Nice opportunity loads for middle of the day

bbbuddy
bbbuddy Solar Expert Posts: 135 ✭✭✭
in Off Grid Solar & Battery Systems #1
It's been 3 months since we went to 2200 watts solar, up from 800 watts. I find that we are in float as soon as 10:30 in the morning. So, looking for some useful way of using the extra watts, I found this radiant heater from Walmart http://www.walmart.com/ip/Optimus-Infrared-Quartz-Radiant-Heater/15162308

It has 2 settings, 400w and 800w. It has very high reviews, and for $25 it seemed like something to at least try.

Well, it works very well. I can turn off my propane heater for 5 hours during the day right now and get plenty of free solar heat using this. When the cold gets down in the minus territory, it will be a nice "personal heater" when the propane heater can't quite keep it as warm as I like.

Another item that was given to me recently in spite of my protestations is a NuWave induction single burner. I can use it for about 5 hours in the middle of the day for making soups and stews(slow cooking) with free solar heat. It has unlimited heat settings from 100 to 500 and thus can use very little to a "bunch" of watts. I haven't actually measured the watts but it looks like the 170 degree setting which allows simmering at our altitude is using about 400 watts...

Neither of these is useful in the morning or at night, but they work great in the middle of the day!
Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: Nice opportunity loads for middle of the day

    be cautious in using the higher powered loads for long term even if during daylight hours as any interruptions in your solar production could throw you into a deficit real easy. i do hope that you did not have the solar expansion's purpose to be to add items like resistive heat as that's not the most effective use for it, but it is your $. as far as quartz heaters go, i love them. they are still not very economical to use even if you're grid tied, but they do put most of the heat into lower objects (including people) rather than heating up your ceiling.
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  • bbbuddy
    bbbuddy Solar Expert Posts: 135 ✭✭✭
    #3
    Re: Nice opportunity loads for middle of the day
    niel wrote: »
    be cautious in using the higher powered loads for long term even if during daylight hours as any interruptions in your solar production could throw you into a deficit real easy. i do hope that you did not have the solar expansion's purpose to be to add items like resistive heat as that's not the most effective use for it, but it is your $. as far as quartz heaters go, i love them. they are still not very economical to use even if you're grid tied, but they do put most of the heat into lower objects (including people) rather than heating up your ceiling.

    Well, let's see...batteries are in float when I use these loads, and are in float when I turn them off...nope, don't see a deficit there :)

    I have 2200 watts to "play with" and my normal daytime loads vary from 250 to 350 watts. I seem to have plenty of extra to play with. :)

    Also, I'm home all day, these loads are monitored by me. Since we added the extra solar, I have not had to use the generator once, even on totally overcast days we have gotten to 100%. We have not had "black cloud" stormy days yet -I know the solar will be "out" then - but on white cloud overcast days my solar is still outputting 400 watts+.

    I have run my washer, and my 110v electric dryer on solar. The only draw I do not yet have on solar is my 220v 1hp well pump, but that's coming by spring...
    Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #4
    Re: Nice opportunity loads for middle of the day

    Eco heater link: http://www.heartlandamerica.com/browse/item.asp?PIN=87317&DL=GAW1&SC=WIG20001& I have had 2 of these for a few years without any problems. Have them for a backup in case gaswell or furnace goes off. They make good use of oportunity loads. They can be bought from Amazon too. Amazon has a better description but I was afraid to send the link from there as I have an account there and didn,t want to send something that has my name in it for sucurity reasons. :Dsolarvic:D
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: Nice opportunity loads for middle of the day

    We had a discussion a while ago about them:

    need reviews of this heater

    One person had some scorching behind his--and recommended another 2" of standoff... Otherwise, electric heat is electric heat. Get the best heater for your needs (this one, standard, base board, etc.).

    And by all means, insulate the best you can to keep the heat inside the home (money).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #6
    Re: Nice opportunity loads for middle of the day

    Here is plenty of reviews from Amazon. http://www.amazon.com/Eco-heater-NA400S-Wall-Mounted-Ceramic-Convection/product-reviews/B004FAMXL0/ref=dp_top_cm_cr_acr_txt?ie=UTF8&showViewpoints=1 I read the previous post about this and still think it is the best back up for me. I have a gaswell that could freeze up at any time and I wouldn,t have any heat at all. The year I got my gaswell I had already bought a full tank of propane and had to use it up before I could switch to natural gas from my gaswell. So with 2 of these ecoheaters and 2 oilflled heaters I heated my home from about january for most of the rest of the heating system and my electric bill didn,t go much over a $100. This was before I decided to get into alternitive energy. I don,t think they were designed as a wholehouse heating system, more for a cold bathroom or bedroom. I only use mine now when I want to burn off a little power as sometimes I want to run my gti inverter ac coupled. The original poster wanted to burn off some of his extra power and I sugested this heater as an alternitive for someone that might want to do the same thing. :Dsolarvic:D
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #7
    Re: Nice opportunity loads for middle of the day

    Another good opportunity load is to have a plug in car. This works especially well for grid tie systems where the utility pays low amounts for the back feed power and the off peak power is also cheap. There is a guy on the GM volt forum that is off grid and has made a controller that turns on his L2 car charger if his battery charger has gone to float, including proper delays to prevent the flip flop problem.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #8
    Re: Nice opportunity loads for middle of the day
    solar_dave wrote: »
    Another good opportunity load is to have a plug in car.

    Provided the car is parked at home during peak solar hours. :-)

    I try to call a load of the type you describe a scheduleable load or a time-shiftable load rather than an opportunity load.
    Opportunity loads apply mainly to off-grid (battery) systems. If you do not charge the car only during the day, when you happen to have excess panel power, you are not using an opportunity load.
    But you do have a very good schedulable load which lets you sell power at a high rate and buy it back at a low rate.
    SMA SB 3000, old BP panels.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #9
    Re: Nice opportunity loads for middle of the day
    inetdog wrote: »
    Provided the car is parked at home during peak solar hours. :-)

    I try to call a load of the type you describe a scheduleable load or a time-shiftable load rather than an opportunity load.
    Opportunity loads apply mainly to off-grid (battery) systems. If you do not charge the car only during the day, when you happen to have excess panel power, you are not using an opportunity load.
    But you do have a very good schedulable load which lets you sell power at a high rate and buy it back at a low rate.

    Yes being there is a requirement.
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  • bbbuddy
    bbbuddy Solar Expert Posts: 135 ✭✭✭
    #10
    Re: Nice opportunity loads for middle of the day

    Temps here yesterday ranged from 5 to 42. We ran the radiant heater for about 5 hours, maybe a bit less. Had the propane heater off most of the day! I also did an equalize, and was in float for 3 hours. Hit 10kw [probably 10 kWatt*Hours -Bill B.] on the pv out! A new high. Going to try to best that today...


    Yes, thanks BB, I did mean 10 kwh...
    Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.
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  • Eric L
    Eric L Solar Expert Posts: 262 ✭✭
    #11
    Re: Nice opportunity loads for middle of the day
    Also, I'm home all day, these loads are monitored by me.

    Since you have a Classic, one thing to try if you wanted to experiment further would be to run some signal wire from one of the Aux outputs to a DC-AC relay to turn the heater off (and also on, if you chose) based on battery voltage. This would probably cost you about $20 if you had to buy the wire: $6 for 100 feet of Cat 5 wire and $12 for a little relay. That would automatically prevent any over-discharge of the batteries, and insure they got a full charge priority ahead of the opportunity loads (again, automatically).

    I have two of these set up with my Classics: one for my electric hot water heater using the Classic's Waste Not Hi PWM mode on Aux 2, and the other for an oil-filled space heater (currently using the Float Hi function with Aux 1, which works best given my other loads). In the summer I do something similar with AC instead of the space heater.

    Like you, I find it's great to make use of nearly all the spare PV power. As I've gotten better with these finding these loads (and the water heater PWM thing which Chris Olson posted about is terrific), I've gotten very close to full capacity utilization on my pv array and my system is generating almost two times what I had expected it to do when I originally designed it. So it's really cool to find these new ways to maximize opportunity loads.
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