Is Jimmywu66 & EastUnitedMusic the same person?

[Battboy]

Why I don't believe in selling on E-Bay. You put yourself in the company of thieves. E-Bay should have some mechanism to regulate these multiple personalities - it's like Wall Street these days. Who's minding the store ? Paypal ? That's like asking the dog to watch your food !

Don

 

[Battboy]

We do make them better but just not nearly as "cheap" as Chinese duct tape packs. And our LiFeBATT Packs require no DIY skills or special diagnostic skills. They come with a 3 Year warranty and are backed by a U.S. company and made in Taiwan - not China. These Packs do not involve soldering, duct tape, or generic BMS boards made by a third party vendor. They have been available for quite awhile - but the price is considerably higher than E-Bay offerings. If you look inside a LiFeBATT Pack you can understand why !

View attachment 1

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Don Harmon

 

[Pete]

Ebikes by their very nature are still a niche market and firmly under the heading of 'under development'. To me this means you either take a personal, hands on interest in the details or you pay big dollars for a pre-packaged solution. Just like a car, you either learn how to do it yourself or you deal with a bricks and mortar shopfront to do the work for you.

For the guys who got wu-ted, it is disappointing you have had such crap intro to ebikes but please don't give up. Once you do get your setup sorted out the EV-grin is worth the teething problems. You guys have probably already done it by now, but browse through the forums and you will find plenty of information on the various battery options available. Obviously, they all rank differently WRT cost, performance, lifespan, build quality, cell quality, seller communication, after sales support, warranty, etc. I really need to get organised and do some more work on the wiki pages

The Lithium chemistry market is still in an embryonic stage with suppliers performance ranging wildly from fantastic to abysmal. Once you figure out your budget, I believe the best option is to get a feel for how your potential supplier has been performing over the previous few months. For me personally, I also work on the assumption that if you are not dealing with a bricks and mortar shop front then you automatically add a level of risk. Regardless of whether the return mailing address is in the same state, country or planet you are still going out on a limb where return freight on warranty problems is just not worth the cost. All you can do is mitigate the risk by researching how the vendor has performed, historically.

The LiFeBATT solution is a premium product with a premium price tag. For many Ebikers the unit cost is either too much to swallow or there are alternative solutions that offer better value for the requirements of the particular rider. Is anybody using LiFeBATTS's, how have you found the product, the sales, aftersales and support experience, and any warranty experiences ? Preferrably start a new thread rather than hijack this one

 

[avsmith66]

Oh well . . . . I wish I had read this before I bid, but at least I think I got a good price. I got lucky on the bidding at the end of the auction, so if I get a battery I think I am going to be doing ok on this even if I have to upgrade the BMS. . . .

24v10ah LiFePO4 for $128 from mp3hk

Since I won I have already conversed with Lau in several emails from the address lau <chan71@gmail.com about shipping, battery dimensions and my phone number.

Lau claims that it will take 9 weeks to be shipped by sea which is included in the free shipping, but has repeatedly emailed me offering to "upgrade" to air mail for 39$$$ more. I pointed out to him in one email that his other listings offered it for $39 for this size/weight battery, and he replied stating the shipping terms for the auction I won was for $60. I decided that I was not in that big a hurry and replied that the "free" shipping would be fine, to which he later emailed me and replied that I was correct and $39 would be the charge for the upgrade. Then I received yet another email asking for the battery size, my phone number again and if I wanted to upgrade again . . . . . sounds like a bit of confusion going on over there as he has several batteries for sale now. I have definitely decided at this point after reading this post to cut my potential losses. I'll be patient and see what arrives. I sense that he is making a decent amount of additional profit on the air mail upgrade(s) and I have never had anything I ordered from Asia take more than 3-4 weeks in the past.

I'll post updates on how this ends up . . . . If it ends up being anything worth posting about.

I'm running with 48v NiCads I assembled from 14.4v Denali tool packs in the meantime, and was planning to use this as a boost pack, so I have plenty to keep me occupied until this arrives, or whatever happens.

Wish me luck!

Avsmith66 :|

 

[lesdit]

If you Google around a bit, you can find some big manufacturers in China who sell various cells and packs. Some are for wheel chair
applications but look perfect for bikes too. The problem is that there are minimum order quantity issues. Just like you can't buy Duracell batteries directly from Duracell.
What then happens is some company like thundersky or whatever will import a bunch and mark them up considerably to make it worthwhile and profitable
for them. They also have to cover returns and cell failures and still make it worthwhile.
One option may be to do a 'group buy' of a popular cell, and get them cheap enough to make replacement cells cheap too. There should be batch to batch cell matching preformed ( which I hope the ebay dealers are doing ) .
I'll bet the cells that the ebay'ers sell can be had for 1/2 to 1/3 the ebay listed price.
We can duct tape them on our kitchen table instead of pings kitchen table
The stuff over there is cheap. I priced automotive turbochargers from CN once, and they were something like $60 each. Amazing.
And that is why we *Americans* are basically screwed, BTW. Notice how the prez candidates won't mention this *little* problem.

example search gave me these 'thundersky type cells :
http://www.made-in-china.com/showroom/unitefortune/product-detailFMCxAiElHpVh/China-LFP-Battery-Single-Cell-40AH.html

are these the ping cells ? 1000 cell min order....;
http://www.made-in-china.com/china-products/productviewdtgnWorkVJiE/LiFePo4-Battery-Prismatical-.html

Yes, buying from China is a huge risk. Why can't someone in the U.S. sell these things? Or do they and they are just hard to find. Another question, is why we can't just make our own packs and skip over these Chinese dealers?

 

[ejonesss]

the ping? cells look like the heter cells and seeing how one failed i am concerned about explosion or fire.

i had the lithium io battery in my 5th gen ipod fail and it bulged the same way.

 

[leamcorp]

I'm re-wiring Jimmy's battery and have a question. I'm puzzled as to where the positive cable gets soldered. On the picture I've posted below - is that correct?

 

[R2R2]

What you have labeled "(+) power cable?" is incorrect. It actually is the negative "output" to your wheel. The other two labels are correct. + power cable does not go onto the BMS anywhere.

 

[R2R2]

By the way leamcorp,
I have seen your "Ebay Lifepo4 pictures -JimmyWu's (pic heavy)" post. Those pictures are quite intersting. So many cells. I may have to get down into the batteries too eventually to replace some cells. Ugh! I apparently blew out a "cell" and am running on "36 volts" instead "40 volts". I'm still waiting for my BMS from JimmyWu. It has actually been air mailed. I'm expecting it any day now and I'm hoping it may solve my problem but I doubt it. So, I may need to get down into the cells too eventually. I'd be interested in reading more on that post as you move along with your rewiring.

 

[leamcorp]

By the way leamcorp,
I have seen your "Ebay Lifepo4 pictures -JimmyWu's (pic heavy)" post. Those pictures are quite intersting. So many cells. I may have to get down into the batteries too eventually to replace some cells. Ugh! I apparently blew out a "cell" and am running on "36 volts" instead "40 volts". I'm still waiting for my BMS from JimmyWu. It has actually been air mailed. I'm expecting it any day now and I'm hoping it may solve my problem but I doubt it. So, I may need to get down into the cells too eventually. I'd be interested in reading more on that post as you move along with your rewiring.

Yeah, I didn't know either. I've just jumped right into this thing and already spent a ton. Let see.. I start with a Ezip in June, then BL36 in July and now BMC and also looking at Bafang - help me.

when you receive the BMS - do check to make sure all the fets are there. I've given up on Jimmy and ordered a BMs from Ping, which have all the parts.

We really do need a good entrepreneur from this bunch. While there are lots of do-it-yourself people here, there probably are lots of "can you build me a robust/reliable battery" from US/Canada and we'll pay more for it folks on this forum.

Thanks for the info.

 

[R2R2]

My BMS arrived. There are four MOSFETS and this time the part numbers are not sanded off. The numbers read:
T430
T5
BN7X2R
on all four MOSFETS.

Now if I only new where to look to find specs.....

 

[dnmun]

R2, can you post up a close up? can you read the manufacturers insignia? i will look them up in digikey, maybe someone else has a better source for identifying parts. just looked, could not find any listings in digikey.

if your pack already has dead cells, that should be covered in the warranty, if not, you will need to root them out and get some more batteries to replace them with. it is now apparent that these paralleled packs are not the way to build a lifepo4 pack, when one cell goes, it takes out all the others in parallel.

leamcomp, i also just looked at that picture and the B- is from the motor. it is the negative side of the motor and the current which goes through the motor and back through the controller and then from the controller to the battery through that wire, (black wire from controller). it enters the BMS at that spot which is why there so much solder which also covers the end of the shunt wires of which there are 4, and the other end of the shunt wires is tied directly to the source of the 4 fets, on the other side of the board, and that spot on the end of the shunt (which establishes the over current voltage delta across the shunt) is also attached to the 14 pin package through that trace that runs up to the corner, which is where the op amp for the gate driver is and you can see the gate trace running back up to the fets, 4 in parallel. the wire marked +power cable is actually the drain from that charging fet on the left side where it is soldered on to the heat sink/drain of the fet. that has to be connected to the negative terminal of the battery. the C- lead is the black wire from the charger, and the red wire from the charger goes onto the positive terminal of the battery.

 

[R2R2]

Attached is a close up of the FETs.

View attachment FETS close up.JPG

 

[leamcorp]

leamcomp, i also just looked at that picture and the B- is from the motor.

Thanks, actually my Cycle Analyst figured that out. When I connected to the other wire, the cycle analyst wasn't turning on. So I've switched the wire to B- and it came up.

I'm next going to test the charger - Jimmy's vs ping. When I test the Jimmy's charger, it goes up to 55.5v and thats what my battery charges up to. My understanding is that Ping's charger goes up to 60+v ...I haven't put right connector, it will be interesting and will confirm if Jimmy's battery is really an SLA charger.

 

[dnmun]

your battery should charge up to 58.4V (3.65x16). your power supply should have an output voltage equal or higher.
that may be why there is not sufficient capacity to reach the stated performance. your battery is never totally charged up.
you bot a charger from ping or is this another source? did you get a BMS from ping too? double good.
there may be a final output voltage adjustment on the jimmy wu charger too. there is a note somewhere about how to do it on the soniel chargers, it should be similar with these little chargers, and it should get up to 59V eventually.

someone smarter should look at the pictures if you open it, but i would expect the feedback from the output is fed back through a resistive divider network to the charger front end, but not sure where. assuming there is a variable potentiometer in line, try adjusting it while measuring the output voltage into a load. always keep track of the original setting since you may be adjusting the wrong pot. mark the spot on the surface of the pot and keep track of the turns, in or out.

 

[Sacman]

Ping uses physically different battery cells than Jimmywu/EastUnitedMusic. I believe that's why the difference in battery voltages.
Ping batteries use prismatic cells that charge to about 3.8V/cell. That translates to (3.8V x 16) = 61V. That's why Ping's chargers are 61V.
Jimmywu/EastUnitedMusic batteries use cylindrical cells (the Valence Saphion variety) that charge only to about 3.4V/cell or (3.4 x 16) = 54.4V. That's why Jimmywu/EastUnitedMusic chargers are only 55V.

I got my battery and charger from EastUnitedMusic.
During the first hour of charge (during it's CC phase) I've seen it go up as high as 58.6V but final voltage at full charge (CV phase or floating phase) is about 55.3V. I've opened up the charger and I saw no variable pots to adjust the voltage. At full charge almost all my cells read about 3.4V. Only one cell reads 3.6V. But remember my BMS is shot too so I'm charging without a BMS and I have no charge balancing or limiting. The cells get all the direct charge they can from the charger. So take what I report here with a grain of salt.

 

[dnmun]

thanks, i thought all the lifepo4 chemistry had the same charging characteristics. is the resting potential about 3.3-3.4V/cell? how did your battery pack end up? were you able to get the BMS replaced because of the bad opto in the corner? i figured you could recover if you got another BMS.

the new headway cells are out, seem to be the best yet. the group buy is gonna ship 10/05. it is possible to contact headway up to the last minute and it will be put into the shipping container with the other packs, but you have to pay up front directly to headway. this seems to be the best deal imo. screw tops allow replacement of dead cells in the future without too much hassle.

 

[leamcorp]

Ping uses physically different battery cells than Jimmywu/EastUnitedMusic. I believe that's why the difference in battery voltages.
Ping batteries use prismatic cells that charge to about 3.8V/cell. That translates to (3.8V x 16) = 61V. That's why Ping's chargers are 61V.
Jimmywu/EastUnitedMusic batteries use cylindrical cells (the Valence Saphion variety) that charge only to about 3.4V/cell or (3.4 x 16) = 54.4V. That's why Jimmywu/EastUnitedMusic chargers are only 55V.

I understand the difference between JimmyWu and Ping battery. What I'm not fully convinced is the ability for Jimmy's charger to balance the battery when it is unbalanced.

My understanding is that SLA chargers will not go into 2nd/3rd stage to balance the lithium battery. If I use Ping's charger, which I would have to assume he have provided Lifepo4 specific charger, it will balance the battery and BMS will cutoff if voltage gets too high.

Once my battery was charged up, I've left the multi-meter to see if there's additional activities. As far as I can tell, it didn't go through different stages... again, I'm only testing voltage so my test maybe flawed? I wonder if R2's battery could use this charger and see if that will bring up the bad or un-balanced cell?

This is all conjecture at this point since my battery is only 1 months old and hard to gauge when a cell will get un-balanced - so we'll have to see over a longer period.

 

[Sacman]

thanks, i thought all the lifepo4 chemistry had the same charging characteristics. is the resting potential about 3.3-3.4V/cell? how did your battery pack end up? were you able to get the BMS replaced because of the bad opto in the corner? i figured you could recover if you got another BMS.

No... I haven't really done anything to fix the BMS yet but I will eventually work on getting it fixed to give myself extra
peice-of-mind that the battery is protected and that it will live thru a maximum number of charge cycles.

Even with a non-operational BMS I still feel that the $600 I spent for the battery (with all shipping costs) was worth
the money and all the trouble and difficulties I went thru dealing with the vendor doesn't bother me as much anymore
like it originally did when I started this thread.

I've been using my battery for about 2 months now and I now have around 70 charge cycles.
So far I'm pretty happy the way the LiFePO4 battery works for my "commuter applications" which are:
1) increase range ... I now get max of 28 miles (not bad for only a 15ah battery), but I only go about 15 miles on my
daily commute so I'm confident that the cells don't get over discharged and are still safe (even without a BMS).
2) increase my top speed ... I can do about 24mph now
3) increase torque for easier/faster hill climbing... now climbs fairly steep hills with much less pedaling effort
4) increase number of charge cycles ... I'm hoping this battery will last me a good 3 years

I did NOT buy this battery for any high discharge (high C-rate) applications.

 

[dnmun]

he should have given you a free replacement BMS without any reservations. you never did any destructive testing that melted the solder. your BMS was obviously damaged in shipping, and if they refuse to replace it you should file with paypal and request that your payment be withheld until he does send you a new BMS. i still think you may be able to use that BMS for charging and balancing if you can get the charging fet to turn on, or just put a jumper over it to allow the cells to charge and balance. that seemed the only problem you had with yours as i recall, but if there is more lemme know.

don't give up, you have solid evidence that you can present to paypal to stop payment, that will get you a new BMS if he won't replace it under warranty. if that fails, go after the shipper and seek recovery, but i think ultimately he bears responsability, imo.

 

[R2R2]

Like Sacman, I too am having to charge my battery with the charger directly. I too would have better piece of mind if I could actually use a BMS. I did get my new BMS as previously posted but it is not charging my battery. I am not exactly sure why. I'm guessing this is because I have a "cell" blown out (Full charge is around 36-37 volts instead of 40-41 volts). However, it seems like a "smart" BMS should attempt to charge the remaining cells even though it is one "cell" down. I'm not sure how I could trick the BMS to charge the remaining cells. dnmum mentioned in the previous post to sacman about putting a jumper over the fet on his bms. I'm not sure how to do this or if it would work for my situation. Additionally, I'm thinking without a complete battery my BMS is useless. When I had a good BMS and battery, the BMS used to cut the battery off at 38.4 volts. Since my battery voltage is now 36.5 volts, it seems the BMS would never kick in, thinking the battery voltage is too low even though the remaining cells are good. I don't know, I haven't had a chance to test it out yet.

 

[dnmun]

R2, i also suspect you have dead parallel cells, i am not familiar with how the sense wires come up, but you could try to establish which ones are dead, but that is of little matter now. can you still charge the battery with the BMS removed? i thought the problem sacman had was with the opto in the corner which was bent out of alignment, and that was why the charging fet would not turn on.

if you connect the C- point (where the black wire comes from the charger), to the heat sink/drain from the charging fet at the end where the black wires are soldered onto the end of the board, you will jumper over the charging fet.

if the charger will then turn on, that will tell you that something is keeping the charging fet from turning on. it could be burned up too, but it may also be because the dead cells have caused the BMS to turn off that charging fet to protect the battery.

i don't think a new BMS will restore the dead cells to life, and i am not sure if you could get warranty replacement or be able to get paypal to withhold payment, but you will need new cells in the pack to replace the dead ones if that is why the BMS is blocking you from charging up the pack.

i know this is more information than you can use, but i don't know what else to do to help. maybe there is someone close to you who is capable of determining which cells are bad, and will help you cut them out and solder new cells in their place, the soldering is the hardest part, because the connecting straps are gonna be hard to solder, so you would need to develop soldering skills beforehand better than most of us who have used soldering irons for decades. you will need to have access to high quality 60/40 solder with rosin core and flux for the straps as well as sandpaper to clean the straps after degreasing. and you need to restore the sense wires too, which may themselves be bad in your current configuration, and the reason it is not charging.

i guess the only thing is to wait for the new BMS, i hope your use of the battery in this period of time hasn't reversed a buncha cells, but if you can reinstall the new BMS, then we can see if it will charge then. so you just need to be patient until it arrives.

 

[R2R2]

dnmun,
My new BMS has arrived and it is not charging the battery. That is what I was talking about.... the new BMS. I'm sorry if you misunderstood my post. I was wondering if there was something that I could do to trick the new BMS to charge the battery. Additionally, I won't be able to get any new cells and have someone replace them anytime soon but I am looking into it. For now, I really don't want to have to cut into my battery pack and get down to the cells. For one thing, the battery "duct tape" was actually put on pretty good and "looks" nice, and, I am afraid that I won't be able rewrap the battery as good. For me, every millimeter of thickness matters for my battery case. If I rewrapped the pack, I could loose a few millimeters and it might not fit into my case anymore. Another thing, if I get down to the cells, I just wouldn't know what to do or who to take it to for repairs. So, I am stuck with having to use the charger with no BMS until I can figure something out.

 

[dnmun]

ok, now i got it. in that case just do what i was telling mr sac.

install the BMS so all the sense wires are in the plug connected, attach the red charger wire to battery plus terminal, attach the black charger wire to C- on the pcb, attach the black wire from the top of that charging fet to the battery negative terminal, turn on your charger, and at this point it is set up properly, but not charging, correct?

now connect a jumper wire across the charging fet from the source to the drain (which is from C- to that heat sink/tab/drain of the fet). or you can connect directly from the black charger wire to the negative terminal of the battery, which is just bypassing the charging fet (which is essentially what you have been doing except the sense wires are not plugged in). this should allow your charger to turn on and start charging the battery, which is kinda what you are already doing, but now you can try to determine if the BMS will balance the cells while it is charging, and you should be able to measure voltages across the shunt resistors. which will help isolate which cells may be bad. not sure if the reason the charging fet does not turn on is because of the dead cells, but i suspect that is the reason. the sooner you can repair it the better it will be, and less chance of something else going wrong. is it possible the charger doesn't put out a high enuff voltage to charge the battery to full capacity?

if you do this, try to use an ammeter to keep track of the charging current and when it drops to the level of the shunt current, you should be fully charged up. cells should read 3.65-3.8V each. but sac is saying that there is some difference in resting voltage between the cylindrical cells versus the prismatic pouches.

i agree it is a hassle, but once you push current through a lifepo4 cell below about 2.1V the cell is reversed internally and it causes damage to the charging surfaces inside the cell, and it is usually toast after that, with no useful capacity. that is what i was hoping to help you avoid.

 

[dontsendbubbamail]

Inside JimmyWu

Everything was working well until I blew my first bms through negligence on my part. I ordered a new bms and you can see the results from the first run.

I was getting some weird readings from the first couple of cells, so I decided to see what was inside.


After the first layer of duct tape there is a layer of plasticized paper.
View attachment IMAG0006.JPG

More duct tape and hot glue.
View attachment IMAG0008.JPG

A layer of rubber and plasticized paper between the halves of the 16s14p pack.
View attachment IMAG0010.JPG

The two halves unfolded.
View attachment 2

Next to last layer of duck tape removed. There is a layer around every bank of cells.
View attachment IMAG0013.JPG