Fechter's Throttle Interface for RC controllers

[deecanio]

hehehehe,

well i would want one of the cables and the software for sure - Gary do you have an extra cable for sale at all?
i'll take a look at the new thread too, the parameters that are adjustable are very interesting to me, hell, usb connection and software is one of the few things i do understand

Cheers,

D

 

[MitchJi]

Hi,

Tower didn't ship it until Wednesday but it might arrive on Friday or Saturday. If not Monday or Tuesday should be good (Union City is close):

Shipped Via: United Parcel Service / United States Postal Service
Date Shipped: 25-Feb-2009
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Tracking Link(s)
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Feb 25 2009 Received at UPS Mail Innovations Origin RPF Union City, CA
Feb 25 2009 Processed at UPS Mail Innovations Origin RPF Union City, CA
Feb 26 2009 Manifested (Postage Paid)

 

[fechter]

It's here!

Man, is that thing tiny. It's about half the size I was thinking it was. The servo tester board is much larger. Guess we'll have to go surface mount on the servo tester once all the bugs get ironed out. Now to do some testing....

 

[northernmike]

Richard, don't let the small package worry you! This thing is a BEAST!

And don't worry about micro-sizing the interface board. I'd rather it be bullet-proof than micro! I mean, as long as it's reasonably sized..

SO happy to see this progressing

 

[recumpence]

It's here!

Man, is that thing tiny. It's about half the size I was thinking it was. The servo tester board is much larger. Guess we'll have to go surface mount on the servo tester once all the bugs get ironed out. Now to do some testing....

Just think of it, that tiny thing propels my recumbent to 35 mph in 5 to 6 seconds and maxes out at 42 mph and it is only using one third of its capacity mantaining that speed.

Amazing, isn't it?!

Matt

 

[northernmike]

30A = 42mph!?!

Oh my god. Richard. Get this thing going, I need to try this.

 

[deecanio]

Hi Guys,

amazing indeed Matt
Will Richard need to upgrade the caps before testing?
I'm planning on getting the same ones matt used later today and send them down to steve, Matt do you need to replace all the small caps? I'll read the thread again to see if i can answer that myself as well, but as far a i can see you replaced two of eight is that right? and which two?


Cheers,

D

 

[northernmike]

Wait, my understanding was that you could just add a bank of caps upstream of the controller and leave the board intact.

 

[GGoodrum]

The new throttle convertor board has space for 4 of these big add-on caps, so there's no need to replace what's there.

 

[recumpence]

Gary is correct. Richard's board will eliminate the need to add caps to the controller because they can be on the board.

I have replaced caps on my ESCs and just added them in-line. Both work fine.

The easiest way to add caps (without Richard's board) is to add them close to the ESC on the input leads.

Matt

 

[northernmike]

With all the excitement about testing, I'm realizing how bad I need this thing, and thought to ask how it will be made available.

Ready to run? Assemble-it-yourself kits? Empty boards, buy your own components?

 

[deecanio]

for sure it's a life saver for most of us, i didn't know it also eliminated the need for cap replacement on the esc....cool 8)
hopefully Richard will let us know whats what with the boards once he's had a chance to test it good, then gents it'll be game on

Cheers,

D

 

[GGoodrum]

I'm ready to run the boards, as soon as Richard gives me the go-ahead. Not sure about doing boards-only, kits or completed units yet. This is a helluva lot simpler than the 300+ part BMS, so we have more options.

-- Gary

 

[fechter]

I think I'm inclined to fully assemble and test the boards myself once I get all the bugs out of the design.

 

[northernmike]

That's music to my ears

 

[etard]

Yes, I would much prefer tested and ready to go, no matter what price

Richard, will it be possible to add anything else to this board, like watts, amps, and volt readings that can be sent to a small display like an elogger?

 

[northernmike]

etard, why not just use the Cycle Analyst?

I understand the desire to have a single board do everything, but we can't have it all, yet!

Think of all the things you could make an expensive, complicated box do:

BMS, charging, throttle control, regen braking, lighting including turn signals, data logging, accerometer, bluetooth interface, mp3 player, CB radio...

:wink:

Richard can I get you a coffee? How's it coming along?

 

[etard]

Mike,
I guess I'm just being a cheap weight weenie. I just figured since this board has a microchip, maybe it can be used to do more than one thing. :wink: That way all my system gets fried with one swoop.

 

[fechter]

Things are working out pretty good. I need to speed up the loop response to avoid overshoot in the current, but that's easy.

I just got the programming cable from Gary, so now I can play with the settings more.

I still need to get the components tweaked and set it up on my Vego to do some street testing with actual loads.

 

[deecanio]

Hi Richard,

I thought i might as well ask this as everyone will want to know the same thing so.............
what sort of time frame do you invisage for some V.1.0 boards to be available to ship?
I know this question is a meaningless as your still testing but can you have a best guess?

Cheers,

D

 

[fechter]

Hard to say. I'm hoping I can nail down the design this week, but things have been really busy lately. I have to go to work on Saturday this week :x It bites, but I'll do little bits at a time until I'm satisfied. Once the design is final and we make the layout changes to the board and submit it, it takes about a week for the boards to get done. Then I have to assemble and test them. I'm guessing it might take 3 more weeks, but possibly less if things go smoothly.

I'm also learning a lot about the CC controllers. Very interesting little units.
They do not have current limiting like I think of it. They have more like an electronic circuit breaker that trips and kills the output when they are overloaded. The current limiter part of my circuit should keep that from ever happening unless something fails.

The 'soft brake' feature will regenerate back into the batteries. The 'hard brake' simply shorts the phase wires and will not regenerate. The problem with the brake feature is it does not have any 'coast' mode and automatically comes on whenever the throttle gets down to near zero. As a result, I don't think the brake mode will be very useful. It can be disabled by programming.

I'm also having an issue with the throttle auto-calibration as my circuit will feed the controller a slightly lower-than-zero signal when the LVC or brake switch input is activated. I'm trying to work around that, since it would be a nice feature if it works properly. It could automatically compensate for a hall effect vs. a resistor throttle, for example.

The current limiter response is too slow I can see as I get a major overshoot before it settles down. This is easy to change, but I know it will oscillate if I speed it up too fast. This needs to get dialed in with an acutal load.

On the final versions, I can somewhat customize the current limit adjustment end points. I think the highest I can go without risking overcurrent will be around 90 amps. I think most people will never really need more than around 60A, as this is enough to overheat most motors over any length of time. For smaller controllers, the maximum end point can be made lower so the adjustment stays within the controllers limitations. I guess there could be an option for 'on-the-fly' current adjustment knob vs. a board mounted trimmer.

 

[recumpence]

Richard,

Use fixed end point setting and you won't have to worry about auto calibration.

So, is this thing scaleable? I am building a monster machine that I want a 200amp limit for.

Anyway, 90 amps is perfect for nearly all appliactions. I would love on the fly adjustability.

Matt

 

[GGoodrum]

If you are using two motors and two controllers to get to 200A, you could always use two throttle boards, fed from the same throttle.

 

[fechter]

Good news, the auto calibration was giving me problems because my bench power supply was dropping out under load. When properly calibrated, the auto calibration feature works great.

Yes, they do make a 200 amp version of the current sensor and they have them in stock.

Doing a bit of math, the current adjustment will go from about 7.5% to 95% of the sensor rating with the divider I'm planning to use. A narrower range could be done with a resistor change.

 

[recumpence]

Oh, Man, that is too cool!

Gary,

I spoke with Bob from Astro at length today. Good man! We went over quite a bit. He is excited about this prospect.

Matt