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2018/2019 Electric Bus Project


Express691

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Why am I not surprised that both buses are 5-10 min behind schedule while the others running on the 100 are running the typical 0-3 min? Sure one could argue that both faced heavy loads and delays, but the ~5 min charge time is most likely the reason they're running late. Hopefully they add another couple blocks in the near future to fix this.

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On 1/26/2019 at 6:34 PM, Millennium2002 said:

It'd be very cool if they could integrate charging into the existing trolleybus infrastructure... but don't the trolleybuses run at a lower voltage? From what I can gather from Siemens and ABB, the voltage required to quickly charge a bus can go up to 1000 volts DC; on the other hand, the trolleybus network is fed 600 volts DC? Can the existing wires, rectifiers, relays, etc. handle such a bump?

 To answer some previous technical questions, I found some information at yesterday's launch. The voltage supplied to the battery buses is 480V DC. The transformer has a maximum power rating of about 500kW - I can't be more precise because the rating plate says 500kVA which isn't quite the same as 500kW because you need to know the efficiency to convert kVA to kW. But it's powerful.

At the presentation the cost of each charging station was quoted at $1m. The system probably needs one fast charger for every 3 or 4 buses so the system is not cheap.    

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On 9/12/2019 at 8:44 AM, 8010 said:

Why am I not surprised that both buses are 5-10 min behind schedule while the others running on the 100 are running the typical 0-3 min? Sure one could argue that both faced heavy loads and delays, but the ~5 min charge time is most likely the reason they're running late. Hopefully they add another couple blocks in the near future to fix this.

And this is why there is a testing phase.

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43 minutes ago, 9924 said:

2 weeks into testing?  Pretty sure that's a bit too early to come to any conclusion.

There were some issues before launch, hence the reason why the whole pilot was delayed until September. I wouldn't be surprised if there's still some issues here and there, this is still relatively new technology, especially for TransLink and CMBC.

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I was away last week, so I resumed my BEB hunt this afternoon. I went to 22nd Street Station and luckily 19302 arrived fairly soon after I arrived. I managed to chat to the driver and some of his colleagues at the charging station so I'll divide my report into two sections: driver information; and personal impressions.

i) 19302 arrived with only two minutes before its departure time at 17.01

ii) the driver said that the bus consumes about 40% of its battery charge on a one way run.

iii) charging from 60% to 100% charge takes about 10 minutes

iv) Management require drivers to charge at each terminal -even if the bus is already late.

v) Management is proceeding cautiously with their introduction. One of the other drivers said "they don't trust them (yet?)" 

vi) Another driver said they will soon be doing some experimental night runs.

vii) The driver didn't think the BEB required a change in driving style. He thought that "take off" was a bit less than normal, but I suspect that engineers have deliberately restrained the acceleration rate.

My overall impression is that is an very good bus. It is quiet and smooth and performed well on the route. However I do have the following observations:

- There does seem to be an element of brake snatch both at slow speed stopping and also speed changes at normal road speed. There is a technical reason for this: These BEBs use Permanent Magnet Motors, which means that as soon as the driver takes his foot off the "gas pedal", the bus immediately switches into braking mode. In contrast Translink's trolleybuses use Induction Motors, which are capable of allowing the bus to coast until the brake pedal is depressed. This gives a smoother  transition from say driving at 50kph, coasting to slow down to say 40 kph and then applying the brakes on approach to a red light. 

- on this outing there was an annoying high pitched whine from a unit in the roof behind the driver's cabin. I had not noticed this on launch day.

As has others have said, teething problems are inevitable at this stage. The main thing is to collect experience, data etc over the long term of the trial.

 

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6 hours ago, martin607 said:

Permanent Magnet Motors, which means that as soon as the driver takes his foot off the "gas pedal", the bus immediately switches into braking mode. In contrast Translink's trolleybuses use Induction Motors, which are capable of allowing the bus to coast until the brake pedal is depressed.

Wonder why this is. One would think that coasting would be an advantage in order to get more mileage without using up battery power. Nothing like a good coast on a trolley !!!

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1 hour ago, captaintrolley said:

Wonder why this is. One would think that coasting would be an advantage in order to get more mileage without using up battery power. Nothing like a good coast on a trolley !!!

Sounds like the bus is regenerating some of the power used for propulsion when braking.

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2 hours ago, Peterbiltguy1989@gmail.com said:

Sounds like the bus is regenerating some of the power used for propulsion when braking.

Yes, it switches immediately to regenerative braking, but that causes the brake snatch feeling -it's not smooth. In contrast a bus with an  induction motor can coast, just slowing down naturally and then either brake or pick up speed again as traffic conditions dictate.

I've experienced this in electric cars. The VW eGolf allows coasting but the BMW i3 switches immediately to rather fierce regenerative braking.

Technically, coasting can be more energy efficient as there are none of the electrical conversion losses present with regenerative braking.

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27 minutes ago, martin607 said:

Yes, it switches immediately to regenerative braking, but that causes the brake snatch feeling -it's not smooth. In contrast a bus with an  induction motor can coast, just slowing down naturally and then either brake or pick up speed again as traffic conditions dictate.

I've experienced this in electric cars. The VW eGolf allows coasting but the BMW i3 switches immediately to rather fierce regenerative braking.

Technically, coasting can be more energy efficient as there are none of the electrical conversion losses present with regenerative braking.

The Nissan Leaf EV allows coasting, but you have to switch it manually into neutral to do that. I think it is designed that way, coasting IS an option but some OEMs engineer things to make it easier than others do. I suspect you can coast in the BMW i3 too, but you have to know how to switch to that mode. Should be the same with buses.

The bus driver's thinking that the electric bus does not require a change in driving style is curious. Everything I know about EVs is that there is a lot to learn to maximize smoothness and the efficiency potential of the regenerative braking. Other TA's and drivers have said that. For example, knowing how to coast and learn how to use the brakes as smoothly as possible. Regen braking (friction brakes are also part of the braking experience) has a different feel and its easy to waste a lot of battery power and drive less smoothly than possible.

As you point out, the bite of the regen braking is programmable and can be made stronger or weaker.

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1 hour ago, Matt Dunlop said:

If the kneeler and ramp are used often, would that affect the range? Same for HVAC? 

Yes. HVAC uses a lot of energy. Although the effect is less in a coastal city like Vancouver, experience elsewhere in cities with a continental climate (think Toronto) is that in a cold winter the HVAC can use about half of the battery energy.

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