How to create dummy load for Solar City system during outage

I just had a Solar City PPA system installed. I'd like to be able to use it in the event of an extended utility outage (like after an earthquake here in California). As I don't own the system, I don't want to mess with the equipment itself. It's a Power-One 3.8KW 240V inverter. There is no battery backup.

My thought during an extended outage is:
1. Turn off the inverter.
2. Shut off the main breaker to the grid.
3. Turn on some sort of dummy load to bleed off excess power. This would be connected to another breaker which would normally be turned off.
4. Also plug in a small battery-powered inverter to supply power to support the inverter.
5. Turn on the inverter.
6. Before sundown, turn off/unplug the battery inverter.

So my questions are,
1. Would this work?
2. What would work well, and safely, for a dummy load? Does it have to be 240V or could I just use a 120V 20A circuit for this and plug it into a wall outlet? How big does it need to be?
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to create dummy load for Solar City system during outage

    No it won't work.

    Standard GT systems do not need a "dummy load" to get them to function, they need an active power signal. If they do not detect proper Voltage and frequency on the line they shut down.

    There is a way to present them with this signal when the grid is down. It involves using a compatible battery-based inverter to provide the proper V & F so the GTI's will function. But there are several precautions which must be taken, including being certain the grid is 100% disconnected so there is no chance of back-feeding it during an outage (and thus defeating the purpose of the anti-islanding circuitry).

    On the whole it is a tricky thing to do. Only certain inverters will work (it's called "AC coupling" btw) and the battery capacity has to be large enough to make use of the power the GTI supplies if the household loads don't (some regulation will be provided by the OGI).

    SMA makes a Sunny Island which is entirely suitable to this purpose. It works best with SMA Sunny Boy GTI's of course, but can also work with other GTI's.

    One thing you should remember: the GTI will provide power only when the sun shines, so any power needed after that must be stored in the batteries.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to create dummy load for Solar City system during outage

    Short answer--It will not work as you think. The GT Inverter is designed not to run without an outside source of 120/240 VAC AC power. Period.

    There are several ways of getting power from your solar panels to run your home. They are both fairly technical and range from DIY to off the shelf off grid systems.

    Both require you to install a Battery Bank and off grid inverter to make AC power.

    The options are how you get power from the array to the battery bank/AC loads.

    The first method is to connect a high voltage MPPT Solar Charge controller to the solar array before the GT inverter input connection. Connect this when the AC utility power is down, and use to recharge the Battery bank/run your AC loads. Probably violates your lease 7 ways to Sunday.

    The second is to get an Off Grid inverter that can run with AC Backfeed from the GT inverter.

    Basically, you create a local grid with your Off Grid AC inverter (120/240 VAC) that is larger than your GT inverter. It turns out that some/many True Sine Wave off grid AC inverters can actually have a GT inverter connected together and share the loads with the GT inverter and the OG inverter can actually "run backwards" and recharge the connected battery bank.

    You can make a DIY battery bank charge controller system (dump controllers, a voltage controlled relay that can kill the GT inverter output).

    Or you can buy one of the few OG AC Inverter's designed for this setup... They "move" the 60 Hz powerline frequency +/- ~1 Hz when the battery bank is full and this causes the GT inverter to shut down for 5 minutes (and then the GT inverter will "reconnect" once the AC voltage+Frequency from the OG inverter is in specifications).

    Either method is expensive (large battery bank + AC inverter + Charge controller + etc.) and usually not worth it unless you have a lot of local power outages and/or you expect weeks-months of power outages at a time.

    In general, if your needs are for a few days or 1-2 weeks, a backup AC generator with stored fuel is usually more cost effective and a practical solution.

    If your emergency power needs are small (a refrigerator, lighting, laptop, cell charger, small well pump, etc.)--If you can get down to the Honda eu2000i (1,600 watt) or similar class Honda/Yamaha genset--These only use 1-3 gallons of fuel per day (run a few hours at night and morning). 20 gallons of stored gasoline (if you can) will keep you in emergency power for 1-2 weeks.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mbernhardt
    mbernhardt Registered Users Posts: 10
    Re: How to create dummy load for Solar City system during outage

    I'm not trying to install a battery setup. Basically I'd like to be able to keep our freezers running during the day and maybe have some communications options. As I said, I don't want to mess with any connections in the inverter itself since I don't own it.

    My battery inverter is a small portable thing with a battery inside, intended for powering small appliances on a camping trip or whatever. I can check it with an oscilloscope to see how clean the wave form is. My thought was that if it is clean enough, it could provide the voltage and frequency needed to keep the inverter running. And the output of the solar system would keep the battery charged during the day so that it can keep the "signal" going.

    You guys are saying that can't work?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to create dummy load for Solar City system during outage

    Your 3.8kw gt inverter will try to dump 3.8kw of power back through your og inverter + battery bank.

    In theory, you could use a variable ac load to shave off the extra ac power. I practice, it is very difficult to do the software and hardware for this function (not possible for a diy home project).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to create dummy load for Solar City system during outage
    mbernhardt wrote: »
    I'm not trying to install a battery setup. Basically I'd like to be able to keep our freezers running during the day and maybe have some communications options. As I said, I don't want to mess with any connections in the inverter itself since I don't own it.

    My battery inverter is a small portable thing with a battery inside, intended for powering small appliances on a camping trip or whatever. I can check it with an oscilloscope to see how clean the wave form is. My thought was that if it is clean enough, it could provide the voltage and frequency needed to keep the inverter running. And the output of the solar system would keep the battery charged during the day so that it can keep the "signal" going.

    You guys are saying that can't work?

    Even if the waveform were good (and it would need to be same Voltage as the GTI system i.e. 240 VAC) the battery is too small to take on 3.8 kW of power and the unit has no built-in regulation because it was never meant to be used this way. Hook it up and if the GTI is tricked in to running kiss it goodbye.

    No more sure-fire recipe for disaster than using something for a purpose it was never meant for.
  • mbernhardt
    mbernhardt Registered Users Posts: 10
    Re: How to create dummy load for Solar City system during outage

    So, there's the SMA Sunny Boy inverter which can be connected to the Power One somehow and has the option of a 1500W outlet. But I would imagine that the SMA inverter has to be connected directly into the Power One so that's pobably a no-go unless I can get approval/assistance from Solar City.

    And there's the option of buying a generator. Other than spending thousands on a battery system I may never need, are those the only options?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to create dummy load for Solar City system during outage

    The systems that backfeed og inverts must take 100% of the gt inverter output when recharging the battery bank.

    As Marc says, SMA has a new gt inverter that can run a 10 amp 120 vac outlet if the grid is down and there is enough sun.

    But that requires a new gt inverter. Your leasing company would have to approve.

    The aux 120 vac outlet has some limitations. I would get a Honda eu2000i instead with a siphon and a couple of gas cans plus fuel stabilizer.... Which is exactly what I did.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to create dummy load for Solar City system during outage
    mbernhardt wrote: »
    So, there's the SMA Sunny Boy inverter which can be connected to the Power One somehow and has the option of a 1500W outlet. But I would imagine that the SMA inverter has to be connected directly into the Power One so that's pobably a no-go unless I can get approval/assistance from Solar City.

    And there's the option of buying a generator. Other than spending thousands on a battery system I may never need, are those the only options?

    The Sunny Boy is a GTI; it's powered by panels the same as the GTI you've got. The Sunny Island is a battery-based inverter that can accept and regulate AC coupled GTI. A couple of others will do this, but you are looking at a lot of money.

    A generator will provide back-up power in an outage. It can not be AC coupled to your GTI. Same problem as before: no place for the power to go and no method of regulating it. Trying to regulate that power by adjusting loads will be a nightmare and bound to fail; the variation in output of the GTI has to be compensated for as well as the variation in loads you're actually trying to use. Big headache.
  • mbernhardt
    mbernhardt Registered Users Posts: 10
    Re: How to create dummy load for Solar City system during outage
    Even if the waveform were good (and it would need to be same Voltage as the GTI system i.e. 240 VAC) the battery is too small to take on 3.8 kW of power and the unit has no built-in regulation because it was never meant to be used this way. Hook it up and if the GTI is tricked in to running kiss it goodbye.

    No more sure-fire recipe for disaster than using something for a purpose it was never meant for.

    But wouldn't having some kind of dummy load to drain off unused power avoid this problem?
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: How to create dummy load for Solar City system during outage
    The Sunny Boy is a GTI; it's powered by panels the same as the GTI you've got. The Sunny Island is a battery-based inverter that can accept and regulate AC coupled GTI. A couple of others will do this, but you are looking at a lot of money.

    A generator will provide back-up power in an outage. It can not be AC coupled to your GTI. Same problem as before: no place for the power to go and no method of regulating it. Trying to regulate that power by adjusting loads will be a nightmare and bound to fail; the variation in output of the GTI has to be compensated for as well as the variation in loads you're actually trying to use. Big headache.
    It is possible that the OP is thinking of the newer SunnyBoy TL-xxxx-US models that include a separate "Secure Power Supply" output circuit that can be explicitly switched on only when no grid power is sensed. It gives up to 12A at 120 volts in an off grid mode to an isolated duplex receptacle without using batteries. If the insolation drops below what is needed to support the connected load it switches off and retries periodically hoping that the load was reduced or the cloud moved on.
    It does not have any connection with the GTI function except possibly sharing some internal components.
    It also does not use any of the technology used for the SunnyBoy/Sunny Island AC coupled hybrid system.
    SMA SB 3000, old BP panels.
  • mbernhardt
    mbernhardt Registered Users Posts: 10
    Re: How to create dummy load for Solar City system during outage

    Yes, that's exactly what I had read about. Where does that baby connect and approximately what does it cost? I think I'd read as you implied that it doesn't replace the GTI, it complements it.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to create dummy load for Solar City system during outage

    The only way you could use your existing system and not violate their policies would be to set up a 4kWatt Off Gris system with a 120/240 VAC Split Phase AC inverter + 400 AH @ 48 volt battery bank (roughly). And set up a sub panel where the OG system provides emergency/backup power, and wire the GT Inverter's AC output into that sub panel.

    It can be done--It can even be done legally (your local codes may through in some monkey wrenches). But it will not be very cheap.

    Maybe ~$2,500 worth of batteries (minimum), and a 4.5 kW @ 48 volt inverter for another $2,400. Add a few $k more for rewiring, new sub panel, aux equipment, etc... You might do it for under $8,000 (plus labor, taxes, permits, shipping, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to create dummy load for Solar City system during outage
    mbernhardt wrote: »
    Yes, that's exactly what I had read about. Where does that baby connect and approximately what does it cost? I think I'd read as you implied that it doesn't replace the GTI, it complements it.

    It is a different Brand/Model of GT inverter and would replace your present Power-One GT inverter. I am not sure I have seen one for sale yet--But probably ~$2,000 or so for a "new" 4kW GT inverter with the AC backup power option--Plus any rewiring on the solar panel side that may be needed (not sure if the two inverter can be swapped without reconfiguring the array--Need to look into the details more).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    Re: How to create dummy load for Solar City system during outage
    mbernhardt wrote: »
    But wouldn't having some kind of dummy load to drain off unused power avoid this problem?

    No. The problem is not the dummy load; the problem is the lack of an accurate AC signal to sync to. (And before you ask - no, you can't use a small inverter to provide this.)

    If you get frequent blackouts then go with either a generator or a dedicated battery backed hybrid inverter system. If you have infrequent outages and just want a little backup then get an SMA inverter with a "secure power supply." This is a string inverter that will give you 1500 watts of independent power during blackouts. If you want a slightly better system get the SMA and then get a $99 UPS from Best Buy, then charge it from the outlet during the day.
  • mbernhardt
    mbernhardt Registered Users Posts: 10
    Re: How to create dummy load for Solar City system during outage
    If you have infrequent outages and just want a little backup then get an SMA inverter with a "secure power supply." This is a string inverter that will give you 1500 watts of independent power during blackouts. If you want a slightly better system get the SMA and then get a $99 UPS from Best Buy, then charge it from the outlet during the day.
    So I'd have to convince them to replace the current Power One with a Sunny Boy that includes the emergency outlet as it doesn't tie to the existing GTI. Does that sound like an accurate assessment?

    I assume the little UPS(s) would be to power small items...

    Or buy a generator. Such a waste when the darn thing is generating energy already, to buy a generator...
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: How to create dummy load for Solar City system during outage
    mbernhardt wrote: »
    I'm not trying to install a battery setup. Basically I'd like to be able to keep our freezers running during the day and maybe have some communications options. As I said, I don't want to mess with any connections in the inverter itself since I don't own it.

    My battery inverter is a small portable thing with a battery inside, intended for powering small appliances on a camping trip or whatever. I can check it with an oscilloscope to see how clean the wave form is. My thought was that if it is clean enough, it could provide the voltage and frequency needed to keep the inverter running. And the output of the solar system would keep the battery charged during the day so that it can keep the "signal" going.

    You guys are saying that can't work?
    That is exactly what we are saying.

    Even if the standalone inverter could produce a clean and stable enough waveform for the GTI to qualify it as grid, it cannot the same electrical characteristics that the GTI is required to look for to see that it is connected to an essentially infinite power sink (the grid).
    And even if it got past those tests, as soon as the GTI output went above the connected load it would try to feed energy back into your small inverter.
    No dummy load or automatic shutdown could react fast enough to prevent damage.
    Finally, if that does not convince you, it will void the warranty on both the GTI and the standalone inverter and would not be legal to connect to your house wiring.
    (You were planning on opening the main breaker separating the GTI from POCO, right?)

    Short and sweet answer: Forget it.


    You can use a listed hybrid system designed for the purpose, such as the combination of an SMA Sunny Boy and Sunny Island. But if you do not own the GTI equipment, forget that too. :(
    SMA SB 3000, old BP panels.
  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    Re: How to create dummy load for Solar City system during outage
    mbernhardt wrote: »
    So in layman terms, it sound like you're basically saying I'd have to install a 2nd inverter w/batteries which would be powered with the existing system and come on line if the existing one went down. Everything but the panels. Or, I could convince them to replace the current Power One with a Sunny Boy that includes the emergency outlet. Does that sound like an accurate assessment?

    Both those should work. I wouldn't consider the first option unless you really want to do it, or you have frequent blackouts.
    Or buy a generator. Such a waste when the darn thing is generating energy already, to buy a generator...

    It can be frustrating to have a solar power system that's not generating anything during an outage, when you could really use it. I had several friends/relatives who lost power for a few weeks during Sandy, and they had neighbors who had solar power systems that were rendered useless by the lack of power. It was _very_ frustrating for them, especially since a few of them didn't realize that their grid tie systems could not generate independent power.

    However, the question comes down to how much money you want to spend. If you don't mind spending the money and doing the battery maintenance, the full blown hybrid system might be an option. But for low cost it's hard to beat a $500 generator and a few cans of gas.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: How to create dummy load for Solar City system during outage
    mbernhardt wrote: »
    Yes, that's exactly what I had read about. Where does that baby connect and approximately what does it cost? I think I'd read as you implied that it doesn't replace the GTI, it complements it.
    Well, it is a good sized GTI inverter that includes that additional capability.
    Check it out here. And on YouTube for the reading challenged here.
    SMA SB 3000, old BP panels.
  • mbernhardt
    mbernhardt Registered Users Posts: 10
    Re: How to create dummy load for Solar City system during outage

    OK, thanks everybody!!
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to create dummy load for Solar City system during outage
    However, the question comes down to how much money you want to spend. If you don't mind spending the money and doing the battery maintenance, the full blown hybrid system might be an option. But for low cost it's hard to beat a $500 generator and a few cans of gas.

    I would go with the $1,000 Honda/Yamaha type inverter-generators (~1,600 watt, pull start). It is hard to appreciate how noisy a typical genset is until you fire one up for 4 hours in the evening in a quiet residential neighborhood. If you have some land around you and don't mind the noise (and/or build a shed), you could go with a noisier genset.

    If you need more power and/or electric start, electric start inverter-generators are available in the ~3+kWatt range (Honda/Yamaha, around $2,000+).

    For me--I looked at conservation/minimum loads during emergencies (just one step above camping).

    The typical 3.5-5 kW genset is cheap, but will pull ~0.5 to 1.0 gallons of fuel per hour. That 5 gallon can will not even last 1 day.

    The smaller 1.6 kW inverter generators will run around 1/10-1/4 gallon per hour (depending on loads~400-1,600 watt). 1-2 gallons of gas will give you 1 day of morning/evening power pretty easily.

    If you need more power (A/C, larger home, etc.)--Fuel storage becomes an issue. Natural Gas/Propane are nice options. Diesel is safer than gasoline too, but the exhaust fumes/noise may cause issues with the neighbors (arguments about how long you can store diesel--Gasoline, around 6-12 months with a fuel stabilizer--I just recycle into my vehicles every Christmas).

    There are lots of options--But few good ways to nail the problem.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mbernhardt
    mbernhardt Registered Users Posts: 10
    Re: How to create dummy load for Solar City system during outage

    I have to get more info on maintenance, capacity, etc. but Solar City can lease me a Tesla battery backup for $1500 + $15/month. That doesn't seem unreasonable considering I'd still be paying way less than I've been paying PG&E. Any thoughts?
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: How to create dummy load for Solar City system during outage

    their web page tell you nothing about the capacity of the battery (system) just a typically vague statement about running "your house for a few days"... then there is a faint ASTERISK that takes you to the bottom of the page for the disclaimer... I would be wary...
    http://www.solarcity.com/residential/energy-storage.aspx
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to create dummy load for Solar City system during outage

    This thread points out one of the problems with a leased solar power system: if it turns out it doesn't work for you, you're stuck; you can't change it around to suit because you don't own it. And good luck arguing the case with the lease company because chances are they don't have an EE on board anywhere either.
  • mbernhardt
    mbernhardt Registered Users Posts: 10
    Re: How to create dummy load for Solar City system during outage
    westbranch wrote: »
    their web page tell you nothing about the capacity of the battery (system) just a typically vague statement about running "your house for a few days"... then there is a faint ASTERISK that takes you to the bottom of the page for the disclaimer... I would be wary...
    http://www.solarcity.com/residential/energy-storage.aspx

    Well I won't get it until they give me specifics obviously. But I think the "running your house for a few days" referred to using it as a backup to the grid, not as storage for a solar system (which they mention also as continuing "indefinitely"). But assuming that it's sufficient for most of our needs, does it sound like a reasonable cost?


    Technically the system isn't leased, it's a PPA. They bill me for the energy generated and they own/maintain the system. I liked that route because even though it's more expensive, there's no up front cost and if it isn't maintained, THEY are losing money on me. I figured leasing/purchasing would take 13 years before it saved money over this arrangement and I am unlikely to be in this house then, so why own it?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to create dummy load for Solar City system during outage

    Get the specifications... And figure out how much energy your home uses in one day.

    A 3.8 kWatt GT system can generate around 20 kWH per day on a nice sunny spring/fall day.

    20,000 Watt*Hours / 48 volt battery bank = 416.7 AH @ 48 volt per day storage

    A typical off grid system designed to operate a home for many years (not short term emergency) would have 2 days of storage and 50% maximum discharge for a lead acid battery system.

    416.7 AH * 2 days storage * 1/0.50 max discharge = 1,667 AH @ 48 volt battery bank.

    If you wanted to get a large Fork Lift type battery--A pair of this batteries:

    Crown Industrial Battery - 24 Volts, 1720 Amp-hours
    Price: $6,801.40

    Or about $14,000 for a set of batteries that should last about 20 years.

    In the end, we recommend A) lots of conservation around the home first, and B) measure/estimate your loads that you wish to support when the power is down.

    A Tesla battery bank is around 53kWH--So, depending on how deeply it is cycled could be a possibility for running your home (20 kWH per day, 2+ days of storage).

    The Tesla battery bank weighs around 900 lbs, the forklift batteries above weigh around 3,700 lbs for the pair.

    There are a whole bunch of questions that need answering before opening your wallet... But you can see what the basics may look like and you can scale them for your place (the above numbers are really rough--There are more detailed calculations to be made--But they are close enough for a first cut at the question).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to create dummy load for Solar City system during outage

    For back-up power you don't need to supply everything in the place, just the essentials.
    If the outages are infrequent and short-lived a generator is a far better investment to deal with them than any battery-based system.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: How to create dummy load for Solar City system during outage

    From their web page

    Tesla's long history of research and development has enabled a cost-effective, wall-mounted storage appliance that is small, powerful and covered by a long lasting full 10 year warranty.

    The actual battery unit is about the size of a solar power inverter, and will be mounted on the wall in your garage or near your electrical panel.

    *Limiting power use to essential devices such as lights and refrigerator.


    sounds to me like about a 3 -5Kwh capable bank/day for ~2 days... of essentials.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • KenZ71
    KenZ71 Solar Expert Posts: 58 ✭✭
    Re: How to create dummy load for Solar City system during outage

    Reviving an old thread.... a bit of rambling but also trying to provoke thought & discussion.

    From a purely financial point of view a standalone generator makes sense. However that is one more mechanical item to maintain.

    We also were in Super Storm Sandy's path. Only lost power for 18 hours, not bad at all in comparison. A few friends had generators that did not work or broke down. Also fuel availability was a problem.

    Seen a few posts where hybrid vehicles have been tapped as the battery source. I don't have a hybrid but thinking about it to have a backup power storage that ccould possibly work with a grid tie system.

    So I guess the point of my rambling would be could power be taken from the Solar array before it enters the inverter and sent to a charge controller to charge batteries? It seems silly to convert the 12 Volt stream with the inverter then drop it back down to go into the batteries.

    If charging would be possible then maybe the battery bank in a hybrid vehicle could be used to run critical loads i.e. 'fridge, freezer, maybe small loads like modem & router. Of course an inverter would be needed but that should be a relatively small challenge to power SMALL emergency loads.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to create dummy load for Solar City system during outage

    Check out Techntrek's thread on using a Prius as a generator.
  • KenZ71
    KenZ71 Solar Expert Posts: 58 ✭✭
    Re: How to create dummy load for Solar City system during outage
    Check out Techntrek's thread on using a Prius as a generator.

    That post is one that got me really thinking along this line.

    I view the solar panels and inverter somewhat like allowed to run off into a drain then paying a lot of money for irrigation. Also, I usually have bad luck with machinery held in reserve. Case in point, we had a couple very mild winters so the snowblower slipped into disrepair. When a big storm hit we were screwed!