School Buses Are Perfectly Suited To Be Electrified Cheaply, Efficiently, And Yes, Crappily

Illustration for article titled School Buses Are Perfectly Suited To Be Electrified Cheaply, Efficiently, And Yes, Crappily

For many of us with offspring that we don’t keep chained in basements or workhouses, today was the first day of school. I sent my own kid, Otto, off to his first day of third grade, which he was whisked to by a huge, yellow, loud, lumbering diesel beast that hasn’t changed appreciably in decades: a school bus. I’ve been thinking about school buses a lot, and I’ve realized they may be the perfect candidates for electrification. And not just any electrification—kind of crappy electrification. Let me explain.

I know there’s a lot of people that believe that only the absolute best will do when it comes to their children, and while I can respect that in theory, the truth is that’s rarely really true. There’s lots of cases where something very far from the best is just fine for your kid, and in the case of school buses, this is already quite true.

School buses are not, by any metric, particularly sophisticated vehicles. They’re basic diesel truck chassis with big boxes full of seats bolted on. Many (maybe most?) don’t even have seat belts on those seats. That may seem alarming, but the truth is it’s generally fine, because the use case of a school bus is slow and predictable.


School buses travel pretty slowly, they go on set, pre-determined routes day after day with little or no variation, at two pre-determined times per day.

That’s it. In fact, the routes that school buses tend to travel only average 31.73 miles, according to an SAE study of over 1,500 school bus routes nationwide called, erotically, A Statistical Characterization of School Bus Drive Cycles Collected via Onboard Logging Systems.

The average speeds of a school bus on a route were found to be about 23 MPH, with a minimum average of about 13 MPH and a maximum of 54 MPH. School buses, as is news to nobody, are not fast.

So, let’s put this all together: school buses are part of centrally-operated fleets, have fixed-length routes, these routes involve a lot of stopping and starting (good regenerative braking potential), they have limited speed requirements, and in between their two daily routes there’s a whole school day’s worth of charging time.


I can’t think of a better set of circumstances for an electric vehicle of any kind. It’s practically tailor-made to be the absolute least taxing setup for an EV, which makes it sort of insane that we’re running these things on diesel (or sometimes gasoline) still.

I mean, I know why it’s like this, of course—schools are perpetually broke, and they already have a huge legacy inventory of buses, so why replace them?


There’s no way around this, and no way American schools are going to en-masse replace old buses with modern EV buses. But that’s okay! Because there’s a way we can transition America’s school bus fleet to electric power without breaking the bank! How?

By doing it slowly and crappily.

Here’s what I’m thinking: instead of replacing buses with brand-new EV buses, let’s just tackle this bus-by-bus and convert old buses to electric power. Basically, when a bus has a reasonably expensive repair that’s needed somewhere in its drivetrain, that bus isn’t repaired, but instead is sent for EV conversion.

Illustration for article titled School Buses Are Perfectly Suited To Be Electrified Cheaply, Efficiently, And Yes, Crappily

The way the buses are converted is designed to be as simple as possible: the engine is pulled (and sold to trucking companies or whomever for revenue that goes back to the school system) and an electric motor is fitted in the most basic way: with an adapter plate right onto the existing transmission.


This is a proven and simple method that’s similar to how companies like Zelectric converts old Volkswagen Beetles: it converts with the least amount of change to the base car. There’s plenty of underhood room for control electronics and charging systems and all that. There’s a limited number of school bus types across the country, so a few basic “kits” would be available to adapt to, say, Ford drivetrains or International ones, and so on.

Torquey electric motors will have no problem meeting the power needs of the bus engines they’ll replace, especially, since, remember, these things rarely do over 35 MPH.


As for the batteries, this is where things really get good: no bus will use brand-new batteries. Instead, buses will become the primary recipients of used, no-longer-ideal batteries from mainstream consumer EVs.

We know that EV batteries do degrade over time and lose capacity; Tesla, for example, has a 70 percent degradation warranty within 100,000 miles (or 120,000 for the bigger battery) or eight years on their Model 3.  Nissan suggests that 15 percent loss over two years is to be expected on the Leaf.


So, at some point, Tesla or other EV owners will decide that they want their original range and capacity again, and decide to get their battery swapped out, hopefully for them while it’s still under warranty.

These discarded batteries still have, potentially, 70 percent or so of their original capacity left—in the case of a similarly degraded Tesla Model 3 battery, that means an effective range of 168 miles.


So, even if we figure that the vastly higher weight and brick-like aerodynamics of a school bus will take a huge hit on that range, 168 miles has an absurdly huge margin, considering the average bus route length of 30 or so miles.

Illustration for article titled School Buses Are Perfectly Suited To Be Electrified Cheaply, Efficiently, And Yes, Crappily
Graphic: SAE

Plus, remember, the bus is just sitting for the entire seven-or-so hour school day, so it can be recharged, as well as overnight. There’s never any reason for a school bus doing its usual job to be in any danger of running out of range.

You could use Tesla batteries with less than half their original capacity, or Leaf batteries or Chevy Bolt batteries, or packs of hybrid batteries—ideally, school bus conversion kits would be flexible enough to adapt to whatever batteries are available at the time to make it work.


Currently, Tesla and other companies are putting a lot of effort into finding the best ways to recycle batteries—a second life as school bus batteries would certainly help to maximize the potential use out of these expensive and environmentally taxing objects.

There’s even a safety benefit to school bus EV conversion—school buses are notoriously top-heavy, which leads to poor handling and the potential for tipping or rolling (growing up, I remember these as the most common sorts of bus accidents, right after mailbox-beheadings), but mounting some heavy battery packs under the floor would help things out a lot, center-of-gravity-wise.


To recap, this is my proposal: we should electrify school buses, as they represent the ideal EV use case of almost any sort of vehicle. Existing buses will be converted one by one, in lieu of repairing or replacing their combustion engines, and the conversions will be done as simply as possible: electric motors mated to existing drivelines, batteries sourced from mainstream EV discards with, say, at least 40 to 50 percent remaining usable capacity.

Pictured: Potential driver of EV bus with repurposed Tesla batteries

The benefits are considerable. Once converted, EV buses will require far less maintenance than combustion-engine buses, money will be saved on fuel, oil, and servicing, which would very likely be more than enough to cover electricity charges and conversion costs and charger installation costs.

Since the conversions aren’t being done en masse, there won’t be a need for a massive cash infusion, either—plus, it may be possible to convince EV makers to donate or severely discount the batteries they’re pulling from cars to replace with new ones.


Is there a downside here? Quieter, safer, cheaper, less polluting—why wouldn’t school systems want to do this?

I know the Thomas Built Bus company is not far from me at all, based in High Point, NC. If anyone from Thomas wants to stick a junkyard Tesla or Bolt battery and motor in a bus, I’ll be the first one to put my kid on it. Just let me know. I’ll even call the school and try and sweet-talk them into trying it out! It’ll be fun!

Senior Editor, Jalopnik • Running: 1973 VW Beetle, 2006 Scion xB, 1990 Nissan Pao, 1991 Yugo GV Plus, 2020 Changli EV • Not-so-running: 1977 Dodge Tioga RV (also, buy my book!:

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Is there a downside here?

A few.

One, a lot of districts like to have a standard fleet, for the same reason airlines like Southwest standardize on one or a few models of aircraft. One model means a standard set of tools and parts to fix any bus. This would require an additional outlay on tools, parts, and even hiring mechanics who know how to work on them. And you’re talking using used battery packs, which means those won’t be standard either.

Two, the range you quotes was one half of the daily driving. They run the routes in reverse at the end of the day. So ~63 miles a day, so a degraded battery pack has less margin. And there’s not a ton of down time in that, since there are frequently three runs on each leg (Elementary, Middle, High school routes), so the bus is really only down for lunch times. The good news is that means we claw back some of that 63 miles in terms of needed capacity, but not that much as you also don’t want to fast-charge the bateries too often if you want the (expensive) battery pack to survive, so doing it on a daily basis is a bad idea. Also, you want to keep the charge under 80%, and above 20% if you want to maximize battery lifetime, so the margins of a degraded battery for a big, heavy, unaerodynamic bus... it’s not favorable.

Three, busses frequently are used in addition to the daily route to run special trips. Field trips, away games for sports teams, band events, etc. on top of that, and a degraded battery that has been run all day will definitely have trouble there.

None of those are insurmountable, but a new, standard conversion kit with a much larger battery than is in a small passenger sedan to maximize the range margins, as well as standardize on parts, tooling, and mechanical training, and possibly an optional range extender (A small gas engine optimized for efficiency that can recharge the battery on longer routes) seems like a better option.