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What AWG wire are you using all the DC that connects to your 1500w inverter? Remember that this would be 63 Amps. Look at this chart -> https://www.bluesea.com/resources/1437
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I have some bad news for you. In my estimation you will not be able to use much of what you currently have purchased for the loads you just added to your description. The electric hot water heater is really hard with solar, and I hope your dryer is not electric, is it?
In addition you say "pay off". The bad news here is that you will never make off-grid "pay off" for what you have listed if you have grid power at this location. Solar with battery will cost much more than the most expensive POCO electricity. The price of the batteries alone will kill you. How much did you spend for your 24v 100 AH of AGM batteries? You will probably get at best 1000 cycles from them at 50% DOD, and that is if you do everything right.Comment
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I think you did not look at the video I posted about lower voltage hot water heating elements to change out for your electric hot water heater
Here are some other videos on the DC water heater element item which uses less wattage for solar.
See also https://www.youtube.com/watch?v=6QaBJ7uwoBM
and https://www.youtube.com/watch?v=iGCMwsDYmAw **
They sell 200 watt-600 watt dc heating elements for $35.00 that you can replace your 16000 watt ac elements in your hot water heater. They are intended to run your hot water heater at much lower wattage off of a solar panel and not to be wired back to the grid. Right now though, I am testing the idea of turning off the circuit for my hot water heater right after I take my shower and turn it on ONLY 2 hours before I take my shower. So the hot water heater will be off 22 hours of the day and only on 2 hours/day from now on. If it works out for me, I will get a timer for my hot water heater to turn it on and off for me automatically at those times. Added to this, one could exchange your regular shower head that gives 10 gallons/ hour to one of the new shower heads that only shoots 1 or so gallon/hour under pressure. I will also wrap it in 3" hot water heater blanket to make it keep the water warm inside longer with the heater turned off all day.
Here is another set up to run a regular electric hot water heater directly off of 300 watts of solar panels
This guy sells a device called a solar hybrid hot water controller on ebay that runs a dryer plug to a shut off and then to solar panel wiring. It can be used to plug in either your hot water heater or a clothes dryer to your solar panels. See his website listed in the description box of the video.
As for the refrigerator, I think I may ultimately downgrade to this refrigerator which uses 75 watts and can also be run off of solar. Maybe i will find something a little bigger than this one.
WAIT HERE IS A STYLISH REFRIGERATOR THAT ONLY USES 30 WATTS!!! Kenmore Chill
The batteries were about 150 each.
PS So in essence, the 2 additional panels I just ordered totally 272 watts could be a start in powering a smaller refrigerator and the 200 watt water heater elements. I will try to get one more which would make a total of 408 extra to handle a 30 watt refrigerator and a 200 watt hot
water heating element just long enough to take a daily shower. The water in the tank stayed hot all night long though I cut it off at 2 or 3pm, it is still hot now at 7am the next day! the water runs cold for about 20 seconds but after that it gets hot ! I will turn it on again for maybe just ONE hour today, take a shower and then turn it right back off for 23 hours. I will do this for a month and see how it changes my electric bill.Comment
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I didn't mean that solar hot water was "hard" in the sense that it was difficult to put a solar heater into one. I meant that it was hard make it pay off. I don't know where you got the figure of 16000 watts for a hot water heater. Is that the size of your heater? Here is a 50 gallon that takes 4500w. (http://www.whirlpoolwaterheaters.com.../es50r123-45d/)
Turning electricity into heat is not rocket science. Wattage is power and almost all of it turns into heat. It also does not take much energy to keep an insulated water tank hot if water is not used. So, lets say you take a 200w heater element and replace the 4500w element. 4500/200 = 22.5, and so it will take your heater element 22.5 times longer to heat your water. Putting a timer on the hot water heater will not save you money, at least not what you can measure. When I put a hot water heater in my cabin, I called the manufacturer, and asked them about adding extra insulation for a winter climate. They said, not necessary, it was already insulated enough and that it would cost me $30 per year to keep the water hot if I did not use any. The cost is in heating the cold water that fills your tank to replace what you have used. There is one way I think a timer could save you money. If you have a TOU (Time of Use) electric rate plan, you could heat your water at night at the lowest rate. I may actually do that myself, as my baseline allotment will cost me 1 cent per kWh if I change my plan.
Lets assume this web site is correct and it takes 0.0002931 Kwh to raise 1 pound of water 1°F (http://waterheatertimer.org/Kwh-temp.html)
Lets start with a 50 gallon hot water tank and fill it up with water at room temperature, 77F. How many kilowatt hrs to heat the water to 102? 50 gallons of water at 8 pounds per gallons = 400 pounds.
0.0002931 Kwh X 400 lbs X 25 = 2.93 kWh
At 11 cents / kWh that will cost 32 cents.
With a 4500w heater it will take less than an hour to heat. With a 200w heater it will take 15 hours to heat. But you don't have 15 hours of solar. You have 4.5 hours but with some shade. If that is summer, winter is probably 2-3 at best. So it takes days to heat that tank. How many people in your family and how long are your showers?
The average American shower uses 17 gallons. That is about 1kW. 1000 / 200 = 5 hours to heat that water back with your 200w element. That is one shower. If your utility rate is 11 cents / kWH that is what your shower cost you.
Have you figured out how much solar you need to reheat the water for one shower? If I remember correctly you have 408w of panels and are talking about adding 2 more for about 600w. I estimate that those 6 panels might cost from $100 to $150 each. Lets say you get 3 hours of sun a day, that is 1.8 kW which at 11 cents / kWh is about 20 cents of power per day. You don't quite get two showers with that capacity. And you are using up all of your solar capacity to take 1.8 showers per day. You batteries die because you don't have any capacity to charge them.
Now lets say that you paid $1.5 per 100w for your small panels to get 600w. That is $900. Have not added the rest of your solar system, the charge controllers, wiring, breakers, panels, etc.
1.8 kWh X 30 days X 12 months X 10 years = 6480 kWh lifetime. $900 / 6480 kWH = 13.8 cents / kWH for just the cost of your panels. You can play with the numbers with your own estimates of panel life, life of electronics, replacement of heating elements, etc. I also doubt that in 10 years you will have these same panels because as you expand your system there will be better technology and cheaper panels. You could reduce your panel cost with larger grid-tie size panels.
Next topic, cost of powering from your battery. Lets say you get even more panels so you can charge your batteries and take 1.8 showers per day. AGM batteries are not cheap and they don't get the best cycles per lifetime.
100 AH X 1/2 (%DOD) X 1000 cycles X 24v = 1200 kWh for the lifetime of your batteries (you will replace them every 2.73 years, if you take perfect care of them). $300 / 1200 kWh = 25 cents per kWh. I estimated that Costco batteries at $84 ea and 1220 cycles are about 11 cents / kWh.
This figure needs to be further "nuanced" with inverter inefficiency, charge controller inefficiency, etc. Also add the cost / kWh of your panels and electronics, etc. Pretty soon your "free" energy is costing your upwards of 50 cents / kWh and higher, and that is if you don't have any battery failures or need to replace any electronics.
Finally, I said you probably won't be able to use much of what you have already purchased if you expand to power what you have outlined. That is because you have almost outgrown your 24v system already. You will need 48v if you want to run an entire household with hot water heater, washing machine/dryer in addition to all your other appliances. That means different batteries, different panels, different charge controllers, different inverter, etc.
Check my calcs. I do make mistakes, especially when in a hurry. I am also not doing this to discourage you. I am likely going to add batteries and solar to my generator backup because I want the experience and also for backup purposes. But it does not hurt to go into this with ones eyes open.Comment
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Why are you a "solar fanatic" then? Thanks for your opinions anyways.
I send you bright sunny skies devoid of all doom and gloom.
Best wishes.Comment
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I have another question. Someone referred to my system as 12v although I am using 12 v batteries in series to make 24 volt and with a 24 volt inverter. My panels each have open current of 46.6 volts. Doesn't that mean the system is 24 volt as opposed to 12 volt? The vendor told me these panels can be used for either 12 or 24 volt systems.
PS It is refreshing to see a few equations. Reminds me of my calculus classes from long ago. I will have the hang of the math involved in this in no time I'm sure with the constant reinforcement here.Comment
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Thank you. I disagree that I will have to throw all of this in the trash to upgrade it. I can just get a new charge controller. I will certainly not throw my new panels or my batteries in the trash though . That was a bit harsh.Comment
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Performance
If you expect anything to actually perform, try to understand the math instead of denying
reality by name calling doom/gloom/opinion. One more thing to mention. DC heater
elements can meet their specs when matched up to a battery system. If you try to use
them directly connected to PV panels, the available power will practically never be fully
used. That is because the heater resistance will only match up to the available power at
one particular level of sunlight. Bruce RoeComment
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Thanks for the suggestion. I am not afraid of a few simple equations at all.
And with regard to my doom gloom comment, I was trying to lighten the air because a few unnecessarily harsh and unnecessarily antagonistic statements came from out left field and are in the record of this thread. They have nothing to do with math which is one of my fortes.
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I don't recall using the word trash. Also, when I made that comment, it was not made for this short term project where you are balancing the items you just acquired. It was your description of a system that was fully powering a household by adding the water heater, washer/dryer and refrigeration to what you already had listed. If you add all that up you will find it hard to expand your starter system to accommodate it.
As for the panels, sure you can use them. But for bigger systems, the larger grid-tie panels are much more economical.Comment
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