CroBorg Super Commuter

Can you explain again how you have the CA connected and how the WAtts-up? Do you calibrate the CA during charging? Do you use a DP or a SA version? Would you calibrate using a fixed-current through the controller shunt, or using an external shunt?
 
Hook the charger up at the controller connections. Then the ca will count down.. With the watts up in line also you could see if they agree. I do this with mine, a stand alone unit. Cass
 
Alan B said:
Calibration

So today the battery was charged, and I didn't have to slow down or pedal so much on the way in. :)

But the calibration between the CA and the charge cycle on the Watts Up continues to baffle. I adjusted it a few times, but they bounce around . Usually the CA reads higher (more amp-hours) than the watts-up. Today they are 12.2 for the watts up and 12.0 for the cycle analyst. I know the watts up reads slightly low on voltage and current, so that is just about perfect agreement. They haven't agreed that well in the past. Something's not consistent.
Click to expand...

Useable capacity changes based on c rate... high current discharge will offer less capacity then lower charge/discharge. I suggest running the bike limited to 600W and see if it's closer to the watts up
 
Had a great discussion today with Venkat, the battery researcher. He had a lot of questions about the 'Borg. He was very impressed with the acceleration he observed when following me a couple of weeks ago. :)

His commute is 35 miles of mostly freeway. It would be very difficult to do it by ebike. One way would be to use a folding electric bike and use BART. I wonder how long that would take. E-bike to the E-train. :)
 
What charger do you use? Can you use it as a constant current source, or do you have another constant current source?

One of the easier and more reliable ways to calibrate your CA is to drive a constant current through the main ground of the controller to one of the phase wires, while at the same time have the controller powered. You will need to unhook your controller from the motor (to access one of the phase wires) and make the main ground accessible, while still being able to connect to the battery / power source. Then start the constant current (10A) with a low/intermediate voltage (36V). The CA will see the current as negative. You can even hook up your Watts-up in series. As long as you trust your constant current source, you could even see how well your Watts-up is calibrated. Then change the rdshunt value in the CA until it shows the correct current.

I have used the iCharger as a source for constant current, but you could also use whatever battery + load (lamps) is available to you.

gensem said:
Ok, so I was trying to calibrate the shut using Justin/Methods way.

1) I plug the CA into your controller
2) I attach a power supply to your controller 24s lipo charged to 4.1
3) I set the iCharger constant current source (Foam Cut) to 10A
4) I attach the (+) iCharger output to your main ground
5) I attach the (-) iCharger output to one of your phase leads
6) I turn on the controller to power the CA
7) I activate the iCharger to drive the constant current
8) I note the value displayed on the CA
9) I turn off the current source
10) I calculate your new CA setting and program it
11) I then repeat the test to confirm settings are +/- 0.1A
Click to expand...
 
Thanks for the suggestions. I'll have to work on calibration. I think it is pretty close, but something is inconsistent. This inconsistency is not the calibration itself and needs to be fixed before the calibration will be worth refining. There is no point in calibrating accurately yet. So what is the actual problem?

One possibility is the shunt pickoff. I've noticed on some of these controllers they pick off the shunt voltage in the wrong place, so it gets contaminated with other voltages and noise. The separate shunt would solve this problem and that might be the way to go so changing controllers does not change CA calibration. That's tempting. Could make an adapter to break the shunt wires out before they go to the CA and take them to a separate shunt. Then the DP plug will still work and it minimizes the wiring. Will consider that. Maybe look on eBay for shunts.

Ran the vest this am on low. Took 660 mAH in about 40 minutes. Not a lot of heat but definitely helped. This morning was foggy in the lowlands which usually are clear, so it was a cool ride in. It will get hot later today so I didn't want to wear the heavy jacket, so the electric vest came in very handy. This is the first time I've run the vest on low, and it is low but still useful. My arms were cool but I could feel the heat under the vest and it was enough. Broke out of the fog before going up through the park so it warmed up.

Rode past a mile or so of cars waiting for the light just past the end of the lake where they always pile up, between the speed limit dropping 50 to 25 and reaching the first stoplight for 7 miles. That's where I turn right anyway, and take the road less travelled winding through the park. :)

Ran a test with the regen the last couple of days. On the steep downhills I applied it and held it on solid. The speed settles out at about 12 mph. Strange to be going down a steep hill at a constant 12 mph, but it is kind of relaxing. It was generating about 500 watts of regen at that speed on the 7-12 percent grades. Regen was 2.3% and considering I only used it less than one mile out of 13 that's pretty impressive.
 
Clean Sweep

So today makes a week of 100% 'Borg commuting. :)

Passed 1,000 miles on the 'Borg yesterday. :)

This morning's commute used 65 watt hours per mile and took 33 minutes. It was relaxing and fun and I passed a half mile of cars at the stoplight.

Motor is 106 degrees F over the magnets half an hour after arrival. Side covers a bit cooler.

This ebike is performing really well as my primary commuter. Hal did a great job on the design! It takes things in stride, the occasional pedal strike doesn't cause any excitement, for example. Same for a bit of gravel or glass on the pavement, or a bit of moisture. The ride is pretty smooth compared to my hardtail mountain bike.

A co-worker happened to follow me down through the park a few days ago and he remarked that he could not really see the white battery covers on the road, they are not that visible either from front/rear or even from the side when the rider's legs are breaking them up. This contributes to it really looking like a bicycle when going down the road.

I checked the pack balance, still quite well balanced, most cells read 4.16 or 4.17. I have not balance charged for a long time. :)
 
Really nice weather, warmed up the last few days to hot.

Set to speed 1 this morning, came in on 9.5 amp hours instead of the usual 12.5. :) Took 10 minutes longer, too. Did the same yesterday on the way home, took about 7 amp hours. So at speed 1 the range is 25+ miles in these hilly conditions. On the flat it would be 40-50 miles.

Received a goodie yesterday from ebae, a vacuum variable capacitor good to 35 amps at 30 mhz:

DSC_5571.JPG
 
Alan B said:
Received a goodie yesterday from ebae, a variable capacitor good to 35 amps at 30 mhz:
Click to expand...

How are you going to use that?
 
Hot Controller

Today I decided to see how hot the controller was getting. Under the fairing I can't normally tell. I ran it pretty hard on the way home. Then when I arrived home I took the side cover off and took measurements:

ambient: 100F
front tire 100F
rear tire 103F
motor magnet ring 125F
motor side cover 117F
batteries 89F
24 FET controller 120F

Pretty amazing, only 20F warmer than ambient with essentially no airflow.
 
External Shunt

The external shunt from ebae showed up a few days ago. Not terribly pretty, but it should do the trick:

DSC_5573.JPG


When I get this installed it should improve the accuracy of the CA in the current and integrated current measurements. Also it will make changing the controller easier, no recalibration of the CA will be required. This one is 100A 75mV so 0.750 milli ohms.
 
Alan, love the cap!
Help me with scale though…is that, what, 10" long?
It would look awesome on your Borg I might add.
Ross
 
You nailed the length pretty close Ross. Do you have experience with these? It is a 15-750 pF 5KV 35A vacuum variable capacitor. It is photographically interesting with all that copper staying clean and unoxidized inside the vacuum. It is 8 inches long. The screw drive meshes the staggered diameter copper to adjust the capacitance while the copper bellows maintains vacuum integrity. The capacitance is not much for bypassing controllers, but it can handle pretty good RF current at high frequencies. We could use it to tune the response to controller transients. :mrgreen:

The 100 amp shunt is much smaller, less than 4 inches long. Still pretty big for an eBike. Especially once I put it in a PVC pipe for insulation.
 
Bummer, Alan.
Great e-bike day in Boston, too. I got home and still wanted more... Grabbed a fresh set of batteries and went back out for a ride. Picked up some fresh fixin's for supper & a six pack. Life is good.

I'll be riding all winter. Just out-sourced a tune-up of my spare folding bike, which I think I'll keep as a pedal-only machine. That way, I'll always have a pedal bike, no matter what the mechanical state of my primary bike. Now I turn to the task of finishing my second electric bike, because I never want to be without an e-ride. Nice project to work on as the days get shorter...

Hope you're back in the saddle Monday (holiday?)/Tuesday...
 
Monday is looking like rain, but we'll have some good weather next week also.

I'm not planning to ride in the rain, at least not at this point.

I don't want to be without ebike, so I have three. No pedal bikes left. :)

Plus the son's ebike and there is the daughter's pedal bike but I'm not likely to ride that.
 
RFID

I think I will add an RFID ignition key to the Borg. I was going to do a keyswitch, but an RFID would be more fun, and easier to mount. With the plastic covers of the Borg it will be easy to put the pickup coil on the inside and have nothing visible outside at all except perhaps an LED somewhere that indicates lock status.

So I sketched out a design and ordered a board and some keys from http://www.seeedstudio.com.

The board puts out a serial stream with the number from the key fob/card, so a small micro can decode it and release the ebrake if it matches one of the allowed keys. I already have a power on switch, so I won't change that, but even when turned on the bike won't operate until the ebrake is released. So I will program the micro to pull down the ebrake as soon as it boots up, and wait until a valid code appears, then release the ebrake. The micro can even remove power from the RFID at that point since it isn't needed again. In fact the same circuit that powers the RFID under microprocessor control can power an OPTO that pulls down the ebrake line. And there is no drain when the bike is off. It only looks for the key when the bike is turned on. It could even time out after a few minutes and shut down to save power (and ideally shut the controller/CA down as well).

To lock just turn off the power. When the power comes back on the micro again locks the ebrake waiting for the code.

I'm thinking of putting the key fob on my gloves. Could be sewn into an elastic band that is strapped on the glove, so a very innocuous brushing of the glove against the Borg plastic would arm the bike after turn-on, someone watching would not likely even notice it. A spare credit card type key can be kept in the wallet for backup.

I'm also thinking of putting a reader on the garage and using the same keys for opening the garage door. Then I won't have to carry any house or bike keys or a garage door transmitter at all around with me. Just bike lock keys and work keys.

It also looks like the keycards we use at work are the same frequency so I may be able to use that as another backup key...

Jeremy did something similar, and others have talked about doing it but I haven't seen their results. My design is a fair bit different from Jeremy's but the end result is equivalent.
 
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