My electric bikes & projects

[sendler]

Right now in New York state all electric bikes are expressly illegal and are being fined and confiscated in NYC. But there is legislation sitting in commitee that will legalize Class 1 pedal assist bikes as they are well known in Europe for many years and bring the legislation into line with what California and D.C. have already done which is to say that a class 1 e-bike is still a bike. Not a moped or motorcycle. Contact your state legislators to get all states onboard with legal e-bikes.
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https://peopleforbikes.org/
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[Stubby79]

They're perfectly legal here. Up to 500-watts. Have been as far back as they've been selling cheap chinese ones, 15+ years ago. There are some other stipulations, like needing a seat and pedals, but that's the extent of it. My other one is shaped the same as a 50cc scooter(moped, as some of you call 'em), except it has pedals, so it's legally an electric bike!

Back on topic...batteries don't appear to be completely dead. Self-discharged beyond what's safe...I'm trickle charging them at something stupidly low(safe?), ~1 watt, with a "dumb" charger. Either the charger they come with doesn't know how to deal with over-discharged batteries, or else the BMS is blocking them from charging. Probably a good thing, since who knows what will happen if you put full charging current in to a "dead" battery.



The first one has come up and stayed up. I briefly tested that the charger that came with them is now willing to charge them, but only for a few seconds. I want to bring them up gently. The second one has just started it's slow recovery. Fingers crossed, they come back to life and still retain reasonable capacity. I don't think I want to have to try and replace the cells, the way they're basically "woven" together by the bus-bars!

[Stubby79]

OooOOooh....it's a nice ride, even without electric assist. I can keep up with my kid again!

[Stubby79]

Battery charged up without complaint. Cells perfectly balanced. Bike powered up and works. Battery didn't complain with a heavy load put on it. All is looking well at this point!

It took a good 90% of full amp-hours to charge the battery, with very little heat given off by the cells. Promising. Proper battery capacity/load testing will commence tonight.

[Stubby79]

Full capacity!!

[Stubby79]

Bike works flawlessly. I move on it like I was 20 and in shape again!

[Stubby79]

Loving this little guy right now:



It's a digital DC-DC converter / Power supply -- give it power, from a battery or a fixed DC power supply, and set it to whatever voltage and current combination you want. Up to 60v DC in, up to 120v DC out, up to 15A in or out.

In the photo, I was charging a "nonoperational" 18v lithium cordless power tool pack. It was being powered by a 12v/5a power supply I have a few of. Set the final charging voltage, set the maximum current I wanted to charge at (output watts equal or less than input, of course), and just let it do it's thing.

I didn't trust it's accuracy at first, but after confirming that it was stupidly accurate (identical current and voltage readings as my best DVM), I decided I could trust it. Which is a relief...especially when dealing with lithium cells!

Lithium...my new-to-me hybrid bike has given me new appreciation for it. And I've been learning a fair bit about it. But that's a topic for another time...

[Stubby79]

I've been mostly tidying up my shop...I'm one messy pup when I get working on things. It was something to do while keeping an eye on charging batteries and staying in out of the cold...

I cooked the 24v SLA charger I was using, somehow. It survived charging the ebike batteries (though it required adding a bunch of resistance to slow it down and not overload it), and then went out on something else in spite of all the resistance I had in to slow it down. Go figure?

Took it apart this morn. Not the first charger like this I've "cooked". Found what I was looking for pretty quick...





That was a 1 ohm resistor. Seeing as I had bought two when I fixed the other charger, I still had one hanging around. Easy fix.

Adjusted the output voltage as well. It was too low for my liking...



Might help keep the batteries healthier. Probably wishful thinking. But hey, while I was in there, why not?

I shouldn't be frying any more, seeing as I rediscovered my programmable power supply. It can give me exactly the voltage and current I want to output to a battery of just about any voltage.

[Daox]

Originally Posted by Stubby79

Loving this little guy right now:

It's a digital DC-DC converter / Power supply -- give it power, from a battery or a fixed DC power supply, and set it to whatever voltage and current combination you want. Up to 60v DC in, up to 120v DC out, up to 15A in or out.

Where did you get said little guy?

[Stubby79]

Originally Posted by Daox

Where did you get said little guy?

Ebay. They're about $25. Search for "120v DC-DC converter 900w" and dozens should pop up.