when i saw our new 50W solar panel, it was much smaller than i'd imagined. my father had already hooked it up to our 35Ah battery. instead of MC4 connectors, this panel came with a small junction box that had an USB plug and a standard 12V plug. my father had jerryrigged a standard 12V adapter with two wires coming out of it into the controller to charge the battery.
we decided to hook up the solar panel to the wattmeter to get a better idea of the power output. the wattmeter said it was only generating 6W (0.5A x 12V), in full sun no less, not the advertised 50W. we took a direct reading of the panel (carefully inserting the probes into the 12V plug) which showed 18V, not 12V. why the voltage drop? when we checked the wattmeter-controller setup in the basement, it was reading 14V; not 18V but also not 12V either. so the new panel seemed off. we couldn't figure out the voltage drop, but i theorized that maybe there was a tiny safety controller in the panel junction box that was keeping the voltage at 12V whenever it encountered a load.
the solar panel current was unexpectedly low however, and when i read the specs (not sure why i didn't before), it said the maximum current was only 1.1A, with an open circuit voltage of 20V. so even if everything was operating at peak efficiency, we could still only achieve 22W maximum, not the 50W advertised. this was just a 20W panel being sold as a 50W. even the solar cell count was off. this one only had 6 monocrystalline cells, while our 100W panel mounted outside had 36 cells (9x4). to achieve 50W, a panel should have around 18 cells.
we opted to return this underperforming 50W solar panel and get a new one instead, one that's actually 50W. after some searching on ebay, i found a US-based seller that carried flexible 50W monocrystalline solar panels for $54.45. the going rate for panels is about 1W/$1 so this was a fair price. besides being waterproof, this panel also used MC4 connectors, a larger gauge wire that's standard for large solar panels. specs-wise, the working voltage was 18V while the working current was 3A for a maximum wattage of 54W. there were a few cheaper vendors but they all shipped out of china, so who knew how long it'd take to arrive. this way the panel would hopefully arrive by next week.
after finishing some noodles for lunch, i went into the backyard to take a survey. i was happy the lotuses had survived despite the nightly cold weather. the 3rd aerial leaf is slowly opening. one thing i noticed is that some aphids have invaded the stem, which i removed easily enough with some fingers.
my father and i readjusted the shelves on our grow room wire shelving units. we raised the middle shelves so they were near the top, then capped the ends of the top posts with double hanger rails. we hung the led grow lights from the bottom of the relocated top shelves, and laid 2 rows of fluorescent T8 shop lights on top of the hanger rails. the 45W led light still hung on top of the papyrus reeds, while the led shop light hung over the topiary bushes.
not trusting the efficacy of the XECCON grow light, we decided to get yet another grow light, and maybe possibly return the XECCON. it didn't take long to decide. we weren't going to get a light with reflectors: they produce more PAR but only in a small concentrated area. a regular led grow light would cast a wider beam. nothing really stood out in terms of quality for the price, so we decided to get another iplantop grow light for $69, scheduled to arrive tomorrow.
i noticed my parents had received a letter from the town of belmont's tree warden, informing them that the partially dead maple tree growing in front of their house will be removed. finally! i've been writing to the town every spring, asking them to at the very least remove the very large overhanging branch above the driveway, but they always refuse, saying that the tree is still alive (even though it's covered in lichen) and to remove that branch will rob the tree of too much nutrients. but it's so obvious that it's a safety hazard, glad they finally came around. i should've realized something was up when i noticed wood shavings around the tree, like maybe somebody was doing some work on it, but i didn't see any cut branches. they probably were going to do some pruning, but decided it was better just to remove the tree altogether. the letter didn't say when they'd take down the tree, nor if they were going to replace it with something else. there was also no mention of if they were going to fix the sidewalk, which has since buckled from the underground tree root to the point where you can wheel over it anymore.
my father found a neighborhood female gingko tree that was setting fruits and collected a few. the last time i saw gingko fruit was in 2008 when i went with john to prospect park in brooklyn, and saw some asian women collecting them in the park. though they're an asian delicacy, the thing most people recognize about the gingko fruit is how bad they smell. i remember they were pungent, but smelling them again, i don't remember them to be this bad. they smelled like stinky blue cheese. imagine having a gingko tree fouling the neighborhood with the smell of feet.
without even paying much attention to it, but today's solar production graph was a perfect bell curve. i'm thinking about using it as the default production value moving forward.
i needed transistors to make a darkness sensing circuit. a lot of videos and write-ups i saw online mentioned the BC547 transistors, which i was about to buy on ebay, but decided to rummage around in my electronics parts collection to see if i had any lying around. sure enough, i came across some 2N series transistors. apparently transistor availability is regional: in europe and india, BC547 are more common, while here in the US, 2N-series are more common. i bought these 2N transistors not so long ago, in 2012, from the porter square radio shack no less. it was probably the last time i purchases electronic components in a store than online.
armed with my newfound transistors (i only needed one, i picked 2N3904), i built a functional darkness sensing circuit. i'm still not quite sure what i did, i need to study the circuitry a bit more to make sense of it.