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<\/a><\/p>\nVersion 2.0. A stack of cards, most of them dashes, because the inverters had
\nstopped reporting to the vendor’s cloud the morning before. The one live number
\nwas the battery, from the Victron shunt, and it said 5.8 percent and falling at
\n1.7 kW. The “power left tonight” card said zero minutes, because it was
\ncounting down to a 15 percent floor we had sailed through hours earlier.<\/p>\n
That screen had three problems that shaped the whole weekend. It depended on The plan: move the operation to a second laptop that lives in the solar room, The work ran as two Claude Code sessions, one on the laptop that travels and The tank link is two Heltec LoRa boards. The one that goes up the hill got That photo caught the first real bug. BASE says GOOD, sequence 5, one second Then the walk. It failed in the front yard.<\/p>\n Fifteen pings missed in a row, through one wall and some Douglas fir. The The next walk reached a quarter mile. Then a 40 minute drive around town with Solid out to about half a mile, a ten minute stretch of nothing at the far The level sensor is a waterproof ultrasonic module, the kind used for parking Getting four wires onto the right four holes took longer than writing the First power-up: every one of nine pings came back as a pulse of exactly 35.2 Two modes came out of the bench testing. TEST takes a reading about once a The sensor went onto the tank 3.7 feet above the water. The tank rules are deliberately blunt. A reading of one foot or less is FULL. Deep sleep had never run before the unit was on the hill, so it got a staged The fill and drain rate is the slope of a straight line through the last 45 Where to put the base station is still not solved. Next to the solar The battery monitor’s hub, a Victron Cerbo, had been reaching the internet An Ethernet switch, a WiFi extender used as a bridge, and one cable to the The hub wanted a password before it would hand out data, which took two With live data arriving, the cards stopped being good enough. The brief for First cut, 3:37 in the afternoon:<\/p>\n Good, and wrong in two ways that two of us spotted independently. The battery’s wire hung off one inverter and the pump’s wire off Second round, 21 minutes later:<\/p>\n The inverters swapped sides to match the real wall. A wire chase appeared That counter deserves a paragraph. The old screen had claimed a 21 day Third round, eight minutes after that:<\/p>\n Two months along the bottom. Today’s energy at the top, made against used. A few rules settled along the way and are now permanent. Every number shows At this point the version was set to 4.20 and pinned there. By instruction, Last job of the day. Each inverter has an RS485 port that normally feeds its Two USB adapters, two cut-down network cables, brown and white-brown on the And then nothing. Read-only requests at three speeds and two addresses, on Silence is a clue. A wrong speed gives you garbage. Silence means the The inverter calls pin 7 “B” and pin 8 “A”. The adapter also has terminals One inverter on the wire, the other still dark, and the totals showing dashes The second pair of wires got swapped, and at five o’clock:<\/p>\n<\/a><\/p>\n
\ntwo vendor clouds, so when either one hiccupped it went blank. It was slow: the
\nbattery figure came from a database that only produced a new sample about every
\n105 seconds. And it told you nothing about water, which on a ranch is the other
\nthing you run out of.<\/p>\n
\nwire that laptop directly to the equipment, and put a level sensor on the tanks
\nhalf a mile up the hill.<\/p>\nTwo machines, passing notes<\/h2>\n
\none on the laptop that stays, messaging each other over a Tailscale network.
\nOne did the radio firmware, the phone app and the coordination. The other owned
\nthe wall display and everything plugged into it. Most of what follows was
\ndecided on a phone, standing next to whatever was being wired.<\/p>\nThe radio link: three bugs before the first walk<\/h2>\n
\nnamed HILL, the one at the bottom BASE, and the name is printed in big letters
\non each screen so they cannot be mixed up. The first firmware was a range
\ntester: HILL pings, BASE answers, both screens show signal strength in both
\ndirections.<\/p>\n<\/a><\/p>\n
\nold. HILL says sequence 38 and no link. BASE was frozen. With its USB cable
\nplugged in and nothing reading the log, the log buffer filled after six lines
\nand the board hung waiting to write. The fix was to drop a log line when the
\nbuffer is full instead of waiting. The same photo shows the second bug: “NO
\nLINK” was two characters too wide for the screen.<\/p>\n<\/a><\/p>\n
\nowner’s reaction was the right one: something is wrong. It was. These boards
\ncome in two revisions with different radio amplifier chips, and on this revision
\none control pin has to be flipped for every transmission. The firmware was
\nholding it in the receive position, so the amplifier never switched on and the
\nsignal leaked out roughly 40 dB down, about a ten-thousandth of the intended
\npower. With the fix, the same two boards on the same desk went from -40 dBm
\nto about 0.<\/p>\n
\nthe logger running:<\/p>\n<\/a><\/p>\n
\nend, and a clean recovery on the way back. One calibration came out of that
\nchart: on these boards a receive amplifier sits ahead of the measurement, so the
\nsignal figure reads about 20 dB high. The link dies near -100 on the screen,
\nnot the -125 you would expect from the radio chip alone. Signal-to-noise is the number
\nto trust.<\/p>\nThe sonar: which hole is hole 6<\/h2>\n
\nsensors. It runs from a switched 3.3 volt pin on the board, which matters
\nmore than it sounds: the module idles at about 5 mA, and left on all day that
\nwould be several times the rest of the power budget combined. Switched, it draws
\nnothing between readings.<\/p>\n<\/a><\/p>\n
\nfirmware. The manufacturer’s diagram shows the front of the board; the holes are
\nlabelled on the back; and one early message called them “pin 17 and pin 15”,
\nwhich are positions along the row and also happen to be numbers printed on four
\nunrelated pads. The numbers printed next to the holes are the ones the code
\nuses. The hole between the two sonar wires is the amplifier control pin from the
\nprevious section, so it stays empty.<\/p>\n<\/a><\/p>\n
\nmilliseconds. That is the module’s own “I heard nothing” timeout, which was
\ngood news in disguise. It proved the board was powered, triggering and replying
\nat 3.3 volts. It just had nothing in front of it. Pointed at a wall, it returned
\nnine good pings out of nine.<\/p>\n
\nsecond, for aiming the sensor with the unit in your hand. FIELD takes one on a
\nschedule and sleeps in between. A button on either board flips the mode, and the
\nbase station can change the schedule from the bottom of the hill, because every
\nanswer it sends back up carries the settings.<\/p>\nOn the hill<\/h2>\n
\nThe display said 3.7 feet.<\/p>\n
\nSeven feet or more, or no echo at all, is EMPTY. A sensor that produces no pulse
\nwhatsoever is a FAULT, because “no echo means empty” would otherwise turn an
\nunplugged cable into an empty tank. Three 2,500 gallon tanks in parallel make
\n7,500 gallons, which works out to 1,250 gallons per foot of water.<\/p>\n
\ntest from below: one-minute readings first. HILL slept and woke itself three
\ntimes, 63, 63 and 59 seconds apart. Then ten minutes, and the next reading
\narrived 597 seconds later.<\/p>\n<\/a><\/p>\n
\nminutes of readings. The sonar is good to about a centimetre, which here is
\nabout 40 gallons, so at one reading every ten minutes the rate is honest to
\nroughly one gallon per minute and anything smaller is shown as “steady”.<\/p>\n
\nequipment it heard the hill well but had poor WiFi, and something in that room
\nputs bursts of radio noise on its receiver. On a roof nearer the access point
\nthe WiFi was fine and the radio was at the edge of what it can decode. On top of
\nthe generator, about the same. A tall antenna for the base station is the next
\nexperiment.<\/p>\nThe Victron on a wire<\/h2>\n
\nover weak WiFi. That afternoon the wall showed its data as 3,668 seconds old.
\nMost of that hour was real: the hub had been off the cloud for most of two and a
\nhalf hours.<\/p>\n
\nhub fixed the path. Then one switch on the hub’s own screen:<\/p>\n<\/a><\/p>\n
\nattempts to get right. Once it accepted one, the numbers were not subtle. The
\nfirst value arrived 0.6 seconds after connecting, where the cloud feed took
\nanywhere from five seconds to a minute. Updates come once a second. A ping to
\nthe hub over the wire takes 0.4 milliseconds; over its WiFi a few minutes earlier it took
\n429.<\/p>\nThe wall display grows up<\/h2>\n
\nthe 27 inch touchscreen was one paragraph: it should look like a picture. Solar
\npanels at the top. The two inverters in the middle. The battery on the left. The
\nload on the right, drawn as a water pump. And coming off the pump, the tanks,
\nwith blue water at the real level.<\/p>\n<\/a><\/p>\n
\nthe other, as if one charged and the other pumped. Both do both. And the battery
\nwas green while it was draining.<\/p>\n<\/a><\/p>\n
\nunderneath them, because there is one, six feet long, and that is where the
\nwires actually go. The battery turned orange while discharging; it is green when
\ncharging and red only when it is genuinely low, so red still means something.
\nAnd the “days off the grid” counter was replaced with a month of daily bars in
\nthe style of a utility bill.<\/p>\n
\nstreak. Part of that streak was a day when the inverters reported nothing at
\nall, which the old code had read as “zero grid use”. The new chart has a third
\nstate for exactly that: a day with almost no solar recorded is marked as no
\ndata, not as a win.<\/p>\n<\/a><\/p>\n
\nAnd the words “hardwire” and “wireless” replaced by a tiny plug and a tiny WiFi
\nsymbol on each part, driven by the path the data is really taking. They are
\nsmall on purpose. One person in the family wants to know which parts are on a
\nwire. Another just wants to see the water.<\/p>\n
\nits age in minutes and seconds. A reading that stops arriving is never blanked;
\nthe last good value stays up with its timer running. And a total is never built
\nfrom half the system: if one inverter is silent, the total shows dashes and says
\nwhy.<\/p>\n
\nit stays 4.20 forever.<\/p>\nThe inverters: two wires, wrong way round<\/h2>\n
\nWiFi dongle. Pull the dongle, plug in a cable, and the inverter will answer
\nquestions directly, about once a second instead of every couple of minutes.<\/p>\n<\/a><\/p>\n
\nscrew terminals exactly as the guides on the internet show. Both dongles came
\nout. The wall went grey on the inverter side, as it should.<\/p>\n<\/a><\/p>\n
\nboth cables: zero bytes back. Not garbage, not errors. Silence.<\/p>\n
\ninverter is not hearing the question at all. The socket was right (the upper
\nleft of the two unlabelled ones at the top). The settings were right (19200
\nbaud, address 1, confirmed afterwards against two independent sources). That
\nleft the two wires.<\/p>\n<\/a><\/p>\n
\ncalled A and B. They are not the same A and B. Swapping brown and white-brown
\non one adapter turned twenty requests into eighteen clean replies: battery 52.4
\nvolts, one solar string at 239 volts and 762 watts, the other at 342 volts and
\n906 watts, output at 239.0 volts and 59.91 hertz. The inverter also reported
\nits own serial number, which is how each cable is now pinned to the right
\nbox.<\/p>\n<\/a><\/p>\n
\nrather than half the truth. One detail from that first frame: the inverter
\nbelieved the battery was at 81 percent while the shunt said 35. The dashboard
\nignores the inverter’s opinion and always has.<\/p>\n