Written by the Stonebotclean product team · Updated October 2026
Three numbers decide whether a cordless pool vacuum cleaner is still working in its second season: the battery it carries, the runtime it delivers under load, and the waterproofing rating that keeps water out of the electronics. Everything else on a product listing is easier to read and less likely to end the machine’s life.
We quote this category every week, and the same three questions come back from distributors and importers: why a bigger battery does not always mean a longer cycle, what IPX8 actually covers, and when a battery replacement has to be planned for. This page answers all three with the figures we publish on our own cordless range.
If you are still deciding which type of cleaner suits which pool, start with the full pool vacuum cleaner buying guide. This page is the battery and waterproofing layer that sits underneath that decision.
The short answer
- IPX8 is a pass/fail item, not a feature. It is the rating for continuous immersion. “Water-resistant” describes a splash, not a two-hour working life at the bottom of a pool.
- Runtime under load is the only runtime worth comparing. A figure measured on a clean floor with no filter loading is not the figure the machine delivers at minute sixty.
- A larger mAh figure does not buy more minutes on its own. Capacity is one of three inputs; current draw and workload are the other two.
- The battery is the wear item. Whether the pack is user-replaceable decides whether year three is a service part or a warranty claim.
IPX8 is a pass/fail item, not a feature
IPX7 and IPX8 are not two points on the same quality scale. IPX7 covers temporary immersion — the standard’s test is 1 metre for 30 minutes. IPX8 is the rating for continuous immersion, with the depth and duration defined by the manufacturer and documented in the test report behind the rating.
A pool vacuum works for one to three hours at a time under water, cycle after cycle, season after season. That is an IPX8 duty, not an IPX7 duty. Every model in our pool range is rated IPX8, and we treat that rating as a pass/fail item rather than a feature — you either have the document or you do not.
Underwater electronics fail in one of two ways: water gets in, or heat cannot get out. A rating claim with no test documentation behind it tells you nothing about either.
What to ask for: the immersion test report for the exact model number you are importing, not for a sibling unit in the same range. If the document covers a different model number, treat the claim as unevidenced — re-testing a modified unit is a genuine cost that belongs in your landed cost calculation, not in your margin. The IPX8 requirement treated as pass/fail is set out in full in the buying guide.
The three places where water actually gets in
Waterproofing does not fail evenly across a machine. It fails at specific points, and none of them are visible in a product photograph:
- Motor seals. The first point to fail under continuous immersion, and the most expensive to repair.
- Battery compartment seals. The seal protecting the lithium pack. A pinched or under-specified seal here is how a “waterproof” unit becomes a corrosion claim.
- Charging contacts. The external contacts and their covers — the parts the user handles with wet hands on a wet deck.
The practical check is a sample unit on a real pool, not a showroom demonstration on a clean floor: run a full cycle, then inspect the seals and the contact area before it goes back on the charger. That single check answers more about build quality than any specification sheet, and it costs a fraction of a bad bulk order.
Runtime under load is the only runtime worth comparing
A runtime figure quoted for a single slow pass on a clean floor is not the number the machine delivers at minute sixty, with the brushes engaged and the filter basket loading up. Both figures can be perfectly accurate. Only one of them describes the work your customer is actually paying for.
Look at how a range is published. Our ST-SP1X runs 100–120 minutes on a 30 W drive system. Our dual-brush ST-SP2X runs 110–180 minutes. The 110 is the honest figure in that pair — it is the floor of a measured range, not the ceiling of a marketing one.
Cold water and a heavily loaded basket both reduce runtime, and both are the normal working conditions of a cleaner on a service route. So the two questions worth putting in writing are:
- Under what conditions was this runtime measured?
- What does the runtime look like at minute 60, with the filter loaded?
A supplier who can answer the second question has tested the machine. A supplier who answers only in peak figures has read the catalogue. How to choose a pool vacuum cleaner by pool type covers the coverage side of the same decision — a rating of 120 m² on a flat bottom does not transfer to a pool with a slope and a hopper, because the cleaner spends part of the cycle re-tracing the gradient.
Why a bigger mAh number does not buy more minutes
Battery capacity is only one of three inputs to runtime. The other two are how much current the machine draws and how hard it is working. A single soft-touch drive on a clean liner draws far less than a dual-brush unit agitating a silt-loaded floor.
That is why capacity figures and runtime figures are not interchangeable between models. The ST-SP1 carries a 4,500 mAh pack; the ST-SP2 carries 5,200 mAh. Runtime on our range is published against the drive system each model uses, because that is what actually sets the cycle length at the pool.
So compare machines the way the pool will use them: minutes per charge on the largest pool in the fleet, in the cleaning mode the customer will actually run. mAh tells you how much energy is on board. It does not tell you how long that energy lasts in the water.
The battery is the wear item — plan for year three
A lithium pack loses capacity as it is cycled and as it ages, and heat is what accelerates the process. On a cordless cleaner that makes the battery the component which ends the product’s useful life — more often than the motor, the drive or the brushes. In our own experience on the supply side, battery condition is the single most common end-of-life event for cordless pool cleaners.
This is where a specification decision turns into a commercial one, and where two very different second seasons come from:
| If the battery pack is… | What year three looks like |
|---|---|
| User-replaceable | A service part and a repeat order. The unit goes back in the water and the customer stays on contract. |
| Sealed and glued in | A warranty claim, a refund, or a working machine that becomes waste — and a review you cannot answer. |
Three questions settle this before the order is placed: what the cycle-life test actually showed and how it was run, what the replacement pack’s part number is, and how long that pack will remain available in small quantities. A cleaner with no available replacement pack becomes scrap the first time the cells fade, in the same way a cleaner with no replacement filter basket does. Over two seasons the cost that matters is unit price plus baskets plus brushes plus one battery — and that total frequently reverses the ranking of two units compared on headline price.
Cordless is a sourcing decision, not just a convenience
There is an operational argument for cordless units: no cable across the deck, no tangled float line, no connector sitting in a puddle. There is also a commercial argument that matters more to anyone buying to resell. A corded unit has to be built in regional voltage variants, which doubles inventory and splits spare-parts stock. A single cordless SKU covers North America, Europe, the Gulf and Asia without a separate production run.
Voltage is not the whole story if you also import corded units or accessories: plug type, cord length and socket compatibility still have to be confirmed market by market, and they belong on the purchase order rather than in a verbal understanding.
Seven questions to put in your next supplier email
- Send the IPX8 immersion test report for this exact model number. What depth and duration does it cover?
- What was the runtime measured under — a clean floor, or brushes engaged with a loaded filter?
- What is the runtime at minute 60 with the filter loaded?
- What did the battery cycle-life test show, and how was it run?
- Is the battery user-replaceable, and what is the replacement part number?
- How long will that pack stay available, and can it be ordered in small quantities?
- Which spare parts wear first on this model, and what is their availability?
The four cordless models, side by side
Each model in the range is specified for a different pool and a different debris load. Read the pool column first — the specification columns then show what the step up buys you.
| Model | Pool type & floor | Battery / runtime | Filtration | Drive & obstacle crossing |
|---|---|---|---|---|
| ST-SP1 | Above-ground, flat bottom | 4,500 mAh battery, IPX8 body | Coarse basket — leaves, sand, algae | Single soft-touch drive, liner-safe |
| ST-SP1X | Above-ground, flat bottom | 30 W drive, 100–120 min per charge, IPX8 body | Same basket class, with rinse assist | Triple-action: brush, rinse, suction |
| ST-SP2 | Above-ground and in-ground, flat bottom to 120 m² | 5,200 mAh battery, IPX8 body | 0.1 mm fine filter | Dual brushes |
| ST-SP2X | Above-ground and in-ground, flat bottom to 120 m² | 110–180 min per charge, IPX8 body | 0.1 mm fine filter | Dual brushes, 6 mm obstacle crossing |
Two things this table cannot tell you. All four are floor cleaners — they work the pool floor, and none of them cleans walls or the waterline, so no customer should be left expecting wall climbing. And the finer filter is not automatically the better specification: a 0.1 mm mesh holds silt, which is what keeps water clear, but it also needs rinsing more often. If a market buys almost entirely for coarse leaf debris over a vinyl liner, the coarser basket is the correct specification and the finer mesh buys nothing except a longer cleanout routine.
Where this fits
This page covers the battery, runtime and waterproofing specification layer — the three numbers that decide whether a unit survives to its second season. To compare the range on one page and match a model to a pool list, use the pool vacuum cleaner category page or browse the cordless pool vacuum cleaner range. For MOQ, OEM and private-label terms on this category, send us your target market and expected annual volume and we will confirm the structure in writing.
Frequently asked questions
How long should a cordless pool vacuum cleaner run on one charge?
Long enough to finish the largest pool it serves in a single cycle — that is the only useful benchmark. In practice, 100–120 minutes covers most flat-bottom above-ground pools, and 110–180 minutes with the larger pack suits larger in-ground pools and service routes where a mid-cycle rescue is not an option. Ask for the runtime under load rather than a peak figure measured on a clean floor, and allow for the fact that colder water and a loaded filter both reduce it.
Is IPX8 waterproofing really necessary for a pool vacuum cleaner?
Yes, for any unit with its electronics inside the body. IPX8 is the rating for continuous immersion; IPX7 and “water-resistant” describe temporary or splash exposure. Because these machines run full cleaning cycles under water, the immersion rating is the difference between a working unit and a corroded one — and the rating is only as good as the test document behind it, so ask for the report covering your exact model number.
How do you use a cordless pool vacuum cleaner correctly?
Place the unit in the pool and let it run its own cycle rather than guiding it, then remove it and rinse the filter basket before the debris dries. A coarse basket with leaf debris can be emptied weekly; a 0.1 mm fine filter needs rinsing more often, and a clogged fine filter quietly turns a good machine into a poor one by reducing flow. Charge it out of the water, with the contact area dry.
What filter rating do I need for sand, silt and algae?
Fine sand and silt are the demanding materials, because anything that passes through the basket re-suspends and settles again a metre away. A mesh rated to 0.1 mm captures both and makes a visible difference to water clarity. Coarser baskets are adequate for leaves and twigs and clog less often, which is why some pools benefit from a two-stage setup: a coarse pre-basket holding the bulk load and a fine layer doing the actual capture. Algae is a separate matter — a vacuum removes the dead algae that has settled, but if the chlorine and pH are not corrected at the same time the pool is green again within a week.
Which cordless pool vacuum cleaner is best for my pool?
There is no single best model, and a supplier who names one for every pool is describing one scenario. Work backwards from the pool list: a flat-bottom above-ground pool with a vinyl liner needs a light unit with a liner-safe drive and a coarse basket; an in-ground pool with a slope, a hopper and floor fittings needs more grip, verified obstacle crossing and a larger pack; a spa or pool step needs a compact unit with a fine filter on a scheduled cycle. Match the cleaner to the floor first, then to the debris — and check the specification questions above before the price.
Written by the Stonebotclean product team. We design and supply cordless robotic pool vacuum cleaners and floor care equipment for distributors, retailers and professional cleaning operators, and we publish our battery, runtime, filter and immersion ratings for every model. If a specification question is not answered here, ask us and we will answer it with the number.