Moecycle

sorry, it’s already in the landfill…

Hey! I’m moving to a country that only has 110v electricity and need to get rid of my battery welder. So, if anyone is in London and would like a free battery welder, come grab it before it goes in the bin! It works great, would be a shame to toss it. I only welded maybe 80 cells with it. It’s like new. Pick up in Canary wharf. Must be collected before March 21st. First one to come gets it. SUNKKO 737G Dual Mode Foot Spot Welder Welding Machine For 18650 / 21700 Battery AC220V Use range 1. Lithium battery and nickel battery factory, mobile power and rechargeable battery manufacturers assembly welding use. 2. Laptop repair store battery repair use. 3. Mobile phone and digital products repair store battery repair use. 4. Power tools repair store battery repair use. Specification Use voltage: AC 110v1220V910% Primary current: 2A-15A Welding current: 50A-800A Welding needle pressure: 200g-700g Single pulse welding: 0.05-0.12mm sequential nickel piece Double pulse welding: 0.12-0.15mm screen degree nickel piece Machine weight: 4.3KG Machine size: 140x245x200mm Single package weight: 5.5KG Single outer package size：215x370x310mm Welding method：pressure type Power kw：2800

Just as an update, I’ve put many miles on the battery, and all I can say is WOW. These cells are nuts- the added capacity is incredible. If anyone is having trouble choosing between 18650 vs 21700, it’s a no brainer IMO. I’ll only be building 21700 from now on. These cells are great.

From what I can tell that frame doesn’t have mounts for disk brakes. That’s something I always look out for in a donor frame. Not sure how powerful a motor you’re going with, but something to consider. I converted a Dawes Discovery with a YOSE 350W kit and was very pleased with the results. I personally think rear-wheel drive is the way to go. https://www.pedelecs.co.uk/forum/threads/dawes-discovery-201-yose-350w-700c-kit-samsung-25r-10s4p.41139/ Good luck!

Thanks for the feedback everyone! It wasn’t a complete failure, the battery would clip when under heavier load (250W bike). It was my first battery build so there were a lot of points of failure. I tried my best to dissect it to diagnose. I found two of my welds on cell group 9 failed. Didn’t dig much after that. It was a very rough build. No cell spacers so it was under structural strain. It’s just basic foam padding to protect the battery from light impacts. https://www.ebay.co.uk/itm/261530567751?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=FeISftz6Rwi&sssrc=4429486&ssuid=zHDEdvKzSRC&var=&widget_ver=artemis&media=COPY Great idea! Do you happen to have a photo? Yeah I’m only taking 20A max. There is actually a 20A fuse in there (it’s powering a street legal 250w bike). Agreed that if I was going to draw 30A I would need to rethink my busses. this was definitely the most frustrating part of the build. I love the idea of the Y leads. Do you happen to have a photo of how you arrange these on a 4p? Yeah I’m pretty concerned about this. I had to apply way more heat than I wanted to attach those copper wires on the first and last group. If anything fails it will be this. Not doing that again… Do you have a photo of this sandwich approach? I’m thinking of a higher powered bike for my best build. Cheers everyone

Hey Folks, The first battery I build finally failed, so I got to make a new one! Decided to go with 21700 cells this time. Last time I posted my battery I got a lot of great feedback on mistakes I could improve. So if you feel like giving me some feedback on this build, would be very happy to hear it. The p42a cells are from Nkon.nl BMS is a cheap Chinese unit from ebay

No, Nkon took care of everything. Price listed is all you pay. molicels are doing great so far

Bike is all built! we took it for a ride across London Yesterday and it was lovely. 30km ride and battery still had some life in it. Very happy with this kit, my partner said she felt she always had power available when she needed it. Likely too fast for her, but she can finally keep up with me and not have to put in any effort. Thanks for the wise words on my battery build. I agree I need to do better on the positive terminal insulation, and will buy those Rings you suggested for my next build [mention=4809]vfr400[/mention] For anyone wondering what you should budget for a build like this, here is the final Bill: Item Price (GBP) Donor bike (Ebay) 92 YOSE kit 239 BMS 11.69 Molicel 40x 137 Power switch 3.74 brake sensor 10.24 Nickel 8 foam 4 Anderson connectors 5 battery bag 17.49 Battery foam, heat tape, shrink wrap 5 disk brakes 14.94 cable wrap and holders 7.5 Brake cable 7 Fuse 2.5 kick stand 9 Panier rack 12 TOTAL 586.1

I just got mine on Amazon, but the price was considerably higher (240gbp vs 190eur) shipping was quick and painless.

Thanks for asking. The controller is rated at 9a cont., 18 peak. Nickel strips are 8mm x 0.15mm. I installed a 20A fuse. I had a look at this chart at by the looks of it. Even a single nickel strip would be sufficient for the continuous current, no?

New battery built. Ended up going with Molicel p26a since Samsung 25R was sold out everywhere, Took the bike for a spin and it was great. Hit close to 40 km/h with the throttle only. It’s nice that the controller lets you easily set a max speed. I think I’ll keep it to 30 since my partner isn’t that confident on roads. Only complaints about this kit is the cables are too long, and the brake sensor connectors are male instead of female. I had to splice the connectors to get my magnetic sensors to fit. Last step is to bundle everything in a frame bag nicely.

I bought a YOSE 350w 700c kit from Amazon, shipped from Germany last week. Ordered on Sunday, arrived Tuesday Morning (somehow!). https://www.amazon.co.uk/YOSE-POWER-Conversion-Freewheel-Brushless/dp/B07MW3CTV3/ref=mp_s_a_1_1?dchild=1&keywords=yose+power+700c&qid=1621850539&sr=8-1

Placed an order for 40 Molicel from Nkon on May 15th, delivered today May 21 by DPD they took care of customs/vat paperwork. Great price overall.

Hi Folks, First off, thanks to everyone who provided feedback! Build is going pretty well so far. Rear wheel went on like a charm. Disk brake as well. If I'm lucky I'll be able to wrap up the electronics and brake cables this weekend.

Thanks! I’ve ordered the kit. I also ordered some magnetic brake sensors (seemed they will do the trick). For the disk brake, I’ll go with a mechanical disk caliper. I’m pretty sure it will fit on the frame (photo attached). I’ll sort this part out after the kit arrives.

Hi Folks, I'm working on a conversion for my partner. She wanted a very light bike that could maintain speed so we could bike together (she has a smaller pedelec now with 20" wheels) I'm going to be working off of a Dawes Discovery 201 donor I've picked up for 90GBP. From what I can tell, an easy/affordable conversion kit I can go with is the YOSE 700c 350w which is available on Amazon/Ebay for 240GBP: https://www.amazon.co.uk/gp/product/B07MX3C9XM/ I'm hoping to be pairing this with a 36V battery I built out of Samsung 25R cells (10s4p). This is the first time I'll be converting from a donor bike - so if any of you happen to have some thoughts/suggestions, I would love feedback before I buy the YOSE kit. Things I'm not sure about: Will my 7 gear cassette fit on the YOSE wheel? Will I need to worry about a 350w motor on the frame? Do I need any special mounting brackets? Will the PAS sensor fit on easily? What type of brake sensors should I buy? Current levers are integrated with shifters. What type of disk brake should I purchase for the new wheel? (Currently it has a V brake on the rear) Is this the wrong conversion kit, and should I be looking at an entirely different model? I've attached some photos. Looking forward to this build, its a lovely bike and incredibly light. Hope this will go smoothly!

Just a short update here. I've tried supplying that 3'rd control connector anywhere from 2.8->28v. No difference in terms of response from the Bike. Seems the electronics are complex enough that you can't really operate this bike without at least an original BMS. I'm going to try to source a new battery from Japan. If that proves too complex, I'll likely try to just swap out the controller itself and see how much of the original electronics I can salvage (hopefully the 250w motor).

Hi There, had some time to spend on this during the Christmas break. I've come to the conclusion there is something wrong with the current BMS. While the battery has ample charge (26v), the output of the +/- of the is never 26V, and the LED light indicators show no sign of life. I decided to re-wire the terminals of the battery to directly connect the anode+cathode to the outputs, and see how the bike would react. The good news is that the bike shows signs of life. Unfortunately, no power going to the motor yet. Here is a short video: https://photos.app.goo.gl/Kwfmjx1zAKDsm1wf6 The flashing indicator lights on appear to be an error code related to the "connector" according to the Sanyo Enloop Manual. This seems rather expected as I left the middle connector (Yellow, unknown BMS output) blank. At this point, I'm not really certain what to do next. I would like to debug what that yellow battery connector is for, and if I can somehow emulate/replicate it. I opened up the rest of the bike, and its unfortunately it didn't reveal many interesting info. *If anyone happens to have any idea what the non-power terminals on Sanyo/Panasonic batteries are for, would really appreciate it!* More photos for reference:

Thanks for the input. The charger is the only device with the S and T ports, so I may have to import one from Japan to figure this out. The bike only has + , Y, - (photo below). I'll open up the bike this weekend to see if I can get any clues. I'm beginning to fear the issues with the battery are more severe and the BMS is junk as well. I'm slightly tempted to just build a new regular 25V battery and see if I can get this bike moving.

This morning the battery remained at 25.4V, so at least it's holding a charge overnight. I reconnected the BMS, but unfortunately that didn't go well. It has a button with 4 lights which "should" show the charge level, but the button doesn't seem to be doing anything. Furthermore, when I tried connecting the charger directly to the anode/cathode of the battery after the BMS was installed, I didn't see any voltage change across the cells and the light on the charger was flashing red (usually solid red when charging). I turned it off after that. On the output of the BMS, the voltage from from the main terminals is only 170mV. As expected, when I plug it into the bike (which only has ports -,Y,+), no response at all. Here is a diagram of the voltage drops across the terminals now. I'm wondering if I can attempt to charge it through the BMS? I'm quite perplexed by the terminals. Thoughts on if I can connect a 29.4V charger to any of these terminals?

Hi Folks, Short update here, parts came in and I've given it a charge. I decided to remove the BMS in the off chance everything went terribly wrong and it fried. I've charged the cells at 29.4V 2A for 1hr. Very happy to see consistent voltage across the parallel groups throughout the charge cycle. Also happy to see what one would expect from a Li-Ion charging V curve. Very rapidly from 1.6V -> 2.5V (~5 minutes), more consistent from 2.5V -> 3.6V (15 minutes). After 3.6V, it definitely slowed quite a bit. Charged for 1 Hour total and reached 3.75V. 10 minutes after charging, battery is at 25.4V the cells groups are sitting at: C1: 3.66 C2: 3.66 C3: 3.66 C4: 3.66 C5: 3.66 C6: 3.66 C7: 3.66 I'll follow up tomorrow evening to see if they held the charge at all. If that goes well, I'll try to charge for 12+ hours on the weekend outside. My goal here is to get this battery to a point where I can test the rest of the bike. I'm likely going to swap in new 18650's after I figure out what else this bike needs.

Thanks Nealh and vfr. Ordering in some components and follow up when I have some results. You have been very helpful, very glad to participate in this community.

Right - parallel cell groups. Thanks for the battery 101 lesson by the way So, measurements are in: 1.6V - Group 1 ~ 1.6V 3.14V - Group 2 ~ 1.54V 4.65V - Group 3 ~ 1.51V 6.25V - Group 4 ~ 1.6V 7.91V - Group 5 ~ 1.66V 9.55V - Group 6 ~ 1.64V 11.22V - Group 7 ~ 1.67V So, max difference of ~0.16V

Thanks vfr. Seems I'm out of luck, 11V no matter where I measure. Do you mind if I know how you calculated this? 20v @ 21 cells ~~ 1V/cell? Given this, I'm likely going to replace the cells in this pack myself. I'm having a hell of a time opening it to begin with, hopefully I manage to get it open without complete destruction. I've attached a number of more photos. If you or anyone else has any suggestions on how to: 1. dis-assemble, or, 2. how to charge when I finally get it back together, I would be infinitely grateful. HD album here: https://photos.app.goo.gl/PSdhRUNi3S3ji3xw8

Thank you all so much for the prompt replies! I'll be posting more photos and measurements today after work. You're correct, I was only measuring from the terminals of the batteries, before the BMS (just to see if there was any life in the cells at all). I'll re-measure with the fuse replaced & the full circuit. Cheers