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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    note that in one of the circuits the signal is driven into the IGND pin instead of VMS RX. this is perfectly fine. but maybe this caused confusion.
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    did this on the laptop in the waiting room at the doctor's office and took a webcam shot. no desktop, sorry for the unsteady handwriting. (bug: the labels below (VMS to USB and viceversa) are reversed!) I hope it's clear enough. I still don't know the correct polarity for the signals, so I did...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    > i'll bet that pump will show less than 4uA leakage from one side to the other the pump doesn't isolate. it's true that it'll tolerate a *DC* bias on it's output, but if you apply an AC bias, it'll feed back through C2 and C3 to U6 and destroy it. current surges on the pack will cause AC bias...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    a ghetto-cad schematic... ouch, that hurt! I don't know what polarity you need to use, but you don't need a 3rd power supply. here are the circuits, inverted or not, and with or without buffering (depending on the USB bridge output type): if you want to drive both VMS RX and WAKEUP with the...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    > the problem is that there are 3 separate grounds (PC, VMS, Vehicle) and only 2 separate power sources (PC, VMS) and in order to isolate all 3 a third power source is needed. I am attempting to do that using a charge pump... no need man! call the VMS ground "OGND" (for outputs and +5V), and...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    > these boards come in 12V and 48V flavors. i believe that this is the 48V you're right.
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    very sorry to hear about the mishap with your pack. I had a similar episode involving a single A123 cell left on an untested charger that I'd just hacked (badly!) out of a mobile charger. the cell overvolted to 5.5V for a few hours. surprisingly it came out undamaged and to this date it performs...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    finally I set the charger to N*3.5V and it failed too... in the end it seems only N*3.65V does the job right.
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    apparently, the graph that showed increased shunt current above 3.6V was a fluke, I couldn't reproduce it. maybe the VMS boards just delayed the turn on of the shunts and chance had it that the cells were precisely at 3.6V at turn on. I set the charger to N*3.6V and tested... the FET cut on...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    > (but I found out that at least I can balance the cells at 3.6V; later...) this is the pack on tricle charge: from sample 0 to 15 the cells are being brought down by the VMSes and the charge FET is off; this is the result of an earlier OVP force and release pair of commands (not shown). at...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    > it is most obvious that I sould ditch the so-called "display board" and instead either get an original or roll-my own version of the charge/discharge board. why? if you want to use the FET charge protection, keep in mind that you also need a charger that goes to trickle < 200mA for this...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    ok, this BMS was apparently designed with the covert intent of frustrating me. I thought I could solve problem A (4.1V overvolts) for a charger without trickle current by modulating the OVP signal so that cells don't trip over a certain safe voltage. but nooo... when the VMS detects a 4.1V...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    > soon as i get the oppourtunity i'll likely discharge my pack till i get the LVP line active and i'll measure the voltage across the LVP opto to confirm. you don't need to if you have serial access. here is the latest version of my scripts. configure in ane-config and use the...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    excellent diagram, very clear! I'm happy someone could trace a VMS since all my info was indirect or inferred. so, according to your diagram, if you haven't left out any resistors one can say about CN2 (which is our interesting port): -the 4 output signals include an on-board current limiter...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    hi Andy, same here, please do send everything you think might help, and thank you very much again!
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    I had access to an ANE USB/cutoff board (the one shown in these pictures) but not to a VMS board. I had no docs, not even a USB cable for the board, I didn't know it had USB at all. I had to rev eng this cutoff board to find out how to use the 10-pin flat cable connector used to bind all the VMS...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    Ypedal, sorry I forgot! so there are two problems with these VMS boards. problem B, cells not ending up being balanced, was discussed earlier. problem A, cells overvolting, can be dealt with in several ways: -analog: if charge current is limited to < 200mA cells won't overvolt. you could add a...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    fech, oh man, I didn't know there was an 87 page discussion! I guess every possible idea must have been tossed around a couple of times, but just in case: > cap and FET heating does not seem to be an issue at charge currents up to 20A good to hear that, sometimes I tend to "overdesign" a bit...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    that's a very handsome pack! :D I can't see the ribbon-cable-to-DB9 board, whatever it's name is. don't you have one? do you have the pinout of the ribbon connector?
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    rk, > 1. adding 2 opto's to fully isolate the RS232 signals to the USB to TTL converter. the power of these opto's is supplied by the PC-USB connector on one side so the PC and USB is isolated from the VMS/Battery pack. > 2. Reconfigure the "Wake" switch so that it switches VMS +5V through a...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    that's something I wanted to discuss. the VMS beeps 3 times when a cell reaches 3.9V. at 4.1V it disconnects the charger, and when cells relax below 3.5V it connects the charger again. a CCCV charger would then overvolt the cell again and again. but some chargers detect end of charge (current...
  22. L

    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    no, use 0.2V. this equation makes that clear: > VCmax - VCmin = 2 * VCtol
  23. L

    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    hi Gary, fech, one more comment on your BMS. (I know it only by what you posted on this thread.) when the charge FET is off, the charger climbs to its max voltage and stays there. when the FET turns on, basically it shorts the charger to the battery, which has very low impedance. if the...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    ok, day 2... next day and without having used the pack I charged it again: we can see two things: -after perfectly balancing the pack and only 24hs of storage, imbalance is enough to raise the voltage of a cell up to 4.0V. clearly this problem A is serious. I don't have a clue why they...
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    ANE (All New Energy) BMS (BMI/LifeBatt/PSI)

    hi Gary, thanks for the description of your BMS project, very informative. > Your "problem B" issue, as you discovered, is simply because the total charger voltage was not high enough for the shunts to kick in. actually, problem B is the extreme sensitivity of the system to charger voltage...
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