biohazardman
100 kW
ejonesss said:
PM me your addy and I'll send you a couple to shorten your wait. You can return them when yours arrive.
Duane
Even Newer 4 to 24-cell Battery Management System (BMS)
- Thread starter GGoodrum
- Start date
PM me your addy and I'll send you a couple to shorten your wait. You can return them when yours arrive.
Duane
GGoodrum
1 MW
proempiet said:
No, this is the surface mount version. The "CB" means SOT-23 packaging. "ZB" is the TO-92 part. See page 13 here: http://ww1.microchip.com/downloads/en/DeviceDoc/21434g.pdf
You can, however, substitute the non-complementary output version, the TC54VN2102EZB. Mouser doesn't stock that normally, but Digikey does: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=TC54VN2102EZB-ND
-- Gary
that is what i ordered and will have to settle with dangling wires upwards like shown
http://www.endless-sphere.com/forums/download/file.php?id=14817
also when mouser gets the part back in stock i am considering ordering a bunch for you es'ers so when mouser runs out i can sell them to keep you es'ers happy for a while.
http://www.endless-sphere.com/forums/download/file.php?id=14817
also when mouser gets the part back in stock i am considering ordering a bunch for you es'ers so when mouser runs out i can sell them to keep you es'ers happy for a while.
proempiet said:
The ones at Digikey should work fine.
TC54VN2102EZB-ND is really the part I designed the board for. You don't need to dead-bug them, they go in exactly like the other ones.
They show nearly 2,000 in stock.
TC54VN2102EZB-ND is really the part I designed the board for. You don't need to dead-bug them, they go in exactly like the other ones.
They show nearly 2,000 in stock.
@ggoodrum or anyone who has a lot of experience with a123 cells.
i was wondering if a cell is stressed by a lack of lvc protection can the cell be recovered?
because like i posted earlier about what happened with the bms board a cell did get stressed but fortunately when the lvc kicks in it is so close to the controller's lvc that the cell could not have been stressed too much?
thanks for the help there
i was wondering if a cell is stressed by a lack of lvc protection can the cell be recovered?
because like i posted earlier about what happened with the bms board a cell did get stressed but fortunately when the lvc kicks in it is so close to the controller's lvc that the cell could not have been stressed too much?
thanks for the help there
GGoodrum
1 MW
What did the resting voltage of the cell end up at? If it didn't go too far below about 2.0V, it probably is okay. One way to tell is fully charge the cell, wait about 10-15 minutes and then check the voltage. Healthy a123 cells will hold the surface charge, up around 3.55-3.60V. Stressed cells will not hold the surface charge at all, and after about 10 minutes the voltage will drop to somewhere between 3.35-3.45V, depending on how stressed/damaged it got.
-- Gary
-- Gary
I plan to use this bms on about 42 Thundersky 160 Ah cells, but I am a bit nervous about overcharging as the charging current during the initial constant current phase will be about 20 to 30 A. I plan to use a Manzanita PFC20 or PFC30 charger which can be set to charge in constant current mode to a preset (pack) voltage, then it cuts back to under 1 A charging current for a time determined by a preset timer. Seems like it should work if I set the preset voltage to about 3.6V per cell or 150V, yes? Fetcher previously warned that the difference in pack charged and discharged voltage must be less than 100V. I only intend to discharge at most 70%, so maybe 2.9V per cell from say 3.8V so about 38V difference. Even 2.7V per cell is only about 46V. What do you think?
GGoodrum
1 MW
tomw said:
Couple of things. First of all, there's no problem running 20-30A in the CC mode, even if the current isn't dropped to 1A. The charger control logic actually limits the current anyway, by using a FET to cutoff the charge current completely when any channel's shunt comes on full. This causes the voltage in the cell to drop slightly, causing the FET to come back on. This oscillation keeps the shunts right at their limit, without becoming swamped. For this to work right, however, the charger max voltage needs to be just higher than the sum of the shunt voltages. With the specified voltage divider resistors, the shunt voltage is 3.68V. With 42 cells in series, the sum would be 154.6V, so the charger should be a bit above 155V. If you only want to charge your cells to 3.60V, you need to adjust the resistor values slightly. If you use 68k instead of 75k, that should drop the shunt voltage to 3.57V, so the sum for 42 in series would be 150V. The charger needs to max out at about 151V. If the charger limit is 150V, then you could use a resistor value of 66.5k in place of the 75k, which sets the shunt voltage to 3.56V, and the sum would be 149.5V.
-- Gary
update 1: i just charged them and surprisingly they all came back up pretty quickly so it may be recovering.
update 2: i just checked them again for up to 20 minutes and they are at 3.6x.
i may be lucky since the controller's lvc is close to the voltage sag under load ( when under load it is a volt or 2 from the controller's lvc when the bms lvc kicks in so it may be lucky).
also i saw on the a123 site the specs call for an lvc of 1.6 volt under pulsed discharge mode so i wonder if that may have something to do with it?
also is the formula still the same or did a123 systems change the formula resulting in better stress management/recovery.
the cell rests at 3.3 to 3.4 when not connected to the bms.
all the cells are pretty much balanced
does the board creat a load on the cells even when the 2 minus wires are not connected?
if so that explains the false reading.
i am going to have to re charge them and then disconnect the bms and let you know again.
update 2: i just checked them again for up to 20 minutes and they are at 3.6x.
i may be lucky since the controller's lvc is close to the voltage sag under load ( when under load it is a volt or 2 from the controller's lvc when the bms lvc kicks in so it may be lucky).
also i saw on the a123 site the specs call for an lvc of 1.6 volt under pulsed discharge mode so i wonder if that may have something to do with it?
also is the formula still the same or did a123 systems change the formula resulting in better stress management/recovery.
the cell rests at 3.3 to 3.4 when not connected to the bms.
all the cells are pretty much balanced
does the board creat a load on the cells even when the 2 minus wires are not connected?
if so that explains the false reading.
i am going to have to re charge them and then disconnect the bms and let you know again.
GGoodrum said:
Roy Von Rogers
10 W
I would not advice tasking an A123 cell below 2.0 volts.
Roy
Roy
GGoodrum
1 MW
Eric --
I think the cells are fine, if the are holding 3.6V that long after being charged.
To answer your other question, the BMS does not put any real load on the cells/pack if the charger control logic is not powered, which would mean the small negative wire is not connected to anything. The TC54s draw a few uA in the standby mode, but that is about it. The self discharge rate of the cells is higher.
-- Gary
I think the cells are fine, if the are holding 3.6V that long after being charged.
To answer your other question, the BMS does not put any real load on the cells/pack if the charger control logic is not powered, which would mean the small negative wire is not connected to anything. The TC54s draw a few uA in the standby mode, but that is about it. The self discharge rate of the cells is higher.
-- Gary
mimichris said:
Yes, it will work fine.
Thanks Mr Fechter !
When do I use the regeneration of the battery with the system of the BMS (on-line brake-GND on the controller) is it that the limitation of load maximum of the battery to 3.6V functions as with the charger, for me, it seems that no, because one supply the pack of battery directly by the controller without passing by the system of tension maximum limitation to 3.6V who functions with the charger, is this exact? In this case, one risks to overload the battery if it is not empty and that one has big coming down for example in mountain.
(excuse me because my English is not good, I am French...)
Maxime
When do I use the regeneration of the battery with the system of the BMS (on-line brake-GND on the controller) is it that the limitation of load maximum of the battery to 3.6V functions as with the charger, for me, it seems that no, because one supply the pack of battery directly by the controller without passing by the system of tension maximum limitation to 3.6V who functions with the charger, is this exact? In this case, one risks to overload the battery if it is not empty and that one has big coming down for example in mountain.
(excuse me because my English is not good, I am French...)
Maxime
Yes, during regeneration you could exceed the voltage set point since you are bypassing the charge control FET. The cell shunts will still be working however, and will help limit the voltage to some extent. If you have a way to control the amount of regen current, you could interface to the 'any shunts' line on the BMS to reduce the regen current if any cell gets over the set point.
Normally, if you went up the mountian first, you could never overcharge on the way down since regenerative braking is very lossy and you might recover about 25% of the energy if you are lucky.
Normally, if you went up the mountian first, you could never overcharge on the way down since regenerative braking is very lossy and you might recover about 25% of the energy if you are lucky.
steveo
100 kW
lol im working on geting some nice tires for him dont woryDoctorbass said:Crazy Steveo.. 48 series cells on a 5304
Pay attention to avoid your rear tire getting out of the rim with centrifugal force while runing at 88mph!! :lol:
88mph on a steel rim would make beautifull firework!!..
Doc
or we can just down size to a 20 and get crazy torq lol
Any shunt active means one or more cells has its shunt fully activated and it is time to reduce the charging current to prevent going overvoltage. The any shunt line throttles the charge current.
The all shunt active line swings when all of the shunts are on, indicating all cells are up to voltage and charging can terminate. The all shunts line triggers the shutoff, which latches the charging current off.
The all shunt active line swings when all of the shunts are on, indicating all cells are up to voltage and charging can terminate. The all shunts line triggers the shutoff, which latches the charging current off.
julesa
10 kW
- Joined
- Jun 23, 2008
- Messages
- 950
Doctorbass said:Crazy Steveo.. 48 series cells on a 5304
Pay attention to avoid your rear tire getting out of the rim with centrifugal force while runing at 88mph!! :lol:
88mph on a steel rim would make beautifull firework!!..
Doc
But can his cells put out 1.21 Jigawatts?
http://www.youtube.com/watch?v=i7JwCUIY3Qo
drunkencat129
100 W
- Joined
- Aug 5, 2008
- Messages
- 116
LMAO well the goal is to get enouf power to power my gocart and then travel back in time and kick the oil compony ceos b4 that push gass prices high lmao
lol thiss ones betterhttp://www.youtube.com/watch?v=bnqtXOi1iaY&feature=related
and then travel back in time and kick the oil compony ceos b4 that push gass prices high lmao lol thiss ones betterhttp://www.youtube.com/watch?v=bnqtXOi1iaY&feature=related
In the note of the BMS "test instructions" it is written :
..........This oscillation has the net effect of keeping the shunts at full bypass, but not getting swamped,
which would cause the shunts to overheat. Like the LVC circuits, the shunt optos outputs are all ganged
together, so that if any one turns on, the FET will turn off, cutting power.........
On my BMS Tppacks with Ping battery 36V and 15Ah, 12 cells, I didn't notice an oscillation, when I plug the charger (charger Ping 36V and 2A), the bicolored led is orange, and orange remainder lasting all the time of the load, once the loaded cells, leds oranges ignite the then once some after others they are all alight, they die out enough quickly and the bicolored led becomes green.
Is what this working is normal on my BMS ?
..........This oscillation has the net effect of keeping the shunts at full bypass, but not getting swamped,
which would cause the shunts to overheat. Like the LVC circuits, the shunt optos outputs are all ganged
together, so that if any one turns on, the FET will turn off, cutting power.........
On my BMS Tppacks with Ping battery 36V and 15Ah, 12 cells, I didn't notice an oscillation, when I plug the charger (charger Ping 36V and 2A), the bicolored led is orange, and orange remainder lasting all the time of the load, once the loaded cells, leds oranges ignite the then once some after others they are all alight, they die out enough quickly and the bicolored led becomes green.
Is what this working is normal on my BMS ?
GGoodrum
1 MW
mimichris said:
It sounds fine, to me. The oscillation happens at a fast rate, so you aren't going to see it. The LED being orange is an indication the oscillation is happening, because the red and green portions are alternating on and off. It goes solid green after all the shunts are fully operating, which means the cells are full.
-- Gary
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