Enphase promotes gas-generators over battery back-up, do you agree?

frank.thomson Registered Users Posts: 15

Wonder if this is to downplay that their micro-inverters or modular storage can't be used for back-up or off-gird capability. Their reasoning that Tesla pulled back the back-up version of power-wall from market, hence people don't need battery back-up sounds strange. What do you guys think?



  • BB.
    BB. Super Moderators, Administrators Posts: 33,404 admin
    If you have grid power--Most people will never need more than a handful of hours of backup power... Either live without lights/power/etc. for a few hours, or possible a genset (fuel, someplace to install/store genset, etc.).

    For those folks that have two weeks or more a year (ice storms, etc.), rural areas that take days/weeks to restore power, etc... Then you are looking at (possibly) justifying a solar power and/or backup generator system.

    But batteries, by themselves, only give you hours to a couple of days of backup.

    Batteries are expensive and have a definite storage and operational life (5-20 years, depending on lots of factors and costs). And do consume electricity to float--Need service, testing, cycling, etc. Perhaps some new chemistry like Li Ion of some sort can address many of these issues (low self discharge rate, don't need to check water, cycling to keep plates working, etc.).

    In the end, it depends on your needs and personal choices. But--I would have to agree that a battery backed grid tied system (to me) would be large enough to run some lights/computer/tv overnight (small system)--And fire up the genset during the day (run appliances, washer/drier/etc.).

    If you live in a climate where extreme heat/cold is live/death factor--Then having a layered backup power plan is important.

    But if your power failures are due to heavy wind storms or earthquakes--Then your battery/solar/and home may not be usable/livable anyway (broken panels, flooded home, city sewer/water unavailable, etc.). And all that investment may be useless.

    It is possible to setup an Enphase array with a hybrid AC inverter (including internal AC to DC battery charger) to run Enphase units "off grid"--But this is still a pretty sophisticated system that needs maintenance. Besides battery life--Once the AC inverter and such get over 10+ years--Eventually they will need replacement. A small backup genset running fuel of choice (natural gas, propane, diesel, gasoline, etc.) is usually a lot cheaper and portable if the home is unlivable. And, for me, storing 20 gallons of gas can be used for bugging out in the car/pickup/van (with the hassles of fuel stabilizer and replacing fuel at least once per year)..

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,711 ✭✭✭✭✭✭
    If it is time to cycle some of that gasoline Bill,  where are you going to go? You have to make the trip before the kids get out of school.
    Hint hint!

    Tesla quit the first version of their "power wall because it was only good for 500 cycles. Others are building a 4,000 to as high (they say)
    as 10,000 cycles. Placing inverters outside anywhere is just against the whole reliability thing in offgrid applications in my opinion.

    I like all the nice specs on LFP but I really am looking for more failure mode data. The lowly 85% efficient flooded battery has a very nice slow failure mode that can be detected in large systems for months or even years in advance in most cases.
    "we go where power lines don't" Sierra Nevada mountain area
    E-mail [email protected]