I need electrical / solar help

thrasherfox

BUSA
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So, I purchased one of those 45 watt solar panel kits from Harbor freight.

I also purchased an 800 watt continous / 1600 watt peak power inverter.


The system will be the 45 watt panel system (3 15 watt panels) connected to its system then a deep cycle 12 volt battery. the 12 volt battery will be connected to the 800 watt inverter


I am trying to run a wall a/c unit that peaks at around 254 watts when it first turns on and runs at 115 watts continous


I am not real up on electrical knowledge.


In a setup like this, what determines how many watts you can produce? the intverter? or how may watts are going into the inverter?


Can someone tell me basically what I need to do solar wise to run the wall A/C unit?
 
well your inverter needs 12 v to run so all you need to worry about is the recharge rate of the panel to the battery the battery should do the rest. Just make sure your panel is not overcharging the battery you may need an automatic switch that will stop flow of current when the battery is at full charge..
 
volts x amps = watts, so 45 watts @ 12 volts = 3.75 amps, that alone won't over charge your battery, what you find you will need is MORE POWER! hope this helps :thumbsup:
 
If in rush wattage is 254 and running wattage is 115, just design for the 115.
 
What kind of A/C only uses 115 watts? That sounds like it's only the fan running. Most usable A/C units will pull between 500 and 1,000 watts with the compressor running. ???
 
What kind of A/C only uses 115 watts? That sounds like it's only the fan running. Most usable A/C units will pull between 500 and 1,000 watts with the compressor running. ???

Yeah, your right.

I have one of those watt meters.

When I first turned it on it spiked to a little over 250 watts, then came back down to 115 watts and it stayed at 115 watts for at least 30 minutes

I left it connected and when I looked at it a few hours later it was pulling about 615 watts.


My question still stands tho. I have two inverters (forgot about the other one) I have an 800 watt inverter and a 2000 watt inverter.

What do I need going into the inverter to be able to run an A/C unit pulling 615 watts (or more)

Should I have enough solar panels so they are producing the same amount of watts being used? how many batteries do I need?
 
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this is intresting... keep us informed on how to go green
 
Should I have enough solar panels so they are producing the same amount of watts being used? how many batteries do I need?

Not even close. You didn't mention the capacity of your battery, but since you make it sound as if it's a single battery, I'm assuming it's not more than 200AH. That won't last more than 2-3 hours with the compressor running, and possibly less than that.

I assume your watt meter shows long term usage? Run the A/C at a given set point for 24 hours on the meter, and then switch the meter to KWh. I'll use an out-of-the-hat figure of 10KWh.

10KWh is a LOT of power, and requires in the neighborhood of $1-1.5K in batteries alone. If you want them to last any length of time they need to be bigger so that they aren't being run down as much.

Then to have a positive power income, so as not to slowly run the batteries down, you'll need about 11-12KWh coming in via the solar cells, to account for charging losses and the inverter efficiency losses.

Then figure that you're only going to get 10-12 hours a day of sunlight at best, and at 12KWh in 12 hours this means you would theoretically need 1,000 watts of solar. Which is getting into the territory of serious installations, so instead of just trying to run an air conditioner, you might as well go whole hog and cover the roof and have a proper tie-in converter, with net metering. With careful energy conservation, you can come out ahead on that deal within 10 years.
 
You will need much more in the solar panel output. Good topic. I'm putting a solar array on my RV, when I get it, that will have about 1000 watts of output. It will be tied into a charge meter, then to the RV batteries. The batteries will be able to run the RV for 6 to 8 hours at night. The solar array will also supply more power than I will need during the day. The surplus will be used to recharge the batteries. Hopefully the system will remove the need to use the generator. The fuel savings will go into the tanks of my bikes. :thumbsup:
 
You will need much more in the solar panel output. Good topic. I'm putting a solar array on my RV, when I get it, that will have about 1000 watts of output. It will be tied into a charge meter, then to the RV batteries. The batteries will be able to run the RV for 6 to 8 hours at night. The solar array will also supply more power than I will need during the day. The surplus will be used to recharge the batteries. Hopefully the system will remove the need to use the generator. The fuel savings will go into the tanks of my bikes. :thumbsup:

I'd go for more battery capacity than that... Lead Acid batteries don't really like going beyond 50% DOD. (Depth Of Discharge)
 
Not even close. You didn't mention the capacity of your battery, but since you make it sound as if it's a single battery, I'm assuming it's not more than 200AH. That won't last more than 2-3 hours with the compressor running, and possibly less than that.

I assume your watt meter shows long term usage? Run the A/C at a given set point for 24 hours on the meter, and then switch the meter to KWh. I'll use an out-of-the-hat figure of 10KWh.

10KWh is a LOT of power, and requires in the neighborhood of $1-1.5K in batteries alone. If you want them to last any length of time they need to be bigger so that they aren't being run down as much.

Then to have a positive power income, so as not to slowly run the batteries down, you'll need about 11-12KWh coming in via the solar cells, to account for charging losses and the inverter efficiency losses.

Then figure that you're only going to get 10-12 hours a day of sunlight at best, and at 12KWh in 12 hours this means you would theoretically need 1,000 watts of solar. Which is getting into the territory of serious installations, so instead of just trying to run an air conditioner, you might as well go whole hog and cover the roof and have a proper tie-in converter, with net metering. With careful energy conservation, you can come out ahead on that deal within 10 years.

Thats what I was looking for.

thanks..

Yeah, I am getting a new quote for the entire house.

I got one today and it is $7000.00 less than it was a year ago, plus about 10k in rebates. and I can write off the entire amount on taxes. I guess up until recently there was a $2,000.00 cap. now there isnt any cap on how much I can claim on my taxes.

From the quote it looks like I can do my entire house for out of pocket around $26,000.00

My last month electric bill was $800.00 so with electric bills like that a solar system would pay for itself within under 5 years
 
My last month electric bill was $800.00 so with electric bills like that a solar system would pay for itself within under 5 years

Holy crap... My parents highest bill was under $300, and I thought that was ridiculous. What kind of house you got?

Also, don't forget to talk to the electric company about net metering... Negative power bills are nice. :thumbsup:
 
Holy crap... My parents highest bill was under $300, and I thought that was ridiculous. What kind of house you got?

Also, don't forget to talk to the electric company about net metering... Negative power bills are nice. :thumbsup:

The house is part of the problem.


Around 2600 square feet and single pain old windows everywhere.

And a pool with 2 pumps that are over 10 years old.

Just recently we have been able to replace all the windows this month to new dual pain and we are noticing a differance already.

And I also had both pool pumps replaced with brand new energy efficient pumps that were on PG&E's site and we were able to get a $200.00 rebate back on both.

So we want to see how these changes effect our monthly bill. Trying everything we can to get energy efficient. but it takes money and most of the time you just dont have it.
 
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