 1-1/4 hp - whose battery is supposedly able to cycle 50 times without a charging source. What I fail to find info about is what size panel it required to run (when sunny) and charge (when not) such a simple setup. And is it that simple? Should I have an extra battery? I'm in southeast Michigan, do I need this extra battery in a ventilated, insulated box? Why?

Is it really just simply attaching a 100watt panel to the southern face of the front of my garage, running the line inside, getting the opener installed, and hardwiring it?

I look at plans and websites and see 'inverter," followed by, "cheap is bad," or "only have a professional electrician install an inverter."

I just know that I ain't paying $4500 to get power to my garage.

Thank you in advance! Safe Travels.
 

FilterGuy

What, me worry?
I am aware of DC, battery-backed-up openers that have their own lighting - maybe 1/4 to 1-1/4 hp
Could you provide a link to one of the DC openers you are looking at? It would help us answer your questions on how to hook things up.


As far as sizing goes..... let's do some math.

1.25HP is 932W. Let's round up to 950W.
Lets assume it takes 15 seconds to open the garage door and 15 seconds to close it. (A total of 30seconds to cycle open then closed)
Now lets assume it is cycled 10 times per day. (probably high.... but lets be conservative)

So... you have 950 * 30 * 10 = 279,000 Wseconds per day or 77.5Whr/day for your load consumption. I assume you would use the light at times when you are not opening and closing the door so lets call it 85Whr/day.

If you had a single 100W panel and the Insolation number for your area is 4, you would get 400Wh/day. That is 4.7 times the daily need so with that single panel you could ride out many cloudy days. You could probably get by with a 50W panel because even on cloudy days you will get some production.
 

SilentP

Time wounds all heels.
Could you provide a link to one of the DC openers you are looking at? It would help us answer your questions on how to hook things up.

This is what I was looking at-

But my garage door guy says that 1/2hp would be enough for the uninsulated door he installed.-

BUT....I now hear that Chamberland suggests a "regulator" to not overcharge the battery and burns out the circuits (???).
 

FilterGuy

What, me worry?
It does not look like either of those have provisions for charging the battery directly. They both seem to only charge through 120V.

That means you would need some type of inverter between the solar panel and the opener. Ideally you would be able to find an inverter that does require it's own battery.
 

FilterGuy

What, me worry?
Did they provide any information on how to tap into the battery for charging? Did they tell you what chemistry is used?
 

FilterGuy

What, me worry?
Did they provide any information on how to tap into the battery for charging? Did they tell you what chemistry is used?
When I say chemistry.... I mean type of battery. Example: Lead acid? LiFePO4, etc

Also, since this is in a detached garage, do you have any concern about it getting to 0c or lower temps? (You must not charge LiFePO4 at sub zero.)
 

GSXR1000

Solar Enthusiast
surly it is agm type... and wire pwm charge controller to the battery on 100w.. you're out under $200
 

FilterGuy

What, me worry?
surly it is agm type...
A couple of years ago I would have bet on AGM...... but things have been changing fast so I figured I would ask.
and wire pwm charge controller to the battery on 100w.. you're out under $200
Yup. That is what I was thinking too. Get a small charger that can handle the battery type and you're good to go.

1616715708910.png

Note: Assuming the battery is 12V, you want to pick a 12V panel if you are using PWM. If you use MPPT it does not matter but MPPT is overkill for this job.
 

SilentP

Time wounds all heels.
Did they tell you what chemistry is used?
I wouldn't know that as a question to ask...(sigh)...

But let's step back from that and look at this 100w "find" -

Would this with a lead battery and inverter work?

I mean, yes, here in the Detroit area, we get sub-zero degrees Celsius often.

And if I get - say - two separate batteries from one that is within a garage door opener, with the plug-in inverter, I might save money on the type of opener, right?
 

SilentP

Time wounds all heels.
I just did some poking around and I am pretty sure the opener uses a 5Ahr 12V AGM battery. That will only hold 60Whr so a 100W panel is big time overkill. Even a 50W panel would produce 200Whr in a day.
Wow...thank you. you all have been busy whilst I was away. This latest (earlier) stuff is INTERESTING.
 

SilentP

Time wounds all heels.
Also, I am very encouraged by the information. Especially realizing a 50w panel seems more manageable given my limited skill sets.
 

FilterGuy

What, me worry?
5Ah probably shouldn't be charged at more than 1A.

I vote 20W panel.
I was about to comment on that when your post popped up.
You are right, even a 50W panel would be too big. I am not well versed in lead acid so I just looked it up.

Manufacturers recommend a charge C-rate of 0.3C, but lead acid can be charged at a higher rate up to 80% state-of-charge (SoC) without creating oxygen and water depletion. Oxygen is only generated when the battery is overcharged. The 3-stage CCCV charger prevents this from happening by limiting the charge voltage to 2.40V/cell (14.40V with 6 cells) and then lowering to a float charge about 2.30V/cell (13.8V with 6 cells) at full-charge. These are voltages below the gassing stage.

Test show that a healthy lead acid battery can be charged at up to 1.5C as long as the current is moderated towards a full charge when the battery reaches about 2.3V/cell (14.0V with 6 cells). Charge acceptance is highest when SoC is low and diminishes as the battery fills. Battery state-of-health and temperature also play an important role when fast-charging. Make certain that the battery does not “boil” or heat up during charge. Put an eye on the battery when charging above the manufacturer’s recommended C-rate.
For a 5AH battery, .3C is ~1.5A so a 20W or 25W panel looks about right.


There are some 'kits' that come with a charge controller, but I have no idea if the controllers are any good.
 

FilterGuy

What, me worry?
And if I get - say - two separate batteries from one that is within a garage door opener, with the plug-in inverter, I might save money on the type of opener, right?
If the only thing you are powering is the opener, you don't really need an inverter. Just hook the output of the small Charge controller to the plus and minus of the battery in the opener.

1616737630954.png

The cost of the panel and inverter and miscellaneous wiring and such will be less than $100


If you want to have 120V available in the garage, it becomes a whole new problem.
 

G8trwood

New Member
The panel for my gate opener is a 10 watt panel. 7ah la battery. Mighty mule, been working 15 years not counting battery changes. Now nowhere near 1/2hp as gate swings free
 
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