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[newbie] e-bike battery _commercial-availability_ lifetime


1 µW
Oct 13, 2023
dirty desert east of Phoenix


Assume you're buying an e-bike, in 2023, from a reasonably large/respectable manufacturer, who is in turn sourcing parts from reasonably large/respectable suppliers. How long can you reasonably plan to be able to purchase a replacement battery via reasonably-normal means? In other words, what's the "commercial-availability lifetime"[1] for an e-bike battery currently? (notes at end)

I realize this is a somewhat vague question, that moreover requires forecasting. But I'm not asking for an exact answer based on a large dataset (unless you have one); I'm just asking for informed opinion from folks who have much more experience with e-bikes than I do.


(I've been using normal/human-powered bicycles for ~50 years, but e-bikes for only 1 month, so apologies for any ignorant/uninformed statements I may make.)

Hopefully the following examples will flesh-out what I mean by commercial availability of replacement batteries, with answer parameters including

  1. standardization
  2. manufacturers: number, reputation
  3. retail channels: number, reputation, speed of access
  4. effects of time delta between host-product discontinuance and when you want/need to get a replacement
  5. OEM vs 3rd-party suppliers

(and hopefully won't TL;DR you).

commercial availability of AA batteries​

Suppose you buy, in 2023, something powered by AA batteries. Given that AAs have been manufactured for over a century, and standardized since WW2, you can reasonably assume that you'll be able to purchase replacement batteries ~forever (barring nuclear holocaust), from a variety of reputable manufacturers, through a huge retail network, whenever you need a replacement. (This is more true of nonchargeable than rechargeable AA batteries, but even rechargeables are, in 2023 in the US, widely available from several manufacturers via multiple retail channels, from supermarkets to online.)

commercial availability of laptop batteries​

(Feel free to challenge the following section--I haven't bought a laptop for 5 years--but the following estimates reflect 30 years of laptop-purchase/ownership experience. OTOH, I consider the assertions made above regarding AA batteries indisputable.)

Suppose you buy, in 2023, a laptop from a reasonably large/respectable vendor (who may have manufactured it, or may just be reselling a whitebox), who is in turn sourcing parts (notably including your laptop's battery) from reasonably large/respectable suppliers. You can reliably assume that

  1. your laptop's vendor will cease to sell replacement batteries for the model you own ~1 year after the vendor ceases selling that model (which the vendor may sell for as little as a few months, maximum ~3 years[2])
  2. OEM replacement batteries for your laptop--that exactly match your laptop's factory-installed battery--will cease to be manufactured 1-2 years after your vendor quits selling your model.
  3. depending on how strongly your laptop's model sold during its lifetime, you may continue to find retailers (for possibly as long as 5 years after your laptop's model {"discontinues", ceases to be sold}) selling non-OEM/3rd-party batteries which the retailer claims match the actually-existing/originally-installed battery in your laptop. However you are likely to find (probably due to lack of standardization--but that's another topic), that
    • (in the best case) most non-OEM batteries will perform (electrically) more poorly than your laptop's original battery
    • (in the worst case) any given non-OEM battery is probably sufficiently spatially/dimensionally different from your original battery that it won't actually connect mechanically with your laptop's unnecessarily-complicated and non-standard battery adapter[3]
  4. After ~5 years from model-discontinuation date, your probability of purchasing an usable replacement battery via "reasonably-normal means" (e.g., reasonably-reputable web-based vendors) approaches zero. If you can't/won't make your own battery, or live with battery-less operation, and "move on" to the next laptop model, your only options are things like niche for-sale forums, flea markets ... the Dark Web ... psychiatric counseling ...

commercial availability of e-bike batteries​

So my question can be restated as follows: is the commercial availability of "most e-bike batteries" (in 2023) more like AA batteries:

  1. you can expect to find/buy replacements quickly
  2. you can expect replacement batteries to be ~identical to those that shipped with your device, both dimensionally and electrically
  3. ... so you can just buy replacements when you need them[4]

... or more like laptop batteries:

  1. time required to find/buy a replacement battery will at best be non-trivial, and at worst will approach infinity
  2. the longer you wait after purchasing the battery's host device, the more likely that any candidate replacement battery you find will be
    • inferior in electrical performance to your original battery
    • sufficiently dimensionally different from your original battery that it may fit loosely (e.g., separate in transit) or not fit at all (without substantial work) into your host device
  3. ... so you probably want to keep at least one spare/backup battery (just for emergencies), and you should probably
    • think about how long you plan to keep the host device
    • lookup the expected lifetime of a replacement battery (which you might wanna discount)
    then do the division and buy enough replacement batteries in advance.

... or (I'm guessing) somewhere in between, but closer to one side than another?

Thanks in advance for providing useful information/guesses for folks new to the e-bike domain in general, and especially its components and their markets, and for your time/effort.


[1]: Just to be very clear: by "commercial-availability lifetime" I do not mean how long an individual battery is electrically useful, or any of the metrics typically used to characterize a battery's lifecycle. What I want is a measurement (if only "ballpark") of market behavior with respect to a given e-bike battery model: how long can one expect to be able to commercially acquire a battery of that model through "normal channels"?

[2]: If you're wondering something like "wait--hasn't Apple been selling MacBook Airs since 2006?" ... "MacBook Air" is not what I mean (nor what is generally meant) by a "laptop model"--MacBook Air is a brand, or an ongoing collection of models. If one looks instead at (e.g.) this long list of Mac models, you'll see that laptop models (not desktops, which behave differently for reasons beyond present scope) only rarely last more than 3 years, and usually less.

BTW: if anyone knows of similar model lists--with dates for both start/launch and end/discontinue for each model--for other laptop make/models, please reply with a link. E.g., I've seen several lists of ThinkPad models, all of which have start dates, but none have end dates.

[3]: In such cases, a Dremel-type tool may be useful ... or its use may just result in a battery that is both nonfunctional and nonreturnable.

[4]: Though as an old I gotta say: Spares are good. Period.
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You didn't state the only fact that matters, what company makes the ebike. Many of them lock down all the parts with custom CANBUS communication and you can only get a battery repaired or replaced from them at huge markup. Many other companies just need a positive wire and negative wire off the battery, like Grin's controllers.
what company makes the ebike
I would say this gets to the heart of the matter - how specialized the battery is.

With laptops, the intimacy of the space to fill leads to per-device-custom-batteries, pushed by the desire for smallest form factor, cooling requirements, etc. My slightly older thinkpads use 18650 cells in removable cases and can likely be rebuilt, and the rest of the machine disassembled by the user for other repairs - but they aren't quite the smallest, lightest possible.

Products designed for repair can be repaired. Others are disposable.

If the battery is fitted to a particular form of bike/trike/etc the lifespan is threatened. My batteries attach to the rest with wires, and bolt to flat surfaces, and are fitted to generic mass-produced cases, and thus use standard non-specific cells - 18650 or 21700. These are likely repairable/replaceable until the market for standard non-specific cells runs out - such as when we get Mr. Fusion generators or some such. Even a switch to a safe/more powerful/better battery type is likely to take advantage of those form factors due to the size of the existing market unless forced to another form factor by physics or perhaps economics. And then the battery is still connected to the rest of the machine by wires, and can be bolted on somewhere else.

How long depends on breakthroughs, legal changes, economic collapse. Difficult to predict. But stick with batteries that connect by wires and have generic cases.
Batteries/bikes designed to be closed by the maker are disposable products The difficulty and price of a replacement battery when needed is the what nudges you back to the dealer who will start the process of selling you a new bike.

ebike batteries are much like laptop batteries which mainly use similar 18650 cells to those with a higher drain capacity used in ebike batteries. And as laptop batteries can be rebuilt, at a cost, so can all generic and some custom e-bike batteries, replacing only cells keeping the bms h/w and enclosure.

Hopefully many folk who are tied by a manufacturers design decisions to exploitative costs will consider replacing the whole control systems of their bikes to enable use of the cheaper generic batteries.

whats the 2nd use ebike market like round you? here its not a sellers market, and many ebay auctions requiring collection close without any bids.
the only fact that matters [is] what company makes the ebike.

Thanks for your assistance! Accordingly I posted a new question focusing on that issue (which I'm calling vendor lock-in).

whats the 2nd use ebike market like round you?

I'm not sure yet. I'm guessing fairly strong, since

  • "the valley" (of which my local area is just a very small part, waaay out by the mountains) has a "booming e-bike industry"
  • the proportion of e-bikes to all 2-wheeled vehicles (including Harleys, which the local olds seem to love) seems-to-me quite large

but the locals are not major bike users in general (despite ~perfect weather (i.e., ~0 precipitation) and relief (i.e., mostly quite flat)), so I dunno.