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RegGuheert
Posts: 6178
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: Battery-electric bus discussion

Fri May 11, 2018 6:49 pm

AVM 27' electric shuttles fully charge 50-60-kWh batteries in 10 minutes:
InsideEVs wrote:The AVM EV27 is mid-size 27-foot long shuttle for loop-based routes supporting corporate and school campuses, hotels and rental car facilities, airports, and affording “first/last mile” solutions to private communities.

The vehicle stands out due to its 350 kW ultra-fast charging through CCS Combo in less than 10 minutes.
I've only ever heard of chemistries which can withstand 10,000 full cycles out there, which could yield a few years of cycling in such operations, but the article claims that the LTO chemistry used here can withstand 20,000:
AVM as quoted by InsideEVs wrote:“AVM’s exclusive joint venture is powered by Yinlong Energy, one of the world’s leading energy manufacturers and innovators. AVM shuttles are powered by Yinlong’s proprietary lithium–titanate battery (LTO) technology. An extremely safe and long-lasting lithium-based technology, LTO cells can endure more than 20,000 cycles, ensuring the batteries’ lifespan exceeds that of the vehicle. This robust and proven technology takes full advantage of AVM’s 350 kW CCS 2.0 high-powered charger, enabling the EV27’s rapid charge time.
In fact, the following cycle-life curve at the AVM website indicates WAY more than 20,000 cycles with less than 10% degradation:

Image

One possible issue with 350-kW chargers is the risk of fire at the charging point. Clearly this technology is improving steadily, but I think there will be some growing pains as well as issues related to wear that occurs with connectors used so frequently at such high power levels. I suspect roof-mounted high-current contacts will tend to be more successful in many applications (except in the case of snow and ice). We'll have to see how things play out.
RegGuheert
2011 Leaf SL Demo vehicle
10K miles: Apr 14, 2013, 20K miles (55.7Ah): Aug 7, 2014, 30K miles (52.0Ah): Dec 30, 2015, 40K miles (49.8Ah): Feb 8, 2017, 50K miles (47.2Ah): Dec 7, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

GRA
Posts: 8359
Joined: Mon Sep 19, 2011 1:49 pm
Location: East side of San Francisco Bay

Re: Battery-electric bus discussion

Wed May 16, 2018 5:29 pm

Via GCC:
San Francisco commits to all-electric bus fleet By 2035; MUNI Board approves pilot program
http://www.greencarcongress.com/2018/05/20180516-muni.html

. . . SFMTA will only purchase all-electric buses starting in 2025 to meet the goal for 2035.

The SFMTA Board of Directors on Tuesday approved a resolution supporting the commitment towards an all-electric bus fleet along with a pilot program to evaluate and implement battery electric vehicles. MUNI currently operates the largest fleet of electric trolley buses.

The trolley buses, like all light rail, streetcar, and cable car vehicles in the city, run on Hetch Hetchy hydroelectricity via overhead wires. MUNI also runs a fleet of hybrid electric vehicles which use renewable diesel. . . .

The SFMTA has been rolling out new electric hybrid buses with higher capacity on-board battery systems. The increased on-board battery capacity will allow the SFMTA to run a test program to operate “Green Zones” along several electric hybrid routes that would run only by battery for significant portions of the route. The “Green Zone” signifies an area in which the vehicle will not produce any emissions. The SFMTA is working to identify these zones throughout the city.

The SFMTA said it will move forward with electric bus technology when manufacturers can prove their electric buses can withstand heavy ridership and the steep hills characteristic of San Francisco. The agency would also have to consider new facilities that can charge a large fleet and developing a systemwide infrastructure to charge vehicles in service or on the street.

    While the battery technology is emerging rapidly, it isn’t quite ready for primetime. Manufacturers aren’t yet producing the number of all-electric buses San Francisco and other urban areas would need, nor could we guarantee that the vehicles would work for the required 15 years with heavy ridership and challenging topography.

    —John Haley, SFMTA’s Transit Director

In 2019, the SFMTA intends to purchase a limited number of battery electric buses and test them in service throughout San Francisco to evaluate how they perform on crowded and hilly routes. SFMTA said that the most important step to support the zero-emission goal is to determine the infrastructure needs for electric buses, including upgrades for existing facilities to accommodate charging requirements and maintenance.

Of the nearly 900 all-electric buses purchased across the country, only 207 are actually in service, SFMTA said. By contrast, MUNI is currently operating 250 electric trolley vehicles. . . .

San Francisco’s transportation sector generates approximately 46% of the City’s total greenhouse gas emissions, mostly generated by the use of private cars and commercial trucks. MUNI carries 26% of all trips in the city, but accounts for less than two percent of these emissions.

On 19 April 2018, Mayor Mark Farrell committed San Francisco to net-zero greenhouse gas emission by 2050.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

GRA
Posts: 8359
Joined: Mon Sep 19, 2011 1:49 pm
Location: East side of San Francisco Bay

Re: Battery-electric bus discussion

Sun May 20, 2018 3:38 pm

IEVS:
Proterra Switches To SAE J3105 Standard For Overhead Charging
https://insideevs.com/proterra-switches-to-sae-j3105-standard-for-overhead-charging/

Proterra, who as one of the first to introduce its roof-fast charging system (proprietary one, for a 10-minute recharge – see photo above) is now turning to SAE J3105 standard (OppCharge – see photo below). Previously, in 2016, Proterra opened patents covering its solution.

The new Proterra Catalyst buses will be offered with:

SAE J1772 CCS combo (IEC Type 1) inlet
SAE J3105 Overhead Charging Standard

The SAE J3105 will enable sending of up to 500 kW of power, while the J1772 Combo will be used for 60 or 125 kW charging. According to Proterra, buses will be ready for bi-directional, vehicle-to-grid power flow (V2G), for smart-grid purposes. . . .
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

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