Brammo Owners Forum
Brammo Empulse Discussion => Brammo Empulse => Topic started by: Jeff on January 06, 2014, 04:05:17 PM
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This morning on the commute in there was a small traffic snarl in the rightmost lane of the bridge, with a couple tow trucks and a CHP. Imagine my surprise when I look over and see a black Empulse R sitting between the tow trucks!
I wish I could've stopped . . . rider and bike both looked ok though, thankfully. Didn't entirely look like an accident -- technical difficulties, maybe? Was it anyone here?
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Yep, that was me. I saw you go by. It was both frightening and embarrassing. The bay bridge is a MUCH different place when you're not moving.
No accident though, thankfully. I was heading into work with less battery than usual. By the time I exited the tunnel and starting climbing the western span, I had 9% left. I thought to myself, no problem, I've less that a mile to go. A few seconds later, I lost power, looked down and saw "RECHARGE BATTERY" and 0%. I was in the worst possible place on the bridge to stop. I was in the middle lane, and still climbing the bridge so I couldn't coast off the bridge. I tried rebooting on the fly, which of course did nothing. I had just enough momentum to merge over to the right and stop at a call box. I leaned the bike with my brake lever on the curb, and watched tensely as cars, trucks and busses passed within inches. Pretty frightening.
Caltrans came and towed my bike. When they started pulling heavy chains from the back of their truck, I was pretty worried they were going to do something damaging. But they were great and very careful. The driver was kind enough to go out of his way to drop me at the garage I use with a changing station.
Thankfully, everything came out ok. But it leaves me with not much trust in my battery meter. I rarely let my battery get down that far, but now I don't know where the bottom really is.
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I'm glad that nobody was hurt!
Something to keep in mind - free roadside assistance for your Empulse: http://www.brammo.com/roadside-assistance/ (http://www.brammo.com/roadside-assistance/)
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Scary!
What was the temperature? I've ridden my bike to 0 a couple of times and she still would keep going...but that was in Summer...
I don't mess around in Winter with my range...I don't like to get below 40%, unless I'm heading home. But then winter here means below freezing...
Glad you are ok...I rode the Enertia Plus across the Golden Gate Bridge...I wouldn't have liked to be stranded on the edge...the Bay Bridge is even longer with even crazier drives...eeek.
G
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Oh, and welcome to the site :)
Gavin
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I did that once. I had 9% and was going up a hill. Gave it a bit too much throttle too quickly to and get up the hill and the bms saw a voltage drop.... Due to the current increase. The batteries at that low of an SOC are at the knee and fall off fairly fast. I pulled over and let it sit with the key out and tried 10 min later.The batteries came up a bit and I rode to the nearest charge station and charged a few minutes.
I was on the edge of my range and had never done that before.
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Well that's a scary story. I have run the battery down to the wee digits several times and never noticed anything unusual in the rate of discharge.
Temps have been moderate here in the Bay Area, was probably above 50 when you crossed the bridge.
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I think Frodus hit the nail on the head - too much acceleration/draw and not enough SOC. I've never had that happen above freezing, however. Send Brammo your logs. My guess is that their SOC algorithm will be changing soon.
Also, I noticed with mine after this happened once dropping to 0 from ~25% that it would let me ride with it at 0%. I was very, very light on the throttle, however, and did not go more than a quarter mile before plugging in.
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Holy CRAP. Ugh, and of course it happened right when you get onto the old span where there's no shoulder. Glad you are alright.
On my way up to Thunderhill once I literally ran the battery down to 1% and had no issues (aside from, y'know, nearly being out of juice and rolling on frontage roads at 30 mph) . . . it seemed pretty linear to me. And it was definitely not super cold out (http://www.wunderground.com/history/airport/KOAK/2014/1/6/DailyHistory.html) today. I agree it seems like some logs the Brammo folks would want to see.
Haha if only there was a J1772 to J1772 charging cable!
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I treat the SOC gauge as I do petrol gauges: Never trust 'em!
When my battery says 10% and all the lights are flashing, I'd better be rolling into a charge station.
I HAVE run it down to 3% without incident, but it was at midnight on an Interstate and I won't do that again!
+2 on no heavy throttle at low SOC and on sending logs to Brammo. If you don't know how to send the logs, they can direct you. Just give them a call and ask for directions. Basically you load up your thumb drive on you computer, look for the files of the date you want, and copy them to your computer and then attach them to an email to Adam at Brammo. Or, Scuderia West can probably do it for you.
I ran out of gas on the same bridge at 11 p.m. and for the same reason you did (BMW gauge said I had 19 miles to empty). It was no picnic. Sure wish the Empulse had hazard flashers. Any EE guys here can give directions on how we can cook one up?
Glad you're OK.
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Very sorry that you had this experience. We do everything we can to keep this exact event from happening, but obviously it was not enough in this case for you.
You can rely on your SOC, but should also understand that unlike a fuel tank, the remaining battery capacity is dependent on how fast you're drawing it out. If you discharge the battery at a high(er) rate, then there is less usable capacity available. Maybe we could start a thread on driving techniques/considerations at low SOC (i.e. below 10%)? Here are my suggestions:
1. Make sure your firmware is updated. A lot of our firmware updates are to address "boundary case" behaviors - like low SOC, low temperature, wheel up, etc...
2. If it's cold (below 10C = 50F, for the batteries) AND you're at low SOC, know you've got a higher potential for problems.
3. Accelerate lightly and try to keep the power displayed below about 9-10 kW (which is a 1C discharge from the battery pack) to avoid any sudden drop in voltage that could trigger a cut-out.
4. Stop, and check on your smartphone for a public charge station where you can grab 15-30 minutes of charging. The rest time on the bike will allow the battery voltage to recover slightly, so you'll be less likely to have a cut-out on your way to the charge station.
I'm sure there are others...
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Yes, a hypermiling thread would be good. Brian, I believe it was you that said there's a guy up in Oregon that is famous for getting high mileage and you would try to get him to post here. I haven't seen such posts, but I could have missed them.
On my 800 mile trip to SoCal and back, I found myself holding the clutch in on long downhills and letting the bike coast to save watts. Even during shorter periods of deceleration, I would squeeze the clutch in as early as possible (if there was no traffic behind me!) and slow down very gradually, letting the clutch out to regen for any braking needed to come to a stop.
Of course none of the above would have helped on the Bay Bridge!
The main determinants of range seem to be rate of acceleration and overall speed (and ambient temperature, which I haven't figured out how to control ;)). I find I can ease on the throttle and still keep up with most cars as they sluggishly make their way from a stop. By traveling in the rightmost lane and keeping my speed just below the speed limit, I feel I can save watts from wind resistance and still maintain safety. If I'm lucky, there's a slow truck or older driver in the right lane I can get behind.
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Slow and Low....my motto with "low" SOC...with a slight modification to the Beastie Boys' song
"Slow when Low, that is the tempo"
http://youtu.be/kwenqnZnX2g (http://youtu.be/kwenqnZnX2g)
G
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'Tis the Season. I added a risky leg to a trip last weekend and nearly paid for it. I was so confident in my calculations on the way home that I spaced out and flogged it like I normally would. SoC went from 10% to 0%. The temperature was in the mid 30's. Thank goodness for the flashing lights! I noticed it and actually crept home about 4-5 more miles at 0% SoC.
Anyhow, I'm far from complaining. I just thought I'd share a little range anxiety. Heck, that's the first time I've really even come close on the Empulse. We e-moto riders have a huge advantage of our 4-wheel'd counterparts. It's far easier to hypermile; relatively speaking. My friends in their Leafs are suffering this Winter. They try to hypermile, but it just doesn't pay off for them. Since the Empulse is far less aerodynamic and way harder to accelerate slowly, we sort of get used to a total range of 55 miles with speeds around 80-100mph. Then as soon as we start doing a little simple math at around 40% SoC; we cut it back to the speed limit, accelerate slowly, and start drafting trucks...and we get another 30-35 miles. :)
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I don't think I've ever gotten more than 60 miles, even drafting trucks at 65mph in good weather...
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This happened repeatedly to me when I first got my Vectrix. I just quit expecting to have any charge left when the fuel gauge got low. Vectrix never did figure out how to address the inaccuracy of the fuel gauge. (I know I'm comparing apples to oranges - no offense to Brammo!)
This problem hasn't occurred since I swapped out the NiMH batteries for the LiFePo batteries.
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I don't think I've ever gotten more than 60 miles, even drafting trucks at 65mph in good weather...
Yeah, I think I was probably exaggerating there on second thought. I know I regularly get 55 mile range on my long commute but that's going 70mph with some drafting and short easy stints on surface streets. My short commute is a lot more aggressive with half interstate at 75-80 mph with shorts stints at 100 mph (my favorite sweeper) and then surface streets. And that chews up 35% which comes out to about a 35-40 mile range. I have a surface street route for my short commute. It would be interesting to see how I would do if I hypermiled it.
Anyhow, I should probably shut up about range until I have some proper experiments. A) I don't want to mislead future buyers and B) no one likes a fishing story. Besides, I'm not really a good data point since I rarely run the Empulse low. Consequently I'm in the throttle a lot.
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Ha - you and I are pretty similar. Range is not an issue for me usually, so I usually have multiple WOT pulls on my way to work and cruise between 75 and 80 for a good 20 miles. My 35 mile round trip gets me home with around 40%. Hypermiling doesn't add a whole lot of range for me, ironically.
But when it's cold and getting low on SOC, staying out of the throttle as much as possible is good advice.