Author Topic: Empulse Rider Questions  (Read 6363 times)

Shinysideup

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Empulse Rider Questions
« on: December 28, 2012, 10:46:49 AM »
Moving some stuff from the mods thread to this new one:

Q: (Shinysideup)

Today I ran the battery down to 15% for the first time, and, when accelerating up a long hill, I noticed some brief, partial cut outs. No cut outs, really, but more like a brief, subtle rapid stutter, with no degree of power loss that was concerning me, just noticeable. Probably some low voltage sensor getting tweaked at the current I was demanding. If this is something that shouldn't have happened, please let me know. Otherwise I can easily live with it.

How can I adjust the suspension so it is the softest possible, reacting as quickly as possible to sharp changes. On the rear shock and the front forks there are screws with + and - signs on them. I turned everything as far as possible toward the negative and the ride was a bit smoother, less harsh. Any suggestions on how to turn this magnificent sporting machine into a water bed? A Gold Wing? OK, something softer than it came to me?


A: (BrammoBrian)

Given that the ambient temperature is still rather low, meaning the batteries will be relatively cold, and you were accelerating up a hill with low SOC, I would guess what you felt was the low voltage protection kicking in.  If you are at a low SOC (State of Charge), then the voltage on the battery pack is also low.  For the same power, you now require the pack to deliver more current.  When you deliver this current, the pack voltage "sags" or drops.  If any of the cells reach below about 3.0Vdc for more than a short period of time, then the motor controller will start reducing current to prevent the pack from being damaged. I'm guessing that once you made it to the top of the hill or to a flatter section, the issue went away as the current demand (and thus battery voltage sag) were not as high.  Managing the battery at low SOC becomes quite difficult as the capacity remaining depends heavily on how it will be drawn out.  We, of course, try to leave a safety margin there so you do not experience the protection scheme above single digit SOC, but it is difficult to account for every situation.  When you return to Scuderia for your first service, they can pull the log file and verify this is what was going on.  They will be able to see recorded ambient temperature, speed, battery voltage, current, motor controller parameters, throttle position, and any error codes or flags. The diagnostic tool set for the bike is pretty impressive (IMHO).

Point taken on the streets in SF.  The Empulse R does have adjustability in the suspension, but it's still on the "sporty" side rather than the "plush" side.  Getting the bike to the Goldwing setting may not be possible.  Next steps I would recommend would be looking at dropping tire pressures ever so slightly or changing to a less sporty, year-round tire that has a bit more compliant side wall.  In the meantime, I'll ask Aaron Bland, suspension guru, if there's more that could be done on the settings from what you've already described.

BrammoBrian

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Re: Empulse Rider Questions
« Reply #1 on: December 28, 2012, 03:17:12 PM »
Regarding the use of the 12Vdc accessory port...

The DC-DC converter is rated for 276W continuous, and 336W peak (2 minutes).

The bike's normal operation consumes 217W (with a margin).  This leaves 59W (about 5A) for Auxiliary devices.  The fuse on the line is 10A. 

My take is that we could easily run heated gloves/grips and most likely a heated jacket, but not both at the same time.  Hope that clears things up.  We'll have more detailed info like this in the official release of the manual.  Thanks for your patience! 

Shinysideup

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Re: Empulse Rider Questions
« Reply #2 on: December 28, 2012, 04:14:24 PM »
Thanks, Brian.

I just got this in my email:

"The accessory port provides approximately 100W @ 12VDC which should be just fine to run your heated jacket. It might be a push to run both your jacket and gloves. Let me know if you have any additional questions.

Happy riding,

Adam Lukoic
Service Manager
Brammo Inc."

My guess is that I'll probably be finding out where that fuse is!

I'm thinking you might want to increase the capacity of that converter by about 100W, if it fits. :-\
« Last Edit: December 28, 2012, 04:29:05 PM by Shinysideup »

flar

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Re: Empulse Rider Questions
« Reply #3 on: December 28, 2012, 04:45:38 PM »
[Edited to remove bad math due to misreading...]

My only current plan for the accessory socket is a garage door opener...
« Last Edit: December 29, 2012, 05:20:08 AM by flar »
Current bikes: 2013 Brammo Empulse R, 2005 BMW R1200RT
Prior bikes: 1988 Honda Hawk GT, 1997 BMW F650
Future bikes: something with 300 mile range and 0-60 faster than a liter sport bike?

BrammoBrian

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Re: Empulse Rider Questions
« Reply #4 on: December 29, 2012, 03:52:47 AM »
100W would mean a consumption of 1.2kw. 

100 Watts would mean a consumption of 100 Watts, maybe you were thinking 100 Amps?  If you rode for one hour, it would be 100 Watt-hours (100Wh).  Given that the battery pack is 9,300 Wh (nominally), then the use of 100Wh would cost you about 0.8 of a mile (based on 121Wh/mile) in range if you used the full battery capacity on a ride. 

This is a good opportunity to show why it's not such a big deal to have an LED headlight (if an affordable one existed)...

Current headlight = 55 Watts
Theoretical LED headlight = 20 Watts
Savings = 35 Watts

Ride for one hour, you've saved 35 Watt-hours = 1,530 ft (.29 mile) in additional range.  Every little bit counts, but it's still a relatively small improvement versus some of the other ways of improving overall system efficiency... 

BrammoBrian

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Re: Empulse Rider Questions
« Reply #5 on: December 29, 2012, 03:55:31 AM »
"The accessory port provides approximately 100W @ 12VDC which should be just fine to run your heated jacket. It might be a push to run both your jacket and gloves. Let me know if you have any additional questions.

My calculation had some margin built into it, so Adam and I are still in agreement.  100W should be just fine.

flar

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Re: Empulse Rider Questions
« Reply #6 on: December 29, 2012, 05:17:56 AM »
maybe you were thinking 100 Amps?  If you rode for one hour, it would be 100 Watt-hours (100Wh).  Given that the battery pack is 9,300 Wh (nominally), then the use of 100Wh would cost you about 0.8 of a mile (based on 121Wh/mile) in range if you used the full battery capacity on a ride. 
Indeed, I'm not sure why I was thinking amps.

And it would only cost about .5 miles at 70.

For me, the city range is uninteresting because I'm not likely to do 120 miles at city speeds.  I'm much more likely to be range limited at highway speeds...
Current bikes: 2013 Brammo Empulse R, 2005 BMW R1200RT
Prior bikes: 1988 Honda Hawk GT, 1997 BMW F650
Future bikes: something with 300 mile range and 0-60 faster than a liter sport bike?

Shinysideup

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Re: Empulse Rider Questions
« Reply #7 on: January 12, 2013, 01:07:05 AM »
After riding the Empulse for a couple of weeks now in heavy traffic, I have an idea for an improvement.

The braking that comes from regen, especially the stronger version in "Sport" mode, is very effective in slowing the bike down. It's so effective that, especially on the freeway, I was cautious to back off the throttle without dabbing my brake pedal to flash the brake lights.

It occurred to me that the electronic geniuses at Brammo could monitor the regen current, and when it exceeds a certain threshold, have the circuit turn on the brake lights, preferably with a quick flash or two before a steady on, until either the brake is also used, or until the regen is no longer engaged.

No need to send me royalties for my idea!~  :-\

skuzzle

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Re: Empulse Rider Questions
« Reply #8 on: January 12, 2013, 04:24:01 AM »
Quote
No need to send me royalties for my idea!~  Undecided
Sorry Tesla does this already.  From an autoweek Tesla S review:
Quote
Part of the reason that the brakes feel so natural is the Tesla's approach to regenerative braking. Unlike many manufacturers, regeneration isn't controlled by the brake pedal at all--it's handled solely by the accelerator. Let off the pedal slightly, and the car begins meting juice back into the pack. Remove your right foot entirely and the sedan generates electricity at its maximum rate. A gyro measures the rate of deceleration and flicks on the LED brake lights accordingly.

Read more: http://www.autoweek.com/article/20120625/carreviews/120629886#ixzz2HketZGO0

implovator

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Re: Empulse Rider Questions
« Reply #9 on: January 12, 2013, 11:33:27 AM »
That is a great idea, and it's diminished none by the fact that the Tesla guys beat you too it. I've owned a few big twins and I use my brakes very little around town or on the interstate, so I always get in the habit of tapping the brake lights. It's really tough for cars to judge the distance and speed of motorcycles so I think this idea could be applied to all motorcycles.

Shinysideup

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Re: Empulse Rider Questions
« Reply #10 on: January 12, 2013, 01:21:42 PM »
A gyro measures the rate of deceleration and flicks on the LED brake lights accordingly.

Weird they would use a gyro rather than just monitor the rate of flow back into the battery pack. But then I guess that's why I'm a RN and not an EE.

Oh well, there goes THAT $Million. :(

7racer

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Re: Empulse Rider Questions
« Reply #11 on: January 12, 2013, 03:31:55 PM »
I have a Tesla Roadster and it actually makes a lot of sense.  The reason is sometimes if you are at speed and you let off the "gas" pedal a bit, you slow but still have forward momentum and speed.  This is more like if you let off the gas pedal in a normal ICE car but you are still traveling forward.  The problem if it was not using a gyroscope is that the taillights would keep coming on and the people behind you would think you were riding your brakes. 


Shinysideup

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Re: Empulse Rider Questions
« Reply #12 on: January 14, 2013, 01:41:21 AM »
The reason is sometimes if you are at speed and you let off the "gas" pedal a bit, you slow but still have forward momentum and speed. 

But if you let off "a bit", wouldn't there be very little current flowing back into the pack? That's why I thought the process could be more simply monitored by having a current threshold that would have to be exceeded before the brake lights come on. But Tesla probably knows what they're doing! (Lucky you, owning the Roadster!)

flar

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Re: Empulse Rider Questions
« Reply #13 on: January 14, 2013, 02:17:54 AM »
Power generated would vary by speed as well as amount of drag (deceleration), so it probably wouldn't directly correlate.  Also, a small power output while climbing a hill might not tell the whole story when gravity is responsible for additional deceleration.

If I were going to base the tail lights on something that could already be measured, I'd probably base it on the change in the speedometer, but even that could be fooled by varying traction conditions.

A gyro would give a reliable measure regardless of a lot of conditions that might fool other sensors...
Current bikes: 2013 Brammo Empulse R, 2005 BMW R1200RT
Prior bikes: 1988 Honda Hawk GT, 1997 BMW F650
Future bikes: something with 300 mile range and 0-60 faster than a liter sport bike?

Shinysideup

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Re: Empulse Rider Questions
« Reply #14 on: January 14, 2013, 10:36:58 AM »
Power generated would vary by speed as well as amount of drag (deceleration), so it probably wouldn't directly correlate.  Also, a small power output while climbing a hill might not tell the whole story when gravity is responsible for additional deceleration.

If I were going to base the tail lights on something that could already be measured, I'd probably base it on the change in the speedometer, but even that could be fooled by varying traction conditions.

A gyro would give a reliable measure regardless of a lot of conditions that might fool other sensors...

Thanks. That makes perfect sense. And I guess, gyros are not as costly or complex as I first imagined, since there's probably one in my iPhone.
« Last Edit: January 15, 2013, 01:11:57 AM by Shinysideup »