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Joined 1 year ago
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Cake day: June 11th, 2023

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  • Unfortunately, yes.

    I’ve had multipe experiences with seeing a flashlight battery which, according to labels, ought to have the capacity of an electric vehicle cell. And of course they don’t - on EBay or AliExpress, there’s a 100% chance that they’re just deceptively labeled. :)

    If one needs high current, measuring the current with a known and low resistance (e.g. car headlight bulb) helps.



  • No experience on that front, sadly.

    Compared to iron redox flow batteries, it has about 5 percentage points of more efficiency (75 vs. 70%), slightly better cell voltage (1.8 vs 1.2 V) and better energy density per electrode surface (0.2 W vs 0.05 W / cm2).

    The “resetting” of cells seems like a nuisance however. Quoting Wikipedia:

    Every 1–4 cycles the terminals must be shorted across a low-impedance shunt while running the electrolyte pump, to fully remove zinc from battery plates.[3]

    It’s probably doable, but not a particularly attractive technology when compared to alternatives.


  • perestroika@slrpnk.nettoDIY@slrpnk.netWeekly What's Up?
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    1 year ago

    Still building a DIY tractor / excavator - racing against time, as autumn is rainy here and you cannot weld water. I need it to improve the road to where I live.

    It can already maneuver, turn and raise the boom, lower / pull the bucketed arm (stick), but the excavator bucket is incomplete and the bucket tilting mechanism missing.

    The remote control system is also missing (relays on a slow boat from China), so currently I have to control it via cables. Limit switches are missing, currently it’s unsafe to use for a careless operator. Later on, it will be remote controlled and limit switches will ensure it cannot break itself.

    My own reason to choose remote control is convenience (better ergonomics as I can write pre-programmed movements and stay out of noise). If it works too well, I might send a recipe to a friend in Ukraine, with the suggestion of asking around - maybe someone needs cheaper mine disposal machines.

    Hydraulic excavators are neat, but too expensive for me, and require far too much power. Thus mu excavator uses ATV winches (meant to pull a 900 kg machine out of mud) to drive and work. Some of the winches have been disassembled: driving uses sprockets and “08” roller chain, turning the boom also uses sprockets and chain. Some of the winches are intact however: raising the boom uses a winch in factory condition, and pulling in the bucket in also uses a winch.

    A big corner has been cut to gain strength asymmetrically and reduce complexity: I assumed I’m never going to do a pushing movement with the bucketed arm. So, where old-fashioned cable excavators used a super complicated winch system to extend the arm, I use a boring simple gas spring. Near-zero pushing-out power to gain the absolute maximum pulling-in power.


  • perestroika@slrpnk.nettoDIY@slrpnk.netFix leaking kettle
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    1 year ago

    I would recommend motor silicone, since it’s often rated for 300 C. The surface being sealed should be scratched or sanded for better adhesion. After it has fully cured (several days), one should probably do about ten “test boils” to flush out anything that might seep into water.



  • I have tried polycarbonate, with miserable results. The clear silicone did not not adhere well, and thermal expansion ratios were in mismatch - the panel destroyed itself soon, interior components separated from the polycarbonate, the panel was mounted vertically and deformation started (tracks started curving downward).

    Test thoroughly and if you have doubts about mechanical resilience, maybe use the panel horizontally.

    Glass is a silicate, and may have the unique advantage of expansion ratios matching silicon wafers.



  • Looks nice.

    I do mow, but it’s more like making hay - when the plants have grown tall, and most varieties have managed to bloom. I also try to de-synchronize it from neigbours’s activities, so the landscape would never be the same in every direction.

    Also, mowing peppermint and dandelions is taboo in my yard. Peppermint blooms very long and repels mosquitos, while attracting lots of other bugs to drink nectar. Dandelions are just nice to look at, so I don’t do anything until they are “ready to fly”.

    If I didn’t cut hay at all, I would get Artemisia growing here and unfortunately their pollen can ruin a week for me.