Even Newer 4 to 24-cell Battery Management System (BMS)
- Thread starter GGoodrum
- Start date
Yes, it is wrong. I need to get that corrected.
It would be true if you didn't have enough voltage to fully turn on all the shunts or if any shunt was off.
It would be true if you didn't have enough voltage to fully turn on all the shunts or if any shunt was off.
when charging the lifepo4 cells how much current is being passed through the cell balancing taps?
i found that for a quick disconnect i can use a db9 serial extension cable and seeing how thing the wires are i am not sure they can handle the current.
i found that for a quick disconnect i can use a db9 serial extension cable and seeing how thing the wires are i am not sure they can handle the current.
The main pack + and - connections take the full charging current. The tap wires will carry 500ma at maximum. If the cells are very closely matched, the tap wires carry no current. I think you can use a serial extension cable for the tap wires.
also another function of the charging system. let me see if i understand this right.
the shunts act like a dummy cell in bypass mode thereby the rest of the pack is only getting voltage for 1 less cell because the full cell shunt is acting as a dummy cell?
the shunts act like a dummy cell in bypass mode thereby the rest of the pack is only getting voltage for 1 less cell because the full cell shunt is acting as a dummy cell?
light effect on diodes.
http://www.muzique.com/news/effect-of-light-on-diodes/
while checking on about calculating the resistor values need to build an led based night light and light bulbs.
i found an article on light affecting the electrical properties of some parts like diodes and leds.
i was wondering if this will affect the bms making the lvc trip at a different voltage or the charger over charging or under charging when exposed to sunlight.
some of us (i know me) would be using a tupperware like container as an enclosure unfortunately tupperware like containers are clear (the cheap sterlite ones at walmart) .
would we need a normal light proof enclosure? or is there enough tolerance built into the bms lvc and charging circuits that the small effect caused by light would not hurt the cells?
http://www.muzique.com/news/effect-of-light-on-diodes/
while checking on about calculating the resistor values need to build an led based night light and light bulbs.
i found an article on light affecting the electrical properties of some parts like diodes and leds.
i was wondering if this will affect the bms making the lvc trip at a different voltage or the charger over charging or under charging when exposed to sunlight.
some of us (i know me) would be using a tupperware like container as an enclosure unfortunately tupperware like containers are clear (the cheap sterlite ones at walmart) .
would we need a normal light proof enclosure? or is there enough tolerance built into the bms lvc and charging circuits that the small effect caused by light would not hurt the cells?
Never heard of that one. I can try it sometime. My guess is that only direct sunlight would be strong enough to affect anything, and at that, the only thing that could change is the maximum shunt current. None of the voltages would change.
Charge in the shade....
Charge in the shade....
Malcolm
10 kW
I'm back with another small problem 
I plan to use a Curtis switched mode 36V/30A charger for fast charging my pack. This charger has some pretty big capacitors and makes a meaty spark when I connect it to any pack.
My 12 channel board tested out fine for low voltage and high voltage cutoffs and for charge control using a smaller, non-sparking 36V charger, but when I try to connect the Curtis charger I seem to be blowing individual channels on the BMS.
When I connected the Curtis charger with the pack already connected, one of the channel LEDs came on straightaway, while the rest were off. It turned out that Qx01 (KSA931) and Ux02 (LM431) had blown. I replaced these and tried again, only to have a different channel blow in the same way. Am I right in suspecting that it's the high inrush current that is causing the damage, and if so, what would be the simplest way around this? I guess I could use a precharge resistor to reduce the initial current, but is there a simpler way?
I plan to use a Curtis switched mode 36V/30A charger for fast charging my pack. This charger has some pretty big capacitors and makes a meaty spark when I connect it to any pack.
My 12 channel board tested out fine for low voltage and high voltage cutoffs and for charge control using a smaller, non-sparking 36V charger, but when I try to connect the Curtis charger I seem to be blowing individual channels on the BMS.
When I connected the Curtis charger with the pack already connected, one of the channel LEDs came on straightaway, while the rest were off. It turned out that Qx01 (KSA931) and Ux02 (LM431) had blown. I replaced these and tried again, only to have a different channel blow in the same way. Am I right in suspecting that it's the high inrush current that is causing the damage, and if so, what would be the simplest way around this? I guess I could use a precharge resistor to reduce the initial current, but is there a simpler way?
to prevent the spark treat the charger like you would do for charging a car battery.
always connect and disconnect the battery from the charger with the charger unplugged from the 110 outlet.
then you are not connecting a charged charger to the battery.
you may still get a spark but only because the capacitors are being charged by the battery and not the charger.
another possible way is to connect a switch between the charger and the output with a resistor across the switch so when in the off position the resistor would limit the output so there be little or no spark.
in the on position it charges the battery at full power.
it is sort of like what the high tension line workers to by flying in with their pole and gets closer to the line so they charge up to the level of the line slowly to prevent taking the full voltage of the line.
always connect and disconnect the battery from the charger with the charger unplugged from the 110 outlet.
then you are not connecting a charged charger to the battery.
you may still get a spark but only because the capacitors are being charged by the battery and not the charger.
another possible way is to connect a switch between the charger and the output with a resistor across the switch so when in the off position the resistor would limit the output so there be little or no spark.
in the on position it charges the battery at full power.
it is sort of like what the high tension line workers to by flying in with their pole and gets closer to the line so they charge up to the level of the line slowly to prevent taking the full voltage of the line.
Malcolm said:I'm back with another small problem
I plan to use a Curtis switched mode 36V/30A charger for fast charging my pack. This charger has some pretty big capacitors and makes a meaty spark when I connect it to any pack.
My 12 channel board tested out fine for low voltage and high voltage cutoffs and for charge control using a smaller, non-sparking 36V charger, but when I try to connect the Curtis charger I seem to be blowing individual channels on the BMS.
When I connected the Curtis charger with the pack already connected, one of the channel LEDs came on straightaway, while the rest were off. It turned out that Qx01 (KSA931) and Ux02 (LM431) had blown. I replaced these and tried again, only to have a different channel blow in the same way. Am I right in suspecting that it's the high inrush current that is causing the damage, and if so, what would be the simplest way around this? I guess I could use a precharge resistor to reduce the initial current, but is there a simpler way?
Malcolm said:I'm back with another small problem
I plan to use a Curtis switched mode 36V/30A charger for fast charging my pack. This charger has some pretty big capacitors and makes a meaty spark when I connect it to any pack.
My 12 channel board tested out fine for low voltage and high voltage cutoffs and for charge control using a smaller, non-sparking 36V charger, but when I try to connect the Curtis charger I seem to be blowing individual channels on the BMS.
When I connected the Curtis charger with the pack already connected, one of the channel LEDs came on straightaway, while the rest were off. It turned out that Qx01 (KSA931) and Ux02 (LM431) had blown. I replaced these and tried again, only to have a different channel blow in the same way. Am I right in suspecting that it's the high inrush current that is causing the damage, and if so, what would be the simplest way around this? I guess I could use a precharge resistor to reduce the initial current, but is there a simpler way?
Nobody's ever tried a charger that big before.
That earns you a guinea pig award:
The spark and inrush current should not be blowing the shunt transistors. In fact, usually the spark is from the batteries charging up the capacitors in the charger. It would be much more likely that the FET blew and is no longer able to throttle the charging current (that will blow transistors).
Try to test the FET by triggering one the opto outputs and getting the status LED to go green and verify the charge current stops (all channel LEDs go out). Do this with your small charger.
Lowering the output voltage on the charger would help also.
If the inrush current is blowing the FET, that might be a bit challenging to work around since the body diode in the FET is conducting the current in the reverse direction. If you had a switch in series with the charger connection, and a resistor across the switch, that might do it.
Malcolm
10 kW
Mmmm, crunchy.
Yes, triggering any of the optos turns the status LED green, but it doesn't kill the other LEDs, so it looks like I need to replace the FET.
Once I've fixed that I'll try the switch with a resistor in parallel. Would 470 ohms be in the right area?
Yes, triggering any of the optos turns the status LED green, but it doesn't kill the other LEDs, so it looks like I need to replace the FET.
Once I've fixed that I'll try the switch with a resistor in parallel. Would 470 ohms be in the right area?
Yes, 470 ohms to 1k should be in the ballpark. I'd suggest a 5w one.
Depending on the charger configuration, there can be a big surge when the batteries connect to a bunch of discharged capacitors in the charger. Since this is conducted by the body diode in the FET, there's no easy way for the circuit to soften the surge.
It may help in your case to use two FETs in parallel, since this will cut the current each one sees in half. When using parallel FETs, each gate should have it's own 100 ohm resistor. The other connections are straight parallel.
Another approach would be to simply use a long set of wires to connect the charger. The resistance in the wires will limit the inrush current. Having some inductance in there might help too, but that could cause problems when the circuit throttles. I haven't tried that yet.
What FET were you using?
Depending on the charger configuration, there can be a big surge when the batteries connect to a bunch of discharged capacitors in the charger. Since this is conducted by the body diode in the FET, there's no easy way for the circuit to soften the surge.
It may help in your case to use two FETs in parallel, since this will cut the current each one sees in half. When using parallel FETs, each gate should have it's own 100 ohm resistor. The other connections are straight parallel.
Another approach would be to simply use a long set of wires to connect the charger. The resistance in the wires will limit the inrush current. Having some inductance in there might help too, but that could cause problems when the circuit throttles. I haven't tried that yet.
What FET were you using?
Malcolm
10 kW
fechter said:
I ordered all the parts through Mouser using Gary's list, so it's the one specified.
I guess that's a STP160N75F3
The diode is rated for 480 amps pulsed, 120 amps continuous (actually limited to 70 amps by the package leads).
That must be a really big spark you get to blow that thing.
You must also have very low resistance wires going to the charger.
Longer / higher resistance wires would help a lot.
The diode is rated for 480 amps pulsed, 120 amps continuous (actually limited to 70 amps by the package leads).
That must be a really big spark you get to blow that thing.
You must also have very low resistance wires going to the charger.
Longer / higher resistance wires would help a lot.
cycle9
10 W
I've played some with these NTC thermisters, they work really well for preventing sparking and etc in situations like yours:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=570-1016-ND
You'd just put it in line with the main charging circuit. They're kind of big, so they probably won't fit on the board without some rearrangement.
They will waste a bit of energy as heat, but that's better than fried components every time, and a lot easier than having to play with a switch/resister combo each time you want to charge.
Morgan
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=570-1016-ND
You'd just put it in line with the main charging circuit. They're kind of big, so they probably won't fit on the board without some rearrangement.
They will waste a bit of energy as heat, but that's better than fried components every time, and a lot easier than having to play with a switch/resister combo each time you want to charge.
Morgan
Malcolm
10 kW
It is, and if there is a way of blowing something up I will find it.fechter said:
The charger leads are about 1 metre long and AWG 6 (16mm2).It's not impossible though that I've blown the FET through sheer carelessness, so once I've fixed things up I'll try again with the standard setup. If it blows again I'll try the resistor.
Thank you! I will try one of those if the charger proves to be the problem.cycle9 said:
one other way that may work is if you can crack open the charger (if it is not heat sealed or glued or molded as 1 piece) you can remove the capacitors on the output and replace them with lower uf rating.
correct me if i am wrong but the batteries should act as a capacitor as far as being able to smooth out the output.
now if the spark is coming from the batteries charging the charger's capacitors then putting a diode in series with the charger and the battery should prevent power flow back into the charger.
if the charger has a voltage control like the soneil chargers you may have to turn it up to make up for the voltage drop caused by the diode.
correct me if i am wrong but the batteries should act as a capacitor as far as being able to smooth out the output.
now if the spark is coming from the batteries charging the charger's capacitors then putting a diode in series with the charger and the battery should prevent power flow back into the charger.
if the charger has a voltage control like the soneil chargers you may have to turn it up to make up for the voltage drop caused by the diode.
Placing a diode between the charger and the BMS would work but there are some drawbacks.
The diode will have some voltage drop across it that would need to be compensated for. Depending on the diode and current, the drop will be around .5v to 1v.
The diode will get really hot at 30 amps and need a rather large heat sink.
It will need to be rated for full pack voltage. For smaller setups with lower charging current, the diode heat would be easier to dissipate. A low forward drop Schottkey diode would be the best.
Some chargers need to get voltage from the batteries before they will produce output (safety feature). In this case the diode would block the battery voltage. If this is the case, you could put a resistor (470 ohms) across the diode to charge the caps. Once the caps charge up to a certain voltage, the charger kicks in. This should take about 1 second.
Malcolm, I think the 6ga. wire did it.
If you have a 36v battery feeding a bank of low ESR capacitors with a combined ESR of something like 50 milliohms, plus about 1 milliohm for the 6ga wires, that gives you a peak current of 720 amps, which will blow the FET. Two FETs in parallel would probably survive.
Precharging either with a switch or diode as described above would be the best way to avoid the spark. If you added about 3 meters of 12ga. or 10ga. wire to the charger leads, the resistance will limit the peak current.
If the FET shorts, then the shunts can get swamped and overheat. They can probably take it for a few seconds. If the charger voltage is dialed in just above the finishing voltage, then even if the main FET shorts, the shunts won't go much over their design voltage and would not be as likely to blow.
The diode will have some voltage drop across it that would need to be compensated for. Depending on the diode and current, the drop will be around .5v to 1v.
The diode will get really hot at 30 amps and need a rather large heat sink.
It will need to be rated for full pack voltage. For smaller setups with lower charging current, the diode heat would be easier to dissipate. A low forward drop Schottkey diode would be the best.
Some chargers need to get voltage from the batteries before they will produce output (safety feature). In this case the diode would block the battery voltage. If this is the case, you could put a resistor (470 ohms) across the diode to charge the caps. Once the caps charge up to a certain voltage, the charger kicks in. This should take about 1 second.
Malcolm, I think the 6ga. wire did it.
If you have a 36v battery feeding a bank of low ESR capacitors with a combined ESR of something like 50 milliohms, plus about 1 milliohm for the 6ga wires, that gives you a peak current of 720 amps, which will blow the FET. Two FETs in parallel would probably survive.
Precharging either with a switch or diode as described above would be the best way to avoid the spark. If you added about 3 meters of 12ga. or 10ga. wire to the charger leads, the resistance will limit the peak current.
If the FET shorts, then the shunts can get swamped and overheat. They can probably take it for a few seconds. If the charger voltage is dialed in just above the finishing voltage, then even if the main FET shorts, the shunts won't go much over their design voltage and would not be as likely to blow.
the schematic at the bottom of page 6 of the instructions.
is the the entire lvc circuit?
i would like to build a separate lvc so that way i can only need the lvc when in use then disconnect the battery and connect to the bms for charging.
also doing that may make it easier for me to use the Schottkey diode method to prevent weaker batteries from pulling down good batteries on the cell level so for example a 16s2p system would have 32 Schottkey diodes to prevent a weak cell from pulling down the other cell(s) in the other 16s*p strings.
and be configurable so that the lvc function would be able to work.
also would Schottkey diodes between the cell and the bms affect the charging?
is the the entire lvc circuit?
i would like to build a separate lvc so that way i can only need the lvc when in use then disconnect the battery and connect to the bms for charging.
also doing that may make it easier for me to use the Schottkey diode method to prevent weaker batteries from pulling down good batteries on the cell level so for example a 16s2p system would have 32 Schottkey diodes to prevent a weak cell from pulling down the other cell(s) in the other 16s*p strings.
and be configurable so that the lvc function would be able to work.
also would Schottkey diodes between the cell and the bms affect the charging?
ejonesss said:
Hmm.... I can't seem to find a copy of the instructions...
The LVC circuit consists of the TC54 and an optocoupler for each cell. Pretty simple there. Gary used to sell an LVC only board.
Putting diodes between the cells will throw all the voltages off, not to mention waste a fair amount of energy. I don't think you would want to do that. Normally you just connect all the parallel cells at the cell level and leave them connected. They will charge and discharge at the same rate. If you have a bad cell that is pulling things down, you should replace it. If you have one cell that has lower capacity, you won't gain anything by using diodes.
here is the link to the instructions.
http://www.tppacks.com/documents/4-24%20-%20Cell%20LiFePO4%20BMS%20Kit%20Assembly-Test%20Instructions.pdf
i was asking about that because i was thinking of paralleling a bunch of different cells like a123,18650 and 40138 (lifebatt,bmi).
because after i do some tests with cheaper cells i would like to be able to still use them when i upgrade to bigger cells.
http://www.tppacks.com/documents/4-24%20-%20Cell%20LiFePO4%20BMS%20Kit%20Assembly-Test%20Instructions.pdf
i was asking about that because i was thinking of paralleling a bunch of different cells like a123,18650 and 40138 (lifebatt,bmi).
because after i do some tests with cheaper cells i would like to be able to still use them when i upgrade to bigger cells.
fechter said:
GGoodrum
1 MW
Yes, that circuit is pretty much it, for the LVC circuit. Just the TC-54, an 820 ohm resistor and the CNY-17F optocoupler, for each channel. In the BMS, and the later versions of the LVC boards I've done, we use a dual-channel ILD2 optocoupler, one for every two channels on the LVC. For the BMS, half of the ILD2 is used for the LVC, and the other half is used for the charger control logic.
Unless you have a space problem, I'm not sure why you would need to separate the LVC out from the rest of the charger control logic in the BMS. The LVC circuits work completely independent of the charge control logic, which is not even enabled unless the charger is connected, and on.
I have an updated, LVC-only board that I have ready to get made, but I'm just not sure there's much demand for just the LVC board. I could do a small run of these, but that makes them pretty expensive, so I'd have to charge about $25-$30 each for them. Here is the layout:
This uses the same "tear-off" feature to support any number of channels up to 24. It also includes Randomly's active cutoff circuit, which doesn't have to be populated if not used. Actually, you can simply break off how ever many channels are needed from the right side of the board, if the active cuttoff is not needed. If active cutoff is needed, by using a pair of 4110 FETs, it will handle 100A+. It draws next to nothing in standby current.
Anyway, if there is enough interest, I'll get these done this week.
On the BMS front, Richard an I are working on a slightly updated version. The big change here is that the new version will now also support using other Lithium chemistries, like LiMn/LiCo, simply by cutting a jumper for each channel. Actually, the jumper will be simply a through-hole connection pad, so all that need to be done is the holes would need to be drilled out to break the connection. What this will do is change the LVC cuttoff from 2.1V up to about 3.0V, and it will change the shunt cutoff from about 3.68V to 4.18-4.19V.
We are also adding a couple parts to the 12V regulator circuit so that much larger pack voltages can be supported. I think the limit right now is about 72V. but now it should be able to support up to a 48s/144V pack configuration.
Finally, I'm thinking about adding Randomly's active LVC cutoff circuit to this version, as I continue to get requests for this feature for some who want to do 12V and 24V SLA replacement packs, which need to be stand-alone (i.e. -- no ebrake/throttle cutoff on the controller...). What I'm thinking is that can add it to the far left part of the board, and add the "tearoff" holes for those that don't want active cutoff. The other option is simply to do a separate 4/8-channel version, with the active cutoff.
We are alos working on the surface mount cersion of the BMS. After we fully test the new version, we'll finish up the conversion, and get fully populated boards done. This will still be a couple of months away, before we can actually have them ready to sell, but this is the path we are on.
Anyway, I hope to get this new version in for production early this coming week. Because we are so close, I've decided not to do another run of the current version (v2.2), so for those still waiting for these to be back in stock, you will have to wait another week, or so.
-- Gary
Unless you have a space problem, I'm not sure why you would need to separate the LVC out from the rest of the charger control logic in the BMS. The LVC circuits work completely independent of the charge control logic, which is not even enabled unless the charger is connected, and on.
I have an updated, LVC-only board that I have ready to get made, but I'm just not sure there's much demand for just the LVC board. I could do a small run of these, but that makes them pretty expensive, so I'd have to charge about $25-$30 each for them. Here is the layout:
This uses the same "tear-off" feature to support any number of channels up to 24. It also includes Randomly's active cutoff circuit, which doesn't have to be populated if not used. Actually, you can simply break off how ever many channels are needed from the right side of the board, if the active cuttoff is not needed. If active cutoff is needed, by using a pair of 4110 FETs, it will handle 100A+. It draws next to nothing in standby current.
Anyway, if there is enough interest, I'll get these done this week.
On the BMS front, Richard an I are working on a slightly updated version. The big change here is that the new version will now also support using other Lithium chemistries, like LiMn/LiCo, simply by cutting a jumper for each channel. Actually, the jumper will be simply a through-hole connection pad, so all that need to be done is the holes would need to be drilled out to break the connection. What this will do is change the LVC cuttoff from 2.1V up to about 3.0V, and it will change the shunt cutoff from about 3.68V to 4.18-4.19V.
We are also adding a couple parts to the 12V regulator circuit so that much larger pack voltages can be supported. I think the limit right now is about 72V. but now it should be able to support up to a 48s/144V pack configuration.
Finally, I'm thinking about adding Randomly's active LVC cutoff circuit to this version, as I continue to get requests for this feature for some who want to do 12V and 24V SLA replacement packs, which need to be stand-alone (i.e. -- no ebrake/throttle cutoff on the controller...). What I'm thinking is that can add it to the far left part of the board, and add the "tearoff" holes for those that don't want active cutoff. The other option is simply to do a separate 4/8-channel version, with the active cutoff.
We are alos working on the surface mount cersion of the BMS. After we fully test the new version, we'll finish up the conversion, and get fully populated boards done. This will still be a couple of months away, before we can actually have them ready to sell, but this is the path we are on.
Anyway, I hope to get this new version in for production early this coming week. Because we are so close, I've decided not to do another run of the current version (v2.2), so for those still waiting for these to be back in stock, you will have to wait another week, or so.
-- Gary
webfootguy
100 W
Any ideas on how to scale this design up to more cells? I am building a pack that will be 112S4P of A123 M1 cells. My only real hurdle is the BMS side. Everyone seems to want to move to 10 to 100 Ah cells but they don't fit my form factor for space reasons.
space is not so much of the issue. mostly it is that it would be easier to have a separate lvc so the diode method for paralleling on the cell level would work better because if 1 cell goes bad it would not take down the other cells and would not affect the lvc or charger.
if i put the diodes to prevent the dying cells from draining good cells then it means that the battery will not charge but the vlc would work.
although i guess i can use a combination of diodes and relays so charging would turn on the relays bypassing the diodes and when disconnected from the charger the diodes would be enabled again.
also can the voltage drop of the diode be reduced by paralleling diodes?
i know that paralleling resistors halves the resistance and doubles wattage that they can handle. series'ing does the opposite.
ok is that better ?
the cost verses demand could be improved by if you dont have the demand to worthy mass production you can (if you are up to diy radioshack etching) i remember in the 80's there was etching kits you would get a bottle of etchant (ferric chloride i believe it was ). and it removes the copper plating that is not covered by a photoresist (comes in a pen for very small circuits or printable templates).
i believe that disposal of ferric chloride can be a problem especially in large amounts.
http://www.mouser.com/Search/Refine.aspx?Keyword=etching
depending where you live ordering large amounts of the etchant MAY require license or even be banned.
diy etching allows for prototyping and small runs.
actually you could just have pins stick up and use computer jumpers like you see on the motherboard or hard drive to set the master/slave or cable select and older motherboards to set the clock speed.
I have an updated, LVC-only board that I have ready to get made, but I'm just not sure there's much demand for just the LVC board. I could do a small run of these, but that makes them pretty expensive, so I'd have to charge about $25-$30 each for them. Here is the layout
if i put the diodes to prevent the dying cells from draining good cells then it means that the battery will not charge but the vlc would work.
although i guess i can use a combination of diodes and relays so charging would turn on the relays bypassing the diodes and when disconnected from the charger the diodes would be enabled again.
also can the voltage drop of the diode be reduced by paralleling diodes?
i know that paralleling resistors halves the resistance and doubles wattage that they can handle. series'ing does the opposite.
ok is that better ?
the cost verses demand could be improved by if you dont have the demand to worthy mass production you can (if you are up to diy radioshack etching) i remember in the 80's there was etching kits you would get a bottle of etchant (ferric chloride i believe it was ). and it removes the copper plating that is not covered by a photoresist (comes in a pen for very small circuits or printable templates).
i believe that disposal of ferric chloride can be a problem especially in large amounts.
http://www.mouser.com/Search/Refine.aspx?Keyword=etching
depending where you live ordering large amounts of the etchant MAY require license or even be banned.
diy etching allows for prototyping and small runs.
actually you could just have pins stick up and use computer jumpers like you see on the motherboard or hard drive to set the master/slave or cable select and older motherboards to set the clock speed.
I have an updated, LVC-only board that I have ready to get made, but I'm just not sure there's much demand for just the LVC board. I could do a small run of these, but that makes them pretty expensive, so I'd have to charge about $25-$30 each for them. Here is the layout
methods
1 GW
When you quote, please try abbreviating like this:
Jack said "... blah blah ..."
(not the "..." in place of 5 paragraphs of information)
Otherwise your post is 3 pages long and becomes hard to read.
*** LIPO ***
BTW: I am about to order the parts for my 24 cell Lipo version.
TC-54 is now available in the TO-92-3 packaging @ 3.0V in quantities of (1) (in stock at Digikey) for those doing LiPo. You will have to use the Open Collector version but it should behave just the same. (right?)
Only two changes that need to be made to do Lipo on the current boards:
For HVC: Swap the 75k resistor at R101 with a 110k resistor to get a 4.2V cut off. (Could be done other ways)
(swap part: 270-75K-RC|24 for part: 270-110K-RC|24) - Mouser BOM
For LVC: Swap the 2.1V part with a 3.0V part (TC54VN3002EZB-ND) - Digikey
I have not actually tested this yet so not fact until tested
-methods
Jack said "... blah blah ..."
(not the "..." in place of 5 paragraphs of information)
Otherwise your post is 3 pages long and becomes hard to read.
*** LIPO ***
BTW: I am about to order the parts for my 24 cell Lipo version.
TC-54 is now available in the TO-92-3 packaging @ 3.0V in quantities of (1) (in stock at Digikey) for those doing LiPo. You will have to use the Open Collector version but it should behave just the same. (right?)
Only two changes that need to be made to do Lipo on the current boards:
For HVC: Swap the 75k resistor at R101 with a 110k resistor to get a 4.2V cut off. (Could be done other ways)
(swap part: 270-75K-RC|24 for part: 270-110K-RC|24) - Mouser BOM
For LVC: Swap the 2.1V part with a 3.0V part (TC54VN3002EZB-ND) - Digikey
I have not actually tested this yet so not fact until tested
-methods
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