here is some info on 20v yardworks lithium ion

Some unusual testing results.

I-reran a "medium-low load" test with the DMM right at the battery terminals and got some unusual results:

Original results used an 8 ohm load, had a nominal voltage of 19v and nominal current of 2.375 A. Original test indicated about 5.75 amp-hours at average of 19 volts for about 110 watt-hours.

New test used a 9.4 ohm load, had nominal voltage of 18.8v and nominal current of 2.00 A. New test ran 167.7 minutes and indicated 5.57 amp hours and 104.7 watt hours. I'll have to try re-running at 8 ohms to explore this further.

http://www.molienergy.bc.ca/pdf/IMR26700.pdf
 
I ran a lower current test that I targetted at 0.5 amp. I used a lightbulb in series with heater and got about 40.4 ohms. Initial voltage was 20.70 under load and current was 0.512 amps.

But the bulb and heater quickly shot up to about 156 ohms at which point 0.133 amps were flowing and about 2 watts in the bulb. So anyway, this became more like a 130 mill-amp test.

Curve was roughly similar to prior curves. It ran 2820 minutes or 47 hours. That's 6.13 amp hours or 116.5 watt hours at average of 19 volts.

So to summarize my tests, from loads of 1.87 ohms to 156 ohms I see 5.6 AH / 104 WH to 6.1 AH / 116 WH. I'd like to do 20 and 30 amp tests too.

I have a new DMM now, best they had at CTire, listed $60 but cash rang it as $40 go figure. Mastercraft 52-0052-2. Old DMM is Equus 4320. New DMM voltage reads almost 1% higher. I think the new DMM is more accurate. Anyone know precise voltages of small new lithium like 2032/2016 ? I get 3.306 on 2016 on new DMM.
 
I now have 6 batteries. Was only going to get 1 or 2, but random young CTire guy at 1660 CARLING AVENUE, Ottawa freaked me out when he said:

- C-Tire is dropping all YardWorks products. I had thought YardWorks and C-Tire were closely related, but perhaps not. So who else sells YardWorks or are they under a different name ? Answer from confident random CTire woman at other store: Yes, Yardworks = CTire and no there is no such dropping of YW line.

- There have been many returns of the Trimmers and batteries due to problems. I wonder if people are just dissatisfied with the lack of power relative to cheaper gas models ? But he claims they come in broken, but does he know ?

- There is no more stock coming in. If so called "over the counter replacement" is needed, I guess they'll just refund the price. I note that the warranty info with the separate batteries I bought today specifies replacement with same model or one of equal specs. I don't think they'll find one of equal specs. Of course, if the batteries aren't very good, then we'd probably just want our money back anyway.

For some reason, the batteries were $109.99 at 1660 Carling, and the chargers were $29.99. I got the last 2 batteries and 1 of the last 3 chargers. Perhaps this individual store is marking down prices on parts they know are discontinued already.

Then I went to Merival CTire and cleaned out their last 3 batteries at the same $110 price and spoke with woman mentioned above. Hmm, so catalogue and some stores have these batts at $130, but 2 other big stores are at $110 and shelf tags indicate $110 and it's not a red sale price tag. At first store, scare dude let me have the shelf sticker in case problems at cash and since no new stock was expected.

So now I have 6 batteries and 2 chargers. I might consider 2-3 more, but 6 is enough for now and sales might come up. I think I'd prefer 4s, but 3s2p might be OK too. Then there's 4s2p, 3s3p and for the adventorous, 5s2p :) :)

Bells Corners never had any batts or chargers that I saw and I asked yesterday. They had 1 trimmer until I bought it and still have 4 lonely hedge trimmers with no batteries to equip them. Hmmm, maybe they'll be $9.99 soon...

I checked Kanata store last Friday and they had no visible batteries or chargers and I didn't ask because nobody was handy. They had some trimmers w/ batt & charger. If these ARE discontinued, perhaps there will be some blowout prices... :)

At 1660 Carling store there are now 0 batts, 2 chargers and 6 trimmer combos.

At Merivale store there aer now 0 batts, 2 chargers and I don't know how many other things.

So now all I need is a plan and diodes for hooking these batts up. Would prefer parts I can get locally at Future or wherever.

And I also need an ebike too, but hopefully I will have all parts needed this coming weekend. :)
 
mikereidis said:
So to summarize my tests, from loads of 1.87 ohms to 156 ohms I see 5.6 AH / 104 WH to 6.1 AH / 116 WH. I'd like to do 20 and 30 amp tests too.
Click to expand...

Ran nominal 14.6 amp tests on 4 new packs with a 1.235 ohm load.

First 2 packs were taken off charger within 10 minutes of green light going off, and were left to stand for several days. Second 2 packs were charged and left in charger for several days. IMO, the first 2 lost almost no charge over several days in storage. The second 2 packs had a 1-4% advantage in voltage, current, AH, and WH, IMO due to the extra long presumably trickle charge.

about 86 WH, 18.02v, 14.59a, 1182 seconds, 4.8 AH
about 89 WH, 18.04v, 14.61a, 1218 seconds, 4.9 AH
about 90 WH, 18.11v, 14.7a, 1212 seconds, 5 AH
about 90 WH, 17.85v, 14.63a, 1236 seconds, 5 AH

So yes, as expected, you lose V, AH and WH when you increase current I, and the AH and WH loss isn't just from internal resistance, which I estimate at 50-60 milli-ohms per 20v pack.

So for fully charged batts, average current on the left, next is average volts to full discharge, next is amp hours and watt hours:

0.1a 19.0v 6.1ah 116wh
2.0a 18.8v 5.6ah 105wh
9.2a 18.5v 5.6ah 104wh
14.6a 18.0v 5.0ah 90wh

One more advantage of Yardworks batts, is it should be easy to return a pack to the store if it underperforms. Technically, they all underperform their 6ah ratings, in my tests, unless you pull less than an amp or so from them. 1 Amp doesn't cut it for grass trimming etc, though.

Regardless, these seem like good batts, especially if you get them at the bigger stores where they may be $110 each. Too bad we have to pay the Ontario PST for these bike parts...

Canada Post has my ebikes controller and throttles so I hope to have a 2s pack to test my first real e-biking on Monday (My first conversion: http://endless-sphere.com/forums/viewtopic.php?f=3&t=5749 ) . Just for kicks, I'll try a single pack too, although Xlyte 24-72v ctrlr might cut out at 19v or so.

Then it's on to 3s, 4s and soldering shunts... :)
 
nutsandvolts said:
Hey thanks for the additional test results. I am finding that I just want to ride!
Click to expand...

I'll be riding once I get my controller and throttles tomorrow...

It appears that "just riding" might actually be good for these batteries. Maybe they "learn high currents" and thus enjoy high throttle runs.

I say this because this is my just completed high current test for my first battery, which I tested a bunch already:

about 100 WH, 18.11v, 14.35a, 1386 seconds, 5.5 AH

That beats the best virgin battery by 10 WH and 0.5 AH, OR 10% in capacity. And the original batt had only sat on charger for 1 hour after going green, while virgin battery sat for several days.

I'll watch the other batts to see if they get better with use. If not could be due to different date/manuf method for the batt I got with the Trimmer.

Happy trails...
 
The $20 lower $109.99 battery price is now on CTire Website, as well as $10 lower $29.99 price for charger. Guess those are the new standard prices now.

I completed my 6 Yardworks battery pack: http://endless-sphere.com/forums/viewtopic.php?f=3&t=5749&p=87462#p87462

Once I install my controller and throttle this morning, I'll be ready to road-test... :)

3600 peak watts power, 600 something WH, 20 pounds, $800 something Canadian with taxes. Only in Canada you say ? Pity...
 
nutsandvolts said:
For $109.99, methinks me must go for 3S3P :mrgreen:
Click to expand...

For range or amps ? I wonder if lower DOD really helps the life of these particular LiMn batts ?

My maiden voyage with 6 batts, manually switched on 3 2s's with no diodes (needle-nose and elect tape on side of bike path), is complete. http://endless-sphere.com/forums/viewtopic.php?f=3&t=5749&p=87630#p87630

I got as good as 10WH/km at 25 KMH max.

I'm disabling my "Tape nut over battery check button" mod on the batts, because it prevents their BMS from automatically resetting. Voltage sits at 0.7v when this happens.
 
My manual voltage switch / BMS:

bikeswfl 008.jpg

Works well. Uses 3 way switches to allow series connection of any combination of 1, 2s, 3s, 4s. Straightforward: Switch 1 up is battery 1 on, etc. I reached around for "turbo boost" on my worst hill, but 2s was OK and is generally fine for me.
 
:lol: I thought I was getting stange looks from people around here because of my bike... I could imagine what people say when they see your ride, mikereidis!

I just wish I could use my [mono-block] ping pack in a parallel/series setup like you guys are doing. I think one good use of this type of setup would be for regen, since halving the battery voltage and doubling Amp-hours would make regen much more efficient (if it could be done dynamically of course).
 
ZapPat said:
:lol: I thought I was getting stange looks from people around here because of my bike... I could imagine what people say when they see your ride, mikereidis!

I just wish I could use my [mono-block] ping pack in a parallel/series setup like you guys are doing. I think one good use of this type of setup would be for regen, since halving the battery voltage and doubling Amp-hours would make regen much more efficient (if it could be done dynamically of course).
Click to expand...

:) I've been midnight riding lately, so all people see is some strange flashing lights, a head mounted light and the silhouette of a weird looking low bike-like thing zipping along... :) I may remount my switches on right side so disgruntled Lycra doesn't flip my switches off as they pass. (Yes, I get passed by Lycra; I don't care; I'm having fun...)

I thunk the idea and the schematics up yesterday AM and walked to the Canadian Tire store and saw a 6 pack of 3 way switches for $9.96 and 2 position plates for 57 cents and thought, well, 15 amps is a little bit lower than my 20 amp controller and much lower than my 10 gauge wire rating, but you can't beat the prices ! I love cheap, simple and functional. My "6 wrench torque arm, lawyer lips, and nut rotation" solution is also very much function over form, and IMO looks cool.


Can you tell me more about "halving the battery voltage and doubling Amp-hours would make regen much more efficient" ??? Why is this so ? I NEED variable e-braking and WANT good regen too.

So far, I'm quite happy with 2s=40v. I might go 3s=60v for some hills, or if and when I get comfortable with the speed (and get my brakes fixed!). At 6 AH and 30 amps maximum, I don't feel a need for parallel, especially if it requires power sucking diodes. I've been looking to do a setup where 6s is possible, but with no intention of going above 4s, unless my controller is rated or upgraded for 120+v. But I don't want some random person or my kids to flip all 6 switches and blow my controller, so I may just go with 1s-4s with these switches and another switch to switch to a 2s "auxiliary tank".

Yep, technically my bike is road-illegal with 3s or 4s (VERY close with 2s). I REALLY don't expect a cop to do a roadside dyno or electrical test though, and REALLY, I will have it in 2s most of the time.
 
nutsandvolts said:
I considered using switching to reconfigure battery pack too, but I don't think I'd really use it.

Regarding the comment about doubt of cop doing roadside dyno test, that's not how things work. If your bike was suspected of being illegal, they'd just take it. But currently, I think you'd have to be doing something really stupid to get into such a situation.
Click to expand...

I agree about cops; just a joke, except for that one guy in Europe (Italy ?) who reputedly got a multi-thousand $ fine for illegal electric bike.

Yeah, I put the switches in for ease of testing different S's and to see if it's worthwhile for ebiking. A fixed 2s3p or 3s2p would be fine for me. Probably 3s2p, or even 4s. My thinking and tests indicate that 3s doesn't use much more WH than 2s, as long as you keep the throttle under control. So I think I'd be fine with 4s even, and would rarely use all of that power.

I'm leaning away from P connections for now, because my controller takes 80+volts OK, and is limited to 20 A. I don't like that P requires diodes, which is time, money, complication, some heat and some wasted power. My DOD should be about the same, because I try to use up all of my batteries on any given cycling trip. If I start going further, and I probably will, I'll buy more batts, if I can find room to stuff them. But my first goal is to find ways to reduce power usage for maximum range.

I'm surprised one 20v battery works as well as it did. My "auxiliary" was supposed to be 2s but some connector issues I think made it 1s and I went riding instead of staying home to fix. It got me home last night with little pedaling, after my other batts crapped out earlier than expected. I got 22 KM one way on 2s and about 16 KM back on the other 2s. The way back has more hills to climb. I notice it in my Prius where my mileage is about 10% worse driving home.
 
I had thought about using the switches as a means of getting the maximum from each battery. But I understand there is little to no recovery effect in Li Ion, unlikes Nickel batts. From my testing I found that once a batt has tripped LVC, it's almost useless. I CAN use it, but as soon as I give it some throttle or climb a modest incline, the LVC kicks in again. Tried with 1 batt, and even all of them. No go. I'm OK with that as I'd rather have power immediately than wait for a batt to recover, and will use 2s as a backup battery.

I also found, as is to be expected, that once one batt in a set trips LVC, they are all about done, assuming they were all charged same and used same.

So it would probably be almost as useful to have a 3 way switch for 2sA, 2sB, and 2sC. 2sA is to get there, 2sB is to get back and 2sC is my "unexpected detour/too many hills etc. get home aux batt".

But switching in 4s on demand is COOL ! Great for demos with no re-wiring. Also, switches allow me to bypass bad batts or connectors without having to do ebike surgery away from home. I'll be very happy if I never again have to whip out the pliers and tape for roadside battery reconfiguration.

I've thought about relay control mechanisms to replace the switches and auto bypass a bad or low battery. But that also has some of the diode disadvantages and would probably be heavy and expensive for 20+ amps.


I found some good info on LiMn and other batts at: http://www.batteryuniversity.com/partone-5A.htm

One thing there I can confirm from that site is that open circuit voltage is a good indicator of battery charge, even when connected to the charger. When I disconnect charger I don't see batt voltage go down like with some other chemistries. So a DMM is better than those 4 batt LEDs, assuming you can estimate percentage of full charge from the voltage.

I see that LVCs for LiMn tend to be around 2.5v-3v. These batts seem to LVC at 15v or 3v per cell, so I guess they were set conservatively to increase reliability.

Those inside battery pics and the charger pics make me wonder if the battery is MORE intelligent than the "intelligent charger". I'm going to do some charging voltage and current tests to see if I can figure just what this charger does. I REALLY suspect most of the protection and intelligence is in the battery. I don't know if the charger does "pulse charging" and without a scope I'm not sure I can tell. I half suspect though, the charger just provides a DC voltage and lets the battery do what it wants with it. Also, charger has short circuit protection (I hear a relay click), and an indicator LED. How else could they sell chargers for $30 ? LI-Ion battery chargers cost more than that at RC shops.

My goal is faster charging of course. 10.5 hours for 6 batts on 2 chargers is too much when I want to ride. Charge 2 overnight, 2 more in morning, then get home and may have to charge 2 more before I can ride at full capacity. Suits the midnight rides, but I'd like to start earlier. I don't want to buy more chargers as I'd rather work on a better solution.


BTW, I've never tripped the 31 amp BMS cutoff on the bike yet. Did once on the trimmer in heavy, wet grass. But my controller is only 20 amps so I imagine that is enough leeway. Only BMS cutoffs on the bike are LVC when exhausted.
 
Ypedal said:
LiMn absolute max low voltage = 3.0v !!!! ( at 2.5v you will have problems !! this would aply to LiFe.. but not LiMn !! :wink: )
Click to expand...

Thanks YPedal, but I think I beat you to it if you look at the post above. :)

BTW, my motor and wheel seem to have survived the MAJOR pothole I hit at 2:15 this AM. :) The tube didn't but thankfully waited until I got home to deflate. :( :/
 
well after starting this thread about yardworks batteries i finally bought some today(on chargers as i type this)
2 bats and 2 chargers for 316 bucks
after 3000 kms on my ct/schwinn izip @36 volts(really 40 fully charged) my sla are saging bad...
my range is less than half what it used to be...
can't wait to lose the sla's and about 23 lbs off my bike...77lbs instead of 100lbs
anyways i finally bit the lithium bullet no going back to sla's
loving this thread

thx wasp
 
a question regarding charging...
i want to put these 2 bats in my orig bat box on my schwinn izip
it will fit no prob there but wiring for the chargers is confusing me?
do i need to use the c as ground and + to charge but while using bats
i need to use - and + so my question is all 6 wires coming out of box
for hooking up...when i charge them will there be a problem having
all 3 wires on the battery at once? i know how to wire it up to work
but i don't want to open the case each time? i want to just reconfigure
my wires like i have been(using a extra 12v 12ah)so when i would charge
it i would use the stock 24v charger and a 12v charger on the extra bat.
thx
wasp
 
nutsandvolts said:
There are only two leads pos and neg to the chargers. Open one up and you'll see what I mean.
I assume that the third signal is for mating with the appliance (hedge trimmer or whatever).
I haven't really thought about what its for, because it's not needed for charge or discharge.
Click to expand...

i know there is only 2 leads on charger but if you look when you hook it to the charger(battery)
it uses the + and the c slot on the battery instead of the -???
so i'm wondering if i need to run 6 wires out 2x- 2x+ 2xc(2 batteries)

thx wasp
 
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