Search found 4073 matches

by Jeremy Harris
Dec 13 2012 10:46am
Forum: Battery Technology
Topic: huge lipo fire , not cool
Replies: 201
Views: 19172

Re: huge lipo fire , not cool

I think that single cell charging is hard to beat for reliability, with the right components. In my case two of my single cell type chargers use high reliability DC DC converters that are pretty much protected against most possible failure modes, and probably a couple of order of magnitude more reli...
by Jeremy Harris
Dec 10 2012 10:21am
Forum: E-Bike Technical
Topic: Weird issue with Mac motor
Replies: 30
Views: 2156

Re: Weird issue with Mac motor

If you're still somewhere near me I'd happily take a look at the motor for you (for free). My guess is that it might only take a little bit of old epoxy is the slot to cause a bit of misalignment. Might even be something as simple as a replacement Hall sensor with a slightly different magnetic flux ...
by Jeremy Harris
Dec 10 2012 8:38am
Forum: E-Bike Technical
Topic: Weird issue with Mac motor
Replies: 30
Views: 2156

Re: Weird issue with Mac motor

Yes, the positioning accuracy needs to be surprisingly good for this motor. IIRC it's a 16 pole pair motor, so 360 deg of electrical rotation is just 22.5 deg of shaft rotation, which means a single degree of mechanical Hall error is a 16 deg phase error.
by Jeremy Harris
Dec 10 2012 7:30am
Forum: E-Bike Technical
Topic: Weird issue with Mac motor
Replies: 30
Views: 2156

Re: Weird issue with Mac motor

I'll lay money the controller is shutting down because it's seeing an invalid Hall sequence with throttle applied and torque removed. Looking at the way the Halls are positioned in that photo, together with the N-S transitions on the rotor magnets, I think it's quite probable that when the rotor rel...
by Jeremy Harris
Dec 10 2012 6:24am
Forum: E-Bike Technical
Topic: LiFePo4 strange behavior.Need advice
Replies: 13
Views: 941

Re: LiFePo4 strange behavior.Need advice

I agree, you need to leave the charger on for a long time to get the pack balanced. I've known a Ping LiFePO4 battery take several hours of cycling the charger on and off during the balance stage before now.
by Jeremy Harris
Dec 10 2012 6:10am
Forum: E-Bike General Discussion
Topic: Folding vrs triangle frame
Replies: 12
Views: 755

Re: Folding vrs triangle frame

The only collapsible bikes that don't give up a large degree of ride quality versus their non-collapsible equivalents are those equipped with S&S couplers, and the Ritchey Breakaway. Those two add only a small amount of weight and a large amount of extra cost in the course of gaining the ability to...
by Jeremy Harris
Dec 10 2012 5:23am
Forum: E-Bike Technical
Topic: Weird issue with Mac motor
Replies: 30
Views: 2156

Re: Weird issue with Mac motor

That's a ceramic capacitor for filtering noise from the supply line. It may be contributing to your problem, but I suspect not, as it's most likely that the Hall power supply would be noisy when the motor is under load, I'd have thought. Very slightly re-positioning the Halls *may* get rid of the pr...
by Jeremy Harris
Dec 10 2012 4:08am
Forum: E-Bike Technical
Topic: Weird issue with Mac motor
Replies: 30
Views: 2156

Re: Weird issue with Mac motor

OK, here's a theory I'm going to chuck out there, but it needs testing, perhaps by using a Hall tester wired in while the bike is running. What if the high pole count in the MAC, which makes physical Hall placement accuracy far more critical, is creating a situation where the Hall static sequence ca...
by Jeremy Harris
Dec 10 2012 3:41am
Forum: E-Bike Technical
Topic: Weird issue with Mac motor
Replies: 30
Views: 2156

Re: Weird issue with Mac motor

I've not come across a controller that shuts off if it's not delivering power before, plus if that was the cause then it should happen with every gear motor when going downhill or coasting for a while, and it's not something I've seen on any of the four different gear motors I have (TongXin, Bafang ...
by Jeremy Harris
Dec 09 2012 1:15pm
Forum: E-Bike Technical
Topic: Weird issue with Mac motor
Replies: 30
Views: 2156

Re: Weird issue with Mac motor

This has been bugging me for the past couple of hours, as I can't for the life of me think why the controller should do this. The MAC clutch should mean that there's no possibility of regen on over-run, so that can't be the cause, unless the clutch is sticking a bit. What voltage are you running at?...
by Jeremy Harris
Dec 09 2012 8:45am
Forum: E-Bike Technical
Topic: In-hub steering
Replies: 31
Views: 9137

Re: In-hub steering

bobc wrote: I'll find out the name of the black structural foam core we used, short name starting with D that I can't recall....
Depron?
by Jeremy Harris
Dec 09 2012 5:06am
Forum: E-Bike Technical
Topic: Wood Bike, 100kph? on a budget
Replies: 29
Views: 3949

Re: Wood Bike, 100kph? on a budget

That looks bloody marvellous! I'm even more looking forward to seeing how this turns out now. Paulownia is an interesting choice, especially as it's such an all around useful tree, fast growing, light, easy to work, can be sustainably harvested (it grows back from the roots once felled) etc. It's a ...
by Jeremy Harris
Dec 09 2012 4:57am
Forum: E-Bike General Discussion
Topic: Sexy Practical Velomobile?
Replies: 59
Views: 11808

Re: Sexy Practical Velomobile?

The velo and trike come from two separate UK companies, Ocean Cycle (http://oceancycle.co.uk) make the velo body and Inspired Cycle Engineering (http://www.icetrikes.co/) make the trikes (and by coincidence I used to live close to their original factory, years ago). I dealt very briefly with Ocean C...
by Jeremy Harris
Dec 09 2012 4:30am
Forum: EV Business World
Topic: A123 Systems: 'No assurance' it can continue to operate
Replies: 193
Views: 26604

Re: A123 Systems: 'No assurance' it can continue to operate

Well, there it is then... Wanxiang wins auction for assets of battery maker A123 A source close to the deal said the purchase price was about $250 million. Wanxiang excluded from the purchase A123’s U.S. government and military contracts. The idea behind that move was to blunt concerns raised by po...
by Jeremy Harris
Dec 09 2012 4:06am
Forum: Alternative Energy
Topic: BMS as solar panel charge controller ?
Replies: 32
Views: 8169

Re: BMS as solar panel charge controller ?

There's normally no problem with just turning off a PV panels electrical connection, even when it's running at full power. The panel will run a little warmer, as it will be absorbing an additional 15% or so of heat energy that would have been taken away as electrical power, but this won't have a big...
by Jeremy Harris
Dec 08 2012 5:19pm
Forum: E-Bike Technical
Topic: New Keyde rear roller motors
Replies: 40
Views: 7909

Re: New Keyde rear roller motors

Yes, they don't work well at high torque levels. If you keep the speed down though they are OK on hills, the real problem is that they heat up fast at anything over around 10A for any length of time. Not surprising really, as they are pretty small. For me this isn't a big issue, as I rarely climb an...
by Jeremy Harris
Dec 08 2012 4:59pm
Forum: E-Bike Technical
Topic: 20in rear electric hub bmx
Replies: 30
Views: 1546

Re: 20in rear electric hub bmx

Thanks for that, I didn't realise that BMXs had narrow rear dropouts. Too old I guess, as they came along long after my youth.........
by Jeremy Harris
Dec 08 2012 4:55pm
Forum: E-Bike Technical
Topic: New Keyde rear roller motors
Replies: 40
Views: 7909

Re: New Keyde rear roller motors

Hmmmmm.........If I could order from Justin I might just do it. Worth the extra money for some peace of mind. I really would like to get the 9C discus off my rear suspension and also get back the freewheel. I found out how draggy those motors are even when the Phase wires are unplugged on our last ...
by Jeremy Harris
Dec 08 2012 4:50pm
Forum: E-Bike Technical
Topic: Powering microcontroller using 5v from controller
Replies: 3
Views: 359

Re: Powering microcontroller using 5v from controller

Yes, regulator and the pre-regulator dropper heat dissipation is a potential problem if you draw more than a few mA extra from the 5V line. The real problem is that the dropper resistor in front of the first stage voltage regulator (the 12V FET drive supply) is very load sensitive, and the 5V regula...
by Jeremy Harris
Dec 08 2012 4:43pm
Forum: E-Bike Technical
Topic: 20in rear electric hub bmx
Replies: 30
Views: 1546

Re: 20in rear electric hub bmx

fasteddy88 wrote:ok ill stick with the hub then. where can i get a hub motor for my single speed 20in?
The Nine Continents 2805 is available in a 20" wheel from ebikes.ca. They can also sell you a good controller for it as well, and most of the other parts you need, like torque arms, throttle etc.
by Jeremy Harris
Dec 08 2012 4:39pm
Forum: Motor Technology
Topic: 20kW Powerstage for "Infineon" 12 mosfet Controller
Replies: 118
Views: 8454

Re: 20kW Powerstage for "Infineon" 12 mosfet Controller

I was trying to follow the xiechang plus bigger fets because I thought it was the easiest. What I need is some programmable brain, good fets, phase current limiter, pedal sensors, torque and cadence, and a brake cutoff... LFP Did you see the 3D pdf on the first post? Lebowski's chip is a pretty goo...
by Jeremy Harris
Dec 08 2012 1:34pm
Forum: Motor Technology
Topic: 20kW Powerstage for "Infineon" 12 mosfet Controller
Replies: 118
Views: 8454

Re: 20kW Powerstage for "Infineon" 12 mosfet Controller

Great input so far, thanks. Jeremy, three questions: - a 36 fets XieChang controller will also only supply ~100mA??? (if so :P) - Can you supply info, datasheet, pinouts, etc of the xiechang stuff? Can't find them around here... - As anyone tried your "NCP5181" solution? Seems to be an intelligent ...
by Jeremy Harris
Dec 08 2012 12:21pm
Forum: Battery Technology
Topic: Cheap programmable bms
Replies: 24
Views: 2120

Re: Cheap programmable bms

Be nice to see what's in the programmer. My guess is that it may be nothing more than some software and a USB to serial interface.
by Jeremy Harris
Dec 08 2012 11:13am
Forum: E-Bike Technical
Topic: 20in rear electric hub bmx
Replies: 30
Views: 1546

Re: 20in rear electric hub bmx

If you do a search here you'll find a few threads where people have stripped out DeWalt and Makita packs for the cells. It's an expensive way of getting cells if you buy new, even with a discount, but can be cheap if you can find a power tool repair place that will let you have dead packs. A few fol...
by Jeremy Harris
Dec 08 2012 10:57am
Forum: E-Bike General Discussion
Topic: Pulsing problems with Gng kit and 9 fet lyen controller
Replies: 34
Views: 1455

Re: Pulsing problems with Gng kit and 9 fet lyen controller

My guess is that the bad cell was making the BMS trip every time any appreciable current was drawn from the pack. Might be an idea to find out why the cell died before replacing it. If the BMS was doing its job and the charger is working OK, then a cell shouldn't have just failed like this, unless i...