The short answer: on a PuraMax 2, the Smart Spray is an optional battery-powered add-on, not part of the box’s cleaning hardware. PETKIT’s manual, version 1.3 dated February 2, 2026, lists it as premium-package only and prints the same footnote under Deodorize and Light on: that function requires the module to be installed. PETKIT’s own Q&A sheet says the module “will only be connected when it is automatically deodorized.” Two r/PETKIT owners, in one thread, describe cells that bulged, sizzled and leaked. Nothing in the manual makes cycling depend on the module, and a $19.99 N50 2.0 cartridge handles waste-bin odor without a single cell.

The thread is ten months old and it still reads like a warning label written by someone who did not expect to write one. A PuraMax 2 owner in r/PETKIT fits the fragrance bottle, fits the cells, notices a smell, and decides it is probably just new electronics. Then the sizzling starts, in an office where she happens to be sitting.

I went looking for that post after reading PETKIT’s own paperwork on the same accessory, because the documents and the thread describe two different products. The paperwork describes a convenience. The thread describes a small heated object clipped to a plastic box.

What the premium package actually adds

The short answer: start with the package list in the PuraMax 2 manual, version 1.3, dated February 2, 2026. It names the main unit, the adapter, the N50 2.0 odor eliminator, the magnetic litter remover, the fine litter filter, a trash bag, and then one line with an asterisk: “PETKIT Air Purifier Smart Spray — Only included in the premium package.”

Document	Date read	What it says about the module
PuraMax 2 manual, V1.3	Oct 24, 2026	Premium package only; Deodorize and Light on both require it
Pura Max manual, T4	Oct 24, 2026	The module “needs to be purchased separately”
Smart Spray Q&A sheet	Oct 24, 2026	Battery-powered; connects only when deodorizing; one bottle lasts about 2 months
PETKIT manual library	Oct 24, 2026	Separate one-page manual listed as “Air Purifier”
Retailer listing	Oct 24, 2026	$39.90, “Battery: 3*AAA (Not included)”

Two app functions hang off that module. The manual prints the identical footnote twice: to perform Deodorize, it is required to install the Air Purifier Smart Spray, and to perform Light on, the same. So a box bought without the premium package is not a broken box. It is a box with two greyed-out buttons and one working odor strategy, the passive cartridge in the waste bin lid.

The Q&A sheet adds the detail that matters for anyone who owns one: “Because Smart Spray is battery-powered, in order to reduce consumption and prolong service time, the Smart Spray will only be connected when it is automatically deodorized.” A module that sits unpowered between sprays sounds efficient. It also means the cells live in a compartment that heats and cools, in a room that smells like a litter box, and nobody looks inside it until something goes wrong.

Two owners, the same smell of hot plastic

The original post in r/PETKIT is titled “Puramax 2 Air Purifier Smart Spray Dangerous Malfunction.” The owner describes buying the box in December, adding the spray months later, and following the instructions: “I installed the fragrance bottle and then the batteries as directed. I noticed a weird smell but thought maybe it is just new electronic smell.”

She had deliberately left the auto features off, which is worth noting. “I did not want it to auto-spray at first… so I didn’t turn it on but I did connect it in the app and turned off the auto features.” The sizzling began anyway. “I pulled the battery door off and there was a battery bulging and making a sizzling sound… One was burning hot and leaking.”

The second report comes from a commenter in the same thread, and it is shorter and worse. “I had the same issue. I put the batteries in correctly. Tested it out and started to hear sizzling, checked it and one of the battery was leaking acid. Almost melted the unit.”

Two reports are not a defect rate. They are, however, two independent descriptions of the same failure mode in the same accessory, from owners who both say they installed the cells correctly, and both of whom end up praising the box. The first owner’s verdict: “The smart spray is not really a necessary part of the system so maybe it is better to avoid it. The litter box itself has been great.”

A cell bank clipped above the waste drawer

Here is the part the manual does not connect. The same safety guide that covers the box tells owners: “Do not place the device in a high-temperature or high-humidity environment.” That instruction is printed in the section about the litter box. The accessory that clips onto that box is a sealed plastic housing holding alkaline cells, sitting above the waste drawer, in the warmest and dampest corner of the appliance.

Duracell’s battery care guide, read the same day, lists conditions that lead to leakage, and most of them describe normal ownership of a pet appliance rather than abuse:

• Remove cells as soon as they are depleted, because some devices keep drawing power from dead cells and that can cause leakage.
• Do not leave cells in a device you expect to sit unused for several months.
• Do not mix old and new cells, brands, or chemistries in the same device.
• Do not put batteries or battery-powered devices in very warm places, since extreme temperatures reduce performance and may lead to leakage.
• Do not take a cell apart or dispose of one in fire, which may lead to rupture or chemical burns.

Mix-and-match is the one owners are most likely to trip over, because a three or four cell module with one weak cell is easy to top up rather than replace. Duracell’s own caution note is blunt about what that produces: some equipment using more than three batteries “may appear to work properly even if one battery is inserted incorrectly.”

The five-minute check that costs nothing

If the module is already clipped to your box, this is the order I would work in. None of it requires a purchase, and the whole loop takes about five minutes the first time.

Step	What to do	What ends the check
1	Open the battery door, read the moulded cell size and count inside	A size that does not match the cells you have been buying
2	Replace the whole set at once, same brand and type	One weak cell left in place
3	Look for a domed wrapper, white crust at either end, or residue on the contacts	Any swelling or crust: stop, do not recharge
4	Feel the housing when the box has been quiet for an hour	Warm housing, a hiss, or a sweet chemical smell
5	If you will be away for weeks, decide whether the module stays on the box	Cells left in an idle device for months

If you find a swollen cell, the handling matters more than the diagnosis. Take the module off the box, keep it away from anything that burns, take the cells out without forcing them, and put them in a non-metal container until they reach a collection point. Do not put a swollen cell back in to “test” it, and do not try to recharge a primary cell. Photograph the compartment and the cells first, because that picture is what a support ticket needs.

Odor control that does not need a battery

PETKIT’s own catalogue makes the alternative easy to see. The N50 2.0 is the cartridge that comes with the PuraMax 2, listed at $19.99 for a three-pack, model P9223, 5 by 5 by 1 cm, 35 g per piece, 30 days per piece. The page carried 142 reviews on October 24, 2026, and they are not unanimous: one owner writes that the scent “seems to fade after a week” rather than lasting the stated month. That is a consumable complaint, not a safety one, and it belongs in the same paragraph as the price.

The N60 costs the same $19.99 and looks like the upgrade, but its compatibility list is the Purobot Ultra, Purobot Max Pro, Purobot Max Pro 2, Purobot Max 3 and Purobot Crystal Duo. PuraMax 2 is not on it. Check the model list on the page before you buy a refill for the wrong box.

Item	List price as of Oct 24 2026	Cells required	What it does on a PuraMax 2
Smart Spray module	Not in PETKIT’s US sitemap (91 products); $39.90 at one retailer	Yes, user-installed	Deodorize and Light on, app-bound
N50 2.0, 3 pack (P9223)	$19.99	No	Waste-bin odor, 30 days per piece
N60	$19.99	No	Listed for the Purobot line, not PuraMax 2
Purifying liquid refill, 4 bottles	$19.99	No (liquid for the module)	Fits PuraX, PuraMax, PuraMax 2, air purifier

The refill line is the tell. PETKIT’s US catalogue that no longer lists the module still sells the liquid it sprays, four bottles for $19.99, described as fitting the PuraX, PuraMax, PuraMax 2 and the air purifier, with 54 reviews. Owners who already have the hardware can keep feeding it. Buyers shopping today cannot buy the hardware from that store.

If the reason you wanted the module was odor rather than a light, and you are also choosing a box, the Purobot Max Pro 2 is the PETKIT model whose smell control runs on cartridges instead of cells: PETKIT’s US store listed it at $549.99 against a $599.99 regular price on October 23, 2026, with 213 reviews, a two-year warranty and Fence 2.0 in the box, and the T5-2 manual fits an N50 in the waste bin and an N60 into the Breezy Smart Odor Eliminator with no battery section anywhere in its 40 pages. Two disclosures travel with that recommendation: the camera version’s playback is a 30-day trial, and some cats refuse a new box for weeks.

What two reports cannot prove

The honest limits, in the same paragraph as the recommendation. We have two owners, one thread, and no failure statistics. PETKIT publishes none, and the module has revisions, so a cell count printed inside one housing tells you nothing about the next.

The brand data points the other way. Trustpilot’s petkit.com profile read 3.7 out of 5 across 358 reviews on October 24, 2026, with replies to 82% of negative reviews inside a week, and the October 5 to October 22 window carried six 5-star reviews about the boxes and fountains: a cat that “took to it right away,” an owner of three kittens buying two more within a week, and a repeat buyer who calls the products “well made and last along time.” None of those reviews mentions the spray module either way.

The PuraMax 2 has its own history on this site, and it is not about batteries. Owners have reported urine escaping at the brim and at the ring that holds the purifier, which is why PETKIT sells a $149 replacement cylinder for the same model. If you are weighing the box itself, that leak record matters more than an accessory failure. The battery question is narrower: a cell sitting in a warm plastic housing, in a device the manufacturer tells you to keep out of hot and humid places.

The placement question nobody asks

There is a second safety-shaped detail in the same manual, and it connects to a decision owners make without thinking about it. The PuraMax 2 app has a Continuous Rotation setting, and the manual describes it plainly: when it is on, “the device will not stop working even if it detects a cat approaching.” Turn it off and the box stops when a cat comes near, which the manual says can let a cat enter while the opening faces down and leave waste at the bottom of the drum.

That is the same trade the mid-cycle lockout problem produces on other machines, where a sensor decision stops the box and no remote command overrides it, and it belongs in the same conversation as any add-on that promises to make the box more convenient. More automation means more parts deciding things about a place your cat has to trust. Our owner-report safety file covers the rest of that pattern.

A last piece of context for anyone who owns several battery gadgets: cells are the least interesting failure in a pet device and the easiest to prevent. The battery and plug checks we published on fountains follow the same logic, and the spare-parts audit explains why an accessory that leaves the catalogue is a bigger problem than one that arrives with a bad cell.

FAQ

Does the PuraMax 2 need the Smart Spray to cycle?

No. The cleaning cycle is independent of the module. PETKIT’s manual lists the Smart Spray as a premium-package accessory and attaches it only to two app functions, Deodorize and Light on. Remove it and the box still cleans, still runs Maintenance mode, and still uses the N50 2.0 cartridge in the waste bin lid. What you lose is the timed spray and the interior light, both of which the manual marks as requiring the module.

What cell size does the Smart Spray take?

PETKIT’s PuraMax 2 manual does not print one, and its Q&A sheet only says the module is battery-powered. The retailer listing we read on October 24, 2026 specifies 3 AAA batteries, not included. Because the module has been sold across several years and revisions, the reliable source is the moulded lettering inside the battery door of the unit in your hand, not a product page.

What does a failing cell look like before it leaks?

A wrapper that domes instead of sitting flat, white or grey crust at either terminal, or a housing that feels warm when the box has been idle for an hour. The two owners in the r/PETKIT thread describe the next stage: a sizzling sound and a hot smell before they opened the door. If any of that appears, remove the module from the box rather than checking it in place.

Can I keep using the box with the module removed?

Yes. Take the module off, leave the N50 2.0 cartridge in the waste bin lid, and use the app for cleaning, weight and schedule. The manual’s Deodorize and Light buttons will not work, and that is the only loss. If odor is the reason you wanted the module, replace the N50 cartridge on the 30-day cadence PETKIT lists rather than adding a powered device above the drawer.

Is the whole PuraMax 2 a bad purchase?

That is a different question with a different answer. This site’s earlier file on the model covers owners who found urine escaping at the drum brim and at the purifier ring, and PETKIT’s own parts shelf answers that complaint with a $149 replacement cylinder. The battery reports are about an optional accessory, and both owners in the thread praised the box. Judge the box on the leak record and the accessory on the cells.

Does the N60 fit the PuraMax 2?

Not according to PETKIT’s own compatibility list. The N60 page names the Purobot Ultra, Purobot Max Pro, Purobot Max Pro 2, Purobot Max 3 and Purobot Crystal Duo. The PuraMax 2 uses the N50 2.0, model P9223, which the company sells in three-packs for $19.99 and lists at 30 days per piece. The two cartridges look similar enough that the model list is worth checking before checkout.

Where can I still buy the Smart Spray module?

PETKIT’s US store did not list it on October 24, 2026, across a 91-product sitemap, while the liquid refill for it remained on sale at $19.99 for four bottles. One PETKIT distributor still carried the module at 179 AED on the same day. If you already own the module, the refills are the easy part. If you do not, the passive cartridge does the same job in the waste bin without cells, and this site’s position on that purchase is simple: buy the cartridge, skip the battery.