Reliable and fast on-board battery charging is a relatively recent development for floor care machines that provides tremendous value to operators. Most notably, mounting a charger on-board ensures that it will be available whenever and wherever the machine needs to be charged. This significantly improves opportunity charging capabilities, enabling longer run times and better operational efficiency.
However, to achieve optimal on-board charging for floor care machines, OEMs should consult their battery and charging partners to ensure the charging device is adequately protected. Providing reliable and affordable performance requires collaborating on and thoroughly testing batteries, chargers, and charge algorithms.
One such test—the Ingress Protection rating—determines a charger’s protection against the ingress of foreign objects and liquids.
Traditional Barriers to On-Board Charging for Floor Care
Floor care machines can be a difficult use case for on-board battery chargers. Throughout the machine’s life, its components are subjected to a wide variety of stresses:
- Vibration and shock from normal operation
- Fluctuating temperatures and humidity due to heating up water and cleaners or steam
- Direct exposure to water and cleaning supplies (e.g., sprays, splashes. spills, submerging)
These conditions directly increase the likelihood of machine failure and safety hazards. While sealed batteries—AGM or gel—help ensure the energypower source remains secure and safe, charging components have been much more difficult to protect and seal.
As a result, most OEMs have continued to design their machines for off-board charging.
However, this challenge has been significantly reduced through the advancements of lithium batteries (and reclaiming on-board space), continued charger technology development, and by meeting industry sealing standards. OEMs can now provide reliable, safe, and affordable on-board charging to increase efficiencies, prevent costly charger swaps or other maintenance, and decrease machines’ total cost of ownership (TCO).
Sealing On-Board Chargers for Floor Care Machines
Sealing an on-board electronic component requires substantial mechanical, electrical, and thermal design effort—and very precise manufacturing. The components must be robust to protect against stresses from everyday use and sealed to ensure water and cleaning supplies don’t damage them or create safety hazards.
Following design and prototyping, on-board chargers must also be thoroughly tested to ensure that the product operates reliably in the expected range of physical and thermal conditions throughout the machine’s life. This testing will provide a rating based on standards developed by the International Electrochemical Commission (IEC).
Ingress Protection Sealing—IPXX
The IP (Ingress Protection) rating is the IEC’s standard for measuring a device’s levels of protection against dust and liquid. It is written as “IP” followed by two digits (i.e., IPXX) and is used for all products—from chargers to smartphones.
This standard defines sealing requirements worldwide and immediately tells OEMs and operators how protected a charger or another product is.
Resistance to Solid Objects—First Digit
The first digit in the two-digit IP code indicates the level of protection against solid objects of various diameters (using the “⌀” symbol). A product’s IP rating for solid objects can range from IP0X (i.e., providing no special protection) to IP6X (i.e., “Dust Tight”).
The seven levels of Ingress Protection for solids distinguish:
- IP0X – No protection
- IP1X – No ingress of solid foreign objects 50 mm ⌀ and greater.
- IP2X – No ingress of solid foreign objects 12.5 mm ⌀ and greater.
- IP3X – No ingress of solid foreign objects 2.5 mm ⌀ and greater.
- IP4X – No ingress of solid foreign objects 1 mm ⌀ and greater.
- IP5X – “Dust Protected” (i.e., minimal ingress of dust but equipment will operate safely)
- IP6X – “Dust Tight” (i.e., no ingress of solid objects at all.)
Products earn their IP rating for solid materials by being placed in a sealed chamber and then subjected to dust or other fine materials being blown at them.
Resistance to Liquids—Second Digit
The second digit in the two-digit IP code indicates to what degree the device is protected from water and liquids. As with the first digit, IPX0 provides no special protection. However, the scale for liquids operates differently than for solid objects.
First, liquid protection can range up to IPX9 (i.e., protection against the effects of close-range, high-pressure and high-temperature spray downs). Second, the test for determining protection levels 1-6 differs from those used to determine 7, 8, and 9 ratings. Levels 7 and 8 are determined by submerging the object in liquid and at various pressures. The level 9 test involves high-pressure and higher-temperature jet sprays.
Because the assessments differ, tested objects may display multiple IP ratings for liquids.
The 10 levels of Ingress Protection for liquids distinguish:
- IPX0 – No special protection
- IPX1 – Protection against dripping water
- IPX2 – Protection against dripping water when tilted up to 15 degrees from normal
- IPX3 – Protection against spraying water
- IPX4 – Protection against splashing water
- IPX5 – Protection against low-pressure water jet spray for at least 3 minutes
- IPX6 – Protection against heavy water jet spray for at least 3 minutes
- IPX7 – Protection against the effects of immersion in up to 1 meter of water for 30 minutes
- IPX8 – Protection against the effects of continued immersion in water at depths greater than 1 meter
- IPX9 – Protection against close-range, high-pressure and high-temperature spray downs
Why Seal Floor Care Chargers to IP66?
Fully sealing electronics for submersion and close-range, high-pressure and high-temperature jet sprays is expensive, complex, and unnecessary. Therefore, in the floor care industry, where water and chemicals are part of everyday activities, prudent electronics engineers should strive to meet an IP66 standard.
Chargers and other items that achieve IP66 ratings indicate they’re optimally protected against all dust and heavy jet sprays—the most stressful conditions during standard operation. Battery chargers are not operational when the floor care machine is at work, but an on-board battery charger can be exposed to significant amounts of water and chemicals splashing around the machine during operation or when the machine itself is being cleaned.
And since the tests for liquid ingress change substantially beyond level 6, an IP66 rating functions as a “soft maximum.”
OEMs Should Ensure Maximum Reliability with IP66-Rated Chargers
Floor care machine designers should not attempt to mount battery chargers with lower IP ratings on-board their machines. This has been tried often, usually including some form of plastic cover surrounding the battery charger to prevent falling liquids or lightly sprayed liquids from damaging the charger. Unfortunately, the limited protection still leads to charger damage, significant replacement costs, and dissatisfied operators who will consider OEMs’ competitors.
Instead, OEMs should partner with a charger expert capable of designing, manufacturing, and testing IP66-rated battery chargers specifically engineered for on-board operation to ensure optimal performance, protection, reliability, and safety.
