Recent content by PaulD

I think the best method is to have features on the cell holders that secure the nickel strips. Otherwise, your welding fixture has to do that job. Generally fixtures are just machined bakelite or similar material. I just 3D printed some with PLA, and they work fine.

Well, I'm just saying that for a battery, safety and longevity shouldn't be sacrificed for ease of repair. I think potted batteries last significantly longer due to better thermal performance, no water intrusion, etc. So instead of a battery dying an early death and becoming garbage (or getting...

I used to agree with this sentiment, and I do for pretty much all products EXECEPT lithium batteries, but I think I've seen way too many shoddy DIY batteries and failures to think its a good idea for most people to work on them. And, honestly, there are very few people that WANT to repair...

I think the easiest way to start is fillet brazing with LFB Low Fuming Bronze (which is actually brass). I've built a few frames with nickel silver (similar to Welco 17), and its harder to build up a fillet due to lower viscosity, and higher melting point. Once you've got a bunch of practice...

I know! I've been pretty slammed these days. I hope to get back on that research soon. I figure most brands are using polyurethane because it's cheaper than silicone. I don't have any inside info though.

If you're considering 10kw, I wouldn't gear the motor to spin your chainring at typical pedaling cadence.

This is an old thread, but there are a number of ways to improve the odds of your cassette and freewheel surviving very high power. Use only the sprockets that are 16T or larger Use a shift sensor - generally side loads during shifting are what kill your chain Have a freewheel on the motor...

Cool. Looks really tough. This one was shown at the Sea Otter that has a "diamond ceramic" coating: https://bikerumor.com/onguard-rock-solid-u-lock/

It looks like there isn't a freewheel in the system to prevent the chain from over-driving the pedals. So, if you stop pedaling suddenly, is the motor and gearbox inertia going to throw your chain off the chainring or break the derailleur? Also, does that torque sensing device work in all gears...

UL 2271 does not have any puncture or thermal runaway test. It is mostly electrical and software tests to ensure the BMS functions properly. The mechanical tests are shock and vibration (similar to UN 38.3), drop, and a few others. The ingress protection tests are very lax. There are also a...

Going to 48V would increase the crank/motor speed by 33%. That is more than it is designed for. V4 will be very similar to V3. Off the shelf low offset JIS square taper ebike cranks are compatible. Miranda makes 155mm i believe.

- I'll have an update with new pricing in the next few months. And only 36V batteries are compatible. Higher voltages result in motor and crank speeds that are too high. - No hot rodding allowed :-) There isn't much thermal overhead, and with a small battery more power is just going to drain...

122mm must be the BB spindle length, not the q-factor. Even pure road bikes have 150mm+ q-factor. You need to add the offset from the crank arms. At this time, the numbers I mentioned above are the only option. This is limited by the torque sensing BB.

Q-factor is about 180mm for a 73mm BB. Q-factor for a 68mm BB is about 175mm. Offset is 3mm towards the driveside. If you use an extra pedal washer or two on the non-drive side that would be pretty close to symmetrical. More info is here: Mid drive kit — Revel Propulsion Ebike Mid Drive...

The short answer is yes. I do still plan on making another batch. I can't pinpoint the date yet, but it will be this year. I'm bogged down with a few big projects right now.