How much does it cost to replace a robot vacuum or mower battery?
A robot’s battery ages even while it sits charged on its dock, and some makers do not sell a new one at all.
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A Roomba j7+ and a Roomba Combo j9+ come from the same maker, and only one of them can take the $99.99 replacement battery iRobot sells for Roombas. The pack fits the e, i and j series, except the i8, and none of the Combo models, the Roombas that vacuum and mop.
Every lithium pack in a robot loses capacity as it works. Keep a robot long enough and you end up on a page like iRobot’s, checking model numbers against a compatibility list. So what will the new pack cost you, and when?
Whoever made the robot sets the price, and some makers sell no pack at all. The robot itself sets most of the timing, through how deeply it drains the pack and how it keeps it between runs. And one common piece of charging advice points the wrong way.
What the makers list for vacuums, mowers and pool cleaners
Among vacuums, one pack often covers a whole family of robots. Shark sells two, one on either side of iRobot’s price. The RVBAT850, at about $60, fits more than 150 Shark robots. The RVBAT85014, at about $108, fits nine newer XE models.
Roborock’s US store has no robot battery to sell. Its accessories run to brushes, filters, dust bags and mop cloths, and stop there. So a Roborock owner whose pack is fading has nothing to order from the maker’s own shelf.
Mower packs cost more. The 8Ah pack for the Navimow X330 costs roughly a sixth of what the mower does, and the pack for the X390 about a tenth of that mower’s price. Both listings call the pack a “plug-and-play replacement.”
Listed prices, September 2026
Navimow replacement packs on two price lists
| Pack | Fits | Segway store | Lawn-care site MSRP |
|---|---|---|---|
| 2.55Ah | i206 AWD | $159.99 | not listed |
| 5.1Ah | i210 AWD, H210 | $199.99 | not listed |
| 6Ah | X315 | $339.99 | $220.79 |
| 8Ah | X330 | $369.99 | $271.83 |
| 10Ah | X350, H220 | $399.99 | $394.53 |
| 12.8Ah | X390, X430, X450 | $449.99 | $489.11 |
Ask elsewhere and the numbers move. A lawn-care site’s own MSRP list runs below Segway’s store for some packs and above it for others, and notes that its prices are subject to change. The same list gives a Navimow pack roughly 1,500 charge cycles before its capacity begins to fall, a rating missing from Segway’s own listings.
Worx takes a different route. Its Landroid Vision WR220 runs on a 20-volt battery from the company’s PowerShare line, which also powers more than 75 of its garden and power tools. A Landroid owner replacing that pack is shopping for the same battery as the rest of the line.
For warranty purposes, the battery in a Beatbot cordless pool cleaner is part of its “drive box,” along with the circuit board, motor and sensors. Beatbot’s US store sells power adapters for its cleaners, and no battery.
Beatbot covers the drive box for two years on standard models such as the AquaSense and three on premium ones such as the AquaSense 2. Inside that term, a failing pack is a warranty claim. After it, the store has no pack to sell you.
Where the old pack goes
Lithium-ion batteries and devices containing these batteries should NOT go in household garbage or recycling bins.
US Environmental Protection Agency, Used Lithium-Ion Batteries
Swap in the new pack and you are left holding the old one. Used packs go to separate recycling or household hazardous waste collection points instead, with the terminals taped or each battery bagged to prevent fires. Tossed in with household recyclables, a pack can be crushed in transport or by sorting equipment and become a fire hazard.
There are more than 20,000 drop-off locations in the Battery Network, the program formerly called Call2Recycle. Most take common rechargeable batteries, and some take high-energy packs above 300 watt-hours. Segway’s listings give a Navimow pack’s capacity in amp-hours only, so its owner cannot tell from them which kind of drop-off to look for.
Husqvarna sends its robotic mower owners to the same locator. A mail-in service is the other route, and it is freight with rules attached: Shark classes its own new replacement pack as a hazmat lithium-ion battery for shipping.
How a robot wears out its pack
So when does that bill come due? Every lithium-ion cell loses capacity as it cycles, and how deeply each discharge drains it sets the pace. A battery reference site’s guide to prolonging lithium-based batteries estimates how many cycles a cell gives before its capacity falls to 70 percent.
For NMC cells, one of several lithium chemistries in its table, the estimate is about 300 cycles when every discharge empties the cell, and about 1,000 when each uses 40 percent. At one run a day, that is the difference between about ten months and close to three years.
At 70 percent, a charge gives your robot about seven-tenths of the runtime it had new. If it finishes its job on less than half its charge, it sits in a different row of that table from one that runs itself nearly flat. And as the pack fades, the same job takes a bigger share of what is left.
Term
Depth of dischargeThe share of a pack’s full charge that one run uses before the pack is charged again. A run that empties the cell is the deepest discharge, and one that uses 40 percent of the charge leaves the rest in the pack. A storage level such as a 40 percent charge counts the other way, as the share still in the pack.You may have heard that topping up after short runs wears a pack out faster. The guide says the reverse: “Partial discharge on Li-ion is fine,” and a partial charge also reduces stress. A robot that goes back to charge long before it is empty is not hurting its pack.
Much of the wear on a docked robot can come from waiting instead. Your vacuum returns to its dock after a run, recharges, and sits there until the next one. A cell held at full charge for a long time can be under more strain than one that is cycling.
The guide’s storage table puts numbers on the waiting. Held for a year at full charge and 77°F, a cell keeps 80 percent of its capacity. Held at a 40 percent charge, it keeps 96 percent. At 104°F, the two figures fall to 65 and 85 percent.
At the makers’ own stores, then, a new pack for a robot vacuum costs about $60 to $110. One for a Navimow mower costs about $160 to $450, and on the X330 and X390 that is between a sixth and a tenth of the mower’s price. Roborock and Beatbot owners find no pack there at all.
On those cycle estimates, the pack in a vacuum run once a day reaches 70 percent somewhere between its first year and its third: sooner if every run drains it flat, later if each uses less than half. Months spent sitting full on the dock pull that date closer.
Then comes winter, and months in storage. Husqvarna tells Automower owners to make sure the mower is “fully charged and turned off before storing it for winter.” The reference’s storage table favors a partial charge for a pack that will sit. An owner putting a mower away in October gets opposite instructions from the maker and from the reference.
