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    bike issue with all 5 new bikes

    Hi everyone,
    I am new to the e bike scene and just bought 5 bikes from China. Don't want to call out the manufacture because I am still trying to get them to help with this issue. All 5 bikes were bought at the same time and all have the exact same issue. They are also new, fresh out f the box. They are 48 volt with a 1000w motor. checked the batter voltage and they are all 52.4 volts. Opened the controller storage box and the controller states that is for a 48 volt 1000w system (see picture). The battery is an LG 48 volt 14.5 Ah Li-ion

    This is the problem, when using the thumb throttle, the bikes will move about 1-5 feet under power then shut off no matter how much throttle you give it. They also as a slight shutter when first taking off. When you ride them under assist mode the power comes on and off. The screen is a XT-LCD W108 (see picture). It shows not codes or signs of anything going wrong. If I lift the rear wheel off the ground the wheel spins under power just fine. Spins up to about 28 MPH.

    Any help with guiding me in the right direction would be greatly appreciated.

    Bill

    #2
    Probably overcurrent on the battery BMS, i.e. they cheaped out and went with batteries that cannot meet the discharge rate. That would be assuming these are fully charged, battery is not frozen or something like that to the point where it has some huge amount of sag. If you see sag without it being frozen then they cheaped out with knockoff cells instead (very likely as this is the most expensive part of the ebike, and easily faked by an overseas supplier with little accountability)

    The right direction would be to buy from an American company instead of gambling on China-direct. Probably not what you want to hear but it's the plain truth.

    Assuming you are stuck with these you could try bypassing the BMS or replacing with a different battery but it's not going to be a super cheap conversion, and it would be unsafe to operate without BMS.

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      #3
      Second opinion, I agree with Paxtana, if I may be so presumptuous as to weigh in. When you have ample voltage at rest, and the wheel will free spin fast, but the bike can't pull a load (move), that is the classic symptom of a battery which can't handle the load.
      Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

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        #4
        Thank you for the help. The supplier thinks it is the controller. I did a dispute on the bikes $400 per bike. Hopefully that will cover battery cost.

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          #5
          I would not be surprised to learn that they are simply sending controllers that pull less current instead of addressing the overcurrent issue in the packs, because that would be much cheaper than addressing the actual issue.

          Which would work but the bikes will not meet the advertised specs.

          It would be very, very unlikely that all five bikes have the exact same issue in the controller itself.
          There's a language barrier so who can say if that's what they meant, but if that is what they point blank said it is a lie.

          If the bike you bought is what's in your profile pic it looks like they just had a local assembler put cells into one of the generic Reention hardcases used by several factory-built suppliers these days. We sell a similar one for 550. To think that the ones they shipped could be essentially the same case but can't even handle a 25A peak is pretty mindblowing (ours are rated for double that).

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            #6
            Post a link to where you bought them, it will give us all a better idea of what you have.

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              #7
              They also indicated a resolution would be re programming the controller. That is new to me. I measured the voltage out of the battery and starting at 50volts, it dropped to 46.7 when it shut off. Noticed that after a couple five foot runs.the controller had a little heat in it.

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                #8
                Is there another way to test the battery? I would think if the voltage only dropped a couple volts under full power the battery should be fine. I was expecting it to drop under 40 volts. What are the chances it's a rear motor drawing too much amperage or would that show up also as a voltage drop greater than what I'm seeing

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                  #9
                  I did more testing today. Use one of my batteries to power up my freinds 48volt 1000w bike. Bike ran fine. His lcd has a watt meter and was able to create enough load to get it to read 800 watts. That should eliminate the batter from the equation. Now is it the controller or motor? His plugs were different or we would have just tried to run his controller on my bike.

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                    #10
                    Originally posted by bschemers View Post
                    I did more testing today. Use one of my batteries to power up my freinds 48volt 1000w bike. Bike ran fine. His lcd has a watt meter and was able to create enough load to get it to read 800 watts. That should eliminate the batter from the equation. Now is it the controller or motor? His plugs were different or we would have just tried to run his controller on my bike.
                    I agree, that's good testing. Since the battery voltage on your bike wasn't dropping much, I don't think that's the problem, either. I don't put much reliance upon driving a different bike at 800W, though. Yours may pull more. Maybe double that. If reprogramming the controller can improve the issue, it's either reducing max current, or reducing the low voltage cutoff point. So, that 'fix' actually supports thinking this has something to do with current draw and voltage sag.

                    Wiring on your bike could be causing a drop in use, not measurable at the battery, too.

                    As noted, without knowing your equipment, it's hard to help you!
                    Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

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                      #11
                      The bikes are manufactured my Aimos Technologies. Model is AMS-TDE-08.
                      Battery: LG 48V 14.5Ah Li-ion battery;
                      Motor: Rear Brushless hub motor 48V 1000W

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                        #12
                        Now that i believe my battery to be good, how do i determine if it is the controller or the motor? The manufacturer feels it is the controller but i would like to be sure. Not sure if the controller is cutting power or motor. I am not getting any codes.

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                          #13
                          IMO the seller should build one and troubleshoot from their end. It's hard to comprehend why you have 5 defective units.

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                            #14
                            It may be a system level issue. Probably is. No one part is defective, but they don't work right, together. So, the "problem" can't be assigned to either the battery or the controller, except in the context of a particular solution option. If so, you won't find it testing or swapping components.

                            If so, then I agree, the system design owner needs to diagnose and fix this. Dial back the power until it 'works', or upgrade battery, etc.
                            Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

                            Comment


                              #15
                              The OEM is testing a new controller and LCD display now. Or at least they have one on order. I was trying to diagnose on my end being they said they tested the bikes before they left. My guess it was a no load test.

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