Andrew Duff Posted November 15, 2020 Share Posted November 15, 2020 Has anyone had this problem with a Veteran Sherman? Mine is saying "bt Lou" in the display and tilting back. I am taking "bt Lou" to mean low battery which explains the tilt back. The problem is that I still have 6 (of 8) bars of battery left and 90+Volts. I charged it about 60 km ago and have been getting a range of around 150 km. Battery low is definitely a false reading. Turning it on and off or connecting to a charger does not seem to help. I had a quick look for loose electrical connections but don't see anything obvious. I have only had the wheel for 3 weeks and done just over 200 km. I'm curious if anyone knows what the issue and fix might be before I ship it back for repair. 2 Quote Link to comment Share on other sites More sharing options...
Popular Post Dominic Winsor Posted November 15, 2020 Popular Post Share Posted November 15, 2020 As I said on Facebook - this could be to do with cell balancing. Lithium-ion batteries are made of a combination of individual cells wired in series and parallel. Simplistically, the series connections raise the voltage, and the parallel raise the capacity. An individual cell is nominally 3.7 volts but around 4.2 when fully charged. In an ideal pack which is fully charged, each cell would be 4.2V. And they’d drop in voltage equally as you use power and regenerate/recharge power into them. However, we live in the real world and nothing is perfect so individual cells will discharge at different rates. Over time the voltages can end up all over the place. A battery management system (BMS) has the job of balancing these cells in the pack to bring things back to an even voltage for each cell. (They also look after other parameters such as temps etc.). Why all this explanation? Well the TL;DR is it can take quite a long time for the battery to be balanced. When my Onewheel gets unbalanced, it can take around 3 days to recover. You don’t need to do anything special - just leave it on charge and let the BMS do it’s magic. The other thing is people persist some bad habits and misinformation about Lithium Ion cells from older battery technologies but that’s for another topic. Attached is a table of cell voltages on my old Onewheel+ XR battery pack, on which a cell eventually failed. You can see how long it takes for the pack to balance! 4 Quote Link to comment Share on other sites More sharing options...
Andrew Duff Posted November 16, 2020 Author Share Posted November 16, 2020 Thanks for your answer Dominic Windsor. I can try leaving it charging and see if that fixes the issue. I'm a little concerned that a problem like unbalanced cells would occur so early. I have only run my EUC down once and charged it fully once. It is basically a new machine with 200km on it. Are you able to measure individual cell voltages on your OneWheel? I am a noob so is that even possible on something like a Sherman (with 240 cells)? I am trying to figure out if it's possible to see if it is actually unbalanced. Quote Link to comment Share on other sites More sharing options...
Chriull Posted November 16, 2020 Share Posted November 16, 2020 6 hours ago, Andrew Duff said: I am a noob so is that even possible on something like a Sherman (with 240 cells)? The 24s10p battery packs are afaik organized in two 12s10p packs. So per pack 12 voltages have to be measured. To measure th oneself one unfortionately would have to cut open the pladtic wrap of the battery. Quote I am trying to figure out if it's possible to see if it is actually unbalanced. @Dominic Winsor assumption makes sense - voltage is high (enough) but the wheel signals low battery - so the wheel could signal some single cell (group) undervoltage. Would be very interesting if this is really true. Looking at the BMS pcb at ecodrifts teardown it could be possible? Maybe even to be sent to a phone app!? Both bms pcbs ?and the mainboard? are connected with some SIO wire - could be some one wire bus? However 6 hours ago, Andrew Duff said: . It is basically a new machine with 200km on it. you should get in contact with your reseller to identify and solve the problem! And/or get in contact with Veteran - they should know what possible causes your situation could have. 2 Quote Link to comment Share on other sites More sharing options...
Andrew Duff Posted November 30, 2020 Author Share Posted November 30, 2020 A follow up to this. My mysterious bt Lou message disappeared after a couple days. (Just before I was about to ship it back for service). But now, a couple weeks and several rides later, I tried to charge the Sherman and it won't charge. This is the first time charging since the above issue. It looks like it's charging but after many hours neither the battery level of the voltage have increased. I suspect that it must be a bad battery pack or BMS. I guess I do need to ship it back for service after all. Sigh... 1 Quote Link to comment Share on other sites More sharing options...
Ben Hatfield Posted January 2, 2021 Share Posted January 2, 2021 this issue just happened to me My Veteran was just off the charger at 100%. I turned it on and trolly-ed it to my living room. I set it on its side in order to do some work with pads/velcro/reflective tape. It was probably on its side for a couple hours, moving it around. I turned it on to move it back, and I got that message on the Veteran display screen, and the wheel just starts tilting back and forth when it is at rest. It doesn't seem like a normal tilt back - the behavior seems completely off imo. Turned it off and on, plugged it in to the charger (it is reading Full charge) - nothing seems to be helping - or reseting. Same question - anyone else had this? solutions? and did the original poster end up having their wheel serviced? 2 Quote Link to comment Share on other sites More sharing options...
Chriull Posted January 2, 2021 Share Posted January 2, 2021 3 hours ago, Ben Hatfield said: Same question - anyone else had this? solutions? and did the original poster end up having their wheel serviced? There is unfortionately no follow up from the op. Afair there was a quite similar case leading to a battery exchange? Anyhow - it's a serious malfunction hopefully within your warranty period. So get in contact with your reseller! Quote Link to comment Share on other sites More sharing options...
Popular Post Ben Hatfield Posted January 3, 2021 Popular Post Share Posted January 3, 2021 Contacted eWheels the error message 'bt lou' does signify an imbalance in the battery packs, Right and Left sides. holding the 'ok' button for bringing up settings - continuing to hold until it brings up voltage, and additional settings/info. press 'arrow' button until seeing two of those settings: '### bu' and '### bt' 'bu' is the left side, 'bt' is the right side. My display read '100 bu' and '111 bt'. the low number is the problem side. my problem is on the Left side. Jason from eWheels asked me to disconnect the problem battery (Left) and power on the Veteran. It will still work with just the Right battery pack plugged in. Unplugging the Left battery pack from the main board, and powering on - no error message. Veteran is ridable. I'll still remove the battery asap, set it aside (original/problem battery pack will be shipped back to eWheels), and wait for the replacement battery pack. video discussing all of this - 11 Quote Link to comment Share on other sites More sharing options...
Andrew Duff Posted January 4, 2021 Author Share Posted January 4, 2021 I ended up sending my Sherman back for service. I have about a 6 week wait while a new battery pack is shipped by boat from China. Groan. I wish I'd known that I could unplug the one battery pack like Ben Hatfield did in his video. Then at least I'd have my wheel while waiting for the new battery pack. Like I mentioned earlier, my bt Lou message did clear by itself (after several days) but I could not charge the wheel any more. I'm curious if Ben Hatfield has been able to charge his wheel OK with only 1 battery pack connected? Quote Link to comment Share on other sites More sharing options...
DjPanJan Posted January 4, 2021 Share Posted January 4, 2021 @ChriullIs possible teoreticaly use GOtway MSP original 100v charger to ballance sherman battery? Potentialy use for sherman Gotway 100@ 1-4A smart charger? Is conector compatible veteran sherman same like GOTWAY? Because some chargers dont know how ballance ,they just reach set voltage and shut charging down. If veteran have 240 18650 batteries is possible one of them is not good like others. Quote Link to comment Share on other sites More sharing options...
Chriull Posted January 4, 2021 Share Posted January 4, 2021 12 minutes ago, DjPanJan said: @ChriullIs possible teoreticaly use GOtway MSP original 100v charger to ballance sherman battery? Sherman's BMS have some extra control wire attached to the motherboard. 12 minutes ago, DjPanJan said: Potentialy use for sherman Gotway 100@ 1-4A smart charger? Is conector compatible veteran sherman same like GOTWAY? Because some chargers dont know how ballance ,they just reach set voltage and shut charging down. Chargers are absolutely dumb and do nothing but provide some max voltage with some max current. And the light a green led once the current drops below some threshold. Gotways chargers are as dumb as Veteran, Inmotion and KS chargers! 12 minutes ago, DjPanJan said: If veteran have 240 18650 batteries is possible one of them is not good like others. Yes, most likely something is bad beyond diy with sherman's showing such symptoms. 2 Quote Link to comment Share on other sites More sharing options...
Popular Post Ben Hatfield Posted January 14, 2021 Popular Post Share Posted January 14, 2021 (edited) I did receive my new replacement battery, and installed with relative ease. Anyone wondering - the fuse module does come with the replacement battery. The little board plug from the slim battery wire is a little annoying to unplug/plug. Batteries need to be balanced on both sides before plugging both into the board at the same time - My existing battery was fully charged and read 100.1V multimeter. The new battery arrived fully charged at 100.5V via multimeter. After installing the new battery I plugged it in alone, and ran it down to 100.2 (multimeter), then connected both batteries to the main board (figuring .1V variance should be fine, and this was confirmed via eWheels). The wheel powers on and operates normally. I have yet to get in a good test ride. The original (defective battery) read 99.5 on the multimeter (and would charge no further), and was sent back to eWheels edit: I did get in a good 40 mile ride. Charged the battery to full. No issue. Edited January 17, 2021 by Ben Hatfield 4 Quote Link to comment Share on other sites More sharing options...
..... Posted January 14, 2021 Share Posted January 14, 2021 (edited) 17 minutes ago, Ben Hatfield said: I did receive my new replacement battery, and installed with relative ease. Anyone wondering - the fuse module does come with the replacement battery. The little board plug from the slim battery wire is a little annoying to unplug/plug. Batteries need to be balanced on both sides before plugging both into the board at the same time - My existing battery was fully charged and read 100.1V multimeter. The new battery arrived fully charged at 100.5V via multimeter. After installing the new battery I plugged it in alone, and ran it down to 100.2 (multimeter), then connected both batteries to the main board (figuring .1V variance should be fine, and this was confirmed via eWheels). The wheel powers on and operates normally. I have yet to get in a good test ride. The original (defective battery) read 99.5 on the multimeter (and would charge no further), and was sent back to eWheels The plague of hoping 240 batteries are perfect. I'm not surprised this happens from time to time. Hopefully E-wheels will stock extras for the inevitable and there wont be much wait. Sounds to me like its a small pain in the ass, but not too difficult. If swapping a single pack is doable for some handy customers, this sounds like a smaller pain than it could be. Thanks for the update guys! Sucks to hear that we arent seeing 100% success on every model with 240+ batteries, but its awesome to hear it can somewhat easily be fixed without shipping 80lbs back and forth across the country. Of course, those with no mechanical ablity and tools are simply fu**ed as usual. Hooray for veteran putting an onboard readout to test these w/o even powering up an app! Techs may not get rich, but they sure can keep their own stuff working for cheaper. Edited January 14, 2021 by ShanesPlanet 2 Quote Link to comment Share on other sites More sharing options...
q3fqewrgfqe3 Posted April 17, 2021 Share Posted April 17, 2021 Had the same issue, in touch with chic-way right now to see about warranty. I'm about 350 miles and 3 weeks into owning the sherman. Here is a quick video walking through my diagnosis and "fix", will update on if I get a replacement or if they have a remedy. https://www.youtube.com/watch?v=dTySOuLngbk 2 Quote Link to comment Share on other sites More sharing options...
Resko727 Posted April 17, 2021 Share Posted April 17, 2021 On 1/13/2021 at 8:12 PM, ShanesPlanet said: The plague of hoping 240 batteries are perfect. I'm not surprised this happens from time to time. Hopefully E-wheels will stock extras for the inevitable and there wont be much wait. Sounds to me like its a small pain in the ass, but not too difficult. If swapping a single pack is doable for some handy customers, this sounds like a smaller pain than it could be. Thanks for the update guys! Sucks to hear that we arent seeing 100% success on every model with 240+ batteries, but its awesome to hear it can somewhat easily be fixed without shipping 80lbs back and forth across the country. Of course, those with no mechanical ablity and tools are simply fu**ed as usual. Hooray for veteran putting an onboard readout to test these w/o even powering up an app! Techs may not get rich, but they sure can keep their own stuff working for cheaper. The other issues I supposed is each pack being a 24s5p there not really easily separated into to 4 packs. 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Chriull Posted May 7, 2021 Popular Post Share Posted May 7, 2021 As these seems an important information - i split the "Battery Case Modification" part off to a separate pinned topic here: 4 Quote Link to comment Share on other sites More sharing options...
supercurio Posted May 8, 2021 Share Posted May 8, 2021 I asked the shop I placed an order from (wheel currently shipping to the shop, planned arrival May 31) if they kew about this issue, linking to @Ben Hatfield's excellent video as reference. The shop contacted LeaperKim who replied shortly that the factory made changes accordingly. Once the shop will receive the wheel, they'll open it and check and I will also when the wheel is in my possession. Let's see which change they made then! I'll share pictures. 3 Quote Link to comment Share on other sites More sharing options...
shellac Posted June 11, 2021 Share Posted June 11, 2021 Some disappointing news. I have a new batch 2021 Sherman with the wider rims, waterproof controls, and the newer side panel which had been already modified to prevent bms damage, and I do get the “bt loy” error and cannot ride it. It won’t charge either. The wheel has never had a serious drop. Early on it fell onto one side at low speed with no damage except for a torn soft powerpad which I fixed. I had never checked the psi on the wheel since I got it so I decided to check it today. I put it on its left side saw the pressure is 20 psi. I pumped up the knobby tire to 30 psi, which btw gives an occasional rubbing noise with the wider rim wheel, and now might be worse after pumping the tire up. After that I turned it on to ride and it gives the dreaded “bt loy” error. I opened it up and don’t see any visible damage. The side panel is already the newer one as you can see in the photos. Anyone have this problem yet on a 2021 Sherman? Wtf? https://ibb.co/RhbBCyvhttps://ibb.co/SQtZ9Hjhttps://ibb.co/QcjSrV3https://ibb.co/hg6FbTw https://ibb.co/Nn69QPK 2 Quote Link to comment Share on other sites More sharing options...
..... Posted June 11, 2021 Share Posted June 11, 2021 (edited) 11 minutes ago, shellac said: Some disappointing news. I have a new batch 2021 Sherman with the wider rims, waterproof controls, and the newer side panel which had been already modified to prevent bms damage, and I do get the “bt loy” error and cannot ride it. It won’t charge either. The wheel has never had a serious drop. Early on it fell onto one side at low speed with no damage except for a torn soft powerpad which I fixed. I had never checked the psi on the wheel since I got it so I decided to check it today. I put it on its left side saw the pressure is 20 psi. I pumped up the knobby tire to 30 psi, which btw gives an occasional rubbing noise with the wider rim wheel, and now might be worse after pumping the tire up. After that I turned it on to ride and it gives the dreaded “bt loy” error. I opened it up and don’t see any visible damage. The side panel is already the newer one as you can see in the photos. Anyone have this problem yet on a 2021 Sherman? Wtf? https://ibb.co/RhbBCyvhttps://ibb.co/SQtZ9Hjhttps://ibb.co/QcjSrV3https://ibb.co/hg6FbTw https://ibb.co/Nn69QPK Are you sure thats not a battery imbalance reference? Perhaps you already know, the images are just proving what the bt lo causes? Try to charge with 1 battery unhooked, then do the same with the other side if works? Of course, dont hook both in if you only fully charge the one. Sucks to hear this, as you may have to get another damn pack. I happen to have a pair of them I rely on as well. I'd imagine mines out of warranty by now tho Edited June 11, 2021 by ShanesPlanet Quote Link to comment Share on other sites More sharing options...
shellac Posted June 11, 2021 Share Posted June 11, 2021 (edited) 13 minutes ago, ShanesPlanet said: are you sure thats not a battery imbalance reference? Iirc, bt lo looks exactly like "bt lo" when you get the error. Perhaps try to charge with 1 battery unhooked, then do the same with the other side if works? Of course, dont hook both in if you only fully charge the one. Well yeah it is a battery imbalance error. It’s the exact same as the errors shown in the first few posts of this thread. The pictures with the 100 bU and 111 bD means the left battery is lower I think. There’s no reason for my batteries to be out of balance. I haven’t even charged it that many times since getting it as you can see by the mileage. I presume there is a deeper problem and there’s something wrong with the battery that’s not fixable just by charging. I haven’t tried charging one side at a time yet, I’ll wait to see what ewheels says. Charging as it now with all the batteries connected doesn’t work at all. Edited June 11, 2021 by shellac 1 Quote Link to comment Share on other sites More sharing options...
Planemo Posted June 11, 2021 Share Posted June 11, 2021 3 hours ago, shellac said: Some disappointing news. I have a new batch 2021 Sherman with the wider rims, waterproof controls, and the newer side panel which had been already modified to prevent bms damage, and I do get the “bt loy” error and cannot ride it. It won’t charge either. Holy smoke, thats not good news. I assumed that the bt loy error was ALL down to the non-modded side panels. I guess it also applies to any imbalance at all, but on a new wheel I am hoping this is a very rare scenario... Quote Link to comment Share on other sites More sharing options...
supercurio Posted June 11, 2021 Share Posted June 11, 2021 7 hours ago, shellac said: Some disappointing news. I have a new batch 2021 Sherman with the wider rims, waterproof controls, and the newer side panel which had been already modified to prevent bms damage, and I do get the “bt loy” error and cannot ride it. It won’t charge either. The wheel has never had a serious drop. Early on it fell onto one side at low speed with no damage except for a torn soft powerpad which I fixed. I had never checked the psi on the wheel since I got it so I decided to check it today. I put it on its left side saw the pressure is 20 psi. I pumped up the knobby tire to 30 psi, which btw gives an occasional rubbing noise with the wider rim wheel, and now might be worse after pumping the tire up. After that I turned it on to ride and it gives the dreaded “bt loy” error. I opened it up and don’t see any visible damage. The side panel is already the newer one as you can see in the photos. Anyone have this problem yet on a 2021 Sherman? Wtf? https://ibb.co/RhbBCyvhttps://ibb.co/SQtZ9Hjhttps://ibb.co/QcjSrV3https://ibb.co/hg6FbTw https://ibb.co/Nn69QPK Thanks @shellac for sharing with us your bad news with precise recount of the wheel history. Do you remember on which side it fell at low speed? It sounds like the BMS fault occurred directly after you laid the wheel on its side to adjust the tire pressure. Looks pretty clear-cut cause and effect... I still have a Sherman on order currently shipping. Wondering if I should cancel. Given the battery shortage and limited duration of warranty on the battery, this issue seem like it could become an annoying and costly endeavour down the line. Do you know if it's possible to replace the BMS board only and get the battery pack re-wrapped by a local battery shop? 1 Quote Link to comment Share on other sites More sharing options...
Planemo Posted June 11, 2021 Share Posted June 11, 2021 (edited) 49 minutes ago, supercurio said: Do you know if it's possible to replace the BMS board only and get the battery pack re-wrapped by a local battery shop? If it is indeed a BMS issue (not a cell/s) then it does seem a shame to have to faff around with shipping packs etc given the weight and transportation issues. Swopping out a BMS board (assuming it is similar to Gotway setups) is really easy and are simple to ship. The shrink wrap is only a few quid too. Anyone with a £10 soldering iron and a hairdryer/heat gun could do the job. Of course you need to go slow and steady, but it's not fiddly nor difficult. The solder pads are big and theres not a lot where you can go wrong - unsolder each tab, lift it up out the way, pull off the BMS. Edit: yeah they are virtually identical to Gotways, Ecodrift teardown pics show: https://ecodrift.ru/2020/07/05/razbiraem-veteran-sherman-iz-pervoj-postavki-mnogo-udivitelnyh-otkrytij/ Edited June 11, 2021 by Planemo 2 Quote Link to comment Share on other sites More sharing options...
supercurio Posted June 11, 2021 Share Posted June 11, 2021 (edited) Agree @Planemo, the current approach to ship packs around (how far?) doesn't seem optimal. And I guess you might receive a refurbished pack with older - or newer cells than what you had before. I guess that since it's safety critical (both operation and fire), these packs are serviced only by specific authorised professionals. Seeing how the huge BMS board covers the entire pack and since the issue occurs due to forces applied from the side covers onto the board: What about flipping the pack so the BMS board would lay on the inner shell instead of the side cover? Wouldn't this inversion reduce the risk to the boards significantly? Edited June 11, 2021 by supercurio Quote Link to comment Share on other sites More sharing options...
..... Posted June 11, 2021 Share Posted June 11, 2021 (edited) 1 hour ago, Planemo said: If it is indeed a BMS issue (not a cell/s) then it does seem a shame to have to faff around with shipping packs etc given the weight and transportation issues. Swopping out a BMS board (assuming it is similar to Gotway setups) is really easy and are simple to ship. The shrink wrap is only a few quid too. Anyone with a £10 soldering iron and a hairdryer/heat gun could do the job. Of course you need to go slow and steady, but it's not fiddly nor difficult. The solder pads are big and theres not a lot where you can go wrong - unsolder each tab, lift it up out the way, pull off the BMS. Edit: yeah they are virtually identical to Gotways, Ecodrift teardown pics show: https://ecodrift.ru/2020/07/05/razbiraem-veteran-sherman-iz-pervoj-postavki-mnogo-udivitelnyh-otkrytij/ excellent info. I was told that it would be VERY difficult to replace. Looks to me like it requires the solder skill of a 3 year old. I'd trust MY solder and skill over that of a random ass underpaid employee from another country, who's ass aint on the line. I wonder how hard it is to get the stock sherman bms? I too would be a little nervous about sending a pack of good batteries off, to only get a new bms on a pack of shit batteries, back. Edited June 11, 2021 by ShanesPlanet 1 Quote Link to comment Share on other sites More sharing options...
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