21.6V 10.4Ah IP68 Waterproof Lithium Battery for Pool Cleaning Robots & Underwater Cleaning Equipment — Multi-Stage Waterproof
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21.6V / 10.4Ah 18650 lithium battery pack engineered for robotic pool cleaners, underwater hull cleaning robots, and submersible cleaning equipment
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IP68 multi-stage waterproof, validated to 20–30 meters submersion depth
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Cell-level fuse protection — each individual 18650 cell contains an independent fuse; any single cell short-circuit triggers immediate fuse blow without affecting adjacent cells or the pack
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1C charge and discharge rate; 800-cycle service life; −20°C to +60°C operating range
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Compact lightweight design; custom voltage / capacity / dimensions / IP rating / OEM accepted
Product Description
The Balder Power 21.6V 10.4Ah lithium battery pack is purpose-built for robotic pool cleaners, underwater hull cleaning robots, and submersible cleaning equipment platforms where the battery operates continuously in a fully submerged environment and safety under sustained water exposure is the primary design requirement.
At 21.6V / 10.4Ah, this pack delivers 224.6Wh of energy through an 18650 cell architecture that prioritizes both runtime and safety in the confined, water-immersed conditions of pool robot battery bays. The 1C charge and discharge rate provides the measured, thermally controlled current profile appropriate for a battery that charges and discharges while submerged — avoiding the heat accumulation that higher-rate designs generate and that water immersion alone cannot adequately dissipate in a sealed enclosure.
The IP68 multi-stage waterproof architecture is validated to 20–30 meters submersion depth. Unlike single-barrier enclosure designs that rely on one gasket compression seal as the sole defense against ingress, the multi-stage system uses sequential sealing layers — each independently tested — so that degradation of one barrier does not create a direct ingress path to the cell array. This architecture is specifically relevant for pool cleaning robots that complete hundreds of full submersion cycles per season, repeatedly transitioning between wet and dry conditions in chemical pool water environments that accelerate gasket degradation in single-barrier designs.
The defining safety feature is cell-level fuse protection built into the 18650 cell array. Each individual cell contains an independent fuse element. If any single cell develops an internal short circuit — the primary failure mode in 18650 packs subjected to repeated mechanical vibration from cleaning robot drive systems — that cell’s fuse blows immediately, isolating the fault without propagating current through adjacent cells or triggering thermal runaway in the pack. This cell-level isolation is a meaningful safety advance over standard BMS-only protection, where a cell-level short must first drive enough current to trigger the BMS response before the fault is controlled. For pool cleaning equipment operating in occupied or near-occupied pool environments, this protection architecture provides an additional safety margin that standard portable battery packs do not offer.
Technical Parameters
| Parameter | Specification |
|---|---|
| Brand | Balder Power |
| Application | Robotic pool cleaners, underwater hull cleaning robots, submersible cleaning equipment |
| Battery Type | Li-ion 18650 |
| Nominal Voltage | 21.6V (fully charged) |
| Rated Capacity | 10.4Ah |
| Energy | ~224.6 Wh |
| IP Rating | IP68 — multi-stage waterproof, 20–30 meters submersion depth |
| Cell Protection | Cell-level independent fuse — each cell individually fused for short-circuit isolation |
| Max Charge Current | 1C (10.4A) |
| Max Discharge Current | 1C (10.4A) |
| Cycle Life | 800 cycles |
| Operating Temperature | −20°C to +60°C |
| Dimensions | Customizable to OEM specification |
| Weight | Customizable to OEM specification |
| Warranty | 12 months from shipment date |
| OEM / ODM | Accepted — voltage, capacity, dimensions, IP rating, connector type, enclosure markings customizable |
| Place of Origin | Guangdong, China |
Features & Advantages
✅ 🛡️ Cell-Level Fuse Protection: Independent Short-Circuit Isolation for Each 18650 Cell
Each 18650 cell in the Balder Power pack incorporates an independent fuse element that responds to cell-level short-circuit events faster than the pack BMS can react. If vibration, manufacturing variation, or electrochemical aging causes any individual cell to develop an internal short, that cell’s fuse blows immediately — isolating the fault at the cell level before it can drive current into adjacent cells, generate heat in the cell array, or trigger a cascading failure. This protection mechanism is particularly important for pool cleaning robots whose drive systems generate continuous mechanical vibration transmitted directly to the battery mounting, and whose operating environment — chemical pool water — can accelerate cell degradation over time. The BMS provides the second layer of protection at the pack level; the cell fuses provide the first layer at the individual cell level, creating a defense-in-depth safety architecture suited for equipment operating in occupied pool environments.
✅ 🌊 IP68 Multi-Stage Waterproof to 20–30 Meters
The enclosure uses a multi-stage sealing architecture with sequential independent barrier layers validated to IP68 standard at 20–30 meters submersion depth. Where single-gasket enclosures rely on one compression seal whose integrity degrades progressively with repeated thermal cycling and chemical water exposure, the multi-stage design ensures that partial degradation of any one barrier does not create a direct ingress path to the cell assembly. This architecture is designed for the operating reality of pool cleaning robots: hundreds of submersion cycles per season in chlorinated or saltwater pool environments, repeated chemical exposure to pool treatment compounds, and the thermal cycling that occurs as the robot transitions between heated pool water and ambient air temperature during recovery and charging cycles.
✅ 🔧 Compact Lightweight Design with Fully Customizable Dimensions
The pack uses a compact 18650 cell layout optimized for the battery bay geometry of current-generation robotic pool cleaners and underwater hull cleaning platforms. Weight and dimensions are configurable to customer specifications — OEM robot manufacturers can specify the exact envelope constraints of their battery compartment and receive a pack designed to maximize capacity within that footprint. Voltage (from 12V to 48V), capacity, IP waterproof rating, connector type, and enclosure material are all available for OEM/ODM customization, allowing the Balder Power pack to serve as the direct battery specification for new robot platform designs as well as a retrofit upgrade for existing robot models requiring higher capacity or improved waterproofing.
Packing & Delivery
Secure & Compliant Packaging
To ensure safe transit for Class 9 Dangerous Goods, every battery is protected with high-quality Pearl Wool (EPE Foam) and encased in UN-certified cartons. For bulk shipments, we utilize sturdy Plywood or Plastic Pallets wrapped in shrink film, fully compliant with international shipping regulations.
Global Shipping Options (Incoterms)
We support flexible shipping terms to suit your business needs, including FOB, CIF, and DDP (Door-to-Door including tax).
- By Sea: The most economical choice for bulk orders.
- By Air / Express: Fast delivery for samples (DHL/UPS/FedEx).
- By Railway: Reliable CR Express service for European and Central Asian markets.
Production Lead Time
Our lead time varies based on product customization:
| Product Type | Samples | Bulk Order |
|---|---|---|
| Standard Models | 5 - 7 Days | 14 - 20 Days |
| Customized Models | 7 - 14 Days | 14 - 28 Days |
Global Safety Standards & OEM Compliance
When integrating a custom lithium battery pack into your device, regulatory compliance is non-negotiable. At Balder Power, our OEM battery solutions are engineered from the ground up to pass rigorous international safety tests. We ensure your custom packs meet CE, UL, and IEC performance standards, while providing the mandatory UN38.3 and MSDS reports required for seamless global shipping. From initial prototyping to final certification, we eliminate compliance hurdles to accelerate your product’s market entry.
FAQ
Q1: What is the multi-stage waterproof architecture and how does it differ from standard IP68 enclosures?
Standard IP68 enclosures typically use a single compression gasket as the primary seal between the lid and the body. If that gasket degrades — through chemical exposure, thermal cycling, or mechanical deformation — there is no secondary barrier preventing water ingress. The Balder Power multi-stage waterproof design uses sequential independent sealing layers, each rated to IP68 independently. Degradation of one layer does not create a direct path to the cell assembly; the remaining barriers maintain protection until the next service inspection. For pool cleaning robots completing hundreds of submersion cycles per season in chemically treated water, this architecture provides the seal longevity that single-barrier designs cannot sustain across a multi-season service life.
Q2: How does cell-level fuse protection work and why does it matter for pool cleaning robots specifically?
Each 18650 cell in the pack contains an independent fuse element integral to the cell construction. If an internal short circuit develops in any individual cell — due to vibration fatigue, manufacturing variation, or electrochemical aging — that cell’s fuse blows immediately, isolating the faulted cell from the rest of the array before it can drive fault current into adjacent cells. Standard BMS-only protection responds at the pack level: it detects abnormal current or voltage at the pack terminals and opens the output circuit, but only after the cell-level fault has already begun propagating. The cell fuse acts before the BMS, at the cell level, providing a faster and more localized response. For pool cleaning robots operating in occupied pool environments — where a thermal event in the battery would be a serious safety incident — this defense-in-depth architecture is the appropriate safety standard.
Q3: What is the minimum order quantity and is OEM/ODM customization available?
Standard wholesale minimum order is 10 units, with tiered pricing at 30, 50, and 100+ units. OEM/ODM customization covers voltage (12V to 48V), capacity, enclosure dimensions, IP waterproof rating, connector type, and enclosure markings. Dimensions and weight are fully configurable to match the battery bay geometry of your robot platform — provide your mechanical interface drawing and we will design the pack to maximize capacity within your specified envelope. OEM minimum is 50 units with a 7–10 working day lead time after sample approval. Engineering samples (1–3 units) are available before volume commitment.
Q4: Is this battery compatible with chlorinated pool water and saltwater pool environments?
Yes. The IP68 multi-stage sealed enclosure provides complete isolation of the cell assembly from pool water chemistry. The enclosure exterior material is selected for resistance to the chlorine concentrations used in standard pool sanitation (typically 1–3 ppm free chlorine) and the higher concentrations present in commercial pool environments. For saltwater pool systems (typically 2,000–4,000 ppm sodium chloride), the exterior surfaces are exposed to a more aggressive corrosive environment; we recommend specifying the enclosure material for saltwater compatibility on OEM orders to ensure the exterior surface treatment is appropriate for the specific salt concentration of your application.
Q5: What is the expected runtime for a typical robotic pool cleaner and how long does a full recharge take?
Runtime depends on the pool robot’s motor power draw. At a typical 150–200W pool robot motor load (approximately 7–9A at 21.6V), the 10.4Ah pack provides approximately 60–90 minutes of continuous cleaning operation. Full recharge from depleted at 1C takes approximately 1 hour on a compatible 10.4A charger. For commercial pool operators running robots on extended daily cleaning cycles, a two-pack rotation — one cleaning while one charges — provides continuous coverage without interruption.
Q6: Can the pack be charged while submerged, and what is the correct charging procedure?
The pack must be charged in a dry environment with the charging connector properly mated and sealed — not submerged during charging. Remove the robot from the water, connect the charger to the sealed charging port, and complete the charge cycle before returning the robot to the pool. Charging while submerged is not supported and would void the warranty. The 1C charge rate and BMS overcharge protection ensure the charging cycle terminates automatically at full capacity without requiring manual monitoring.
