Is Jimmywu66 & EastUnitedMusic the same person?
- Thread starter Sacman
- Start date
dnmun
1 PW
nopingbubba, you can still charge your battery? does the BMS work to charge the battery and then shut if off at the end? i think jimmy wu just has a piece of coal in there, how can the fet have so much internal resistance that it melts the solder, not once, but now multiple times? makes you wonder if jimmy wu has even discharged any of his batteries at all in testing. maybe he doesn't even know that the cheap fets he chose are melting the solder. i wonder if he feels guilty leaving the 4th fet spot empty, knowing he saved 12 cents. this is not rockefeller counting the drops of solder on the oil can. i think this is looking more and more like class action, he has gotta improve the BMS, people bidding have got to get the feedback, ebay is complicit in covering up this fraud. is this special solder? maybe straight lead with no tin?
in those pictures, there is now a direct short through that solder blob, from the input side of the shunt to the drains on the output fets, at that point all the current should be going through the solder blob, and the fets will be bypassed so they should cool down, maybe that is why it stopped flowing, if it cooled down after the short was made.
the welding on the contacts to the end of the cells and strap to strap needs more than one set of 4 spot welds, that will be the quality measure,
(for R2 and others like him with suspected bad cells)maybe load the pack up while it is all open and feel for an unusually warm or cold cell? i wonder if a thermal imaging camera would be able to detect a bad cell in the parallel string? but they take all the other cells with them too i think, but maybe it is not a problem.
in those pictures, there is now a direct short through that solder blob, from the input side of the shunt to the drains on the output fets, at that point all the current should be going through the solder blob, and the fets will be bypassed so they should cool down, maybe that is why it stopped flowing, if it cooled down after the short was made.
the welding on the contacts to the end of the cells and strap to strap needs more than one set of 4 spot welds, that will be the quality measure,
(for R2 and others like him with suspected bad cells)maybe load the pack up while it is all open and feel for an unusually warm or cold cell? i wonder if a thermal imaging camera would be able to detect a bad cell in the parallel string? but they take all the other cells with them too i think, but maybe it is not a problem.
dontsendbubbamail
10 kW
- Joined
- May 28, 2008
- Messages
- 718
With the bms in place the charger thinks the pack is charged. I will bypass the bms and try charging the pack directly while I monitor it. I don't plan to leave it charging unattended. Am I correct is assuming that a shorted or partly shorted cell is the problem with 1-4?
Pre-charging measurements were taken for the cells starting from the negative lead.
1 0.126
2 0.302
3 2.6
4 3.1
5 3.28
6 3.25
7 3.25
8 3.26
9 3.22
10 3.28
11 3.28
12 3.27
13 3.29
14 3.22
15 3.27
16 3.24
Pre-charging measurements were taken for the cells starting from the negative lead.
1 0.126
2 0.302
3 2.6
4 3.1
5 3.28
6 3.25
7 3.25
8 3.26
9 3.22
10 3.28
11 3.28
12 3.27
13 3.29
14 3.22
15 3.27
16 3.24
Sacman
10 kW
Wow that's great! I've never seen one of these recent eBay LiFePO4 batts from China cut open before.
Those are indeed cylindrical cells. Do you see any number "18650" , or any words "Valence" or "Saphion" stamped on the cells?
Most your cells look like they are right around 3.2V which concurs with the spec voltage on the 18650 cells on BatterySpace
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3071
Looks like you could just buy some of these cells to replace your dead ones.
Those are indeed cylindrical cells. Do you see any number "18650" , or any words "Valence" or "Saphion" stamped on the cells?
Most your cells look like they are right around 3.2V which concurs with the spec voltage on the 18650 cells on BatterySpace
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3071
Looks like you could just buy some of these cells to replace your dead ones.
dogman dan
1 PW
Before you give up on the cells in 1- 4 try individual charging on em with a power supply in the 3-4 volt range. If they come back they aren't quite toast yet. If they come back charging in the string, even better. I wouldn't expect the cells in 1 to come back though. The trick now is to connect new cells. I hear soldering em is pretty tricky . Good luck and thanks a million for the info.
Sacman
10 kW
R2R2 said:
Hi R2R2,
You got your BMS from Ping right?
Becareful because it might have a higher LVC and HVC than a BMS from Jimmywu/EastUnitedMusic.
You have cylindrical cells in your battery pack and they have a LOWER charge/discharge curve than Ping's battery packs which use prismatic cells.
I was looking at my 3 BMS's this weekend and trying to get them working and I finally took some closeup pics.
I'm posting the pics here just for your reference and comparison. The ID numbers are partially grinded off
of all my MOSFETs on all 3 BMS's so I picked the best one to show here. I do not know how to lookup
these FET's but I hope someone else can.
Notice that the FETs on the 2 top left are diffent from the 2 top right. And I cannot read the FET on the most bottom left.
Sacman
10 kW
Niky1961 said:
Good to know. Thanks Niky.
dontsendbubbamail
10 kW
- Joined
- May 28, 2008
- Messages
- 718
I removed batteries that were getting hot as I was charging. Only three of the 14 in cells are remaining. The last three have come up to about 3.34 volts, so there may be hope for them yet.
The batteries are marked:
Valence Saphion
1FR-18650EC
VU0988.128053
Off hand does anyone know where there to purchase new ones? I have not done a search for them yet. (Never mind I just saw the link to battery space in an earlier post.)
Does anyone have a JimmyWu they want to sell cheep for parts?
Bubba
The batteries are marked:
Valence Saphion
1FR-18650EC
VU0988.128053
Off hand does anyone know where there to purchase new ones? I have not done a search for them yet. (Never mind I just saw the link to battery space in an earlier post.)
Does anyone have a JimmyWu they want to sell cheep for parts?
Bubba
ZapPat
10 kW
Hi sacman, about your ping BMS FETs:
The four that are paralleled are the discharge control FETs, and are identical. The numbers you have left on them are batch numbers, no use to us (that's why they are still on there).
The one lone FET is the charge FET, on my BMS it seemed to be the same as the other FETs going by the voltage drop measured across them.
The FETs I got originaly were about 25mohms, and I guess they are rated at a minimum of 75V (a common voltage rating after the 60V FETs). I replaced the discharge FETs after I smoked them by accidentaly shorting my battery. I now have about 1/4 the voltage drop across the FETs, so you can imagine that the BMS stays much cooler now during higher power discharges! I left the charge FET there since it was OK.
If you replace the FETs, have a good powered soldering iron handy!
The four that are paralleled are the discharge control FETs, and are identical. The numbers you have left on them are batch numbers, no use to us (that's why they are still on there).
The one lone FET is the charge FET, on my BMS it seemed to be the same as the other FETs going by the voltage drop measured across them.
The FETs I got originaly were about 25mohms, and I guess they are rated at a minimum of 75V (a common voltage rating after the 60V FETs). I replaced the discharge FETs after I smoked them by accidentaly shorting my battery. I now have about 1/4 the voltage drop across the FETs, so you can imagine that the BMS stays much cooler now during higher power discharges! I left the charge FET there since it was OK.
If you replace the FETs, have a good powered soldering iron handy!
Thanks bubba for those pictures,
Lots of interesting things are going through my mind. First, I thought your voltage readings were interesting:
..Yours ................ Mine
1 0.126 ........... (1) 3.44
2 0.302 ........... (2) 0.00
3 2.6 .............. (3) 3.51
4 3.1 .............. (4) 3.39
5 3.28 ............. (5) 3.49
6 3.25 ............. (6) 3.36
7 3.25 ............. (7) 3.40
8 3.26 ............. (8) 3.51
9 3.22 ............. (9) 3.48
10 3.28 ........... (10) 3.57
11 3.28 ........... (11) 3.41
12 3.27
13 3.29
14 3.22
15 3.27
16 3.24
It's interesting that your cells and my cells went bad in the same area of the battery. The pictures below show how I took my volt readings. I took them from the BMS. I'm not exactly sure what I'm doing, but, I'm somewhere in the ballpark of your method probably. My battery is 36 v 10 ah which is why I only have 11 readings versus your 16. And, Sacman asked if I have Ping BMS. No, I have a JimmyWu BMS. I'm not using it at all right now. It seems to be useless until I get my bad cells fixed.
I'm curious what my cells look like now. I'll have to get into them eventually. I'm also curious if I really have a 10 ah pack. I'll have to look into the dimensions and do some calculations to try and figure out how many total cells I have inside.
Lots of interesting things are going through my mind. First, I thought your voltage readings were interesting:
..Yours ................ Mine
1 0.126 ........... (1) 3.44
2 0.302 ........... (2) 0.00
3 2.6 .............. (3) 3.51
4 3.1 .............. (4) 3.39
5 3.28 ............. (5) 3.49
6 3.25 ............. (6) 3.36
7 3.25 ............. (7) 3.40
8 3.26 ............. (8) 3.51
9 3.22 ............. (9) 3.48
10 3.28 ........... (10) 3.57
11 3.28 ........... (11) 3.41
12 3.27
13 3.29
14 3.22
15 3.27
16 3.24
It's interesting that your cells and my cells went bad in the same area of the battery. The pictures below show how I took my volt readings. I took them from the BMS. I'm not exactly sure what I'm doing, but, I'm somewhere in the ballpark of your method probably. My battery is 36 v 10 ah which is why I only have 11 readings versus your 16. And, Sacman asked if I have Ping BMS. No, I have a JimmyWu BMS. I'm not using it at all right now. It seems to be useless until I get my bad cells fixed.
I'm curious what my cells look like now. I'll have to get into them eventually. I'm also curious if I really have a 10 ah pack. I'll have to look into the dimensions and do some calculations to try and figure out how many total cells I have inside.
dnmun
1 PW
i think R2 can find the 12th row of cells between either one end or the other and either the positive or negative terminal of the battery.
it does appear that he has at least one row dead and nopingbubba has at least 2 or 3.
rather than buy cells from someone else, and then trying to weld them together, why not take out the dead rows and have jimmy wu replace the parallel cells already welded together in a row. i doubt if the straps will come attached, but then you can replace the entire row by just soldering a jumper from one row to the next. just as he does with the strap welded between adjacent rows to connect the pack together in series. those straps should all be supplemented as well with a separate wire soldered on to the strap that connects each row in parallel , or in other words, added connectors to reduce the current load on one connecting strap which has just a few spot welds to carry all the current from all those cells in parallel.
anyway, mr wu should be replacing these under warranty, so if you can cut out the bad row of cells, then a replacement row from him is most likely to be equivalent in cell potential and balance. then just the strap connecting the adjacent rows needs to be cut, and sheet metal shears would work fine to cut the strap.
there is now so much evidence of his poor workmanship, and the vulnerability of the BMS to total failure, he should be willing to replace the individual rows, not just individual cells, and you guys can ship him the old rows back if he wants them. but i think a picture of the voltmeter reading while connected should be adequate, he has no use for the cells so seems a waste to air freight them back, and he may expect freight to be covered when shipping out the replacement row, which might be ok if he doesn't charge for the replacement row or require the return of the dead row.
i do wonder if the row which measured 0.00V on R2's pack has a broken wire going down to the cell, the sense wire could be broken or pulled off the end of the strap where it attaches, or even in the plug, so that needs checking again. but then you should have 2 adjacent rows with 0.00V.
so now we need to find everybody who has these problems and show jimmy wu that it is not just one person, but many people who have this problem, and he needs to fix it or we will act to block ebay from allowing him to list, because he has used false and deceptive practices to juice his ratings, and threaten ebay with negligence and complicity in allowing him to continue. maybe even get mr ping to also show his inadequate design. and he needs to reimburse rbguy for sending him crap too.
at the very least we should be able to shake loose some rows of cells, which won't cost him much at all, likely only $15/row and he doesn't have to take the pack back and repair it, so he can keep his ill gotten gain. but he should replace the entire row, all spot welded together in parallel, just like the rows in the packs. then it will be easier to take the pack apart and replace the dead row, then tape it back up. i am thinking his output fets are so bad, they also should be upgraded by him so the on resistance is dramatically reduced. so he should upgrade those fets and replace the BMS of anyone who asks, because his originals do not meet the specs. and with a new row of good cells, the new BMS should work to allow charging to begin. thanks for all the info. dennis
it does appear that he has at least one row dead and nopingbubba has at least 2 or 3.
rather than buy cells from someone else, and then trying to weld them together, why not take out the dead rows and have jimmy wu replace the parallel cells already welded together in a row. i doubt if the straps will come attached, but then you can replace the entire row by just soldering a jumper from one row to the next. just as he does with the strap welded between adjacent rows to connect the pack together in series. those straps should all be supplemented as well with a separate wire soldered on to the strap that connects each row in parallel , or in other words, added connectors to reduce the current load on one connecting strap which has just a few spot welds to carry all the current from all those cells in parallel.
anyway, mr wu should be replacing these under warranty, so if you can cut out the bad row of cells, then a replacement row from him is most likely to be equivalent in cell potential and balance. then just the strap connecting the adjacent rows needs to be cut, and sheet metal shears would work fine to cut the strap.
there is now so much evidence of his poor workmanship, and the vulnerability of the BMS to total failure, he should be willing to replace the individual rows, not just individual cells, and you guys can ship him the old rows back if he wants them. but i think a picture of the voltmeter reading while connected should be adequate, he has no use for the cells so seems a waste to air freight them back, and he may expect freight to be covered when shipping out the replacement row, which might be ok if he doesn't charge for the replacement row or require the return of the dead row.
i do wonder if the row which measured 0.00V on R2's pack has a broken wire going down to the cell, the sense wire could be broken or pulled off the end of the strap where it attaches, or even in the plug, so that needs checking again. but then you should have 2 adjacent rows with 0.00V.
so now we need to find everybody who has these problems and show jimmy wu that it is not just one person, but many people who have this problem, and he needs to fix it or we will act to block ebay from allowing him to list, because he has used false and deceptive practices to juice his ratings, and threaten ebay with negligence and complicity in allowing him to continue. maybe even get mr ping to also show his inadequate design. and he needs to reimburse rbguy for sending him crap too.
at the very least we should be able to shake loose some rows of cells, which won't cost him much at all, likely only $15/row and he doesn't have to take the pack back and repair it, so he can keep his ill gotten gain. but he should replace the entire row, all spot welded together in parallel, just like the rows in the packs. then it will be easier to take the pack apart and replace the dead row, then tape it back up. i am thinking his output fets are so bad, they also should be upgraded by him so the on resistance is dramatically reduced. so he should upgrade those fets and replace the BMS of anyone who asks, because his originals do not meet the specs. and with a new row of good cells, the new BMS should work to allow charging to begin. thanks for all the info. dennis
rguy56
100 W
Hi folks,
Just an update.
This seller is now a power seller under mp3hk, and I wrote ebay about the practice of sellers with poor feedback moving to new, unflagged identities. The letter was clearly ignored by ebay, so those of you who get ripped off later can know that ebay is aware of the practice, specifically with regard to this seller.
I'm still out over $2,000, have followed all of paypal's requests to the letter, and paypal simply keeps changing the date that I should hear from them. (It's now Oct.11)
The last word on the matter is that coverage is "up to $325" in spite of their published rules on coverage.
The price of the batteries is good, and I think the only reasonable approach with this vendor is to fix 'em yourself for now. I think the one year warranty is a joke.
I'd really like to know if anyone has gotten a battery that performed to spec., especially in terms of a.h.
Bob
Just an update.
This seller is now a power seller under mp3hk, and I wrote ebay about the practice of sellers with poor feedback moving to new, unflagged identities. The letter was clearly ignored by ebay, so those of you who get ripped off later can know that ebay is aware of the practice, specifically with regard to this seller.
I'm still out over $2,000, have followed all of paypal's requests to the letter, and paypal simply keeps changing the date that I should hear from them. (It's now Oct.11)
The last word on the matter is that coverage is "up to $325" in spite of their published rules on coverage.
The price of the batteries is good, and I think the only reasonable approach with this vendor is to fix 'em yourself for now. I think the one year warranty is a joke.
I'd really like to know if anyone has gotten a battery that performed to spec., especially in terms of a.h.
Bob
dontsendbubbamail
10 kW
- Joined
- May 28, 2008
- Messages
- 718
R2R2,
I think that we were measuring from different ends. Here is a couple of pics on how I did the measurements. I started from the negative side and worked up to the positive side. My first bank seemed to be total toast and the next three were iffy, so I whacked them turned my pack into a 36V battery.
Bubba
First bank of cells
View attachment IMAG0001.JPG
Second bank of cells
I think that we were measuring from different ends. Here is a couple of pics on how I did the measurements. I started from the negative side and worked up to the positive side. My first bank seemed to be total toast and the next three were iffy, so I whacked them turned my pack into a 36V battery.
Bubba
First bank of cells
View attachment IMAG0001.JPG
Second bank of cells
dnmun
1 PW
nopingbubba, you have your first measurement on the end of the shunt, which is separated from the battery negative by the output fets, so your measurements are not exact. try putting the black probe directly on the heatsink/black lead to the negative terminal of the battery. maybe the measured cell voltage will change. don't you think you could replace the bad rows? seems like you even had bad rows in the 12 cell measurement. BOL, dennis
dontsendbubbamail
10 kW
- Joined
- May 28, 2008
- Messages
- 718
I could have fixed the pack, but I didn't think it was worth the money. Going with JimmyWu was a risk, but someone had to take the same risk with Ping at the start. If I had waited about a two weeks, I would have seen the negative feedback and not done business with JimmyWu. Ping seems to be a stand up business man and would be my choice if I go the duck tape route again.
Bubba
Bubba
hardym
100 W
Great thread and thanks for the pictures. I have been studying various vendors BMS solutions.
I've looked at the R2R2 zoom pics and have put together the first piece of the BMS, for those who are interested. This is a pretty standard BMS, except for the opto isolators.
The ckt below is the balance which works on the charge cycle only. It turns on the 22 ohm power resistor when the voltage of the LiFEPO4 reaches abbut 3.6V. The markings look like an TL431 or AP432.
During the charge cycle, any cell that raches 3.6 V has the resistor kicked in, therby reducing the voltage across the cell until the rest come up.
There is much more to the BMS, but I can't see it all. There is a chip on each cell that does over/under voltage and communicated via the Optos to the power FETs. It is likely a SEIKO chip, with the upper cutoff likely at 3.7, and lower cutoff around 2.5.
Mark.
PS: To Bubba and R2R2. With regard to the potential correlation between cell # 2 on both systems failing....
Note that Bubba count cell number as Cell #1 is closest to the FETs. R2R2 counts cells (on the close up) with Cell # 1 furthest from the FETs. Looking at the circuts closups along with the schematic below, its hard to imagine that the BMS balancing ckt below caused the cells to short to 0 Volts - the balance ckt looks isolated and stable.
I've looked at the R2R2 zoom pics and have put together the first piece of the BMS, for those who are interested. This is a pretty standard BMS, except for the opto isolators.
The ckt below is the balance which works on the charge cycle only. It turns on the 22 ohm power resistor when the voltage of the LiFEPO4 reaches abbut 3.6V. The markings look like an TL431 or AP432.
During the charge cycle, any cell that raches 3.6 V has the resistor kicked in, therby reducing the voltage across the cell until the rest come up.
There is much more to the BMS, but I can't see it all. There is a chip on each cell that does over/under voltage and communicated via the Optos to the power FETs. It is likely a SEIKO chip, with the upper cutoff likely at 3.7, and lower cutoff around 2.5.
Mark.
PS: To Bubba and R2R2. With regard to the potential correlation between cell # 2 on both systems failing....
Note that Bubba count cell number as Cell #1 is closest to the FETs. R2R2 counts cells (on the close up) with Cell # 1 furthest from the FETs. Looking at the circuts closups along with the schematic below, its hard to imagine that the BMS balancing ckt below caused the cells to short to 0 Volts - the balance ckt looks isolated and stable.
dontsendbubbamail
10 kW
- Joined
- May 28, 2008
- Messages
- 718
hardym,
I agree that the balance circuit did not cause the problem. My jimmywu bms came with three fets of which I one or two was getting hot. I tried replacing one cool fet and adding a 4th fet from my old bms, but the original two were still getting hot. Now that I think of it, maybe the hot ones were shorted, because I was still getting current with the cell voltage sense wires disconnected.
With the wires disconnected, shouldn't the low voltage protection shut the current off?
Could you suggest a replacement fet?
Bubba
I agree that the balance circuit did not cause the problem. My jimmywu bms came with three fets of which I one or two was getting hot. I tried replacing one cool fet and adding a 4th fet from my old bms, but the original two were still getting hot. Now that I think of it, maybe the hot ones were shorted, because I was still getting current with the cell voltage sense wires disconnected.
With the wires disconnected, shouldn't the low voltage protection shut the current off?
Could you suggest a replacement fet?
Bubba
hardym
100 W
With even one of the balancer wires disconnected, it should have opened up the optos, and inhibited both charge and discharge FETs. If even one of the fets were shorted, it would allow current in both directions.
So, yes you'll need new fets. They look like to-220 but the center drain pin is missing or not connected.
Mouser sells a STP36NF06L that would be overkill at US $1.20. 30 A, 60 V. Three of these would give you 90A. You'll pay more in shipping than for the FETs
(You'll pay more in shipping than for the FETs)
Assume you are not going to put these BMS in series, and your pack is less than 20 A. If you are going to put two BMS in series, bump the voltage of each FET.
Any of these would probalby work:
http://www.mouser.com/Search/Refine...d&OriginalKeyword=mosfet&Ntk=Mouser_Wildcards
I dont know why your BMS was getting hot. What was the load condition? How big is your pack?
So, yes you'll need new fets. They look like to-220 but the center drain pin is missing or not connected.
Mouser sells a STP36NF06L that would be overkill at US $1.20. 30 A, 60 V. Three of these would give you 90A. You'll pay more in shipping than for the FETs
(You'll pay more in shipping than for the FETs)
Assume you are not going to put these BMS in series, and your pack is less than 20 A. If you are going to put two BMS in series, bump the voltage of each FET.
Any of these would probalby work:
http://www.mouser.com/Search/Refine...d&OriginalKeyword=mosfet&Ntk=Mouser_Wildcards
I dont know why your BMS was getting hot. What was the load condition? How big is your pack?
hardym
100 W
Sorry, but I'd like to ammend my previous post saying the balancing portion is stable. It is not stable.
Upon closer inspection, the balancing function uses a TL431 rather than a 432. The significat difference is that the 431 can only sink 100mA. (the 432 can sink 200mA). When the cell voltage reaches 3.6 V, the balancing shunt turns on across the 22 ohm resistor, with a current of 164 mA, which exceeds the 431's capacacity. This would be a poor design even with a 432 chip.
When the 431 shunts breaks, they can short, which would drain your battery cell to 0v. Not good.
To check if this is the case for the drained cells, measure the resistance across the annode and cathode of the 431 in both directions and look for a short.
Do not hook up a new cell to this until you check for shorted 431 chip.
To fix, you can replace the 22 ohm resistor with a 56 ohm 2W resistor (to reduce the shunt current) and replace the shorted tl431 chips.
Mark.
Upon closer inspection, the balancing function uses a TL431 rather than a 432. The significat difference is that the 431 can only sink 100mA. (the 432 can sink 200mA). When the cell voltage reaches 3.6 V, the balancing shunt turns on across the 22 ohm resistor, with a current of 164 mA, which exceeds the 431's capacacity. This would be a poor design even with a 432 chip.
When the 431 shunts breaks, they can short, which would drain your battery cell to 0v. Not good.
To check if this is the case for the drained cells, measure the resistance across the annode and cathode of the 431 in both directions and look for a short.
Do not hook up a new cell to this until you check for shorted 431 chip.
To fix, you can replace the 22 ohm resistor with a 56 ohm 2W resistor (to reduce the shunt current) and replace the shorted tl431 chips.
Mark.
dnmun
1 PW
hardy, would you analyze a board and loook into the best way to kluge a solution for everyone to follow? i would like it if maybe bob mcree also would look at it too and see if there is some way to use the current BMS printed circuit board, but bypass the BMS for the current returning to the controller through those output fets. use the LVC controls through that opto to sink the throttle signal on the cycle analyst, or the ebrake line from the controller. so then the only function for the BMS would be to protect from overcharging, and to send a LVC signal to either the CA or controller. then we can skip the fix of the output fets. also you mentioned that the drain leg is cut off, that is because the current drains out through the tab in back, where it is soldered onto that buss across the end. the hole in the pcb for the drain pin actually has solder flowed in from the back where the source current is collected in that big mass of solder which also has the shunt termination.
anyway, those fets need to go, we only need LVC and OVC protection, the bypass current may only be part of the problem. if they are chinese manufactured fets, there may be a large range of performance, which may also be affected by how much heat they get when soldered onto that buss bar. it just seems like poor quality work, and cost cutting to the max, not at all like mr ping, who seems to test and evaluate the quality of his stuff, even before it is installed on the battery. jmho.
anybody have a useless board to send to hardy? to just look at close up? then decide later to hack it?
anyway, those fets need to go, we only need LVC and OVC protection, the bypass current may only be part of the problem. if they are chinese manufactured fets, there may be a large range of performance, which may also be affected by how much heat they get when soldered onto that buss bar. it just seems like poor quality work, and cost cutting to the max, not at all like mr ping, who seems to test and evaluate the quality of his stuff, even before it is installed on the battery. jmho.
anybody have a useless board to send to hardy? to just look at close up? then decide later to hack it?
hardym
100 W
I'd be happy to reverse engineer the SIGNALAB board. However, I went to chinabatteries.net, and they will not sell any of these SIGNALAB BMS boards, in fact they dont sell this version anymore, although they are still listed in their website. So these BMS boards may not be avilable if some sort of fix was determied.
I've reverse engineered other BMS boards, and found similar funcitonality to the SIGNALLABs.
I've not mentioned it before, but I've developed my own 12 cell BMS with UV LV cutoff, and balance function. This is identical funcitonality from what the SIGNALAB boards use.
There are two problems with my board:
1. It uses a new SEIKO chip S-8209 that is not in production yet, until december, so I cannot offer for sale. 4 prototypes built with samples.
2. It has a fixed voltage set, meaning that it currently works with 4.2 V Lithium-ion, but woudl not work for 3.7 V cells like the valence lifePo4.
I like the Bob Mcree analysis and enjoied the endless thread, I just thought there was a more simple solution. The S-8209 does all three voltage measurements, and communicates to adjcent chips. Each cell only needs a S8209, FET and balance resistor. It's not perfect, but has been working Ok for me.
I can post some pictures at another time/thread.
Also, I have some of the Valence lifepo4 cells, so I am interested in getting some working BMS for them but dont have the to time start over from scratch. The new Linear Tech chip and Maxim 12 cell chips sound promsing, but they will be a lot of work to get going, AND both are not yet avilable. LT says samples for me not until next month.
So, back on topic, I can test/fix a broken SIGNALAB board, or reverse engineer one.
Mark
I've reverse engineered other BMS boards, and found similar funcitonality to the SIGNALLABs.
I've not mentioned it before, but I've developed my own 12 cell BMS with UV LV cutoff, and balance function. This is identical funcitonality from what the SIGNALAB boards use.
There are two problems with my board:
1. It uses a new SEIKO chip S-8209 that is not in production yet, until december, so I cannot offer for sale. 4 prototypes built with samples.
2. It has a fixed voltage set, meaning that it currently works with 4.2 V Lithium-ion, but woudl not work for 3.7 V cells like the valence lifePo4.
I like the Bob Mcree analysis and enjoied the endless thread, I just thought there was a more simple solution. The S-8209 does all three voltage measurements, and communicates to adjcent chips. Each cell only needs a S8209, FET and balance resistor. It's not perfect, but has been working Ok for me.
I can post some pictures at another time/thread.
Also, I have some of the Valence lifepo4 cells, so I am interested in getting some working BMS for them but dont have the to time start over from scratch. The new Linear Tech chip and Maxim 12 cell chips sound promsing, but they will be a lot of work to get going, AND both are not yet avilable. LT says samples for me not until next month.
So, back on topic, I can test/fix a broken SIGNALAB board, or reverse engineer one.
Mark
rguy56
100 W
I think it's great that you guys will eventually find a way to make a silk purse out of a sow's ear! And I DO have faith that you will.
dnmun
1 PW
so sorry we could not help you out originally rguy. if you need "expert" testimony during your claims against paypal, let us know.
i no longer have much faith that these parts are of normal quality. i suspect the active devices and maybe even the passive devices could be rejects resold inside china and something jimmy wu had no compunction against using because ebay provides him shelter from claims against the warranty. and on top of that it appears mark has found that they even designed it with the wrong components from the start. as though they could not even do circuits, just glue in some junk. and then used the small cylindrical cells too. since people saw duct tape, they just assumed it would be a prismatic cell battery, like mr ping. he has every right to be upset with these guys who have imitated his success on ebay.
i no longer have much faith that these parts are of normal quality. i suspect the active devices and maybe even the passive devices could be rejects resold inside china and something jimmy wu had no compunction against using because ebay provides him shelter from claims against the warranty. and on top of that it appears mark has found that they even designed it with the wrong components from the start. as though they could not even do circuits, just glue in some junk. and then used the small cylindrical cells too. since people saw duct tape, they just assumed it would be a prismatic cell battery, like mr ping. he has every right to be upset with these guys who have imitated his success on ebay.
