here is some info on 20v yardworks lithium ion

[mikereidis]

You live on the edge. And you keep that bms-less diode-less case-less pack between your legs?

At least it's not the snug 10" / 25 cm wide it was before (2 batts side by side with some space for bottom 4). Now I don't even notice it at 14 cm wide, the length of a cell. 84v can shock, when perspired or wires getting pressed into you.

I'm not worried about the lithium so much, more a collision with metal object that ends up welded to my cell terminals and potentially burns from the welding heat. All my terminals are on left now, so left side T-Bone with metal at 3 feet high is worst case scenario. But it might have to through the semi-insulating material my left leg is made of. Unless I ride with my legs/feet "recumbent" on the handlebars like I tried for a minute last night, before thinking about how much emergency manouvres are hampered by that.


Run tonight went well. Cop left me alone. 24.4 KM, avg speed 17.6 KMH,max 35.1 on " big whee" hill at 6.5 KM mark.

Started at about 84 volts or so after settling down from topping up on my own charger at 84.7v. I've read you can extend life nicely by only charging to 4.1v per cell or 20.5v per YW batt.Wonder how much ? I keep thinking some fabulous new chemistry will come out within 2-3 years so only need as many cycles as to get through 3 years.

Going up first, biggest nasty Aylmer Marina park set of hills at 18 KM with battery starting at 76v open circuit. Went 10-15 KMH and ended that set of hills with open circuit 72v. Worst part of hill voltage went down to 63v. Hmmm, maybe some bulged cells have high internal resistance ? Will check; that could cause worse than expected voltage drop and drag down whole pack. Anyway, glad I didn't have some wimpy BMS kicking out on me. Last nasty hill the voltage dropped to 57v and my "manual BMS" compensated by dropping throttle.

I've read that dropping Lithium Mg to under 3v per call when under load induced voltage drop is not so harmful like dropping under 3v open circuit. So maybe "manual BMS" is better. If you're tired and bleeding and just want to get home, you may not care about running them to 2.9v.

BTW, I think zig-zagging nasty hills can raise RPM which at full throttle anyway, improves efficiency. Get some interesting motor noises when transitioning from zig to or from zag.

Arriving at home, open circuit voltage was 71v. Now with bike in garage at maybe 15 celcius, it has risen to 77v 1 hour later; it rose to 75v in first half hour. Some of that is normal recovery; some may be warmth rise; it was relatively chilly tonoght; maybe 9 celcius. These batts are supposed to be worse in cold weather.

Charging heaters moving into house now. $30+ ones are useless as loads; must be some solid state stuff. $25 ceramic is noisy. $20 cheapie has no thermostat but is nice and quiet and fan takes little power. I think this fan is the particularly inductive one that gives me spikes though. It now has 2 cords: one for heater/load, the other for fan which during charging is always running at full 120vac speed.

Price of oil dropping but the heaters will be primary this winter, unless heating oil gets a lot cheaper.

Starting to think of "e-sledding" or "e-windboarding"on frozen river this winter. Batts will warm themselves with internal heat. Just need to find some 120vac outlets though. Probably have some on Rideau Canal. Hmmm, maybe just some studded tires on the bike; is that against NCC rules ?

[mikereidis]

Pics.

"Experimental prototype" tape securing method:
You don't see the cells too well in this pic (see pic after), but you can see the yellow of their sides under DMM and switchbox/charger. Measuring tape extended to 30 cm. 3 original batt cases are shown. On BMS under 20 cm mark you can see just above 18 cm mark the left end of 3 strands of whatever used for the current sensing.

These are the business end of the cells, with terminals. Red tape covers the voltage sensing connectors to help prevent nasty sparks while still keeping package compact. I used transparent shipping tape to wrap the 4 cell packs together, so I could keep an eye on the packs and their bulges without having to rip off yards of duct tape.

A pic to show size comparison of removed 20s cell pack on left with equivalent 4s batt pack on right. Bet that makes you want to ditch those YW cases.

Mounted on bike. A lot more leg room now. Was "snug" before; now I don't notice it and no pedal interference issues.

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Gratuitous pic supposed to be showing my 84.5 volts on right reference DMM before I go ride, but pic got cut off ? Must be my ebikes controller warranty fairy godmum or something.

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[nutsandvolts]

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[pwbset]

Hmm yes indeed.
https://www.ktrakcycle.com/index.html
http://www.youtube.com/results?search_q ... arch_type=

Oh yeah I've thought about that quite often for the long local winters where I live. Apparently they are crap. Fun, entertaining, but completely impractical for commuting. About 2/3rd the way down this thread is the review... entertaining review at that.

viewtopic.php?f=3&t=2853

Not to mention there would be no easy way to get a motor on that thing... forget about front wheel drive... spin, spin, spin. Cool concept though.

[nutsandvolts]

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[pwbset]

Taking the idea custom though, with 5 series motor on treads, would probably be worth a few EV grins.
People around here would go wild if I rode one of those downtown, its all downhill from here.

Haha.. yeah.. I could see the grins from here! Seriously though if you could wire up a 5305 into that and maybe double the width of the tread somehow I bet it would be a LOT more viable. It's going to be like 28 here tonight with a chance of snow... on Sept. 10th... *sigh*... brought in the tomatoes....

[nutsandvolts]

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[mikereidis]

Taking the idea custom though, with 5 series motor on treads, would probably be worth a few EV grins.
People around here would go wild if I rode one of those downtown, its all downhill from here.

Haha.. yeah.. I could see the grins from here! Seriously though if you could wire up a 5305 into that and maybe double the width of the tread somehow I bet it would be a LOT more viable. It's going to be like 28 here tonight with a chance of snow... on Sept. 10th... *sigh*... brought in the tomatoes....

Yeah, that's pretty much an electric snowmobile, no ?

Back to batts/cells:

In the 4 batts with 20 cells, I have 4 bulged badish ones. At rest, they show lower voltages. When charging they show higher voltages. I'm charging now and it's easier with access to all cells, because I simply pick the worst cell, with the highest voltage, and monitor it to ensure it doesn't go above 4.2v. Slows down the charge for the rest, and I'm sure higher internal resistance lowers my pack performance, but it works better IMO, without BMSs than it did when fresh, new and unbulged.

I'm getting the impression it's the physical bulging which actually damages cells. I think that's why they use those super-tight bulge bands around the cells. Interesting to note all bulged cells are either top or bottom cells. My worst is a bottom. Heat has vertical effect...

FWIW here is my voltage readings open circuit, some 20 hours after I finished my run last night:

10:30 PM Wed. Sep 10.

Total: 76.9v

Batts:
19.24+19.33+19.30+19.28 = 77.15
19.33-19.24 = 0.09v variation/range
0.09/19.285 = 0.0046668 variation fraction

Cells: (no decimal points; too tiring)

3836 3841 3845 3842 3839 Top and bottom bulged; bottom has highest voltage charging
3.845-3.836 = 0.009v range Strange that open circuit range is pretty small if this is worst battery

3853 3856 3862 3863 3859
3.863-3.853 = 0.010 range Seems fine

3853 3853 3855 3855 3853
3.855-3.853 = 0.002 range Nicely balanced

3822 3865 3869 3862 3822 Top and bottom bulged
3.869 - 3.822 = 0.047 range Open circuit range pretty big


Actually, I DO have a basic BMS now Overcurrent control in the form of a 30a breaker (Self resetting) and a 30a fuse in series. CB is 12v though; fuse may be same; but I think they're OK(ish). I will see and better than nothing.

[nutsandvolts]

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[mikereidis]

Are you measuring watt hours used in any way? It would be good to know if those bulged cells have less capacity. It would be better to know why they are bulging. I think someone else on this thread said they had bulged cells too, and not from overcharging. Cycle Analyst is great for watt hour usage, thats the main reason I got one. I know my rough range, but wind can really change power consumption. As far as I can tell, my capacity hasn't dropped yet, or if it has not by very much. And I'm hesitant to open these batteries, I opened two just to look at them, they are working so well that I don't want to mess with them. Of most interest is how well they hold up over time and number of cycles.

Only measuring watt hours by rough estimation so far. Open circuit voltage is the best indicator (other than maybe an amp-hour meter) of charge remaining on lithium batteries. That 4 LED indicator on batts is voltage driven, and does not (I think) put a load on batts like normal battery testers need to. It just goes on voltage. I've tried to get a mapping between voltage and charge, but my estimates are still too rough. I'll try some more accurate load tests at some point to find a decent mapping.

Watts Up meter would be cool, but haven't gotten around to ordering one yet. With a few A->D converters and some code, I'm hoping to eventually create my own Super Cycle Analyst anyway (with blackjack, and hookers. ). I actually ordered a CA but they weren't ready and I said just ship the rest ASAP please.

Just as something to consider, one could keep the batteries in cases with BMS intact, and still bypass the BMS for charge only, or discharge only, by running thick wires in through top of case. Could also avoid any connector issues. Also possible to run wires to all cells for voltage monitoring, even though BMS is still connected and operational.

But yeah, I was VERY hesitant to do this at first, so I understand completely if others don't want to take the jump I have. Me; I'm not going back now. Too many pros and not enough cons.

EDIT: BTW, I find it funny that there is a "warranty void if sticker removed" sticker INSIDE the battery case on the top. What is that supposed to protect ?? Someone removing the connector thing in the top ?

I DO suspect that returned batteries will be opened, inspected, analyzed and possibly recycled by the manufacturer here in Canada, and that's why they are easy-ish to open. Maybe 100% of first 100 returned batts, and say 10-20% after that; but if they will recycle could be 100%. So I think they WILL notice if people start returning batts that have clearly been modified or replaced with stones or whatever. Probably more than 10 Joe Cdn Tire returns for every ebiker return at least though.

Maybe in a year when batt warranties run out I could place a sign near new batts asking people to sell me bad ones for $10 each or something. Bet they'd have at least 3 good cells left. I think Cdn Tire is banking on selling many "replacement batteries" when warranties run out. That thinking, IMO is why they call them "replacement" and not "accessory" and why Bells Corners store is not stocking them yet. Bet Mgr figures he'll stock them next year; or maybe he's just clueless that equipment won't sell without batts and chargers. Or maybe they want you to buy trimmer first and use that batt on all other equipment.

[mikereidis]

I didn't get around to riding last night; just watched my bad cell voltage as the pack charged slower (and safer!) than it normally does. Now I realize that with the bad batts at 21.00v, the bad cells were higher than 4.20v, and thus the bad cells just get worse as time goes by.

A smattering of ideas gelled, and the harsh light of morning hasn't diminished my enthusiasm, so here goes:

DMS or "Danger Management System". System is modular. Pick and choose your danger profile and options:

BTW, I'd want a system that could be configured to any reasonable voltage or current. So, you could use this with individual cells or complete batteries.

Over-current protection: I think a fuse and/or circuit breaker are sufficient, to protect against shorts or controller failure. Most controllers have current limit. CA can provide limit. For those who need something better, a solid state, fast acting, over-current module could be built or bought needing just 3 wires I think. This is for charge AND discharge. It's possible you might want a lower limit for charge, but charger also has its' limits too. I shudder to think what a bridge rectifier failure could do though, and that's one reason I have a 40a (or 30?) rectifier unit, with heat sink.

Under-voltage protection: I think a voltmeter and a reasonably conscientious rider keeping an eye on voltage, especially up hills or under acceleration, is a reasonable way to do LVC. A nice upgrade could be a voltage monitor that beeps under specified voltages, perhaps changing sound as voltage decreases further into the danger zone. Another upgrade would cut power completely or partially (reduce current limit) when LVC.

LVC could be done by monitoring a single cell voltage (the worst cell) pretty well IMO. Or could be done monitoring the whole pack voltage or the single battery with lowest voltage. More sophisticated, a switching system could be used to slowly, progressively monitor all cells and figure out which is the lowest and should be watched most closely.

Over-voltage/charge protection: YW batts refuse to power more than a few milli-amps when charged over about 21.10 volts. This is annoying since those are the batts I WANT to discharge to safer levels. Probably protects the YW equipment some. (BTW, saw all 5 pieces of YW LiMn equipment in Bells Corners yesterday; still no batts or chargers.) I'm not seeing a GREAT need to implement over-voltage protection to protect controller, but might be a need to consider. DMM and brain work OK for that.

Charging: This is a biggie, and I think I may have an interesting solution. "Sacrificial cell" monitoring. (Search for sacrificial here and I think you'll get some hits.) I was getting rather bored charging last night; all I had to do was keep my highest voltage while charging bulged cell at 4.20v, and the 16 good cells slowly rose safely from 3.8v to 4.07v, and in unison (no balancing needed). No BMSs were tripping on me, and no ungodly voltages seen. So it seems to me this technique will generally work, so long as you know and can monitor the voltage of the worst cell.

For discharge this sacrificial cell can be used, OR it could be tapped around and used for bike accessories or whatever. (Note that bad cells always seem to be at ends of batts.) Only issue if you don't use for motor power is that before recharging, you'd want voltage on this cell to be as low as all the other cells in pack. If you're unlucky enough that all your cells match exactly, a sacrificial cell could be emulated with a 1-20 milli-ohm resistance in series with that cell.

So I think that safe charging can be done with a single cell (or batt) voltage monitor "module", set to trip at user specified voltage from 1-100v or whatever. If you want more (perhaps you expect that some other cells might get worse and you might not notice and move the voltage monitor connections), multiple modules could be added. 4 bad cells might benefit from 4 monitor modules. Or go full bore and monitor every cell if you must, but I think 1 cell is enough. Regardless, I personally want to be able to check any cell voltage (and charge/discharge current and total voltage of system) at any time in an automated manner, perhaps via USB peripheral.

Cell/batt balancing don't really seem to be a major issue with these batts. Balancing could be done manually, semi-manually, or fully automatically, using just one shunt type circuit on worst cell/batt, or on all bulged cells/batts. But good cells seem to stay nicely balanced all by themselves.

Fast charging could start with a low resistance load, like a 1500w heater plugged into primary outlet, for more or less CC mode. When voltage limit is reached on sacrificial cell(s)/batt(s), primary load is switched off and secondary load, connected through a Triac based light dimmer type circuit (or modified standard 5amp dimmer?) is brought into play. Primary and secondary loads can be anything that works, heaters, lights (although high inrush currents are an issue with light bulbs that dimmers, or a thermistor or something may compensate for) or small stove for the alcohol still.

Triac based light dimmer type circuit would be controlled by voltage measurement(s) of cell(s). Note that, IMO so far, "AC dimming" works well for voltage and current control. The batts/cells seem to average out the 120 HZ modified sinewave peaks, so the dimmer/PWM method of control works OK (Even if peak currents every 120th of a second are higher than average or RMS current).

I have a UPM Kill-A-Watt type meter I use on charger now. Divide watt-hours by 120 to get amp-hours. I think I could set KWH price to get direct amp-hour reading. I DO think my DC and AC current measurements are higher than real RMS though, due to the modified/clipped sine wave. Once I read 16amps DC on charging and around 18-19 amps AC and my 15amp breaker; which is probably less now due to multiple inductive trips, did not trip.

For further danger management, an isolation transformer could be added, but that's a pretty boring expenditure.


I think that covers the bases of danger management. With the right options I think it might actually be fittable into a large 25 pack of king-size, especially if we exclude the size of input and output 120vac inlets/outlets, or use miniature ones.

Disclaimer: "All Danger brand products are sold with no warranty, express or implied. They are intended only for experimental usage by competent professionals with the requisite skills to handle such equipment in safe, controlled laboratory conditions. Do not inhale."

[mikereidis]

Tested and mounted my last 4 batts tonight. All 20 cells were within 3/100ths of a volt at close to full charge. Most were 4.15-4.14, a few 4.13 and one 4.12. I think I'll have to charge them and check all cells to see if any trouble-makers there but I think they are almost virgin. Might be minor bulging on 1 or two, but I think that's almost normal; especially if Cdn. Tire engineered this product just right to maximize replacement sale revenue as usual.

Wow ! I'm never hauling power robbing, heavy and bulky cases and BMS's again ! Bike lost 8 pounds: 1 lb of light switches and 7 lbs of cases and BMSs. Down to 75 lbs from 83.

I saw 19.96 amps a few times before the DMM showed "OL". I think I never hit the Xlyte controller 20a limit before now; was getting 18a max before. Current sense shunt, fuse, and who knows what else in BMS was limiting me. I never tried a discharge test over 15-16amps with these batts, when I did those tests. Now I almost don't care what the BMSs were doing; they're gone now; good riddance. Just like the YW charger; no need.

I think it's time for another top speed test. (And range should be better now too.) Only hit a mere 41.1 KMH tonight; will have to try best pack at full fresh 84v charge in daylight. I'm thinking/hoping something closer to 60 KMH; 65 is still theoretical max with no wind and on flat; I'll have to get a better reading of internal resistance now for the simulator/formulas.

I now believe that if you can't monitor your individual cell voltages, you can't know how your battery is doing too easily. I thought I was charging cells to 4.2v because batt was at 21v, but now I see that puts more than 4.2v on previously damaged cells and those cells just get worse.

Might be time to consider modifying the controller current shunt. I'm suspecting these 4110s and the stock traces/solder will give me 30a easily. But I think I should upgrade the controller power cables; they're a bit wimpy befitting a 20a controller. Time to get some current meter that will work in the 30-100a range. And a good milli-ohm-meter.


"Sacrificial cell" charging takes forever to top up pack when that cell is particularly bad like mine, because current drops so low and other cells still stuck at 4.0 - 4.1v. Things went quicker when I shunted the whole bad batt with heater set to low. Worked well, but some other cells snuck up to 4.23v when I wasn't looking. Automatic shunts would work better of course. But best solution may be to remove bad batt from pack.

I think I may get rid of this bad batt and/or use it for overcharging or undercharging experiments. Not sure I really want to cut bulge straps; I certainly don't have bulge strap installation equipment, nor the straps themselves.

One of these batts had been fixed at factory. Quick disconnects were added from battery to BMS so I suspect BMS was bad. Horrible tape job was done over a cut in wire where some wire piercing thing was probably used to test the problem.

My lowest serial number so far is 050010. I'm really thinking this is the 10th battery produced for consumer sale by Cdn. Tire. Highest is 050384.

[nutsandvolts]

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[mikereidis]

I love your dive in approach. I used to be able to do this kind of thing and get paid for it, around 50% R&D, whatever I wanted, as long as it was interesting. That was a couple of bubbles ago. It is nearly impossible to find companies with the deep pockets to do this now.

Been "hacking" seriously since 12 when I graduated from 300 in 1 kit to soldering and thick TTL data books, and fixing TVs etc. instead of just ripping them apart. At 11 I got embarrased in library should someone see me with same book I read at 9: "A boy and a battery". Had motors you could make from paper clips etc. Don't care what others think or not anymore. Batteries and motors are still cool, especially when they can propel you over 50 KMH for over 50 KM.

The other week I used a CDS photo-cell and "printed circuit resistor" (not even IC really) from that 300 in 1 kit as makeshift hall pullup sensors. I snagged a new similar 1980's kit at Salvation Army this week for $5 for (my son in 1-2 years) and for me for test parts now. Ticked me off, I waited for half price Friday at Goodwill for a really nice one with a big breadboard, and it was gone. Next time, breadboard models get bought right away.


Yeah, I was pulling in pretty juicy contract software developer bucks from 1997 to 2001, and still doing pretty good off and on until 2005. Now I'm salary, a bit better than my 1996 salary with good growing company that is highly Chinese (50% here in Canada, and 100% in Beijing). Network security is a good field now, with big co's dependent on the Internet and too many bad guys out there.

Gotta "Follow the money" if that's what you need. I'm hoping oil price stays high historically so there will be opportunities in electric transport. But I'd prefer to slowly retire into my own small, specialized garage business where I'm the boss, even if the pay is half of what corps will pay me these days.


I'll post some pics of bike w/ batts in my kids mtn bike thread later. Shipping tape is nicer to work with than duct tape, since it's see through and easier to remove and thinner. Almost as strong, for my purposes. Duct tape rules for mounting batts on bike though. I tried hold-down straps, and they look more professional, but add weight and slip much easier. One night I kept having to rotate my batt pack back to vertical and I thought it might fall off ! Adding a half-decent modified lawn-mower bag to the whole assembly hides all taping sins and looks much better. If I ever get out of experimental mode I will build something more "professional", but by that time I'll be on to another bike project and more experiments.

I'm REALLY thinking seriously of trying bike with studded tires this winter, for some occasional fun on not too cold days. Wonder if the snowmobile guys would think (or be right) I'd wreck their trails ? Would never consider that without powered wheel. Need something to work on for winter blahs. Maybe I could commute to work over a frozen Ottawa River.

[mikereidis]

Battery fixed by manufacturer, with quick disconnects added between main batt terminals and BMS/cover. Normally these are directly soldered and require cutting or desoldering to remove. Batt voltage connector can be removed by scraping a bit of white goop off and pulling gently-ish at center with long nose pliers; don't need to scrape all off; watch out for sparks if you use utility knife ! Horrible manufacturer repair job with black electrical tape at top, just right of center but not too visible due to low light.

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Cell packs at top. Note right battery is factory fixed one and has yellower covers or whatever you call those. Maybe battery has compression bands replaced too. Note that there are numbers, letters and UPC codes visible through covers. At bottom right you see that joke of a "Warranty void if sticker removed" sticker. What's it doing there ???

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Cells/batts wrapped with shipping tape #1.

Cells/batts wrapped with shipping tape #2.

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20 cells/4 batts fit perfectly UNDER top bar, instead of sitting on sides of top bar which adds 4 inches of width (different batt orientation). Top pack much shorter and gives me more space.

Bottom batts wrapped in black/white plastic with black facing out. Thus far, thankfully unused fire extinguisher at top left.

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8 batts/40 cells, and XLyte controller as seen from right of bike. Official trail dirt and other debris from riding in rain a bit previous night.

View from top. Tape ain't pretty, but works wonders for "prototyping" and covers cover a multitude of tape and other sins.

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[nutsandvolts]

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[mikereidis]

Aren't these canadian tire coupons cute?
Buy gas and get 6 times the normal amount of canadian tire "money"

Too bad I'm not planning to buy any gas.

Yeah, just post anything so I'm not the only one posting...

Gas is one thing I refuse to buy at Can Tire. (I also refuse to ever use their auto service, unless perhaps I'm in Timbuktu and have no other choice, and couldn't do the repair myself in the parking lot.) Had a few bad Can Tire gas experiences decades ago and heard same from others; Water in gas I think, in my childhood hometown Can Tire at least.

Can Tire money is bogus to me these days. What is it, half a percent now ? My credit card gives me more cash back than that. OTOH, with CC they can track your purchases easier. I returned some broken bike parts the other day and they were able to access my purchase records once I gave them the CC I had paid with.

Someone returning a lot of YW batteries or whatever, in small chunks of one or two batts at a time, might consider paying cash at purchase and giving a fake name/number at return, so they don't give you hassles for too many returns. I don't condone that; just enjoy figuring out the theoretical angles and gotchas...

I like the "Triumph Rave" bike I based my "pocket rocket" on enough, I bought another virtually identical one I saw at the same Sally Ann for $10. First thought: cheap spare parts, 2nd: no rust, perhaps this should be primary, 10th thought: Can use for measurements for non-duct tape "professional" battery etc. mounting. Thoughts 3-9 were more bizarre like building a 4-wheeler (sociable or tandem) with a minimum of parts and work.

Thus far, duct tape has been the most successful method of battery securing. Hold down straps, belts and wires haven't worked as well. But duct tape is a major pain to remove/replace etc.

I want a modular system where batts can be easily accessed, moved around or removed for other purposes, like a 2nd ebike. Now I think my more permanent solution will involve heavy duty velcro in such a way that I can easily try different configurations and battery numbers. I figure that even if the velcro is just good enough to hold everything together long enough to secure with other methods, that would be fine. But heavy duty velcro CAN be very strong if done right, so it might be sufficient for all but the most demanding riding.

Went to King Mtn or whatever last night. MAN those hills are FAST on the way down, and drain batts BIG time on the way up ! With gentle nursing at the end I only got 20 KM from first 4 YW batts; batts DO recover and I was able to use it at lower level or downhill loads for another 4 KM. McKenzie King Tea Room must have reset their breaker; I succesfully recharged those 4 batts at 6-7 amps in about 40 minutes to a relatively stable 79v or so. I avoided tripping breaker again two ways: (1) heater has a seperate cord for highly inductive (and very efficient) fan that I plug directly into other outlet, and (2) I just let the charging run until batt was topped and I was bored and it was time to go. Heater didn't help much with the night chill though as it was only putting out about 250 watts of heat with fan at full.

I LOVE this McKenzie King Tea Room "charging station". I ride the bike right up the gentle ramp there; there's no people or vehicles on the weeknights I've been there; there are very nice chairs to rest; the water fountain works; the washrooms are locked but trees work just as well. I suspect these outlets will be powered 366 days a year; they need power for security system if nothing else.

I accidentally ran my worst battery down to major danger levels on the weekend. Worst cell was 0.688v and other 4 were 1.9-2.2v. Lithium Manganese is often considered damaged or unrecoverable once they get below 2.5v (3.0v is safe LVC of course). Charging was no more trouble than normal though. I bought another batt last week and will likely use it to replace this bad batt temporarily while I return bad one. So 9th batt is now a spare.

From wife/girlfriend: "Is that a rocket in your pocket, a bulge in your lithium, or are you just happy to see me?"

[wasp]

speaking of canadiantire...the one thing you couldn't buy with that funny money was gas...
i was stuck one day and found that out...here's what i did
used my ct money to buy ct gift card...then i used the gift card for my gas purchase
all from the same gas teller...they were stunned after argueing with me about using the ct money
just thought i'd add to the ct stuff on here

[TylerDurden]

I want a modular system where batts can be easily accessed, moved around or removed for other purposes, like a 2nd ebike. Now I think my more permanent solution will involve heavy duty velcro in such a way that I can easily try different configurations and battery numbers. I figure that even if the velcro is just good enough to hold everything together long enough to secure with other methods, that would be fine. But heavy duty velcro CAN be very strong if done right, so it might be sufficient for all but the most demanding riding.

I use wide velcro from weightlifting belts and wrist/ankle weights (found in many secondhand stores). It is very reliable, provided you orient the load such that the force on the velcro is in shear. Even better is when the load pulls the velcro tighter onto itself.... i.e. looped through a ring, back onto itself (like kids' shoes).

[mikereidis]

speaking of canadiantire...the one thing you couldn't buy with that funny money was gas...
i was stuck one day and found that out...here's what i did
used my ct money to buy ct gift card...then i used the gift card for my gas purchase
all from the same gas teller...they were stunned after argueing with me about using the ct money
just thought i'd add to the ct stuff on here

ROFL. You never really know if a cash reg jockey might be the next einstein, but the odds are pretty high against it. So I guess you stunned them with your clearly superior problem solving abilities... Neat trick.

Same sort of trick is sometimes used by people who want to buy one thing at Costco but don't want to pay for a membership. They buy a gift card online and that lets them in and allows them to buy stuff with it.

[mikereidis]

I use wide velcro from weightlifting belts and wrist/ankle weights (found in many secondhand stores). It is very reliable, provided you orient the load such that the force on the velcro is in shear. Even better is when the load pulls the velcro tighter onto itself.... i.e. looped through a ring, back onto itself (like kids' shoes).

Cool, thanks ! I'll look around when I check out my local thrift shops; lotsa cheap stuff with velcro there.

Was thinking of some sort of male and female velcro pattern that holds batteries to each other and the bike frame (with velcro installed on bar). But also, some long velcro strips that could wrap around the whole assembly once it's holding together by itself a bit, much like duct tape, but better looking and easier to remove/rearrange.

Dang, I just threw out my old, decrepit velcro sandals. I'll see if my kids have old shoes we don't need anymore for velcro donations. Gee, this bike will have a bit of everything on it.

[nutsandvolts]

.

[mikereidis]

I want a modular system where batts can be easily accessed, moved around or removed for other purposes

Yeah, I want to load a custom small boat with electric motor on my xtracycle, ride over to ottawa river, and move the batteries to the boat!

I LOVE this McKenzie King Tea Room "charging station".

I found this lonely concrete pole with AC power in vincent massey park, beside a picnic table and fields of green.
It spoke to me and said "will you be my friend"

Boat is do-able, in parallel I guess, assuming 12v or higher motor perhaps that can take 15-21v. I've been eyeing some of those cheaper inflatables, with raising my son as an excuse to buy a few "toys". I'd imagine Can Tire, etc. may be looking to slash prices with the season virtually come to an end, so I'll keep my eyes open for suitable bargains.

But, since I tend to look for ways to make "objects" reusable/multi-purpose/modular, I can't help but think of reusing the bike throttle, controller and motor, in addition to the batts. With all above still attached to the bike and wheel spinning of course. This way you could bike to the shore, inflate boat with compressor, mount bike in special harness on boat, put bike in, boat across, and reverse procedure at the other end. Sort of a semi-amphibious e-boat-bike.

Simplest perhaps would be a paddle-wheel, but it'd need gear down I imagine, unless very small, and probably not too efficient. Perhaps just gears and a prop, or a jet pump might be do-able without gear-down. Hmmm, maybe with a big fan connected to wheel, and enough power you could do a swamp-buggy or hovercraft... but sounds over the top right now; I must be too sober. For a non-inflatable boat; I might think about something smaller, like a cayak or canoe. But should it be instant start or "paddle first" ?

Vincent Massey, huh ? I'd think about an AC outlet mapping on google maps, but the owners might notice, esp. if it gets popular, and shut them down. Probably not a big reason for owners to care too much; 1 hour of charging can't get much more expensive than a nickel or dime or two dimes probably if your electric rate is much higher than Ontario.

For those who haven't heard: I almost had a bike fire this weekend. I had been planning to slam some cut to size rubber kneeling pad or similar onto my batt terminals for some protection on the unfused side, but haven't gotten round to it yet. I now know to never use uninsulated wire to help hold the batts in place. Must have poked through my somewhat airy cover and found a place to poke through or bypass the plastic. All of the sudden, parts of the wire start glowing and smoking and I'm frantically trying to unwrap the damn thing, without getting burnt. Thankfully, only the wire suffered damage, AFAICT.

[mikereidis]

Simplest perhaps would be a paddle-wheel, but it'd need gear down I imagine, unless very small, and probably not too efficient. Perhaps just gears and a prop, or a jet pump might be do-able without gear-down. Hmmm, maybe with a big fan connected to wheel, and enough power you could do a swamp-buggy or hovercraft... but sounds over the top right now; I must be too sober. For a non-inflatable boat; I might think about something smaller, like a cayak or canoe. But should it be instant start or "paddle first" ?

WHAT was I thinking ?? Clearly, the best solution would be a James Bond style Water Walking Ball like this one: http://www.watersphere.com/Welcome.html

They mention a motorcycle, but I don't think a gas engine is a good idea inside a ball, nor would lead acid be, for fumes/venting and spill issues. But a smaller ebike, like mine (just measured: 4 feet, 8 inches or 1.42 metres) should be able to fit and run inside a 6 foot water ball. Devil looks weird; I go mr green:

Just so long as something like this doesn't happen: http://video.google.com/videoplay?docid ... 5525&hl=en

It's sodium, but lithium is the same; but I thought I heard these Lithium Ions, and perhaps moreso the "inert lithium batts" can survive and even work OK in water, although corrosion and electrical leakage are issues.

Ok, enough crazy ideas; time to go ride these raw cells: 84v on the better pack, and 85v on the bad pack; sacrificial cells are sacrificed already anyway... I'll try some flatter riding tonight to see how my range is doing. I note that full throttle on hills seems to drop voltage more than on flats; seems weird since both are generally hitting the 20 amp controller limit. Bad cells are definitely raising my internal resistance and thus my voltage drop under load. But other than my range and max power dropping a bit (how much; don't know yet) I don't really notice, except for charging issues. And I raised range and power by chucking the BMSs so hard to tell at this point.

[mikereidis]

Ummm, I was wrong about the C (other negative) terminal not being used with YW. It's used by the charger, but not the trimmer at least. I take solace only in that I think the only other commenter on this issue said the same thing.

Lesson: never trust 1 or even 2 random guys on the Internet, even if well intentioned and they sound like they know what they're talking about.

So there's a possibility that there IS some balancing and over-charge protection in the BMSs, and perhaps using minus instead of C (for Charge(r) presumably) bypasses those protections.

Anyone using negative to charge, might want to consider moving the charger to C, but still using negative for the motor controller etc.


BTW, I wish Can Tire items could be linked, but it doesn't seem to work. Anyone ? I noted that they also carry an electric/pedal boat as well. Use integrated motor, or just hook bike wheel to pedal assembly, or both.

There seems almost nothing Can Tire doesn't have at least one crappy version of.

I've figured out the schematic for the little 4 LED voltage/capacity indicator board. Just need to figure out the divider resistor values and turn on voltages for each of the LEDs. Will have to use voltmeter with live board, cause ohmeter won't work properly with 4 dividers in parallel... I note documentation indicates percentage capacity for each LED.

I'm looking to re-purpose the board for a charging voltage monitor. But since I don't have the BMSs anymore, I'm tempted to put them on the battery pack, one on each 5 cell batt, with push button switch bypassed so they'll always glow when charged. Forcing them always on (which uses very tiny current), prevented BMS from resetting automatically.