Power in Flux
Likes Likes:  0
Page 1 of 9 123 ... LastLast
Results 1 to 10 of 86

Thread: What stinks and sizzles?

              
   
   
  1. #1
    Senior Member
    Join Date
    Aug 2010
    Location
    Pacifica, California
    Posts
    2,911
    Post Thanks / Like

    What stinks and sizzles?

    So today I rode my GPR-S around for about 15 miles before replacing the dead cell in my battery pack. When I arrived home I noticed a strong pungent odor that smelled something like lacquer thinner and heard a sizzling sound coming from my bike. I immediately thought it might be on fire and removed all of the fairing covers as rapidly as possible. By the time I had access, the sizzling sound had stopped and the odor was slowly dissipating. I checked all of the batteries that I could see and nothing seemed burnt or melted and I could not locate the source of the bad smell.

    I then pulled out the bum battery and replaced it with the one that I received from Harlan. The old shorted-out battery was swollen slightly and had to be pulled out a little at a time as it was kind of tight against its neighbors. The replacement battery dropped right in and I reinstalled the BMS/conductor board. I checked the at rest voltage and it had risen from 74.6 volts (after using 20 Ah) to 77.8 volts. I then charged the battery pack and it is now performing its balancing act. Everything appears normal, the BMS seems to be operating normally and I do not smell any more odors, nor do I hear any more sizzling. Needless to say I am a little worried as I have never smelled this odor before and the sizzling noise was kind of scary.

    Does anyone have any thoughts about what might have caused this odor and noise? I am worried that another of my batteries is cooking itself to death, but I don't know what the symptoms are of a battery going bad or how to check for a failure. Or could it be something else?

  2. #2
    electrician
    Guest
    Stop riding in the rain, lol.

  3. #3
    Senior Member
    Join Date
    Aug 2010
    Location
    Pacifica, California
    Posts
    2,911
    Post Thanks / Like
    It was cool and dry when I went out for my ride yesterday. I am pretty sure that the sizzle was not caused by boiling water. I just hope it wasn't boiling Lithium.

  4. #4
    Senior Member
    Join Date
    Aug 2010
    Posts
    294
    Post Thanks / Like
    It's quite possible that you were overheating your bad cell. I wouldn't even operate a bike with a known bad cell,it was either internally shorted or had very high internal resistance. Since it's in series with the rest of them, it still has to pass current through the cell, which would cause a damaged cell to overheat. You're lucky it didn't damage any neighboring cells.
    Last edited by cycleguy; 24 October 2010 at 0828.

  5. #5
    Senior Member
    Join Date
    Aug 2010
    Location
    Pacifica, California
    Posts
    2,911
    Post Thanks / Like
    The cell that I removed has apparently been dead since the day I bought the GP-S, 1500 miles ago, based upon the CA's voltage readings. It showed no voltage whatsoever when I finally got around to checking each cell, so I don't know how it managed to conduct power, but it did. I really hope that it was what was stinking and sizzling and not another cell that might be in a location that I can not reach. My pack is fully charged today. It is showing 83 volts right now after sitting around with the charger unplugged for the past 6 hours. Normally, I would be seeing 78 volts under those conditions and that has been typical since the day I bought the bike.

    I plan to ride it around tomorrow afternoon, assuming that the weather drys out by then and hope that the stink and sizzle doesn't appear again. But, I am not going to push the bike like I did yesterday. I ran it wide open for most of my ride.

  6. #6
    Empulse R #24 frodus's Avatar
    Join Date
    Aug 2010
    Location
    Portland, OR
    Posts
    2,668
    Post Thanks / Like

    My Social Networking

    Follow frodus On Twitter
    Why on earth were you riding with a known bad cell?


    Thats like driving a car with no oil in the engine. Its just not something you do until its fixed.

    You probably started to reverse the cell and extreme overdischarge it. That would cause the cell to heat up and it probably vented through the tops of the cell.

  7. #7
    Senior Member seanece's Avatar
    Join Date
    Aug 2010
    Location
    Columbus, Ohio
    Posts
    161
    Post Thanks / Like
    Sizzle.... smell.... swollen...... Sounds like that cell wanted to vent (or did)!!!! Good times. Glad you got it replaced ASAP.
    Famous Quotes....
    James May - "It's an ingenious solution to a problem that should never have existed in the first place!"
    BillMi - "Holy Cats! .... (it's) a death trap with extra killing sauce."
    Teresa Dillard - "I can't believe you (Ted) killed a Prius."

    [10-09, 20:32] jpanichella: I was worried I was talking to myself
    [10-09, 20:45] EVcycle: you were I am a bot.....

  8. #8
    Senior Member
    Join Date
    Aug 2010
    Location
    Pacifica, California
    Posts
    2,911
    Post Thanks / Like
    I didn't realize that I had a shorted cell, not having any experience with a 24-cell pack. The voltage was always 76.8 volts when fully charged since the day I bought the bike (as I have mentioned a number of times before during the past year on El Moto), so I assumed that was the normal voltage for a fully charged pack (after all, the GPR-S is described as having a 72 volt system). I only discovered the bad cell when just for fun on a rainy day last month I took the fairing off the bike and started checking each cell with a volt meter. All the cells showed 3.35 volts, more or less, except for that one cell that showed 0.00 volts. I had no idea that a cell could be that dead and the bike would still run OK for 1500 miles. Now that I replaced the dead cell, I am getting over 80 volts, but after riding around today, the at rest voltage sure seemed to drop more quickly than before. Also, bulk charging is now intermittent. It would be really weird if another cell in the pack went bad (after 1500 miles) the very day, and just before, I replaced the dead cell.

    I'll keep an eye on the performance, but I have a bad feeling about this. Any other cells boxes look really hard to remove from the frame.

  9. #9
    SMPS Engineer BaldBruce's Avatar
    Join Date
    Aug 2010
    Location
    Cleveland, OH
    Posts
    487
    Post Thanks / Like
    Most LiFePO4 packs follow this profile.
    24 X 3.6 = 86.4V for a absolute maximum charge. Probably set for slightly less. Almost no gain in capacity by going over 84V no matter what TS web site says.
    24 X 3.35 = 80.4V when the surface charge has been removed.
    24 X 3.2 = 76.8V when operating with a reasonable load. This is the voltage you should see the most when riding around.
    24 X 3.0 = 72V when disharged heavily or getting low in capacity.
    24 X 2.5V = 60V when cold and really heavy current or when the pack is falling off the cliff of capacity. Time to get off the throttle or get of the bike.
    24 X 2.0V = 48V Push the bike home, your done.

    The blue brand cell voltage looks like this graph from Jack: (but they are all similar.)
    blueskydischargecurve.jpg
    I have not failed. I've just found 10,000 ways that won't work.
    Thomas A. Edison

  10. #10
    Senior Member
    Join Date
    Aug 2010
    Location
    Pacifica, California
    Posts
    2,911
    Post Thanks / Like
    Thanks Bruce. That information is really useful. I wish I had known that 9 months ago. At the moment, with my replacement battery, I am getting 84 volts fully charged, 80.4 volts after the pack sits around for a day, so that is looking good. However, my pack still drops to 52 volts when going up a hill and yesterday at-rest voltage dropped to 72 volts after riding a few miles. I need to go out today and check the performance again.

    seanece mentioned that one of my batteries might have been out-gassing. That would certainly explain the stink. If this happened would it occur through the sealed hole at the top of the battery, located between the terminals? I wonder if this hole is a vent. Could I tell which battery might have vented by inspecting this hole? See attached photo of the "dead" cell that I removed from my pack. The hole on this battery looks OK to me, although the sides of the battery are slightly bulging.

    Also, would anyone want to hazard a guess what the numbers on the sticker that is on the side of the battery indicate?
    Attached Images Attached Images

Page 1 of 9 123 ... LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •