Still letting the ideas stew in the back of my head about the swingarm and pivot. In the meantime, I kept digging for all my bits and bobs that might be usable for that pivot, including a bunch of old BB parts I thought I knew where they were (but didn't), and ended up finding all the right stuff at the same time for some of the battery things I meant to do a long time back.
First up was the 48V 1.5A current-limited linear power supplies Bigmoose had sent me (along with several other nifty things), which I had intended to turn into maintenance chargers for my old SLA stacks that don't get used much now, except to power bench experiments, and to occasionally run a UPS during power outages (very rare) or for portable AC power (slightly less rare). (portable being relative, in that the SLA and rackmountable UPS weigh close to 100lbs to run for an hour or so depending on load).
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All I had to do was adjust their voltage pots to about 54V, whcih is pretty much the max it will go to, so it will charge 4 series SLA to nearly full (13.5V each). The current limit I left alone, though I did not check how much current was drawn on the first batch I set up, as it didn't occur to me till later once it was close to charged, and it's only drawing 300mA now.
I have a second set of four 17Ah SLA to put the other one on, after they are closer to equalized by charging up the lower-voltage pair of them (that I used last night to power the Venom to charge the NiMH) to match what the other is at. It's too much of a difference to just hook them all in parallel and let them self-equalize that way (over a volt), cuz it'd probably smoke the small wires I have for that, and possibly cause the electrolyte gel to boil, which is bad.
Once they equalize, I'll hook them up in series again, then the set to the other PSU and make sure to note the current at the beginning.
I also got the BIG Sorenson out, hooked it up, and started charging up the much larger 31Ah SLA. I'd already been trickle-charging one of the three on my little Sorenson, which only does 750mA max, for over a day; it'd already gone down to about 200mA load at this point, so I left it on there to finish, and put the other two on the 55-55 unit, at a 6A current limit, and 14.1V (paralleling the two SLA).
It dropped from 6A to 2.5A within minutes, and was down to 2.3A by the time I was taking pictures an hour or so later. Voltage went up from 13.1V to 14.1V in that time. Not sure how discharged they really are, but they would easily hold 12.5V or so with my 50W halogen on there, before hooking them up to the charger.
Now for the project I have wanted to get back to for AGES, because every time I think I have all the stuff for it, I get some emergency or illness or injury or all three that keeps me away from it, or I misplace some of the stuff while taking care of one of those things, and then when I have time I can't find them.
Anyway, I finally found all the stuff (except the v2.6 Fechter/Goodrum BMS parts
) to build up the Thundersky 32V 60Ah pack. I'd bought the cells from Mechanix some time ago, (maybe a year? I forget now) with payments over several months (by skimping on everything else, back when I could "afford" to do that) and started collecting hardware to bolt them together and such, and make a balancing BMS, etc. The majority of the BMS parts were donated (the rest I had here as salvage with some old/unused parts), as was eventually the bolts and washers for connecting the cells together. I already had braid to make jumpers, and crimp-on lugs, and at one point earlier this year had managed to get all those parts in the same place in the bike parts room, before the city-ordered cleanup. After that, stuff got moved and so now I can't find the BMS stuff.
But I have the rest, so I took an hour or so and made up all the jumpers, bolted them betwee the cells, and found an Anderson SB50 already made up that I used to use on CrazyBike2's SLA pack, before I went to the NiMH and then the Vpower LiFePO4.
The jumpers are made of the tinned copper braid from old 75-ohm RF cable, with the core and the outer jacket removed. This makes them very flexible, so vibration should not break them.
They are simply crimped (no soldering) very solidly into the lugs, although these pics are probably too blurry to really see that.
I have a little "kit" of pre-cut heatshrink tubing that a friend gave me after it experienced a bit too much of our outdoor weather, and most of the pieces have already partly shrunk from the heat. So while not unusable, some pieces can't be fully used, or can't be slid easily over the things they're meant to fit. I just picked a few of the least usable large diameter ones, and used them as sleeves over the jumpers, not shrinking them down, just leaving them loose (sicne they are too large to conform to the lugs or jumper braid anyway).
It's still not strapped into a pack form yet, because it will be made into two 5-cell boxes that can bolt to the cargo rails on this bike, but it is otherwise ready to test and use and charge as a pack.
I still wish I had a few more of these cells, as 32V is too low for a few of the things I'd like to use it for (like pretty much all my hubmotor wheel projects), though it should work fine for things that go thru the gears, as I can just step up the ratios if it's not fast enough (though this will increase current draw, these cells should be able to take that, up to at least 60A continuous, with easy bursts of 120A or more).
For instance, on CrazyBike2, it isn't even enough to be above LVC for the 12FET on there, so I can't engage the motor to do a quick test, whcih I was hoping to do. It's only 32.9V, with all cells being at about 3.29V, plus or minus a hundredth. Ignore the mileage, as taht is from testing RTLSHIP's repaired Volgood pack. It *is* enough to turn on the laptop adapter that boosts the pack voltage to run the CFL taillight, so that part works, but nothing else.
Anyway, for this bike, they may well do fine, as a secondary or long-range pack. Have to wait and see, once I get the bike itself finished.
Also, I finally ran across the two things I meant to use to pack the Vpower pack halves in, but they are just a bit too small in all dimensions for that.
Sharpie on top of one for scale.