Cordless vs Corded Robotic Pool Cleaners: The Real Trade-Offs
Strip away the brand marketing and most pool-robot buyers face one decision: corded or cordless. It is the decision that determines whether the robot gets used every week or sits in the garage, and it is the decision most guides answer with cheerleading for whichever side pays them. Here it is straight — the real trade-offs, the ownership math, and a simple rule at the end.
Corded: unlimited runtime, one cable to manage
A corded robot plugs into a power supply at the poolside and runs until the cycle ends. There is no battery to age, no charge time to schedule, and suction stays consistent to the last minute of the cycle. That is why corded robots still dominate large pools and daily-use pools: the cleaning job is never cut short by a dying battery.
The costs are physical, not financial. The cable is the #1 corded failure item — it tangles, kinks, wears at the swivel, and needs to be laid out, managed, and stored every cycle. The power supply needs a dry, ventilated, GFCI-protected position within cable reach of the pool, and cable length is a hard eliminator: a 40 ft pool on a 50 ft cable is a corner-cutting machine, and no software update fixes a cable that is too short. Corded robots also need the power supply itself protected — it is a ~$210 replacement part and a surge target, so surge protection is not optional.
The corded anchors in our buying guide are the Dolphin line: the Encore at the budget end, the Active 20 as the mid-tier sweet spot for most in-ground pools up to ~40–50 ft, the Active 30 for larger pools and finer filtration, and the S300i at the top. What you are buying into with Dolphin is not just the robot — it is the deepest parts ecosystem in the category, which matters at year 4, not day 1.
Cordless: convenience first, battery discipline always
A cordless robot has no cable to tangle, manage, or trip over, and storage is dramatically simpler — drop it in, run it, lift it out, charge it. That convenience is real, and it is the reason cordless is the category's fastest-growing segment: the robot that is easy to use is the robot that actually gets used.
The trade is battery discipline, and it has three parts. Runtime per charge is the hard limit: the mainstream cordless class runs roughly 90–150 minutes per charge, with premium models reaching 4.5 hours on all-surface cycles and up to 7.5–10 hours in floor-only or surface modes. If your pool needs more cleaning than one charge delivers, you are cleaning in shifts — and a robot that dies mid-cycle parks itself and waits for you. Charge time is the scheduling cost: roughly 4–4.5 hours on the models in this comparison, which means a dead robot is not available again the same afternoon. Battery degradation is the long-term cost: lithium packs lose capacity with cycles and age, and a replacement pack is a real second purchase — check the pack price for your exact model before buying, because it varies widely and it belongs in the 7-year math, not as a surprise at year 4.
The cordless challengers in our buying guide are Beatbot and Aiper: Beatbot at the premium tier (AquaSense family, including surface skimming and app mapping on higher models) and Aiper at the value-to-mid tier (Scuba line, including the S1's floor-only and eco modes). See the head-to-head in Beatbot AquaSense vs Aiper Scuba for the model-by-model numbers.
Cleaning-cycle length vs pool size
This is where the decision gets concrete. A corded robot's cycle length is a setting; a cordless robot's cycle length is a battery budget. Match them to your pool:
| Pool | Corded answer | Cordless answer |
|---|---|---|
| Small / above-ground, up to ~1,600 sq ft | Works, but cable management for a small job | Ideal — a 150-minute robot finishes it in one cycle with room to spare |
| Standard in-ground, up to ~2,150 sq ft | Ideal — unlimited runtime, no battery math | Works — a 4.5-hour all-surface robot finishes it in one cycle |
| Large / complex, 2,150–3,875 sq ft | Ideal — cable length is the only constraint, and the top corded models carry the longest cables | Only the premium tier (Ultra/X class) finishes it in one cycle; mid-tier cordless cleans in shifts |
| Daily-use pool in season | Ideal — no charge downtime between runs | Workable only if the charge window fits your schedule; daily cycling also ages the battery fastest |
The 7-year cost, honestly compared
Corded 7-year parts exposure on a mainstream Dolphin runs roughly $200–$450 (filters, tracks, panels, and the occasional power supply — see the buying guide's parts table). Cordless adds one line item corded does not have: the battery pack replacement. We do not quote a single price for it here because it genuinely varies by model — look it up for the exact model you are considering and add it to the parts total before comparing stickers. The other cordless cost is softer but real: a robot whose battery has degraded to half its original runtime cleans half the pool per cycle, which owners experience as "the robot got worse" and often misdiagnose as a motor problem (see the wall-climbing diagnostic for the battery-sag test).
Against that, corded's hidden cost is the cable: replacement cables and swivel wear are the corded equivalent of battery aging — slower, cheaper per incident, but a recurring handling tax on every single cycle.
The simple rule
This post expands the buying guide, Steps 2–3. Next decision: Best Robotic Pool Cleaner for Above-Ground Pools.