The short answer
A genuine iRobot battery costs $99.99–$169.99. iRobot says a properly cared-for battery lasts “at least 2–3 years” and “hundreds of cleaning cycles.” New Roombas start at $249.99. So on pure math, a battery swap — a Phillips-screwdriver job on almost every model — is nearly always worth one round. The catch in mid-2026 isn’t the math, it’s the shelf: at our 2026-07-29 check of irobot.com, five of the six official replacement batteries were out of stock. Only the $99.99 XLife (for 500/700 and older 600/800 models) was buyable direct.
First: which battery does your robot take?
iRobot publishes the full mapping in its “Features and Compatible Parts” article. Condensed to the models we see most:
| Your Roomba | Battery | Official price | Stock (2026-07-29) |
|---|---|---|---|
| 500, 700 series; 618–660, 870, 880 | XLife Extended Life | $99.99 | In stock |
| 614–695, 801–895, 960 | 1800 mAh Li-Ion | $109.99 | Out of stock |
| 960, 980, 985 (and same 600/800 list) | 3300 mAh Li-Ion | $129.99 | Out of stock |
| e series, i series, j series (not j9+/Combo j) | Li-Ion for e/i/j | $99.99 | Out of stock |
| s series (s9, s9+) | 3300 mAh Li-Ion for S9 | $119.99 | Out of stock |
| Combo j9+ & j7+, select j9+ | 4460 mAh Li-Ion | $169.99 | Out of stock |
A few series need care in reading that table. Several 600/800/900 models appear on both the 1800 mAh and 3300 mAh compatibility lists — the bigger pack fits the same bay, so if both come back in stock, the $20 buys you capacity. The Essential models are the exception in the other direction: iRobot lists no replacement battery for them, and its official battery-removal article says outright that instead of removing an Essential’s battery, “we recommend you put the robot in sleep/ship mode instead.” Same story for the new 105/205/405/505/705 LFP generation — batteries are documented (3,000–6,000 mAh LFP), but no replacement SKU is on the store yet. For those machines, today’s honest answer is: there is no official DIY battery fix.
An honest gap on our side too: with iRobot’s own stock thin, the obvious move is a retailer — but Amazon and Walmart both blocked our price checks this week, so we can’t quote retail numbers. Whatever you find there, verify it’s a genuine iRobot pack before paying (more on why below).
Is the battery actually the problem?
iRobot’s published baseline is the number to test against: most 500/600/700/800 models ran about 60 minutes when new, i series up to 75, s series and the 980 up to 120. If your robot’s runtime has collapsed well below its when-new figure — or it dies mid-room and limps back to base constantly — that’s the battery aging out, right on the 2–3 year schedule.
Before buying anything, rule out the cheap cause. iRobot’s own maintenance advice: a robot “clogged with hair or debris… will strain to work harder than usual and exhaust the battery faster.” Clean the brushes and check the runtime again.
The swap itself
For 500 through 900, e, i, j, and s series, iRobot’s procedure is four sentences long: flip the robot, remove the edge-sweeping brush screw and bottom-cover screws with a Phillips screwdriver, lift the cover, swap the battery. The s9 hides one extra screw securing the pack; newer i1/i3/i5/Combo i5 units have a small battery door instead of a full bottom plate. This is a 10-minute job with no soldering, no clips to break, and no calibration afterward.
Two habits to keep the new pack alive its full 2–3 years, straight from iRobot: keep the robot on its charger whenever it’s not cleaning (“recharge as soon as possible following use; waiting several days can damage the battery”), and if it’s going into a closet for more than a few weeks, use ship mode or pull the battery, then give it a full charge at least every six months.
The third-party battery question
Aftermarket packs are everywhere and cheaper. Know what you’re trading. iRobot’s warranty language is unambiguous: “using accessories or parts that were not manufactured by iRobot will void your Warranty,” and the limited-warranty exclusions specifically strike parts “not provided or recommended by us.” On a robot already past its 1-year warranty, that threat is empty — the warranty is gone anyway, and a third-party pack risks only the robot. On a robot still under warranty, it’s an expensive way to save $30: the battery itself is covered for that first year as part of the product.
The decision math, by situation
Older 600/800/900 with a dead battery: $99.99–$129.99 direct (minus the 15% accessories code running at our check) against $249.99 for the entry Roomba 105X, or $279.99 for a 105 with an auto-empty dock — at a strikethrough discount from $449.99 that tells you these prices move. If the robot is otherwise healthy, the battery wins. If it has other problems too, note that iRobot’s trade-in program advertises up to $150 credit and accepts even 400–600 series machines — a broken-ish old Roomba plus trade-in credit can beat a $110 battery in a machine on its way out.
e/i/j series: the robot is likely still worth hundreds; the $99.99 battery (when stocked) is an easy call. Under one year old? It’s a warranty claim, not a purchase — batteries are covered, and a replaced part carries the rest of the original warranty or 90 days, whichever is longer.
s9 and Combo j9+/j7+: these were four-figure robots; $119.99–$169.99 to get years more service is the best dollars-per-year deal on this page.
Essential and the new 105–705 generation: no official battery SKU exists today. If one of these fails inside the year, use the warranty. Outside it, watch the parts store — and factor “currently unrepairable by the book” into which Roomba you buy next.