How to explain Secure Power Supply to homeowners

SMA’s Secure Power Supply does something that no other grid-tied solar inverter without added storage can: provide power during a grid outage. Solar professionals have been talking about this amazing feature since its inception with the Sunny Boy TL-US and our data shows consumers love it. Now with even more power in the all-new Sunny Boy-US, it’s important to make sure you truly understand how to convey the benefits of this groundbreaking feature so that you can better differentiate your SMA proposal from your non-SMA competition.

To best showcase the value of Secure Power Supply (SPS) it’s important to start talking about it during the initial customer meeting. Let’s take a look at the top things to consider when explaining SPS to homeowners.

1. Make sure the homeowner understands that grid-tied inverters can’t make power during an outage

This seems obvious to those of us in the industry, but average homeowners haven’t been educated on this and it’s our job as industry professionals to teach them. Once they understand why, it’s an easy transition to talk about how SPS can provide up to 2,000 watts to a dedicated outlet without costly batteries while keeping the system fully code compliant.

2. The most cost-effective security you can buy

The $350 to $400 average cost for installing SPS is well worth the security and peace of mind it provides. The additional expenditure equates to only about $.05 per day over the lifetime of the system! And if your customer isn’t ready to commit to SPS right away, it’s a simple retrofit at any time after the system is commissioned. We’re fairly certain that after the homeowner’s first grid outage, you’ll be getting a call to come back for SPS.

3. SPS has a maximum of 2,000 watts and homeowners will want to know what that means

SPS can provide a maximum of 2,000 watts but most homeowners only equate watts with lightbulbs. Don’t be afraid to tell a homeowner what 2,000 watts can power. Help them by relating stories of previous customers who have used it to charge cell phones after a storm or to power gaming equipment for a family competition during an outage. We’ve even heard about a neighbor who used it to keep his beer cold. Your customer stories and suggested uses will make SPS more relatable. One handy and light-hearted way to show some example SPS uses come from our What Can You Power with SPS video (keep in mind this was made for the Sunny Boy TL-US’ 1,500 watt SPS).

What can Secure Power Supply do for you?

4. Nothing bad will happen if you try to use more than 2,000 watts

SPS is undersized relative to most Sunny Boys’ AC output. This ensures that even during cloudy or other low irradiance conditions, SPS will operate at or near nameplate. Think of SPS like a checking account. A homeowner can write as many checks as he or she wants, in the form of various devices being plugged in. He or she will simply be limited by the amount of money in the account. Though a homeowner can overdraw from their SPS checking account, SMA has built-in automatic over-current protection that simply deactivates the feature when either 2,000 watts or 20 amps is exceeded…and there’s no overdraft fee (someone needs to relay this concept to my bank!). The system will wait 20 seconds to reconnect and ensure the energy demands are below the maximum. That wait period allows the homeowner enough time to unplug one or more devices and bring the demands down, then check the inverter’s display to verify the amount of energy being used. This process can be repeated as often as needed for the homeowner to make the best use of the available power without any risk to the integrity of the inverter or the rest of the solar system.

5. If the homeowner has frequent outages and relies on SPS often, maybe they need a Sunny Island

SPS is the perfect first step for homeowners that are concerned about needing backup power. For those living in areas prone to winter storms or summer brown-outs, the initial value of SPS can be the gateway to helping them realize the potential of battery backup all-the-while determining their load demands based on necessity. The ability for these types of homeowners to feel the relief of backup power and determine the “must haves” from the “nice to haves” in times of grid outages creates a prime opportunity to discuss adding a moderate battery bank and Sunny Island to the existing Sunny Boy system. After all, customer education is half the work for battery-based systems. Letting SPS do some of the teaching better prepares the homeowner for the benefits and limits that battery-based systems allow for.

5/5 - (3 votes)
  1. Doug H
    Doug H says:

    Can SunnyBoy SPS outlets be paralleled? Much like how the grid-tie will do AC frequency/phase match, is this possible on SPS ports?

  2. Dan
    Dan says:

    I am planning to install 2 SMA Sunny Boy SB6.0-1SP-US-41 Inverters, is there any way to combine the sps from both converts to one source or combine for 240v?
    In the manual it states that the sps outlet should be within 30m of the inverter. I was planning on installing the outlet in my house which would be 100 ft away from the inverter. What is the downside of the longer distance?
    Also I do not understand the function of the Multifunction Relay. Can it be used to charge batteries?

    • Mike
      Mike says:

      Dan, there is no synchronization method for multiple SPS outputs, so no, you cannot create a 240VAC split phase service from two SPS outputs. The distance limit is primarily to manage voltage drop based on the maximum wire size allowed at the SPS terminals. You can transition to larger gauge wire for a longer run like you envision to minimize voltage drop. The Multifunction Relay is not commonly used. The battery charging function is not used for the Sunny Boy US line as no batteries attach to that inverter.

  3. Joe Burns
    Joe Burns says:

    Hello Mike, (this is really just 2 simple questions)

    Thanks so much for tackling some of these questions.
    I have read all these comments and have seen a handful of questions about when SPS is actually available but no answers.

    Would I be correct in thinking the 2,000 watts is general is only available during the peak sun hours (5.5 for me in Calif.) Assuming on a overcast day the SPS may only turn on for 1hr at “Solar High Noon”, correct? Additionally, when night arrives do you “have” to turn off the SPS switch and turn it on again when daytime arrives or can you leave it on and the SPS circuit will activate once it receives enough sun.

    This also helps answer what happens when the grid returns and the SPS is operating. Does the inverter automatically disconnect the SPS (and I have to remember to turn off the SPS switch so it is ready for next time)?
    Or I have to turn the SPS off and only then the inverter will do its checks and come back online with grid power.?

    I understand the SPS was likely concieved for short rolling outages and not storms and extended outages, but it just helps us understand its strengths and weaknesses compared to batteries.

    • Mike
      Mike says:

      Joe – The SPS can provide 2,000W any time the array can. This amount of time obviously depends strongly on the array size, as well as environmental conditions the array is experiencing. Be aware that in SPS mode the inverter will only provide as much power as the loads ask for, UP TO 2,000W. For operation, the inverter will stay in SPS mode that solar day until the switch is turned off. If the switch is left ON overnight, when the inverter wakes up in the morning, it will check for the grid and go back into grid tied mode if the grid is available, even if the switch is in the ON position (the SPS outlet will not be powered though). If the grid outage is still present the next day, the switch must be turned OFF and then ON again to re-engage SPS mode for that solar day.

  4. Edwin
    Edwin says:

    Ok: I have 7.7-41-us One Strings “A”; With Rapid Shutdown, what happens if I install another string “B” without Rapid Shutdown. Thanks… now this real one.

    • Mike
      Mike says:

      The system will not be in compliance with all of the requirements of 2017 NEC 690.12 without equipping all modules with a Rapid Shutdown receiver.

    • Mike
      Mike says:

      Fernando – the SPS availability for a Sunny Boy US-41 will depend on how you are complying with Rapid Shutdown (if it is required for your system). If Rapid Shutdown is not required, yes, you can utilize the Secure Power Supply. If you are using the Rooftop Communications Kit Phase 2 and TS4-R-O units to comply, then yes you can use the SPS feature but you need particular firmware (3.01.20.R or above) and also some additional hardware (a couple 9V batteries). Please contact SMA Service at for the Technical Note on utilizing the Secure Power Supply with TS4-R-O. PLEASE note the SPS function is not supported if using Tigo TS4-A-O units and external CCA. If you are utilizing SunSpec certified, SMA approved rapid shutdown receivers (JMS-F or TS4-R-F) and the built-in SunSpec shutdown transmitter of the Sunny Boy US-41 to comply, then with firmware version 3.02.08.R or higher, it is possible to utilize the SPS with restrictions. Please contact SMA Service at for the technical note that details the modified operation and other requriements.

  5. Dhanraj
    Dhanraj says:

    Hi Team SMA
    India looks to be a developing market for Solar Microinverters, We are a Solar Company in India & have developed a good market here, we have few projects where we want to use Microinverters and also want to sell the same product in India, please let us know whom to contact & how to reach you.

  6. Tom O'Connor
    Tom O'Connor says:

    I’ve enjoyed explaining the Secure Power Supply to homeowners for years, but now I find myself having to explain why their SPS on their Sunny Boy US-41 won’t work because we put TS4-R-Fs on all their panels.

    Might there be a forthcoming workaround for this situation? Might there be a workaround if I’m willing to forego the rapid shutdown functionality?

    Might a future software update be able to address this issue? Thanks.

  7. Dario Pulcinelli
    Dario Pulcinelli says:

    Hi !
    I’ve just installed a SunnyBoy 5.0-US and had the SPS configured but I thought the SPS output would have been automatically enabled in case of a grid outage, sadly I discovered you have to flip a switch (which is outside, near the inverter). I was planning about installing an automatic transfer switch to keep up my UPSes, network and pc but now I discovered I have to go outside and flip a switch and flip it back when the grid is back up. Is there a way to control the feature remotely if this cannot be automated ?

    • Mike
      Mike says:

      Dario – No, the SPS switch must be flipped to turn on the feature. This switch is asking the inverter to change from a grid interactive inverter (current source) to and off-grid inverter (120VAC voltage and frequency source) where MPPT tracking is not the goal, but load following. All safety checks needed before startup must also be performed after the grid failure and before SPS mode will be enabled, so it will never be automatic. Note that the SPS switch does not have to be close to the inverter or the SPS outlet, so it could be relocated to a more convenient location if desired. For automatic switching to backup power upon grid failure, the Sunny Island is the product you want.

  8. CLARK
    CLARK says:

    HELLO, I have an SMA 3.8 and 3.0 US 40 installed recently with Tigo optimizers Ts4 A 0 mission solar panels 7.4kw. Are there other options [hardware/firmware] in order to use my SPS feature so that I can plug in my fridge during grid outage/off grid during hurricanes?

    SCOTT NELMS says:

    I have installed a 19.2kw system with 60 Jinko 320 Eagle panels and 3 Sunny Boy model 40 inverters with the 3 2000w plugs inside of the hose. How can I test in advance to see if I can run my large but new LG energy star fridge. My idea was to set the fridge part for max cold even if it freezes in the day so it does not cycle on and off.

    There is a master safety disconnect lever between my meter and my inverters. Can I just turn that off to get some idea in advance what can be run? Also, one of my inverters is a 7.0, should I try and identify that for the fridge vs the 6.0s? Or does that make a difference? Thanks

  10. J. Thomson
    J. Thomson says:

    Most of my customers want a secure power supply. A true sense of security means you can depend on it when you need it and it will start the loads you need most. Back-up up power is most valuable during a storm, at night when you need need lights, or when you need to start a well pump. Once I explain to customers SMA’s SPS doesn’t work at night and may not start a pump, the value of this feature is diminished significantly. I prefer to simply avoid the SPS topic all together as it brings up too many negatives and just sell them a battery and keep the customer experience positive.

  11. Brian Brown
    Brian Brown says:

    So looking to hook up 2 sma 7.7 and use the SPS in a sub panel box to make 220 to run my well punp it needs 180 volts plus 5 amps to run. looking to fill up a 500 gallen tank that sits near the house and use gravaty to feed from a 3 inch to 1 inch line. Question when its running will i only have 15 amps and 1820 volts left for house ?

  12. mcsherman chidukwana
    mcsherman chidukwana says:

    i have a sunny boy 3000tl-20 it does not have the SPS connections is it possible to purchase the module and install it
    or it does not support totally

  13. Allan
    Allan says:

    I believe I read that the SPS functionality will not work with DC optimizers. Can you say if that is correct and why it can’t work? Also is this something that could be “fixed” in the future.

  14. Adner
    Adner says:

    In a power outage, is there a way to enable the SPS outlet once the TS4-R-F do the rapid disconnect (per latest 2017 NEC stipulations)?

  15. Ehren
    Ehren says:

    Can the sps be wire directly to a panel with an interlock? If so can two sps feed into the same panel on each leg or will this create a neutral issue? 120v breakers only

  16. Rick Anciado
    Rick Anciado says:

    Can I use the SMA Sunny Boy with SPS feature in the Philippines ? The residential voltage here is 220V and 60HZ.

  17. Wynnn
    Wynnn says:

    Hi, I have 8 panels with micro inverters – the array is physically up for 4 years but never connected. Not sure what happened from previous owner (job never completed?)

    There’s a line to the main panel, but switched to off.

    I was going to ask if I can just connect that line to a Sunny boy and get power from the outlet when the sun is shining, but then I saw that it may not be compatible with Enphase micro inverters?

    What should I do to make this grid-tied off grid even with limited day time only use from a single power outlet?

    8 panels is what <2kWatt? Just want to be able to use it cheaply, safely (not connected to the grid), as opposed to a roof decoration.


  18. Roland
    Roland says:

    Hi, we live in New Zealand and I’ve got a Sunny Boy as well. Is it possible to get the Secure Power Supply here as well? Or is it only available in the US?

    I want power during an outage and without SPS I would have to buy a battery solution which is quite expensive.

  19. william
    william says:

    SMA sunnny boy inverters deliver on value and quality for grid-tied residential systems. I find that customers who aren’t interested in a hybrid with battery back-up array, or who aren’t budgeting for one, will find the SPS mode as a major secondary benefit in essentially allowing the homeowner to have the benefit of back up power when the grid does happen to be down.

  20. Josh
    Josh says:

    Is there an electrical code requirement in California that adds to the cost of upgrading to an SPS system. A local solar contractor is telling by that it will cost $1,500 due to special California electrical code requirements. He mentioned something about needing individual disconnects at the solar panels if the SPS upgrade is provided. Is this correct?

  21. Phillip Glau
    Phillip Glau says:

    My main refrigerator is 13 LRA @ 120VAC (~1560 W) but operates at 6.5 A (under full load) = ~780 W.

    Given the above, it it reasonable to assume the the 2000W version would be able to start the compressor on my fridge?

    Would the 1500 watt version be able to handle the instantaneous draw to break rotor lock?

    Also there a separate peak/instantaneous rating for the SPS as different from continuous rating?

    Are there guidelines/specifications regarding load that have LRA specifications?

  22. Dave Anderson
    Dave Anderson says:

    I have a SB 6.0-1SP-US-40 and a generator connected to the main feed with a manual 125/30 amp transfer switch. It seems if a power failure occurs during the day and the weather is mild so no need for A/C or lights thus the prime need is only for the refrigerator and freezer and maybe a fan then using the SPS power would make more sense than the generator. Is there a way to wire this permanently to a single 110 side of a electrical panel or to wire another 30/30 transfer switch that would be both safe and convenient instead of using extension cords and pulling out the appliances to get to the plugs?

    If no power is being drawn from the SPS outlet is there any reason it could not be left turned on?

  23. Tim O'Flaherty
    Tim O'Flaherty says:

    So, a storm hits, the grid goes down temporarily, I hit the switch on the dedicated outlet/switch installed and I have access to 2kw of power assuming there is enough sun on my array to generate it. If I understand correctly, as sun/available power varies my system will shut down when I exceed available power and attempt to turn back on after a pause to allow me to unplug an item or two. Two questions, does that happens without me using the switch, yes? and… When power to the grid is restored do I need to turn off the switch to the SPS before the full system powers up?

  24. Miguel
    Miguel says:

    Does the SMA 7.7-US come with SPS??
    I am installing an array with this SB but the Inverter hasn’t come yet.
    This SPS may help me while I may get a Sunny Island.



  25. Michael G.
    Michael G. says:

    Hi there, I’m not a solar professional but am interested in disaster resilience — this is very exciting technology. I’d like to get a sense of how many existing residential rooftop systems are compatible with this technology. Can any system be retrofit to add this conponent? Can most added in the last 5 years? I’m in California if that’s helpful information.

  26. Ron
    Ron says:

    My system has two Sunny Boy 3.8-US inverters, each with a Secure Power duplex outlet. 2000 watts per outlet. Can these two outlets be paralleled to provide 4000 watts of power?

  27. Les Kangas
    Les Kangas says:

    Please explain that the sun must be out, meaning, if you are in Oregon and it is raining or snowing, you won’t get 2000w and those are the times the grid goes down.

  28. Carlos R
    Carlos R says:

    Can I install the SPS to a Sunny Boy SN10000TLUS-12? That’s the unit I have but it didn’t come with it installed. If so, how can I get one?

  29. Steve
    Steve says:

    If I have a SUNNY BOY 7.0-US and a 7.7-US, can I use the SPS from each of these to produce 240V or would both of these be in the same phase? If so, can the phase of one be adjusted to make the 240V?

  30. AlexYackery
    AlexYackery says:

    When it is about the householders, it is very important to serve them with the most cost-effective security. As far as cost for installing is considered, $350 to $400 is an average cost and worth spending. Moreover, additional expenditure of only about $.05 per day, that too for the entire lifetime is not at all a bad deal.


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