Say Goodbye to the E-Bike Red-Light-of-Death

Citi Bike is overhauling its dock-light scheme to keep more bikes out on the streets.

Seen one of these lately? You're not alone. Photo: Gersh Kuntzman
Seen one of these lately? You're not alone. Photo: Gersh Kuntzman

Shared e-bike lovers can say goodbye to the ubiquitous red-light-of-death.

In the few months since Citi Bike added 200 pedal-assisted e-bikes to its network, users have grown accustomed to finding those bikes unable to rent, as marked on the dock by a solid red light.

But as of this week, those dead battery bikes will instead be marked by a combination of solid red and yellow lights. Citi Bike is also adding another lighting scheme: blinking red lights to indicate bikes that have been serviced by one of the company’s field mechanics, but need to go back to the company’s Sunset Park home base for further repairs.

Both changes will improve the pace of battery replacements and bike repairs, Citi Bike spokesperson Cory Epstein told Streetsblog.

“With our field team being able to inspect bikes more efficiently, we’re able to more quickly get bikes back on the street for our riders,” Epstein said.

There are currently 200 pedal-assist Citi Bikes in the system, though significantly fewer are available at any given moment. That’s in part because the bikes, whose batteries last an average of just 35 miles, cannot be charged at their docks. Instead, they require Citi Bike staff on-hand with new batteries.

Almost 250 stations have been updated for the new lighting scheme so far, Epstein said. Under the old system, the solid red light could have meant any number of things: a dead battery, a bike in need of field repairs, or a bike that needs to go to the shop. That slowed down Citi Bike’s 31 field mechanics, of which only about 16 are on-duty at any given moment.

Epstein emphasized that the 200 e-bikes currently in rotation are just a test-run for April, when Citi Bike plans to unleash even more of them to help stranded L train riders get across the Williamsburg Bridge during the 15-month shutdown of the Canarsie Tunnel.

In September, Streetsblog reported that the Citi Bike was experiencing a massive repair crisis that took more than 40 percent of its fleet off the road on any given day. That crisis continues, and Citi Bike has not answered questions about when it will recede.

The new lighting schemes are just one of many strategies to keep more bikes out in the field, Epstein said. Citi Bike has also shifted much of its bike maintenance work to the nighttime, when congestion ebbs and crews can get around the city faster.

“We try to triage as many bikes in possible in the field,” Epstein said. “It’s way better for us from an efficiency point of view, an environmental point of view, and service point of view than taking it back to our warehouse to get it fixed.”

Some customers were dubious.

“Who is the main benefactor for this?” tweeted Matt Law. “Like as a customer, what do I do with this info? Or s it good for me because technicians can address things more quickly?”

  • Joe R.

    That’s in part because the bikes, whose batteries last an average of just 35 miles, cannot be charged at their docks. That’s in part because the bikes, whose batteries last an average of just 35 miles, cannot be charged at their docks. Instead, they require Citi Bike staff on-hand with new batteries.

    I had to do a double take on this because it’s so insanely stupid as to defy belief. Usually you have the charging infrastructure in place first. What Citibike has now is a labor-intensive nightmare.

  • William Lawson

    Wow, how could they possibly think that hand-replacing batteries would be an acceptable recharging solution? I was just wondering about the charging thing the other day and speculated whether CitiBike had always intended to roll out e-bikes eventually and so had pre-fitted their docks with chargers. I guess that was way too kind of me, lol. Of course they didn’t.

  • sbauman

    Citi Bike docking stations are not connected to the power grid. There is no power cord to Con Ed. They work entirely off batteries that are charged by solar panels. This permits stations to be moved, when conditions warrant (e.g. parades, special events, etc.). Given the amount of current a quick charge requires, the electrical codes probably require a permanent, hard wired connection to the electrical source with the wires enclosed in conduit. This is an expensive proposition, especially if carried out to every docking station. Battery replacement may be more cost effective.

  • Geck

    Yes. The solar powered docks were a feature that allowed them to be placed relatively quickly and flexibly without the need for utility work. It now creates challenges in the transition to ebikes. Paris has had significant problems with this as well.

  • Mike

    If they can’t be hooked up to the grid it seems like the obvious solution would be to have a large battery pack (think something like the size of the Tesla PowerWall which are battery packs about the size of a bike made by Tesla that are meant to power an entire home) built into each dock that will last for days or weeks and could then be used to charge the individual bike batteries. Then you only need to send a technician out every so often to each dock to swap out the big battery instead of trying to run around to docks all over the city swapping individual bike batteries.

  • Joe R.

    And how often have the stations actually been moved? If they want to remain off-grid, the solution is a few kW of solar panels for each station, combined with a large storage battery so power is still available at night. Or just connect to the grid. Power is available at literally every streetlight. They just need permission and hardware to tap into that.

    Manual battery replacement doesn’t scale well. Maybe it’s fine while the e-bikes were in the experimental stage. Once there’s a full-scale roll-out you need charging stations.

  • Joe R.

    That sounds good until you do the math. If we assume these e-bikes draw about 350 watts from the battery and have a 35 mile range (about 2 hours of riding), then the battery pack is roughly 0.7 kW-hrs. Accounting for charging inefficiencies you probably need about 1 kW-hr per charge per bike. Granted, most bikes won’t have a fully depleted battery but you have to assume worst case when you do the calculations.

    The Powerwall 2 has 13.5 kW-hr of usable storage capacity. That’s basically 13 or so charges. It’s not hard to see how it can easily be depleted in well under a day at busier stations. It won’t be sending out a technician every so often to change the Powerwall. It might be daily, or several times daily. This isn’t to mention that we’re talking a very expensive piece of hardware here costing about $10K. There will be lots of temptation for people to start stealing them. Add up the numbers you’ll need (remember to account for the fact some will need to be charged to replace the depleted ones on-site). Also account for the fact a fair number will get stolen each year. Not hard to see that this becomes a multimillion dollar proposition even for a few hundred e-bikes. Ditto for my suggestion above of larger solar panels and a large storage battery. Then again, the labor to swap batteries will end up costing the same after a few years.

    When you look at everything, the only feasible, cost-effective answer to scale up the e-bike experiment is grid-connected charging stations.

  • sbauman

    And how often have the stations actually been moved?

    I’m associated with an annual event that requires moving several docking stations. I’m sure there are many other such events that require docking station removal. These events are part of NYC’s fabric of life.

    Power is available at literally every streetlight.

    As I mentioned, a lot depends on the amount of power required. A hard wire (no plugs) connection is required by the National Electrical Code. Similarly, one does not lay out a live power cord without protection (conduit in NYC). I see a lot of illegal connections at the various local Christmas lights setups in Dyker Heights and other places.

  • Joe R.

    There are all sorts of answers to that. You can drop the voltage down to 48VDC or less by hardwiring a power supply inside a streetlight base (or next to it). You have a different set of rules once you’re at or under 48VDC. You can then plug the station into this power supply. You also have solar charging stations, although you’ll need some battery storage for those to work at night, or on cloudy days:

    https://electricbikereport.com/swiftmile-electric-bike-solar-charging-stations-videos/

    http://www.advansolar.com/en/blog/2015/02/05/1030/

    The bottom line is manually swapping batteries was fine while e-bike share was in the experimental stage. It’s not going to scale when you have thousands of e-bikes. It’s not even really working now if some people report never finding an available e-bike. And rental e-scooters will be presenting the same set of problems.

  • sbauman

    Accounting for charging inefficiencies you probably need about 1 kW-hr per charge per bike

    KW is more important than kW-hr. Your 1-1 correspondence between ride and charging time (including charging inefficiency) means that each bike must sit an hour at a dock for each hour it is ridden. That’s an inefficient use of bicycles.

    As mentioned, lithium batteries can be charged in 15 minutes. However, they are charged at a much higher rate. That rate would be roughly 8 times the 1 kW-hr rate you suggested. Thus each bike installation would need to be supplied with approximately 8 kW (for 15 minutes). If each station were able to charge multiple bikes simultaneously, the power requirements would multiply accordingly. At this point, we are talking about some beefy power supplies that are beyond the capability of a nearby street light.

  • sbauman

    You can drop the voltage down to 48VDC or less by hardwiring a power supply inside a streetlight base (or next to it).

    You are trading one problem for another. Being intrinsically safe (less than 48 vdc), removes some NEC location requirements. However, the higher current introduces the need for much thicker wire and brute force connection techniques..

  • Joe R.

    We’re not talking about a lot of power here. Maybe a few kW at most, and under 100 amps. It would be a very short run of wiring. These problems I’m sure have been solved elsewhere. Don’t make it out to be like manually swapping batteries will be the only option forever. Might as well forget e-bike rental then as that “solution” hasn’t even worked out with a small number of e-bikes.

  • Joe R.

    You get around that by having a fairly small battery of 1 kW-hr or so in each charging station to supply the peak power. And of course you limit the power being drawn from the grid. If it exceeds a few kW, then you just go to a slower charger rate. The idea here is the charging station battery will likely be recharged by the time the next bike docks. Also, as I mentioned the chances of the batteries being fully depleted all the time are nil. Most likely you’ll be fast charging for only a few minutes. In many cases the battery will be at >80% charge, so you’ll just be topping it off.

    Your 1-1 correspondence between ride and charging time (including charging inefficiency) means that each bike must sit an hour at a dock for each hour it is ridden. That’s an inefficient use of bicycles.

    Versus what, waiting for probably a few hours for someone to manually swap batteries? Read the article. A lot of people are reporting that the e-bikes are never available. Evidentally manual battery swap is taking a lot longer than even a slow charge dock would.

  • sbauman

    Maybe a few kW at most, and under 100 amps

    That’s #6 gauge wire, according to the AWG tables for chassis wiring. Moving it from the lamp post to the docking station, you will require #1 gauge.

  • Joe R.

    If you use storage batteries on the dock to take care of peak demands then the cable connection (and power supply) only needs to deal with the average power. That’s probably only a few hundred watts per charging station at most. You might need #1 gauge and 100 amps at a very large charging station with 20 e-bikes. Most will only have 2 or 3 docks, and they will only need <1 kW on average. That's 20 amps or so at 48 VDC. The cabling requirements aren't onerous. Even at main stations, it's not a big deal having a cable with #1 gauge wires.

    Note also you can supplement grid power with solar power. That downsizes the grid-connected power supplies and wiring further.

    The fact they make grid-connected EV charging stations work tells me we can make this work.

  • AMH

    …and hello to the E-Bike Red+Yellow-Lights-of-Death?

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