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SereneCry

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About SereneCry

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  1. New cells damaged from heat, broken BMS or faulty charger. Replaced (did it right this time) all cells. But now the charger switches to standby after 5 minutes. When I power on it shows 3/4 lights on powerbar. Ridetime 5-10 minutes. Could it be the heat from packing the cells? Used hotglue to stick the cells together and spaceheater to heatshrink 5 layers of shrinkwrap. Might have overheated half the batterypack when I was working on it out in the seering hot sun. Q1: Could the cells be salvaged by charging them individually to the same voltage if they are damaged by heat? Q2: How can I check if the BMS is causing this problem? Assuming the charger and batteries are fine. Q3: Why not glue the packs together with superglue, glue the terminals on with conductive glue then wrap the packs in adhesive plastic sheets? This would eliminate the need for heat, make the pack loose less capacity and make assembly faster & easier. EDIT: Removing hotglue is very easy. Just spray electronics cleaner or dab it will alcohol and it will loose its bond. EDIT2: Used Sony VTC5 with 30A max discharge as recommended by @KingSong69. So cells should be fine from factory. I've had training and experience with welding/soldering so (in fear of sounding arrogant) that point is unlikely to be the problem. What do I do now?!
  2. @Battling Are you happy with those BMS boards? Have you noticed any swelling of cells or reduced batterylife since installing? Is there anything you would do differently if you had to do this again? Can you measure how many volts your spotwelder delivers and did you remove the shunts from your transformer? I made my spotwelder with a potentiometer to control voltage easier and a thick rubber kajigger that holds the electrodes. This makes it more versatile , safer, easier to use and more effective since the rubber kajigger puts pressure on the whatchamacallit while holding it in place so you need less heat to make a solid bond. EDIT: The cardboard insulators around terminals on cells are very important as they are the only thing between the nickelstrips and the opposite terminals on your cells. Forgot to put these insulators on on the last row I welded on the previous build and shortcircuit etc after just a small vibration. Do it right or it will not work...
  3. After alot of time researching and learning about BMS systems I can not understand why anyone would want a BMS. Ultimately they seem to cause more problems than they fix. Could this BMS simply be a way to save production cost on chargers? After I changed my batterypack I don't really know if my BMS is still working properly and part of the circuitboard is drenched in some thick tar-like substance that prevents me from checking the circuit with a multimeter. Why not get rid of the onboard BMS and make a balancing charger? An arduino hooked up to a recycled powersupply from a few old cellphone chargers and scrap components should make that possible for a low price. Would this cause any problems`?
  4. @KingSong69 So it's not just the numbers on specs that matter? Those cheap 30A max discharge batteries are from the same webshop that sold me the EUC which have lasted many years. Some online batteryshops in Norway but all expensive. From the Netherlands I could get them shipped ground-only (costs more than airfreight). What do you think about separating the circuitboards (that the batteries are currently soldered to and packed with) from the batteries and making a plug so I can swap batteries? Any reason those circuitboards are soldered directly to the batteries? If those circuitboards can be separated from the batteries I could get the expensive and the cheap batteries to fieldtest
  5. How heavy would the EV be? Would need powerful motors if you put on doors, roof etc. Perhaps if you get a few used EUCs. I hacked a moped up and welded a simple frame for it a few years back... Just the one wheel in the back to drive it and two wheels up front for stability and steering. I think that motor was 3HP. Might be possible to mod the firmware on a EUC to disable the gyro and instead accept input from a plugin electronic gaspedal. Then clamp the footboards of the EUC in place on a frame with 2 frontwheels with steering and that gaspedal. I might get a used EUC to try this xD Not really economical since hubmotors are so cheap, but I like the idea of a "batmobile" -type vehicle that can be used as EUC or EV using the same parts!
  6. @Slaughthammer wow those are expensive! Best match from available sources: Samsung INR18650 2,5Ah (rated max discharge 22A cont. Max burst discharge 35A) available for 230USD. I'm restricted because of shipping regulations on batteries. Most shops will not ship batteries here. Cheapest high-discharge (noname, 2,2Ah, max cont. discharge 30A) are only 76USD 0_o Do you think these will be at least as good as the old 2Ah pack? http://www.dx.com/p/rechargeable-3-7v-2600mah-li-ion-batteries-kit-green-6-pcs-374256#.WU1CreszerU EDIT: If those noname 30A max discharge cells work I could quadruple the batterysize! If I get more cells than I need can I just build packs same as the primary pack (but without circuitboards) and solder the two wires (positive and ground) from second batterypack onto the plug for the primary battery? Appreciate straightforward answers nomatter how harsh! Makes it easier to get better and learn when I know what I did wrong=)
  7. Thanks guys. Completed dissasembly but will not put these shitty batteries back in. The job may not look nice but I figured the cells would need replacing in a few months anyway so didn't spend alot of time fitting the new cells. Next build will be a proper one seeing as I need the expensive, long-lasting cells afterall. Intensely annoying mistake. EDIT: Turning out to be a nightmare to get the cells free from the circuitboard because I didn't spend enough time to do the build properly. Hotglue sticks too much, flows too far and makes my soldering iron smoke alot while removing solder. GAH! Never again...
  8. @KingSong69 yes they are the protected version that are slightly bigger. The wheel ran on just one 16-pack. Assembled and tried to testride but I couldn't even get on before it died! Had to plug in charger to be able to turn it on again. Same problem second time. Have I blown my BMS or something? Thinking about that spark when I plugged in charger first time... Or maybe the safetykajigger built-in to the new cells have blown? EDIT: tried just tilting the wheel again after plugging in the charger so I could turn it on. I could run it along wih my hand but immediatly after I stepped on it cut off and died again. EDIT: Starting to take it apart again to hack off those protection circuits. Crossing fingers!
  9. @KingSong69 Cells are 18650, 3,4Ah 3,7V. Max discharge just 8A but they were so much cheaper than 40A discharge cells that I can replace the pack 4times before it costs as much as a 40A max discharge pack. Wheel is Esway E3 MarsRover. Batterypack fully charged and now there is no spark or sound when i plug in the charger. Sealed up the pack with glue and thinking about just heatshrinkwrapping it and do a testride. So strange that there would be spark when I plugged the charger in first time though! Afraid I'll damage the motor/electronics/charger. EDIT: Tried connecting everything and tilting the wheel (driving forward) and there seemed to be alot more torque and more rapid acceleration. May be that I've gotten used to the old worn out batteries
  10. Attached is a picture of how I solved the problem with the two clamps not tightening. Abit hard to see since the problem area is under the nut. I simply put them in place and put threadlock in the gaps (on the flat parts of the axle, and on the clamps where they meet the axle) clamped tight, let it cure for 24 hours, wiped off excess. PS: Trying blue (medium strength threadlock) and nylon fishingline wound around the threads this time. Might've been better with just red loctite but time will tell.
  11. Hey. Made a spotwelder and finished my new batterypack. I forgot the cardboard insulators underneath the very last row though! How important is that? Do I need to tear off the nickelstrips and put insulation underneath and re-attach? Won't the batteries get weaker if I do another spotweld on them? Also there was a spark when I plugged in the charger and it looks like the light on the charger glows brighter than when I charged the old batterypack. Everything seems to work but haven't had a testdrive yet.
  12. Inside these two parts that clamp together you might find that the groove that fits over the axle is bigger than it should be because it has been worn. That would cause these parts to be loose on the axle even if you clamp tight
  13. I think it's the metal plates that go in the pedalmounts on each side of the straight part of the axle. These get worn and thus do not clamp down tight enough on the axle. You can try using shims to fill the gaps, and tighten with a torquewrench (with red loctite on cleaned threads). Solder is a bad idea since it can come off while riding and short out your electronics. EDIT: Had a slight wobble on mine. Took it apart just now to do this shimtrick. Found the clampingplates have become askew (see picture attached) aswell as worn where they sit against the axle. This will ofcourse make the problem worse and is something to look out for.. PS: made a handy clamp to keep the wheel from tipping while working on it (see attached picture)
  14. @spellbinder looks like you overtightened so there is too much resistance on the motor. Did you use a torquewrench? Please note that the drivebolts on most EUC are hollow so they wear and break easily if you tighten too much. Cleaning the threads with rubbing alcohol (bolts and nuts), checking bearings for slack, applying red Loctite threadlock, tightening with torquewrench and letting the threadlock harden are all important steps. If not you might have a torn electrical wire and you need to check the integrity of the insulation on every wire.
  15. Thought of how sharkteeth look when I started reducing weight (from a square metal plate on each side). They have incredibly strong teeth because of rounded lines on the inside of each jagged edge. Same principle works with metal. If you round off the shapes that stretch inward the result is a much stronger structure than if you just cut out a square. Future plans: induction charge station to get rid of the charging plug (weak link), bluetooth control bracelet with power indicators (no more lights or holes for moisture to get in), servo hooked up to the driveaxlenut set at the momentum specified, wake-on bios to remove power button completely (to make a completely sealed device totally sealed against moisture). At this point the battery and electronics would be sealed in completely and all wires could be fastened permanently to avoid the problems I've had with wear due to vibrations. Tire could be changed by removing a few connecting rods between the metal plates on each side (rods bolted on the shapes that go further out than tire). I would like to fit a pressure gauge on the tire (bluetooth to send signal to controlbracelet) and wire up a circuit to check the condition of the battery (or maybe the condition of each cell) at certain intervals. EDIT: Controlbracelet is for now with a arduino that is quite big... Once I can afford it I plan to get a Raspberry Pi or programmable blueooth watch so its smaller.
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