Triple Rewind of Unite 500W Motor

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NiCads

Am thinking about my NiCads now that I'm looking to upgrade the racebike to Thundersky 12V cells. The NiCads for the racebike haven't been used at all since the Halbach Disc motor is being worked on and it's not running. So I'm looking into transferring the NiCads entirely over to this old bike and making it a dedicated NiCad machine.

Sort of a copy / paste operation so to speak, but it will save 20lbs and extend the range by doing it.

I like having "backup" with this older machine because while I'm fiddling with other stuff it's still nice to have a ride available at all times when I feel like riding.

Fun still matters with this hobby.

 

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One thing I wanted to try last year and never got around to it was to go for a different combination of Series / Parallel with SLA's and NiCads. Last year I ran a lot with 24 volts of SLA added to 24 volts of NiCad in Series and that was really easy on the SLA's, but was stressing the heck out of the NiCads. This time I tried:

Series 12V SLA + 12V SLA, then Parallel 24V NiCad (making 24V)

...in Series with:

Series 12V SLA + 12V SLA, then Parallel 24V NiCad (making 24V)

...to make up the final 48 volts.

What this does is still give the advantage of the NiCads in that they balance the SLA's and provide a sort of capacitor for them that allows for a lower effective Peukert effect. You still run into the problem of a weaker SLA cell being in Series bringing one part of the overall pack down, but since the Peukert is lower it makes things better.

With just the SLA's I'd be lucky to get 7 "solid" miles at full throttle before sagging, but this way I'm able to get 10 "solid" miles and then about 5 extra of survival energy. This configuration more efficiently uses everything. However, if I just dumped the SLA's and go all NiCad I'd get the same performance.

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Given that the racing schedule is called off it's allowing me to just use up the old stuff some more. The motor is working great, the Neodymium motor still seems solid and reliable. I'm able to pull about 37 mph on the flats with roughly 1000 watts of input which is right where I want to be. The geardown makes an enormous racket still, so it's a noisy machine to ride.

I'm just trying to use up my old SLA's... no sense in removing them yet despite their weight. (I figure another few hundred miles and they will be old enough to get rid of)

Approaching the 8,000 mile mark.

 

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All Or Nothing

Distance - 10.52 miles

Time - 22 minutes and 36 seconds

So:

22 * 60 + 36 = 1356 seconds

10.52 / (1356 / (60 * 60)) = 27.9 mph average

A typical ride. Nice that I can go 10 miles with the extra batteries on board. After 10 miles the batteries were still giving near full power, but you could feel the sag coming on.

NiCad Cell Replacement (all or nothing)

First of all... the Tenergy SubC NiCads I bought a while ago used to cost a dollar each. They now cost 60% more than before so the deal isn't that great now. (would not buy at these prices) But the education is valid for other battery types.

The point here is that cells tend to fail in an "all or nothing" manner. Either the cell is working pretty well and holding it's charge or it completely fails. Seldom have I found a cell in transition so whatever kills them off does it fast. The runt cell does not suffer long.

Last year I ran this set of NiCads at 4C and I think all that stress was a bit hard on them. With the newer wiring configuration I'm using 1.5C on the NiCads and 0.5C on the SLA's. The NiCads are rated as 10C, but that's rather optimistic I think.

SLA 18Ah -> Must deliver half of 20 amps (10 amps or ~0.5C)

NiCads 2.2Ah * 3 = 6.6Ah -> Other half (so ~1.5C)

...but it doesn't work evenly and the NiCads act a little like a capacitor and deliver energy more quickly when needed, but when you let off the SLA's then "catch up" by sloshing some energy back into the NiCads.

Nice day for a ride.

Pack Summary:

Best: A pack with full balancing circuitry

Second Best: A pack with removable cells that can be easily replaced

Worst: Rigidly built packs with no balancing circuitry (one cell can bring it down)

 

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The heat is insane this time of year. 80 degrees and 75 degree dew point at 6 am. Daytime temps up to 96 degrees and 110 degree "feels like" temperature.

I gotta get myself out of the midwest... this is a waste of time.

(long winters followed by big chunks of lost summer time)

No riding even possible... argh...

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On the positive side...

Another thread I was posting on got closed, but it ended on a humorous note:

...now there's nothing wrong with being old (I'm old too) but there is something a little messed up with all these Baby Boomers acting like they are still kids. Come on guys, let's give the kids something to own. Let's think about someone other than ourselves once and awhile. (the bigger picture)

Electric Bicycle Road Racing (EBRR) will be inherited by young people.

(and we need to be okay with that)

We don't live forever...

 

[KilroyCD]

...now there's nothing wrong with being old (I'm old too) but there is something a little messed up with all these Baby Boomers acting like they are still kids. Come on guys, let's give the kids something to own. Let's think about someone other than ourselves once and awhile. (the bigger picture)

Electric Bicycle Road Racing (EBRR) will be inherited by young people.

(and we need to be okay with that)

We don't live forever...

So you are saying that those of us who are Boomers just need to sit back in our rocking chairs and only let those young whippersnappers have a go at it? We are too old to have fun? You think that old riders and young riders cannot compete together? Or do you think that the older riders just don't have the edge anymore? Get real.
Cycling races have classes that based on age, allowing all riders to participate. That same system could be adopted for your proposed racing series.

Also, how does this correspond with the triple rewind of Unite 500W Motor? I'd say that it is more than slightly off topic. Keep it on topic or start another thread.

 

[srdavo]

I'd say that it is more than slightly off topic. Keep it on topic or start another thread.

or.... keep it to yourself.

 

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Cycling races have classes that based on age, allowing all riders to participate. That same system could be adopted for your proposed racing series.

Baby Boomers (myself included) do seem to have this thing about wanting to hang onto youth until the bitter end. It's a generational thing and it probably won't happen in future generations as they didn't grow up with such a fascination about it.

Betty White is all of a sudden "cool". (go figure)

But anyway... it might be a good idea to simply set an age limit for the 1000 watt racing class to make it clear that this is supposed to be about children racing and not adults. The whole idea of Electric Bicycle Road Racing is to give a "safe" place for children to learn the skill set involved with riding a bike on the street at some reasonably high speed (40 mph) without taking excessive risks. Adults that are competitive (50 year olds) are going to turn off children that would want to race with each other. When I started the idea of Electric Bicycle Road Racing four years ago I had no idea that so many old people would be interested.

At some point I'm going to start another thread about Electric Bicycle Road Racing to go into this deeper, but on the day I posted this it was too hot to get into it.

Today is nice and I'm thinking about going for a ride on this bike.(Triple Rewind bike) If anything interesting happens I'll report it here. (I always do)

 

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Mundane Trivia

Okay... this is more back on topic for the thread...

Went for a nice little ride, the motor was great, the batteries are working great, I even started to say to myself:

"Wow, everything is working perfectly now."

...did a few fast laps on my private track (cancelled housing development road) and was on my way home when I got a flat. There were tree cutting people in the area earlier and I suspect that a thorn got spit out into the street somewhere. I made it home okay, but once I parked the bike you could hear the sssssssssssss sound.

How's that for mundane?

 

[wcocc]

Safe,
how long can I run my 36 volt 1000 watt ebay motor at 48 volts? I had a nice half throttle run, full wot, run, maybe four miles total, I was smelling some hot batteries or something when I parked her home. Should I run this at 48 volts 18ah or 36 18 ah, controller is brushed controller 30 amp. It sure does run sweeter at 48 volts!! Any ideas to run the motor cooler? the 12 gauge wires from the motor felt warmer than normal?

 

[safe]

Should I run this at 48 volts 18ah or 36 18 ah, controller is brushed controller 30 amp. It sure does run sweeter at 48 volts!! Any ideas to run the motor cooler? the 12 gauge wires from the motor felt warmer than normal?

30 amps is too much. I run mine at ~20 amps. Using 20 amps I get a peak power output of about 1 hp. If you are using 30 amps your peak power would be about 1.5 hp and at low rpms you are probably running three times your heat tolerance.

What I did is take my controller apart and cut two of the three current limiting shunts. With only one shunt it cuts the current limit way down.

Are you using a cheap chinese controller like something you would get from TNCScooters?

Every controller is a little different, but if you can figure out how to lower the current limit you will protect your motor from excessive heating.