when i arrived in belmont, i found my father had already connected 4x 3.2V LiFePo4 batteries in parallel with busbars so they can balance naturally, i.e. allowing the electricity to flow between the batteries. each of 4 cells ending up settling to 3.264V.
my father made pan-fried dumplings for lunch. after i ate my portion, i ate my father's share as well when he said he didn't want them anymore. the key to good dumplings is the sauce, and i had a really nice one, a combination of garlic, cilantro, soy sauce, and a generous heaping of chili garlic hot sauce.
since the battery cells were balanced, we decided to connect the daly BMS so we could monitor the individual cells. first my father had to crimp ring terminals onto the provided balancing wires. with a lighter, he sealed the heat shrink wrap on each terminal. we arranged the cells so we could connect them in series with 3 busbars. the whole process looked very much like we were building bombs in the dining room, with stacks of mysterious solid boxes connected with various wires and other devices. anyone looking through the window might've reported us.
we ran into a problem with the balancing wires, they barely stretched far enough to connect to the BMS. we had to get creative, mounting the BMS at an angle so it could reach the various battery terminals. once everything was connected, we took a reading from the positive end of the battery to the negative terminal of the BMS. it read 9V. however, when we took a reading directly from the batteries, it gave us a combined 13V. that fact that the BMS read 9V meant it wasn't activated. it needs to receive a bit of current in order to turn on. but the other way to activate the BMS is actually by connecting to it via bluetooth. we downloaded the app, reset the bluetooth dongle, connected to the device, and successfully communicated with the BMS, which also activated it.
in the afternoon we realized costco sales ended next weekend. we could go next week, or go now while we still had time. so we left for the waltham costco by 3:30pm. when we arrived my father realized he didn't bring his membership card, so he went to the membership desk and got a temporary id.
the thing we wanted to get at costco was the sur la table 13qt air fryer, on sale for $80. it features dual cooking trays, so my father could cook double the amount of charsiu pork. it has tons of other features like rotisserie spit and rotating drum basket and kebab skewers, but we just like it for the double frying trays.
we also got a new patio umbrella for the cafe parking lot mini-deck. the one we got last year is cantilevered, and already damaged from rubbing up against the wall on windy days. this new one is centrally mounted (market umbrella), but hopefully that makes it more stable. we tried to find an umbrella stand but they didn't seem to have any for sale; we'll use our old one, if that doesn't work, we can buy a stand elsewhere.
we didn't get back home until after 5pm. it was too late to make a beef stew (which was my father's original idea), so instead we did the next best thing: opened up a large can of dinty moore beef stew. i haven't had this in years, ever since i learned how to make real stew with real beef, not processed meats. my father also made some bacon and asparagus; the asparagus turned out to be really sandy, which we've never seen before. we waited a long time to cook the rice, and it wasn't until the rice cooker popped for the second time did we realize my father forgot to add water to the rice cooker.
i went into the backyard in the early evening to check on the rain barrels. the silicone caulking job we did was perfect, not a single barrel leaked. however, one of the 4-way plastic splitter had a crack in the manifold, and was dripping water. i shut off all connecting hoses and removed the splitter. i thought about caulking it with silicone (is there anything i won't caulk?), but better to just buy a new one.
the bench power supply arrived right when we were having dinner. we paused so we could attach it to our BMS-batteries. it started recharging the batteries, but quickly stopped when it reached full capacity, or at least what we set it to, which was actually 70% of full capacity. we tested it by attaching an led string light. the voltage across the bms was 12.5V, but when we measure the batteries directly, it said it was 13.1V. something was off, most likely because we didn't fully charge the batteries before we connected it in series and attached the BMS. based on the voltage of the individual cells, we were actually at 30% of capacity. the BMS got confused and read that 30% as full capacity, and adjusted all the measurements accordingly.
after dinner we disassembled the BMS-batteries and wired up the battery cells in parallel again. we then used the bench power supply to charge up the cells to 3.6V, which would give us a combined series voltage of 14.4V (3.6V x 4), which is the maximum voltage for a 12V LiFePo4 battery. the power supply was charging at 3.6V, but the amp - even though i turned it up to 10A - was only charging at 2.7A, which comes out to about 10W of power. at that rate it'd take a long time before the 4 battery cells would reach the maximum charge capacity of 3.6V. but as we watched, the current slowly increased. my father did some calculations, said at this rate it'd take 24 hours before the batteries would be fully charged.
i left after 8pm. riding back home, i saw some flowering trees illuminated in street and traffic lights, and stopped to get a few photos with my phone.
it was cold enough that the heat turned on when i got home. the energy miser in me wants to turn off the furnace for the season, but what harm is there to leave my nest thermostat on for another week or two? until the spring weather really takes a turn and we stay warm until the fall.
i ordered some more led strip lights, splurging on a set of 10 barrina 2ft lights for $100. i just need 3 more for my grow closet, but i can imagine using them for future indoor plant growing projects. perhaps set up a seedling station at my parents' place? they have a spare wire shelving rack they haven't assembled yet.