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Wolf early LVC, 53vlts

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    Wolf early LVC, 53vlts

    Looking for some insight into why the BMS on my v1 Wolf cut power at 53vlts.

    my theory is that I have a weak cell / parallel group, and the pack is in need of balancing. I am putting the battery through a set of full charge cycles now in hopes that’s all it was.

    history: the pack has 4500km, roughly 200 cycles, kept between 20-80% most of the time, using a Luna advanced charger for the first two years and a Grin Saitiator for the last 50cycles

    the pack had been left to sit for about 3weeks at 56 volts,
    20km into a ride the screen when dead on my BBSHD, totally power out, the LVC on the controller is set to 42vlts and has always cut out before the BMS (screen has stayed on but power to the motor cut out) this usually happens when I am pushing it and hit the throttle causing it to sag below the LVC.

    I let it rest for a few minutes then reconnected the battery, it showed 53vlts on the screen, I watched the display, it cut out very shortly after on pedal assist 1, no huge load, sagged down to maybe 51vlts, maybe, I didn’t catch it.
    I left it alone, got it home and verified with a good meter that it is in fact 53vlts.
    I charged it to 58.8vlts and left it connected overnight, odd behaviour, I have never seen the voltage vary at the end of a charge, it was fluctuating between 58.8 and 59.2, I’m guessing this was the BMS balancing the cells, I hope.
    I flogged the battery hard on my way to work :) 60kmh where I could, lots of throttle use, and put it on another charge cycle to 58.8 at 2amps, hopefully this battery isn’t worn out, Luna is out of stock

    #2
    Is this a situation where something like the EM3ev battery with that app would help in determining individual cell health/condition to diagnose or at least eliminate a low/bad cell? I do not and have not owned an EM3ev battery and am just going by reading the info on their site. I thought that sounded like a pretty neat diagnostic tool. Does this technology and app really allow the inspection of each cell in a pack? I'm not new to bicycles, but the battery technology of ebikes is a new format for me. Other than something like this EM3ev deal, is there any other way to determine a bad, weak, or imbalanced cell without opening up the battery? I was thinking "no", but...

    Comment


      #3
      Hopefully it will balance out but it doesn't sound good that it can sag that far with a light load. There are lots of pluses to a fully potted hard case battery but being able to repair them isn't one of em. I believe Luna said that some of their BMSs do have bluetooth options but they found that tended to drain the batteries when they sat which caused issues so they disable those functions and don't even offer it as an option. Being fully potted knowing you have a bad cell group doesn't really help so I can see why they decided it wasn't a useful feature.

      Comment


        #4
        73Eldo,
        yup hit the nail on the head, if it’s potted all the data would mean very little.
        while I am a junkie for the numbers and tech I’ll take a fully potted battery hands down, dead reliable and tough.

        I am curious to know if the Wolf will only balance at 100%.

        Also very curious to know what most people are getting for life span.

        Comment


          #5
          I have a V1 wolf I bought used, I think its the 12ah flavor. I think it was bought in late 18 and had about 600 miles on it when I got it summer of 20. I put another 600 on it over about 3 months. The previous owner told me he always charged at 80% and my first ride I killed it in around 10 miles. I'm sure part of that was me not contributing at all and riding in the wrong gear plus that it was way out of balance. I think I did one more 80% charge with similar results then while fixing a bunch of stuff let it go to 100% which took forever, like an extra 3-4 hours. After that I was getting 20 miles with room to spare. When I just had that bike and battery and was doing around 20 miles per day I was usually charging to 90% but about once per month was doing 2 cycles at 100%. When I did it like that those 100% cycles seemed to take maybe an extra hour or so. This was all with the Luna Mini charger that didn't have a display.

          My next build I got the Luna Advanced charger that has the amp and volts display and with that one its easier to tell if its balancing which I have not noticed when going below 100%. I normally charge at 2 amps so the amps will normally stay right around 2 but if I'm going to 100% and have not done it for a while I will notice that it will drop to like 1/2 amp for a period of time at the end which I assume is when its balancing. The lower rate is because maybe only one group is being charged?

          I did have a 12ah V2 Wolf that decided to cut off early. I'm not 100% sure that it changed behaviors since that was my 2nd and soon to be 3rd setup so I was switching around all the time so there is a chance it was defective from the start and I never noticed it before. Luna had me do some specific testing in a specific order and document it on video. They determined it was likely a defect and gave me a partial credit to be used on another pack which I took and got lucky and got a 13.5 pack. I was considering the dire wolf but from what I have seen I would still be waiting for those to come back in stock months later so I think I did alright with the Wolf.

          I also have a EM3EV softish pack I got used but I only use that on my street bike. One reason is the extra weight doesn't make as much difference on that bike because its not swinging around on the streets and also less violent vibrations. I only use the Wolf pack on the trails just because of the great mounting system and the fully potted hard case. Today I noticed I broke some spokes on last nights trail ride. I'm sure what ever did that was a pretty hard slam and I would hate to think of a soft pack taking hits like that.

          Comment


            #6
            Originally posted by Upnorth View Post
            73Eldo,
            yup hit the nail on the head, if it’s potted all the data would mean very little.
            while I am a junkie for the numbers and tech I’ll take a fully potted battery hands down, dead reliable and tough.

            I am curious to know if the Wolf will only balance at 100%.

            Also very curious to know what most people are getting for life span.
            Aren't those EM3ev packs also fully potted? Seems at least you would know without doubt that any problem you're trying to diagnose will be helpful to see the individual cell condition. Understand I'm not promoting EM3ev packs or anyone else's. My current pack is neither EM3ev or Luna. I did try to get a Luna pack that fit my needs, but they were out at the time.

            73Eldo, I tend to agree with you on frame mounted soft packs for real off road. I can't imagine how the constant hammering would take its toll. I'm curious on the term "soft pack", however. I don't believe my Bicycle Motor Works is potted by any means, but it feels like a solid brick. I think you remember that I use mine in a backpack for off road mountain biking, so I'm not as concerned about the vibration from direct frame contact. So I assume "soft pack" refers to all non-potted packs?...perhaps?...even if they're really solidly built?

            On your mention of detecting battery balancing with the Luna Advanced Charger, can you provide more detail on that? I have that charger and hadn't thought about how the display can give a hint at balancing. My battery is supposed to have a balancing element contained in it from research. I kind of get some aspect of it from your description above.

            These freakin' batteries are expensive, and I want to make sure I can learn all I can to get the most out of them...LOL!

            Comment


              #7
              My EM3 pack doesn't look like the triangle one(s) they were selling in 2020 or now. It may be potted, the slight area that isn't shrink wrap has some sort of coating on it but that may be part of the BMS since its near where the leads come out of the pack. The shrink wrap is the heavy more rubber like stuff, not the thin blue plastic you see on many of the ebay or ali packs or inside many of the shark style packs. I opened up one of those to try and help someone and it was a mess, just that blue shrink wrap and some hot glue slapped into that plastic case. Strips were broken and pulled off the no name cells. Very depressing and this person paid a lot for the bike, it wasn't like they knew they were getting a piece of crap.

              When I had the regular mini charger my indication that it was likely doing a balance was that lets say I did a typical ride and was down to a typical voltage on the display. I did the same ride enough that I knew to charge to 80 would take say 3 hours and 90 would take 4 but if I went to 100 it would take 6.

              With the advanced charger if you set it to 2 and start charging you should see the amps quickly climb up from zero to around 2. It seems to bounce around by a few 10ths of an amp but when I am charging to 80% or 90% the amps stay right around 2 the whole time till it hits the full voltage and shuts off at which point the amps go to 0. If you go to 100% at the very end you will see the amps drop below 2 for some period of time. How long and how low seems to depend on how out of balance they are. When I was 'breaking in' my new Wolf pack the first time I saw it drop and stayed there for maybe 30 mins but the next several 100% times I never caught it doing it. I wasn't glued to the thing but I would walk past it and it was still at 2 amps but then next time I looked at it it had shut off which makes me think it was pretty close to in balance.

              I would imagine there is some science to why most BMSs don't balance till you are close to 100% but in E bike land that seems to be the case. I seem to recall hearing Tesla people talk about the cars doing the same thing but on those it can be automated so it just does a 100% charge like overnight when it senses it needs to otherwise it only goes to 80% to try and keep max life. On those I assume its one of the preferences thing you can set if you want it to charge for max range or max life or max charging speed. Us bike people have to keep track of that in our heads.

              Comment


              • 73Eldo
                73Eldo
                Giga Member
                73Eldo commented
                Editing a comment
                I was just using 2 as an example on the advanced charger because its what I usually use. In theory you would get a similar result on any of the settings which is 1-5 amps.

              #8
              Thanks for that info...very informative. I will watch the charger for that pattern...makes sense.

              Comment


                #9
                I just got home, 12km commute. Rode it hard, lots of full throttle up hill. The battery ran well. Started at 58.2, not a bad sag from 58.8 (30mins after disconnecting from the charger).
                Close to home it was down to 53 volts, I held it at full throttle up a hill ( steep enough to be a PIA yesterday with a dead battery) and it sagged to 49 and stayed there. No cutouts. Not bad in my opinion, any thoughts?

                The wolf must have a BMS lvc that watches individual parallel groups, in addition to over all pack voltage, and yesterday it must have been unbalanced.

                Comment


                  #10
                  Most BMSs do watch the individual groups and it does sound like you maybe have a weak one but it sounds like going to 100% so it could balance helped.

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