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Author Topic: Top speed at Sport mode reduced?  (Read 1069 times)

ChainGun

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Top speed at Sport mode reduced?
« on: January 05, 2016, 07:02:49 PM »

Hi all.
I ride a 2015 Zero S. Recently, on two separate occasions, I've noticed situations in which I opened the throttle fully on a flat, open, road but the bike refused to go above 75 MPH. I've seen it reach 93 MPH several times in the past (and since) so I can't understand this behavior. The only explanation I can think of is that my tank was at ~30%, maybe the bike is programmed to prevent me from riding too fast when the tank is low? It wasn't overheating, there was no heat indication and in the past when I encountered a heat warning I was at 75 MPH. The weather was chilly, but Israel chilly is considered hot in some parts of the world :)

Any ideas?
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Electric Terry

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Re: Top speed at Sport mode reduced?
« Reply #1 on: January 05, 2016, 07:40:59 PM »

The less total battery capacity you have, the lower the state of charge, and the colder the temperature will all make it hard on the battery to discharge high current.

Keep it charged as full as possible in cold weather is the best advice.

What size battery does your bike have? Do you have a powertank?
« Last Edit: January 05, 2016, 07:45:51 PM by Electric Terry »
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vkruger

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Re: Top speed at Sport mode reduced?
« Reply #2 on: January 05, 2016, 10:57:40 PM »

Double check the mode programming to make sure something didn't get changed.
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ChainGun

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Re: Top speed at Sport mode reduced?
« Reply #3 on: January 06, 2016, 04:22:55 PM »

Double check the mode programming to make sure something didn't get changed.

Nothing was changed. Today I rode at 93 MPH with no problem. Not sure why sometimes I'm blocked at 75 MPH.
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Richard230

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Re: Top speed at Sport mode reduced?
« Reply #4 on: January 06, 2016, 09:37:52 PM »

I have had my custom programming revert to the "eco" programming a couple of times while I was riding in humid weather.  The custom programming returned when I turned the ignition off then back on.  That only happened a couple of times last year when it was very foggy and the humidity was around 100%.   ???
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Richard's motorcycle collection:  2014 14.2 kWh Zero S, 2016 BMW R1200RS, 2011 Royal Enfield Bullet 500 Classic, 2009 BMW F650GS, 2005 Triumph T-100 Bonneville, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior.

Doug S

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Re: Top speed at Sport mode reduced?
« Reply #5 on: January 07, 2016, 12:35:40 AM »

I had a similar experience fairly recently. I was finishing a ride, almost home, and punched the throttle hard on the freeway just for a quick thrill even though I was getting somewhat low on charge. Nothing happened, which surprised me greatly. A couple more tries gave me no more than freeway speed (~75 mph). After charging it was back to its full-power self.

I don't recall exactly, but I think I was somewhere around 25% charge at the time, and I think that's the answer. I do think below something like 30% SoC, the controller limits you in some way (maximum speed and/or power), either to protect the batteries (which are getting weak), or to maximize range. Hopefully it's just to protect the batteries; I'm the rider and will handle managing my range so I can home, thank you.
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PhreaK

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Re: Top speed at Sport mode reduced?
« Reply #6 on: January 07, 2016, 09:26:58 AM »

If you have a look at your logs, you'll see the bikes do impose discharge current limits. The reduced current output translates directly to decreased torque.

I don't have the details of the exact factors which play into this but I assume it's a combination of minimum cell voltage and cell / controller temps. In general though, it appears to kick in from ~70% SOC downwards on most of the bikes I've seen. Nothing to worry about, it's just your BMS doing it's job.
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ChainGun

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Re: Top speed at Sport mode reduced?
« Reply #7 on: January 07, 2016, 06:16:58 PM »

I had a similar experience fairly recently. I was finishing a ride, almost home, and punched the throttle hard on the freeway just for a quick thrill even though I was getting somewhat low on charge. Nothing happened, which surprised me greatly. A couple more tries gave me no more than freeway speed (~75 mph). After charging it was back to its full-power self.

That's my experience exactly.
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NoiseBoy

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Re: Top speed at Sport mode reduced?
« Reply #8 on: January 09, 2016, 05:09:07 AM »

If you have a look at your logs, you'll see the bikes do impose discharge current limits. The reduced current output translates directly to decreased torque.

I don't have the details of the exact factors which play into this but I assume it's a combination of minimum cell voltage and cell / controller temps. In general though, it appears to kick in from ~70% SOC downwards on most of the bikes I've seen. Nothing to worry about, it's just your BMS doing it's job.

I have seen this in my logs too.  Its really crappy though because I didnt intend to pay so much money for a bike that is only fast for the first 20 miles.
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oobflyer

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Re: Top speed at Sport mode reduced?
« Reply #9 on: January 10, 2016, 05:38:21 AM »

This just happened to me for the first time (top speed dropped to 75 MPH @ 50% SOC). I've ridden on a Zero for four yeas (three years on a 2012 S-ZF9, one year on a '15 SR) and only experienced power loss previously when the battery pack SOC was near 0%.

The only thing I did differently this time is change my charging pattern - after reading the recent thread from the battery manufacturer: 
http://electricmotorcycleforum.com/boards/index.php?topic=5314.0


After losing power this morning I charged the battery back up to about 85% and took it for a spin - all of the power was restored.

I think I'll go back to leaving the thing plugged-in  ;-)

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JasonS

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Re: Top speed at Sport mode reduced?
« Reply #10 on: April 21, 2017, 10:37:33 PM »

Sorry for the late reply on this old thread, but I have some recent experiences here that may be relevant.

The language of the OP says that on two occasions  the the bike refused to go above 75mph.  This is a suspicious figure to me, because I know that ECO mode imposes a limit at 75mph [edited: JaimeC, below, is correct - ECO mode imposes a 70mph limit, not 75 - I mis-remembered as I'm rarely in that mode - Jason], and you can define your own in custom mode.  When you hit this limit, it's like a hard stop.  It just doesn't go faster.  What you do to the throttle really doesn't matter (except if you decrease it enough to allow it to slow down), and the throttle response feels normal right up until you hit that magic figure, 75mph.  If the OPs choice of words were precise, I'd suspect something goofy happened with the mode the bike was in, or the mode it thought it was in.

Recently, my onboard charger failed (Dec '16).  It took about a month to get it to the dealer (thanks to Christmas vacation schedules and such), and during that time my bike sat at ~60% SOC (that was how high it got the night the charger failed.).

When I rode it to the dealer it had decreased to about 56%.  It was chilly that day - 40's I think, but bear in mind I ride year-round, 50miles round trip, sometimes in even colder weather (but usually hotter!)  I experienced something that has never happened to me on the bike before. The power of the bike kept dropping.  At the start of the leisurely 30-35 mile ride, I had to do about three or four miles in interstate.  My top speed was fine - maybe I was having a hard time at around 75 or 80, but I really wasn't trying to go faster. (I wanted to take it easy, because it was chilly, and was longish ride to start out a 56%).  The rest of the ride was back roads as I wiggled over to Conroe, TX, which I anticipated doing at mostly 50-60mph.  Over the course of the trip, though, my top speed got lower and lower, finally limping along with a max speed of ~35mph, with an associated loss of power/acceleration (i.e., I wasn't hitting a limit at 35, it was just running out of oomph.)  I think my SOC on arrival was around 20-25%, but I don't have that written down. 

Since the charger incident, I've been back in the dealer a few times for follow ups on this, and it still hasn't been resolved, though sometimes it's not so pronounced. 

Before this incident, I've had the bike down into the teens, (and even single digits once or twice!) while exploring the limits of the bike, and not seen this kind of behavior.  Conversely, last Friday (Apr 14) I got home from my commute with 15%SOC (dramatically lower than normal for my 50mile round trip, which used to land me home at ~35% pretty consistently), and the bike was topping out at 25mph.  That was scary.  I was having a 'Fred Flintstone' moment, where I had a strong urge to help paddle with my feet!  (The least exciting drag race ever: I pulled away from a stop sign, went full throttle, and by the time I got to my street, about 1/8 to 1/4 mile away, I was bumping along at 25mph.  Still full throttle.)

Anyway, when this type of powerloss/speed limit is imposed, it feels quite different from the 'governor' type limit.  When you crank on the throttle, it just feels like the bike's power output sags.  Almost like at a certain point (which moves as it gets progressively worse), increasing the throttle further causes a slight reduction in power, and then further movement has no effect whatsoever.

I'm still collecting logs and data as I discuss this with Zero.  They're telling me this is normal, and I'm saying "BS!"  I think I have a new battery pack in my near future, or at least a cell replacement or two, because at this rate (I'm currently at 197-- miles, just over two years old), there's no way it's gonna make it to five years/300,000 miles. 

Incidentally, at this moment, the bike is sitting at 63%, and my cell balance (per app) is wiggling from 10-12mv.  I'll check again when I get home.


« Last Edit: April 22, 2017, 09:22:27 AM by JasonS »
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JaimeC

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Re: Top speed at Sport mode reduced?
« Reply #11 on: April 22, 2017, 01:45:42 AM »

Just a note here but in Eco mode my "S" tops out at an indicated 70 mph, NOT 75 mph.  Did that change from previous years, or was that a mistake in the post above?
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JasonS

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Re: Top speed at Sport mode reduced?
« Reply #12 on: April 22, 2017, 09:23:53 AM »

Thanks for keeping me honest, Jaime.  I checked on the way home today, and you're right; mine, too, limits at 70 in ECO mode. 

I've updated the post above for the benefit of anyone who doesn't read beyond that point.
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JaimeC

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Re: Top speed at Sport mode reduced?
« Reply #13 on: April 22, 2017, 06:05:16 PM »

Thanks for keeping me honest, Jaime.  I checked on the way home today, and you're right; mine, too, limits at 70 in ECO mode. 

I've updated the post above for the benefit of anyone who doesn't read beyond that point.

I'm very familiar with that mode because I set it to Eco mode just before getting on to the highway.  My commute is pretty much all highway, so I maximize my range by putting it into Eco mode, lying down on the "tank" and just holding the throttle open to the stop.

The speed limit here is 55mph, but in reality the AVERAGE speed everyone does is 70mph.  One of the things I was looking for when I bought the Zero was that it had to be able to sustain 70mph for a 34 mile round trip.  The 13 kWh battery gives me MORE than enough breathing room to take a ride at lunch time and take rides after work too.

When I'm on surface streets I use "Custom" mode set to 100% power/100% regen.  That way I have more than enough acceleration for traffic lights and I can save my brakes by just using the regen to slow.  It's worked VERY well and based on what I've seen in the "Tire Life" thread I'm also getting far better tire life than a lot of other Zero riders too.
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1999 BMW K1200LT: For everything else

nevetsyad

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Re: Top speed at Sport mode reduced?
« Reply #14 on: April 22, 2017, 06:15:24 PM »

This is my newest problem also. 60-70MPH top speed while at 64% SOC on my 2015 SR. Voltage drops to 92.5v. Check your logs, you'll probably see "Batt Dischg Cur Limited" often. They recommend a firmware update, but say this isn't unusual. Lovely.

07615     01/11/2017 14:26:18   Riding                     PackTemp: h 19C, l 19C, PackSOC: 64%, Vpack: 92.516V, MotAmps: 148, BattAmps: 188, Mods: 10, MotTemp:  69C, CtrlTemp:  26C, AmbTemp:  15C, MotRPM:4564, Odo:12518km
07616     01/11/2017 14:26:18   Batt Dischg Cur Limited    199 A (28%), MinCell: 3249mV, MaxPackTemp: 19C
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2015 Zero SR (4+ months in the shop), 2016 Zero S (Random freeway shutdown, heading to shop soon)
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