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  1. M

    Pack/BMS Problem?

    In the interest of trying to keep things neat and hopefully less likely to short, I'll use resistors instead of bulbs. Figure I can attach them to a piece of wood or something & alligator clip from there to the cell(s). Resistors & clips on order now. If only I hadn't gotten rid of all my...
  2. M

    Pack/BMS Problem?

    OK, I didn't realize that the shunt resistor was left in place during charge. Thought that it was used to drain down a cell after being charged. So conceivably you could have a shunt resistor on 11 of the 12 cells in the pack while you're waiting for the 12th cell to catch up?
  3. M

    Pack/BMS Problem?

    Yeah, the recent readings were not taken while charging. So I put the 6S2P banks on the RC charger one at a time with it set to charge, not balance. Plugged the balance meter into the JST plug and recorded the cell voltages. Cell # Balance meter volts % of charge per balance meter...
  4. M

    Pack/BMS Problem?

    I guess I'm not clear on the function of the BMS. Or else I'm not clear on the function of my RC balance charger. Or else I'm not clear on the differences between LiPo and LiFe. I thought that a balance charger would automatically bleed voltage from a high cell while still bringing a low cell...
  5. M

    Pack/BMS Problem?

    Cells 15/16 have been on the charger for ~5 hours and ~12 a-h delivered. Now showing 3.32 volts, 57% charge, compared to 3.22 and 10% charge when they began. Here's the current status of the pack: Cell # Balance meter volts % of charge per balance meter 9/30/2013 1, 2 3.43...
  6. M

    Pack/BMS Problem?

    If I try charging 15,16 while they're still connected to the BMS through the balance leads and still connected to their neighboring cells by their electrical straps, are there sneak paths that will result in other cells receiving the charge in addition to 15,16? To me it seems that the...
  7. M

    Pack/BMS Problem?

    After being taken out of storage the entire pack of 24 cells had been charged overnight using the charger and BMS that came with the pack. Then it had been used lightly over a 3 day period, drawing probably not more than 5 a-h total before it suddenly cut out going up a hill. (Recovering from...
  8. M

    Pack/BMS Problem?

    Cell # Balance meter volts % of charge per balance meter 9/25/2013 1, 2 3.496 95 3, 4 3.454 93 5, 6 3.333 66 20.42 bank total, 90% 7, 8 3.409 90 9, 10 3.431...
  9. M

    Pack/BMS Problem?

    Finally. As of about 1/2 hour ago I finished wiring in the new balance wires, JST plugs and charge wires so I can charge it as two separate 6S2P batteries using my RC charger to both charge and balance. The first 6S2P bank showed a 78% charge when put on my charge meter. After spending 2...
  10. M

    Pack/BMS Problem?

    I chose cells 13 and 14 to charge separately as a 1S2P arrangement. Starting voltage around 3.22. Began by setting the charge current to 4 amps for no particular reason. Hours passed with the charger timing out every so often. I recorded the individual mah readings each time but due to a...
  11. M

    Pack/BMS Problem?

    Verifying calibration to NIST standards wouldn't be easy, but I grabbed a second meter which should be better quality than the first. Readings below: 9/16/2013 Cell # Meter #1 Meter #2 1, 2 3.68 3.66 All readings taken while charging 3, 4 3.66 3.65 5, 6 3.33...
  12. M

    Pack/BMS Problem?

    After seeing how out of balance the pack is from using this BMS I'm seriously tempted to do exactly that---install the necessary JST plugs plus a set of +/- Powerpoles for charge leads on each 6-cell group and charge them off my iCharger. I just ordered some 7-wire JST plugs but in the meantime...
  13. M

    Pack/BMS Problem?

    Right now the total pack voltage shows 41.8 while on the charger. Out of curiosity I disconnected the charge plug and read exactly zero volts coming from the charger. Unplugged and replugged it from 120 vac & no change. Does it require connection to a load that the meter does not provide in...
  14. M

    Pack/BMS Problem?

    These are for each pair of cells. 1, 2 3.68 All readings taken while charging 9/16/2013 3, 4 3.66 5, 6 3.33 7, 8 3.62 9, 10 3.69 11, 12 3.29 13, 14 3.22 15, 16 3.22 17, 18 3.67 19, 20 3.33 21, 22 3.69 23, 24 3.33 During this...
  15. M

    Pack/BMS Problem?

    So when you say "cell", do you mean a pair of cells? If that's the case I can get readings in a few minutes. It's on the charger right now. If you mean individual cells, I'm not quite sure how that would be done. MT
  16. M

    Pack/BMS Problem?

    Thought you meant put it on the charger and measure the voltages after charging. Charging again is what I was doing now, in accordance with what I thought you meant. With the parallel arrangement of the pairs of cells, how do I measure individual cell voltage while it's charging? A little...
  17. M

    Pack/BMS Problem?

    Here are the readings taken after the pack spent 12 hours on the charger after the BMS shut down. After taking it off the charger it sat for 24 hours before I had a chance to get into it and take these readings. - - - - - - - - - Headway 38120 9/15/2013 Readings taken after 12 hours...
  18. M

    Pack/BMS Problem?

    I acquired a LiFePO4 battery pack back in 2008 as part of the group buy that Joshua facilitated. I realize that this is a controversial subject and I'm not looking to stir anything up. I guess I must have been one of the lucky ones because I experienced no problems with the pack until now. I...
  19. M

    LED lighting question

    @evnewbie: After about 1/2 hour to 45 minutes of running the heatsink is warm. How warm? If it was bath water I'd typically use warmer, so maybe 90-ish F when the ambient air temp is high 70's low 80's. The LED's are reflow soldered at the factory on to MCPCB stars, which are then thermally...
  20. M

    LED lighting question

    If you're into DIY, you can buy the LED's and build your own pretty cheap. The 4-LED shown cost ~$90 less battery. I've built a 3 LED and 4 LED system. 3 watts per LED at 1000 ma. With the 4 LED light on a country road at night I can see reflective road signs 3/4 mile away. Pretty good for...
  21. M

    Light system..not sure which to choose

    Feel like building your own 4x3 watt LED light for $100? MT
  22. M

    Do the Girlie thing and use a bell...

    I use a little electronic gizmo. Push one button and it sounds just like a bike bell, except then a voice says, "Excuse me!" Push the other button and you get a few bars of a well known Mozart melody. Either one seems to get grins from the peds. MT
  23. M

    kill switch for handlebars - recommendation???

    I use the switch pictured above with the red plastic key on a 36V system. Works well. Switch seems very heavy duty & well built. $5 is an excellent price. Since my switch is difficult to reach, I also have a fuse with a tie wrap fastened round it to use as a pull in case of emergency. MT
  24. M

    How do you prevent a flat tube

    I've been running Schwalabe Big Apples with the kevlar belt. Don't have thorns to contend with, only street glass and potholes. According to Schwalbe, Big Apples supposedly have been designed with stiffer sidewalls for better cushioning and to run at lower pressure. I dunno. Been running...
  25. M

    Changing a tire, is there a certain way tube should be?

    I inflate the tube before putting it in the tire. Blow it up until it holds shape, but it doesn't need to begin stretching like a balloon. Then fit it into the tire. I usually have one bead of the tire over the rim at this point. Having air in it makes it easier to handle as you slip the...
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