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here is some info on 20v yardworks lithium ion

Hi guy's
here's a battery space suitable balancing bms for these cells.
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2341
 
So far so good.
My 2 YW are within 0.1volt from each other used in serial.
I ride them in parallel with my SLAs ( with Schottkys )
Last season with SLAs. I'll get 2 more YW (or 4) next year.

They both charge at 20.9v. for 41.8v.
When I measure them after a ride, there's always a little difference. ( < 0.1v.)
I checked the individual cells a few times when charged. All between 4.17 to 4.19
I assume that it's balanced.
Which difference between cells would be considered unbalanced ?
 
I'm no expert but they sound reasonably balanced to me !
At full discharge to lvc (15V per pack) assuming one 0.02v low cell would give 4 cells at 3.04 and the low one at 2.84
I think these cells shouldn't go below 3V or permanent damage occurs so try not to fully discharge these packs.
but even with no leds showing on the battery gauge the pack is still above 15V
I'm running a clite 406 with 72v/35A controller using Yardworks 3S-2P 60V/12AH
I'm thinking of going to 4 serial but am not sure if the controller will handle it
I only have about 30 cycles on these packs and the cells are around the same voltages as yours.

How many cycles have you got on theses packs ?
How deep do you discharge ?
Have you checked all the cell voltages after discharge ?
 
How many cycles have you got on theses packs ?
How deep do you discharge ?
Have you checked all the cell voltages after discharge ?

I received them Oct.22, so only used them for 6 good rides so far ( weather helping ) :(

I discharged once to 32.1(16.03 and 16.1) and 5 times between 33 and 34.
Around 10 short rides, shopping mall and back. ( 36 to 39v. ) Too cold for me for long rides.

I only checked the individual cells twice, and when fully charged. Once before first ride Oct.23 and once Nov.8 ( no difference AFAICT )
If I go for a long ride again, I'll check them discharged.

Since I ride them with my SLAs, I can't tell about range.

A friend of mine bought a Ecolo-cycle with Lithium 36v. 10Ah.
After only 98 cycles, he lost range. :shock: I asked him to let it charge over night. So he did.
Deception, seems there' no balancing going on with the BMS on these bikes. ( if there's one )

I hope our YWs will do better than that.
 
I recently noticed a huge drop in capacity and i am getting bms or lvc cutouts not sure which.
I took the packs apart all cells are good no bulging or obvious damage and the cells are better balanced than the last time i checked all within two tenths of a volt after discharge (per pack) and within two hundredths of a volt after 4 hour YW charge + 1 hour sitting that's @ 40 cycles.
I am putting the low capacity down to the sub zero temperatures i am riding in.
The bms is pathetic in these packs i've already returned and had replaced over the counter 4 of the 6 packs because of bms failure (love that one year warranty).Once they run out of packs and have no replacement I get my money back and could buy more in the spring with a new one year warranty.
I may switch back to my nicd for the winter as they work even better in the cold.

The excellent 4-24 cell bms from the sticky can easily be adapted to these cells I think its "Methods" who is doing one which i will be following closely and doing a copy build of for the spring.
 
nutsandvolts said:
....How cold can we go with yardworks? Will my bike even operate at at -30C? LOL My brakes are acting screwy already and it's just beginning.

I don't know if your bike will operate at -30C, but, I know I wont. :)
3300km. That's how many cycles ?

We can do +-120 cycles a year.( Canada ) 6 months of 20 sunny days ( I WISH :roll: )
My big question is: 1000, 3000 cycles, that's great, BUT
How many years can we expect from Li-Mn chemistry ? LiFePO4 chemistry ?
What good is it to be able to do 3000 cycles if the chemistry lasts only x years ?
 
I changed my parallel diodes to bridge diodes that waste more power as heat and placed them in the bottom of my battery bag not a noticeable change in range but keeps the battery's warmer.

Some one said earlier in the thread, they saw a sign claiming 2000 cycles for these bats.
I do over 200 cycles a year so that is say 9 years and by then there will be better available for cheaper.

Although I am very pleased with the performance of these bats I see these battery's as a solution for now while lithium technology matures.i intend to return them every year after the heavy snow for refund and get a fresh set at the start of the season until something better with equal warranty and convenience of availability/exchange comes along.

nutsandvolts said:
How cold can we go with yardworks? Will my bike even operate at at -30C? LOL My brakes are acting screwy already and it's just beginning.

I think that the only limit depends on how much power your willing to waste to heat the battery's.

Takemehome said:
I don't know if your bike will operate at -30C, but, I know I wont. :)
3300km. That's how many cycles ?

Me and my bike have done minus 30 last year with nicd and i will try it this year with these YW
 
i wonder if using a battery warmer in sub 0 temp would help? maybe another angle/parameter for your tests
 
Nuts and volts are you still using the YW chargers and BMS ?
How balanced are the cells after the 300 cycle mark ?

I've noticed the YW chargers are a little sensitive and sometimes they will terminate a charge cycle and show a pack as fully charged even though it is nowhere near full if there is a power fluctuation/spike.
Also i noticed that the chargers must have been changed at some point as i have one that has one LM3584 chip labeld IC4 on the board missing, as this one is YW 1chip.jpg
all and others have two LM3584 (IC3 and IC4)
 
Nuts and volts, After seeing your original post I also repackaged my 3 chargers which i have on a relay with timers to charge the six packs i have, takes longer to charge but i only overnight charge.
I think i'm going to try the resistive braking using the rectifier.This will be on a clite 406 all the postings are for the 5 series, so anyone know if i need more or less than the 25 foot resistive coil :?:
http://endless-sphere.com/forums/viewtopic.php?f=2&t=583&st=0&sk=t&sd=a&start=45
I will use the resister to heat the pack for the winter.
 

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is anyone using these in sub zero temps?
are they working well?are the insulated?
i am down till jan but will be winter riding then
and was wondering about using electric socks
to warm my 2 yw bats...any thoughts
 
The resistive breaking using the wasted back EMF to heat the battery packs works great.
I used a 25 foot coil on a piece of flat bar which I place under the pack bag. It keeps the batts at room temp with riding temp around zero and wind chill -7. when it gets colder i will probably place the resistor in the battery bag. I think there is a little wasted power bleeding through the bridge diodes as there is no cogging when freewheeling without throttle.
I think this will also save me having to change break pads every month or so. :D
 
29a said:
The resistive breaking using the wasted back EMF to heat the battery packs works great.

Would love to see some photos of your setup. Do you have a build thread?

Also.. I'm having a hard time finding a switch that can handle higher amperage. I want to make a motor brake as well... do you have any info on a good switch to use?

Thanks 29a.
 
That's interesting. So you use a momentary switch to engage the resistive brake? There are brake levers available that have a switch built into them, normally used for input to controller cutoff signal inputs, looks like those would work well with your resistive brake also.

The ebike switch brake levers (which aren't reliable) will not take the volts/amps guess you could use them to activate a relay, you need something pretty hefty as a switch, the back EMF can be higher than the input power.

Also.. I'm having a hard time finding a switch that can handle higher amperage. I want to make a motor brake as well... do you have any info on a good switch to use?
I used a dpdt 125v/20A (used what i already had)
and paralleled the connections for 40A to keep the size down.

I wonder how difficult it would be to make a similar brake that is variable based on how much the brake lever is pulled ... would need some extra circuitry. I just changed my brake pads the other day, they were worn down to metal scraping on metal.

The resistive brake is already variable. The faster you are going the more back EMF the more breaking.
If your going to use it make sure you are using torque arms that stop the axle from rotating in either direction. While breaking the force is in the opposite direction to the normal motor forces.
it's all in the thread http://endless-sphere.com/forums/viewto ... a&start=45

Here is "methods" resistive brake disaster http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=7732

I used the diodes because it is safe if the throttle malfunctions (has happened many times in the past) and is on at the same time as the brakes.

sorry haven't posted any pics yet but will get round to it
 
I just bought 2 new bats.
Both at 19.62v.
Bat1: 5 cells at 3.92v.
Bat2: 4 cells at 3.93v. 1 at 3.91v.
I won't charge these and check them every month.
My 2 other bats after a few short rides went to 18.71v. and 18.87v. I did not charge after every ride like I used to do.
They'll be back on the charger if they get more than 0.2v. difference. ( I know it will eventually )
Even at 0.16v. difference I don' like that. ( I don't know if I should worry or not )
When they'll be more than 0.2v. apart, I'll dismount them from the bike and check individual cells.
Then put them on the charger and check back after a full 12 hours charge to see if they balance.
 
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