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  1. Hedges

    Battery ripple current

    After reading of someone tripping battery breakers at well below rating, I realized that could be due to pulses of current drawn by the inverter. Ideally capacitors would smooth out current draw so high frequency switching pulses and 60 Hz draw all came from the caps, and current from batteries...
  2. Hedges

    U.S. 50% of the way to carbon-free generation The projected increase didn't happen. We're only half as bad as we thought we would be! (In other news, Congress is 50% of the way to balancing the budget.)
  3. Hedges

    Should'a used LiFePO4
  4. Hedges

    California tries to promote Tesla Powerwall (and the like)

    More attacks on grid-tie PV. Of course PG&E is entitled to be paid for the services they do provide. But if this would be $75/month flat rate for a net metering customer, that would be excessive if customer's electric consumption had averaged only $75. Maybe wouldn't have been quite that, looks...
  5. Hedges

    Now THAT's not something you see everyday!
  6. Hedges

    Market rate prices for electricity are great ...

    ... so long as prices are clearly posted on the shelf.
  7. Hedges

    Raspberry Pi Pico (microcontroller)

    Raspberry Pico, a microcontroller to handle overhead without using a massive computer like the Raspberry Pi itself. Programmable in Python, it seems. "Raspberry Pi on its...
  8. Hedges

    When utility-scale PV is cheapest Of course, at some point PV would approach 100% of consumption during productive hours (or 100% excluding other baseline sources.) A bit of overpaneling would fill in for partially overcast periods. Beyond that, value of the...
  9. Hedges

    For those of us who wear tin foil hats

    Apparently we have been mislead, and tin foil hats actually make us more susceptible to the government's microwave transmissions from space: Of course, the government itself was behind the misinformation...
  10. Hedges

    Refinance rates

    If you haven't noticed recent mortgage rates, take a look now! For decades, 6% 30 year fixed was the unattainably low rate my mother had on her house, assumed in 1965 and initiated around 1955. As rates have fallen over the past couple decades, I've paid to refinance over and over again, locking...
  11. Hedges

    Where I Live (not really, although my acreage is in the hills above there) I think even Will would have difficulty qualifying for this (at least until he can document a couple years at his current income.) $8000/month...
  12. Hedges

    Testing Metal-Oxide Varistors (MOV)

    Surge arrestors are used on AC and DC side of PV inverters for protection, to clamp high voltage transients. One inverter I have (actually several) are in the SMA family SUNNY BOY 5000-US / 6000-US / 7000-US / 8000-US. These come with a kit of MOV to protect the DC side: The MOVs are about...
  13. Hedges

    Testing automotive fuses

    After watching a video (sorry can’t find it now) showing resistance testing of cheap fuses and name-brand ones, I decided I’d better test the ones I’ve put in our cars. In the video, it was said that previously Harbor Freight sold fuses, but later recalled them and didn’t carry anymore. Fuses...
  14. Hedges

    Converting a refrigerator/freezer to freezer only

    My upright Frigidaire deep-freeze wasn't freezing anything more concentrated than ice cubes any more. Things were mushy and spoiling. Maybe it just needs a refrigerant recharge; I'll look into that later. Went to the store and found they all have 60 or 90 day delivery. Only come out of China...
  15. Hedges

    Delta LA 602 Lightning Arrestor "Hey! Is this thing on??"

    I've been using Delta Lightning Arrestors on my system since they were spec'd by Real Goods as part of the package I bought from them. I now have a surge capacitor on the AC input as well, which is supposed to slow rising edge of voltage so it doesn't get as high before the Silicon Oxide...
  16. Hedges

    Power Factor and Startup Amps

    Because I have suitable equipment I'm going to put up measurements I've taken, might help someone with planning a system or general education. Motors draw a startup surge of considerably more amps than they draw while running. With grid power you may see the lights dim briefly, but if you have...
  17. Hedges

    Sunny Boy frequency-shift regulation of power output - which models work per spec?

    I'd like to hear from you guys as to your experience with various model SMA Sunny Boy on Sunny Island systems. I'm not seeing them respond properly to frequency shift in "Backup" (default = UL1741 & backup = On All Phases or On, depending on model and interface.) I'm only getting it to work in...