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> Motorcycle Electric Conversion
Sch3mat1c
Posted: September 26, 2017 09:15 am
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I've seen battery tester / conditioner boxes before, but I don't know if they're deep enough discharge / high enough current for what you're doing, or if they'll decide fast enough to be worthwhile.

Tim


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AwesomeMatt
Posted: September 28, 2017 05:53 am
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Most of you already probably know this by now... but I don't buy stuff off of Ebay that often, every few years I'll go on a binge. Holy crap is every electronic dodad you could ever want to own cheap now.

Binging time again...
http://www.ebay.com/itm/Buck-Step-down-LM2...er/161476280982 <-- $2 Buck converters WITH voltmeter. For two bucks including shipping! This plus any old ATX or etc is functionally a power supply, for less than a cost of a fuse. Last time I ordered some 4 or 5 years ago, they didn't have the screw terminals or the LED meter, and they were $3 each only when I ordered 150 of them.

http://www.ebay.com/itm/DC-DC-CC-CV-Buck-C...W-/263106350460 <-- $3.50. 300W power supply (Chinese watts, so, call it 100w), CC and CV, with both panel meters. For THREE DOLLARS AND FIFTY CENTS INCLUDING SHIPPING. [Edited to correct - Oops, no gauges on this one, ones with gauges are $7].

http://www.ebay.com/itm/DC-100V-10A-Voltme...e-/162237038985 <-- $2.30. Digital volt and ammeter, LED. Everything I build should have one of these on it. Shipped to your door. I can't drive to the nearest place that used to be a radioshack for less than $2.30, hell a bus ticket is $2.75.

http://www.ebay.com/itm/USB-Charger-Doctor...ar=412318047120 <-- $2.30. Same as above, except also mounted right onto USB in and out so you can watch whatever your device is doing. I have no need for this but I bought two of them anyway because it's less than fries at MacDonalds and those are gone after I eat them.

http://www.ebay.com/itm/10-Pack-18650-Batt...at/282566747030 <-- $4.40. 10 pieces of 4x5 battery holders. Enough for 100 batteries (need top and bottom both). So I dunno, I bought 4 sets. It's more than I paid for the bike, but, for how long I'll spend dicking around trying to arrange 400 cells, I'm sure some night I'm going to scream and swear and wish I could just spend $20 to make the problem go away, so... merry Christmas future frustrated me.

http://www.ebay.com/itm/10pcs-TP4056-Micro...rd/272570928685 <-- $2.60. 10 pieces of some automated 18650 charging circuits. I bought a 6-pack of butter tarts today for $11 and ate 3 of them on the drive home, so, I bought 2 sets of these chargers. Remember a few years ago when you used to have to go to the dollar store and keep mental inventory of the shit they had there to eye up how you might be able to re-purpose it for your projects? I remember looking at those cell phone battery banks for $3 and being like "Hey, if I ever want to build a lithium charger, I could come in and buy a handful of these and tear them apart." Now they will show up at my door for TWENTY FIVE CENTS EACH. I'll use 'em with a multi-secondary transformer to make a cell balancer for all my electric bikes. And only that because when I looked at the BMS systems there are for $5 I can't quite tell how they work or how to use them.


Anyway, as I said, most of you are probably all ho hum, old news, but, I'm like a kid in a candy store. I don't think I've even spent $50 yet.
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Sch3mat1c
Posted: September 28, 2017 12:40 pm
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Cheap, yes -- but cheap, yes. wink.gif Good luck if you want to run those things up to their ratings, or at corners of operation (like low voltage and high current). And good luck if you need low noise.

If you don't mind derating them, or limiting operating range, or wrapping them in shielding and adding filters in and out, or any combination of the above, then yeah, they're good. smile.gif

Tim


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Answering questions is a tricky subject to practice. Not due to the difficulty of formulating or locating answers, but due to the human inability of asking the right questions; a skill that, were one to possess, would put them in the "answering" category.
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AwesomeMatt
Posted: October 01, 2017 10:52 pm
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Well, it's snowing again for the next couple days so I figured it'd be a good time to service the motor, replace that squealing bearing.

The 3 bearings in the motor are all shielded. They only have 3-digit code and no prefixes or suffixes (also from 1960s, so...). They're shielded. Princess only had sealed bearings so that's what I got, 6204/5 RS. Far as I can tell, sealed are slightly more expensive and have more drag, and aren't good past 11k rpm (I'll max out around 4k). Figure it makes any difference?

Had a hell of a time trying to get the bearings off. They're 1/8" from the copper windings so I couldn't fit the gear puller under it. Only shim some barstock underneath them and clamp that in a workmate. I had a 3/4" punch and hammered it 100 times and nadda. Remember I had a sledgehammer in the van, gave it 50 or 60 swings with that, a few making the full swing.... didn't budge. Point of no return... blowtorched it until the grease boiled... nadda. Hammered it until the punch mushroomed too big for the shaft.

Figured I'd need a press to get it out, but bought a pulley puller in the morning. All of finger pressure on the 3/4" wrench and it came right out. Not even any initial resistance to break it. I've struggled more picking my nose.

I know mechanical advantage of a fine pitch thread and all but... really? All that sledgehammering did zero?

...

Next up...

What should I do to the motor? I have the rotor out, it looks like the insulation is pretty flakey. Run it through any solvents and dip it in my left over floor varnish, or leave it alone? Will balancing be an issue later from varnishing? Just paint some on the surface?

What about the housing and the field coils? They've got a lot of grime in them, but they work. Tempt fate and clean them or leave them be?

...

This motor also doesn't have a fan. What looked like fan fins are actually just the copper 1/2"x1/16" conductors. This was the pump motor, the drive motors do have fans, so, now I'm thinking it probably should have fans. Hard to do without any shaft that protrudes out the front end.

Maybe I'll try liquid cooling from the original radiator. Not sure if I should tempt drilling the motor case to fit coolant lines or if I should just... I dunno... JBweld some along the outside of the case. Maybe an air scoop instead? I kinda need to build something to prevent rain from getting sucked into the motor.

...

I painted the motor with black enamel while it was apart. Maybe I should take the grinder and carve 3/16" fins into the case, all the way around to help with air cooling?
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AwesomeMatt
Posted: October 02, 2017 10:03 am
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Pics from yesterday's update:

Rotor.

user posted image

Closeup of the rotor, fiberglass? String? Varnish it back down?

user posted image

Guess which corner was facing downward in the original?

I suppose I could unbolt these and soak them in a thinner, revarnish them, find new insulating sheets and bolt them back on, but, maybe just spray some varnish on them? I dunno. I don't want to get in over my head.

user posted image

Early disassembly attempt, half way through. Punch is bent and starting to mushroom, no results.

user posted image

Halfass sanded prior to painting. Masking tape and paper? Hrm, I've got scotch tape and paper towels, close enough.

user posted image


All I got so far.

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Sch3mat1c
Posted: October 02, 2017 02:12 pm
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I wouldn't screw with the varnish. At worst, clean things up with rubbing alcohol, then dip in varnish and bake. Note you'll need to mask or scrape any precision machined surfaces after.

Really, I'd just clean it. If it's obvious that stuff is flaking, I'd not use it at all, or consider rewinding it (or getting it rewound -- either way, uh well..).

Tim


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AwesomeMatt
Posted: October 13, 2017 07:52 am
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Been spending some time testing batteries. Here's my procedure:

1 - Shove a dime into the + and - slot on the battery, measure. Shove a paperclip into each of the other pins (breakout for each individual cell) and see if any cells are egregiously out of balance. If so, tape a note: "Failed measuring, Cell #1-5".

2 - If they're loosely the right voltage, charge the pack up to 20v (21 would be max, I allow an extra volt for imbalance so no cells get overcharged). Measure cells individually, see if any are already bad.

3 - Let that battery sit for a few days while I c harge others and do other things because I'm lazy.

4 - Test voltages again. If any cells have dropped voltage, (about 30% of packs will have a cell that did), mark it "Failed Holding Cell #1-5".

5 - Hook battery up to a half or a third of a clothes dryer coil for a half hour or so. Heavy gauge variable resistor, built on ceramic standoffs, with heat shield. Can't get better than this. Measure after voltage has dropped a few volts, mark bad cells "Failed on Discharge, Cell #1-5".

6 - I haven't got this far yet. Presumably it's now time to strip the batteries apart and separate the bad cells for Plan B recovery.

7 - More smartly measuring capacity would be nice, so I could have a better attempt at balancing the end packs.

More on that later.

MAIL BAG!

Fresh off the boat with that familiar Shenzuan Stink:

user posted image

Battery holders and the 18650 chargers.

I was lamenting not ordering a bunch of USB micros, but then I see they have power pads I can use directly, hurray.

My loose plan is to make a a battery adapter from an old drill base, which has pins for each cell, and then individually charge cells to 4.2v so I get perfect balancing without even having to disassemble the packs (yet).

Figure they'd be okay like that off a common fat 5v power rail, or do they need isolation?

...

Matching capacity on individual cells is the next challenge.

I'm now regretting not ordering a bunch of the powerbank circuits that have the low voltage shut off off. I was thinking earlier "These won't help, there's no data logging and I'm not going to sit and watch each cell discharge"... but then I had an idea: Power resistors, LEDs, webcam, time lapse video recording.

Hook up 20 cells at a time, leave the webcam recording, and just watch the timestamps for when the LEDs on a given cell go out. Label each cell with corresponding AmpHour in sharpie.

But... I don't want to wait another 6 weeks on the slow boat. So I might skip it.
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AwesomeMatt
Posted: October 23, 2017 11:05 pm
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So, the little 18650 chargers apparently work fine in parallel off a common power supply (makes sense if they run off USB, which is blindly parallel), but only on isolated batteries. This dashes my hopes of easily making a battery management system out of them.

Ideally what I want to do is build a charger that will charge every cell in a drill pack independently, before I disassemble it. I know there are BMS circuits out there (there's one supposedly even built into the packs themselves) but, they all seem to do weird or unreliable things. I just want to build something that I can confidently and blindly say is ONLY charging each cell up to 4.2v. That's it, that's all. No slow overvoltage bleedoff, no charging from one cell to its neighbor, no misreporting voltage as it's trying to boost it. Just charge every cell, that's it. I'm sure they're out there, but I can't tell one from another and, this is something within my understanding that I can build.

I was going to power this off an old ATX 5V rail, but I guess I'll have to be a bit more ghetto than that. I'll go buy 5 of those 1"x 1"x 1" cell phone chargers and use those as the "isolated" inputs (that only occasionally murder people because of poor separation between the 120v and 5v sides). Plan B is many-secondaried transformer with a bunch of FWBs.

Kludgier than I'd hoped, but, what else is new.


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