Electric Bikes - Problems with my YW batteries

I am having problems with my yard works batteries, and I hoping the someone could share some insight with me.

My YW batteries are effectivelty useless because they keep triping at the slightest current draw. They worked well for about a dozen discharge/recharge cycles, but now I am not able to use them at all. If I'm already going 10kmh from peddaling, and I try to add 1/4 throttle, the batteries trip immediately. So far I've confirmed that my charger is charging them back up to the 20V range, so I am fairly certain that it is the high current cutoff that is causing them to trip, yet, it doesn't make senses because I am certain that they are tripping at a fairly low current draw. Plus, on my first dozen trips with these batteries, they worked flawlessly and the worked awesome!

I haven't had the time to pull them apart to troubleshoot but here's my best guess....I think I read somewhere that the BMS board on these batteries really sucks. I think that I read that the 5 banks don't get balanced at the end of the charge cycle......I think it's possible that 12 uses is enough to cause the banks to go out of balance - so even at low current demand, one or several of the banks are delivering too much current and its causing the entire BMS to cut out....

anyways, I plan on troubleshooting them this week, but would like to hear from some of you guys that are using the yard works batteries. Can you share your experiences with us on this thread?

BTW, for anyone that might be just learning about the YW batteries, here's a link:

http://www.canadiantire.ca/browse/product_detail.jsp?FOLDER%3C%3Efolder_id=1408474396676881&bmUID=1239638862343&PRODUCT%3C%3Eprd_id=845524443303058&assortment=primary&fromSearch=true

Overall, I think they are an excellent battery at an excellent value ( provided that I can fix them - lol)

I'm using 4 batteries, 2 in series and 2 in parallel, so the overall battery pack is a 40V 12Ahr battery pack.

an excellent battery at an excellent value ( provided that I can fix them - lol)


Are you kidding me? How can you say they are an excellent battery if you experienced major problems with it after a dozen charges!? :crash:

I know you want to believe they are excellent but anyway...either way I hope you figure out the problem and hope its nothing major.

update:

I just ripped one apart, and it's confirmed: the BMS is garbage. It's not properly balancing the batteries. I found one of the banks was a full volt lower than the other banks.

I'm going to manually balance the banks with a regulated power supply that I have, then test drive the battery. If all works well, I beleive there is a generic BMS board that I can buy from a site like bulkbatteries.com or what have you.

La Bicyclette,

Even after replacing the BMS boards, these batteries will be closer to half the price of a lithium battery pack from my local ebike store.

And, I'll have twice the capacity.

If you can't handle a little bit of soldering and duct tape, these batteries are not for you. Stay with the trouble free batteries at twice the cost.

Well, it doesn't look like this thread has stirred up any interest. But just in case someone finds this thread in a search, I'd like to provide an update on my findings, I believe that this will be my last post on this thread.

- last wednesday, I started to manually recharge to bank that was at 3volts.
- I stopped charging when it matched the same voltage as the other banks.

So, here's my question.....is the BMS functioning, and is the battery any good?....I took it out for a spin tonight, everything worked awesome! I had lots of capacity, and the battery did not trip during the ride.

My conclusions:
the BMS board works, and the battery is in good condition....

...However.....the BMS does not balance the banks at the end of each recharge cycle.

A BMS board should balance the banks.

My Scooter has a standard..scooter PLUG for Charging a 24-volt System..
that is..its charging the batteries..together..
I've changed that by adding a BATT-separator..
I use 2-12volt BATT Chargers...and run about 6-AMP Charge RATES for 2-1/12 hours...
for my 18-ah InterState Battery's...I then Close the BATT-separator and use the 24-volt Charger as a maintainer ONLY..its basically a Analyzer these days(only)...
===
What I have found..is that the 2-12-volts BATTS..don't Charge properly...
..the REAR BATT..tends to do all the work..while the FORWARD BATT just sits in the circuit..
..you could by some measure just keep replacing the REAR BATT..more often than the FORWARD BATT...
===
I would not suggest getting a more HIGH Powered 24-volt Charger either...or what-ever the VOLT---
===
Create a BATT Separator useing 12-VOLT Battery Chargers...at a higher AMP..Rate...
..it takes away the convienance of the PLUG&PLAY-function...
But I find a more READY-System..it doesn't really seem to change performance..
===
Also...useing your Batteries every day..is a bit rough on them...
If at all possible...having a CHARGE Station..at some Half-way POINT..would FIX...many issues..
===
I'm still working on a Battery Charger..that FIXED to the FRAME...for a 20-minute STOP&Charge...
..something like the automobile uses...needing some 2000-RPMS..and a Regulator..
You can not charge your batteries as you use them/[end]

the yw bats do not use a balancer...
i have also seen them act up thats why i keep them intact and return if needed under ct's warrenty
there is a post on es about adding to the shunt will make them less trippy...
i find reverseing the bats from time to time helps for me it's just a matter of reverseing my jumpers

I'm planning on taking a different approach. I am going to purchase some lithium ion ICs, much like the one that I posted on the battery thread months ago.

The one that I posted is a discontinued part, so I'm reviewing the several hundred versions of this chip to find one that i like.

the chips ussually go for about 2-3 dollars and are capable of handling all of critical charging phases in a single Lithion cell. Some of them even other features, if I'm up to building a full blown BMS board.

I'll need multiple chips, one for each 4.1V cell. Once I get a circuit that I like, I might produce a circuit board with Protel 99. There's a prototype service in Calgary that will produce a prototype board for about $40, and I know of a place out of Vancouver that has better quality and prices for a small order of a couple dozen boards or more.

I think I can get the chips to mount onto a board that is maybe 2"x1" so it will fit into the existing enclosure. But we'll have to see.

I'm thinking of making anything that I build an open source project. but I doubt that it will attract much attention.

the yw bats do not use a balancer...
i have also seen them act up thats why i keep them intact and return if needed under ct's warrenty
there is a post on es about adding to the shunt will make them less trippy...
i find reverseing the bats from time to time helps for me it's just a matter of reverseing my jumpers

by inspecting the boards under the microscope, it looks like they dont do much of anything. There's a 6 pin IC that I haven't been able to identify, if it isn't some sort of lithium charging chip, then I'd say the entire friggen board is a piece of *****

BTW, how many have you returned? out of 4 batteries, I've already lost 2 batteries due to imbalanced charging. I'd estimate that I used them less than 30 times to get them that way.

Also, I may be experiencing the same thing that you guys are talking about. ie it may be that 1 of the 2 batteries in each pack is susceptible to going out of balance.

by inspecting the boards under the microscope, it looks like they dont do much of anything. There's a 6 pin IC that I haven't been able to identify, if it isn't some sort of lithium charging chip, then I'd say the entire friggen board is a piece of *****


yes the bms is cheap!! at least you guys got some charges out of yours. first day i had my yw battery all cells turned bad never got to use the charger :(

speaking of China filling garbage dumpsters of the world!!
How many people are knowledagable enough in electronics who will try to fix/build new balancing BMS. Is Canadian Tire advertising this as DO-IT-YOURSEF kit for the God sake??
CT is doing GREAT disservice to electric bikes by selling this unfinished speaking very delicately product.
Why not to charge $100 extra and tell Chinese contractor to fix problem?
CT cannot hire engineer to test it?
Now try to explain to the doctor or clerc trying to commute on ebike that he must build/fix balancing function.
For all of you probably know that Chinese make all kinds of crappy Lithium cells which WILL NOT last even 1000 cycles.
I strongly suspect YW cells will no way reach 1000 cycles even at 80%DOD of discharge.
C'MON CT bring good product .
YOU GOT WHAT YOU PAY FOR.
The best are A123 next BMI/LifeBatt, of course their 24V10Ah cost 500 bucks but they are the best in the world, easly reaching 2000 cycles, with 300W motor very light service.
Again Canadian Tire shame on you don`t fill dumpsters, how many will just throw it to the garbage?
MC

However, I will admit that I am using these YW batteries for an "off Label" application. And, in that sense, I must understand that I take my chances.

just wondering, If I go to a RC hobby shop, what will a 4.1 volt lithium charger cost me? If its $20-$30, then I'm interested.

update:

here's an example of a single chip solution for charging a 4.1V lithium cell.

http://www.national.com/mpf/LM/LM3622.html

like I said, this is just a sample. If I buy one, I'll make sure that it's availabe through digi-key. there's probably 2000 different chips like this, its quite impossible to review them all, so I'll probably go with the first one that seems to have everything that I want.