BrightCharger FAQ

Does your method work with all battery types?

Our method works with Lithium-ion (LiB) batteries.

How does your technology improve safety?

The incredible flux of wireless technology and electrification we see today would not be possible without lithium-ion batteries (LIBs). The number of LIB powered mobile devices is increasing continuously and it is projected to reach 17 billion in 2023.

However, the more batteries there are, the more the quality varies. Statistics show an increased number of LIB fire hazards that cause danger to individuals and costly damages to property and infrastructure. The safety hazards linked to faulty batteries or chargers are likely to increase in the near future with the exploding number of new  e-bikes, scooters, skateboards, drones, power tools and other rechargeable devices. Faulty batteries and chargers are more likely to cause accidents. Even though thermal events with batteries (e.g., fires caused overheating) are statistically not that common, these events are happening more frequently. And when devices start burning, the thermal development can in the worst case be very quick, sometimes even explosive in nature. This problem is highlighted especially when consumers buy widgets and chargers overseas, outside of the scope of national or EU-wide regulations.

In many cases, LIB hazards could have been avoided by stopping their excessive charging at the right time. There have been examples of plugged-in laptops, resulting in damages worth billions of dollars for device manufacturers. The fact is that we don’t know when there will be the next major flaw in the quality of the battery or the device, and if or when they will result in potential fires. We also don’t know ignites what consequences these events will have (perhaps at airplane, when the device is plugged in?). The real question we should ask ourselves is, do we just want to wait for that to happen, or do something to prevent it?

BrightCharger’s BrightZero makes prevention of these hazards easy. The BrightZero intelligent auto cut-off integrated into chargers and outlets ensures the power feed to the battery is cut off, and the charger set to deep sleep as soon as the battery is optimally charged. This way, all the unnecessary idle and maintenance consumption of energy (used for sc. trickle charge) is prevented, until the charging is activated again by the user. The monitoring process is fully automated, taking the burden off the user’s shoulders and making charging carefree and, most importantly, safer.

Find more about how to prevent LIB hazards in our blog.

How does your technology improve user experience?

The intelligent auto cut-off monitors the charging process and ‘unplugs’ the device and charger for the user, as soon as the battery has reached 90-100% charge level, to optimize safety, battery endurance and device use time between charging sessions. Using regular chargers, users are often required to monitor the charge percentage of the battery. This often results in the device being charged for a considerably longer time (e.g., overnight) than necessary to charge the battery nearly full. With many devices (e.g., headsets) the user’s monitoring via user interface isn’t even possible. Thanks to our technology users may safely leave the charger plugged into power socket (with or without a device connected into it). In addition, our tech ensures the maximal safety when charging any device, regardless of the in-device battery management system (BMS). Our solution also works with the devices without BMS or user interface in place. Our technology has been in daily use around the world over 5 years integrated into our USB-charger. Based on the user feedback, the auto cut-off feature results in a carefree feeling: Users no longer need to worry about leaving the charger and device plugged in for longer than needed, because the power feed simply stopped, and the charger is switched to sleep mode automatically when charging any device (as soon as the battery is charged).

What consumption does your technology eliminate?

In our terminology, charging is divided into three recognized stages:

  1. Idle power (Charger connected to outlet, no load), 2. Charging consumption (includes charger power losses, battery charging and device power loss), 3. “Trickle charge” (the continual “topping-up” of battery charge at certain intervals (depending on device provider*), after a certain charge level has been reached, as long as it’s connected to a plugged-in charger).

BrightZero solution eliminates stage 1 (idle) and 3 (maintenance/trickle) consumptions, after the device is not being used** and battery has reached 90-100% charge (stage 2). 

* For example, with new laptops, when connected to a charger, the system first fills the battery, and then switches to take power from the grid.

** Our algorithm recognizes if the device (e.g., mobile phone, laptop) is used during the charging, so it won’t stop the power feed / switch off charger until the device is no longer in active use.

What calculations are you using to calculate potential energy savings?

Example 1: Annual energy saving potential, case Finland (with conservative amount of devices)

  • Number of occupied dwellings in Finland (2017*): 2 680 000


  • Number of chargeable mobile devices per household:
  • Average maintenance power of chargers (Idle power + Trickle charge): 0,5 W
  • Plug-in time of the charger – average true charging time: 8 h – 2 h
  • Charging times in a year:


0,5 W [Average maintenance power of chargers] × (8 h – 2 h) × 365 [Plug-in time of the charger – charging time, charging times in a year] × 5 360 000 [Number of chargeable mobile devices in this example from Finland] = 5 869 200 000 Wh = 5 869 Gwh / year

5 600 GWh is an estimated annual production of 700 MW nuclear power plant with 8000 h annual peak operation.

Example 2: Standby consumption costs (case Germany*)

Modern chargers are not allowed to not consume more than 0.3 W according to the EU Ecodesign Directive. If we again assume a duration of 22h in standby mode, a consumption of 2.4 kWh, again at an electricity price of 0.29 euros/kWh, results in a cost of 0.70 euros per year.

For the individual user, this seems like a small amount. But if you extrapolate the additional costs to the total population, the sum is surprisingly high: because in Germany, around 60.7 million people were using a smartphone in 2020 (source: statista).

Assuming all location devices of these smartphones remained connected to the grid in standby mode, this would result in an annual consumption of more than 145 GWh or 145 million kWh at a cost of approximately 42 million euros/a. When converted to electricity (2020 energy mix), this results in more than 58 tons of C02 emissions per year (source: UBA).

*Standby mode: energy consumption, costs and C02 emissions: source

Example 3: Energy saving potential (Global):

It can be estimated that if all mobile devices were charged with BrightCharger technology, 52 560 Gwh energy could be saved annually. This equals the energy produced by 9 average-sized nuclear power plants.

2 W [Average maintenance power of chargers, or ‘trickle charge’] × (8 h – 2 h) × 365 [Plug-in time of the charger – charging time x charging times in a year] × 12 B [Number of chargeable mobile devices globally] = 52 560 Gwh. 5600 GWh is an estimated annual production of 700 MW nuclear power plant with 8000 h annual peak operation.

What is the optimal range for charging a lithium-ion battery?

Let’s think about the fully charged device, for example, a mobile phone. Once you unplug it, you realize only after a few minutes, the battery charge may drop by as much as 5%. As a result, you might think that the battery was not full after all. This effect has a scientific explanation, which concludes that the optimal operating range of the lithium-ion batteries with smartphones is 10–90%. It’s because the battery drains the fastest from 100% to 90% and from 10% to 0%. Each battery can only be charged for a set amount of time before it wears out, and with optimal charging its useful lifespan can be prolonged significantly (1 year or more!). It is proven scientifically that charging a li-ion battery to 80% will keep it in shape for considerably longer than by charging it to 100% .This ideal charge level of 80% is usually enough for most users to make it through the rest of the day.

How long does an average li-ion battery last and how can I expand its lifespan?

Typically, a smartphone battery is designed to retain up to 80% health for 500 complete charge cycles, which means about 2,5 years. One complete charge cycle means charging the battery from close to 0% to 100%.

Keeping a phone charged in the 20-80% charged range is proven best for the battery, but it’s not always realistic in practice. You’ll put your phone on the charger at night and wake up to 100% charge. While you were sleeping, the battery was in a cycle between 99-100% for several hours, which already has started to wear out the battery unnecessarily.

The greatest benefit of BrightCharger’s BrightZero technology for the user is the carefree feeling that is provides. It ‘unplugs’ the charger and the device for the user at the right time by cutting the power feed to the device and setting the charger to sleep as soon as the battery is almost fully charged. This improves safety (prevents potential battery, device, and charger fires), prolongs the battery’s lifespan, and saves energy. Longer battery lifespan also saves user’s money, as they do not need to purchase a replacement battery or a new device.

Where can I find more information about prolonging battery life?

Cadex is a battery research company with more than 30 years of experience in lithium-ion batteries. Number of extensive studies can be found at their Battery University database. One of their most interesting and useful studies shows that when a battery is charged up to 80% (instead of 100%), it increases useful battery life by 50%, which equals 1 year or more, until the battery becomes useless (=battery’s max capacity drops down to 70%).

Why does BrightZero algorithm stop charging between 90-100% by default?

The value can be set, but it’s scientifically proven that charging should be stopped a little before the battery is full. The exact battery state, where the charging stops, depends on the battery’s health, sc. Max capacity, which are all extremely different, and varies between batteries and charging sequences. Our default charge level is set at 90-100%, which is a bit above the sc. Optimal 80%. As soon as that level is reached, the power feed to the battery is cut-off totally at the charger. For the user, the battery won’t drain below 80% right away, when the device is taken in use after charging. With an ordinary charger, the battery is held at 100% for a long time (usually overnight). Each charging (and discharge) cycle lowers the battery’s maximum capacity. Although smart devices indicate that the battery is 100% full, in fact the battery will not last as long because real battery capacity is lower than new battery capacity. With some smart devices, you can check battery capacity, e.g., in iPhone Settings: device/battery/battery health (shows current battery max capacity in %). There are a lot of different methods for measuring a battery’s state of charge (SoC), and the fact is none of these are exactly accurate. Here’s an excellent article exploring this topic. In any case, device batteries can only be charged for a limited amount of time before they may become damaged or worn out. This becomes reality when the battery’s max capacity drops down to 70% and below.

How does the BrightZero algorithm work?

The algorithm starts operating after the activation (usually when the charger is plugged into an outlet and device connected to a charger). Charge state is measured by averaging and analyzing power consumption over time periods. When the battery is approximately 90% full, the current level starts to decrease, and BrightZero algorithm identifies the correct point when the charging process should be stopped to maintain battery health. If the device (phone etc.) is used while , the algorithm recognizes this, and will not stop charging until the device is no longer used. BrightZero algorithmcan can be integrated into various charger and outlet controllers, and it works at USB-C, USB-A and 110-240 VAC power sources.

I used a charger with BrightZero feature, but the charging wasn’t stopped until the battery was charged to 100%?

All lithium-ion batteries have extremely different charging processes and capacities, which indicate their overall health. This is based on general usage, number of charge and discharge cycles, temperature, charging methods, etc. Generally, when the battery reaches approximately 90% charge level, the current starts to decrease and BrightZero algorithm identifies the correct point when the charging process should be stopped to maintain battery health. In some cases (especially newer devices that are designed to be charged at 5V or more), the battery might reach 100% until the current starts to decrease. However, instead of staring too rigidly the exact percentage (“100” and “0” on the user facing indicator don’t have anything to do with the actual state), the main thing is to prevent overcharging as soon as the charging process is completed (even in cases the battery manages to reach 100%).

Does the power feed really cut down to 0 after the battery is charged?

Regarding a charger implementation, there will be a very minimal fraction of power feed still left, when the charger is set to deep sleep mode after the charging is stopped. This energy is used by an algorithm to wake up charger when another charge starts (device plugged in).

Does the solution require an activation button / changes to the charger’s or outlet’s mechanics?

The BrightZero feature can be activated at USB-C and USB-A by plugging in a charging cable. The AC outlet implementation needs a separate activation (button etc.) to trigger BrightZero.

Don’t new smart phones already have battery optimization software?

Yes, many of them have one. It is scientifically proven that charging a li-ion battery to 80% will keep it in shape for a much longer period than by charging it to 100%. For most people, 80% is enough to make it through the rest of the day. Keeping this in mind, the newest iOS and Android operating systems provide options for optimized charging. For example, on iOS, if enabled by user, the feature will charge the battery fast up to 80%, and switch then into ‘trickle charge’ mode, topping up the battery to keep it at 80-100% range the whole time it’s connected to the charger (often for many hours straight). The providers also offer manuals for users about manually charging the device correctly to prolong battery life, resulting in extra work for the user. However, there are still billions of devices that have no battery management system (BMS) and smart interface for monitoring battery health. Such devices are also charged continually every day*.

In addition, the currently available battery management systems (BMS) are highly dependent on the device and battery type, which result in interoperability problems across device providers. This can create additional costs. Moreover, an increasing number of devices are delivered with ‘glued-in’ batteries, like iPhones, headsets, etc. With such devices, optimal charging and the prevention of overcharging are extremely important to maintain battery’s longevity, especially when fast charging is applied to them, to avoid unnecessary replacements and costs.

BrightCharger’s BrightZero is a charger-based solution has its default charge level set at 90-100%, slightly above the optimal 80%. As soon as that level is reached, the power feed to the battery is cut-off and the charger is put to sleep. For the user it means, the battery won’t drain below 80% right away, when the device is taken in use after charging. Moreover, the battery will avoid the unnecessary, continuous stress caused by trickle charge mode (e.g., during overnight charging), when it’s still plugged in. Cutting off power feed also improves safety of users and infrastructure, and user experience by our tech basically ‘unplugging’ the charger and the device at the right moment for the user. The solution saves energy when applied to daily charging of billions of devices (elimination of idle and trickle charge consumption). The users of our tech won’t have to think about the right charging sequence. What is more, they do not need to know if their device has a battery management system, how it works, or how to activate it. We think that everyone should have access to optimized and safe charging with any device, anywhere. That’s why our technology is developed not to be dependent on device, battery type or even voltage range.

*There are about 4.5 billion smartphones in 2022, which represent ca. 26% of 16 billion hand-held devices in 2022, and iPhones as high-end products are a tiny fraction, ca. 1/3 out of all smartphones.

Don’t some chargers already stop charging the battery after it is full?

It is true for some device-specific chargers. The charging process can be monitored. However, this typically involves a high level of complexity in the battery or in the charger. Furthermore, a specific charger with the monitoring capability can often only be used for one battery type it was designed for, and interoperability of various manufacturers or different standards is not possible. Some devices, like rechargeable hoovers and drillers, are static, meaning they are used for a certain amount of time until they are left unused and ‘resting’ without any activity.

BrightCharger’s technology can stop the charging and shut off the charger before the battery is full, which is the optimal way to charge lithium-ion batteries. Our technology is also suitable for non-static mobile and handheld devices which may be in use while plugged into the charger. If the device is used simultaneously when charging, our algorithm recognizes that, and won’t stop charging until the device is left unused and the battery is optimally charged. The technology can be scaled easily into all chargers and outlets because it is not dependent on device, battery type or voltage.

You can’t overcharge a laptop’s battery because it already has intelligence for optimized charging

Many new laptops are equipped with a battery specific BMS. Depending on device manufacturer’s settings, when a laptop is connected to a charger and charger plugged into socket outlet, the system first fills the battery, and then switches into taking power from the grid, and performing trickle charge on the battery from time to time to keep it topped up to a dedicated level set by the user or/and by manufacturer settings. This is done repeatedly as long as the laptop is connected to a plugged-in charger (often many hours or even days).

However, keeping a laptop fully charged constantly will affect the battery longevity: The continuous power from the grid to the laptop sets a higher voltage level, at which the full lithium-ion battery is kept for prolonged periods. This results in the degrading of the battery as it consumes its capacity. Therefore, it’s recommended to unplug the laptop and run it using the battery during the day, to keep the electrons “moving” and prevent the battery from losing capacity (=battery won’t be useful after its maximum capacity falls below 70%). However, user often forget this and leave their laptops charging for extended periods of time.

BrightCharger’s charger-based technology (BrightZero) optimizes the battery capacity and safety of laptops, users, and infrastructure (e.g., prevents battery, device, and charger fires in office buildings) by cutting off power and setting the charger into sleep as soon as the battery is optimally charged, and the device is no longer used.

Example use case:

  • A user comes to work early in the morning and opens a laptop. Battery level is probably around 89%.
  • User starts working, and around noon realizes there’s 65% of battery charge left.
  • User plugs the laptop to a charger that has BrightZero™ intelligent charging control
  • BrightZero algorithm monitors and manages the charging current and recognizes when the user is using the laptop while it’s plugged in, and lets the laptop operate the way it’s designed by the manufacturer (e.g., taking power from the grid while the battery is full).
  • By the end of the workday, the user closes the laptop lid, does not unplug the charge cable, and leaves the office for the weekend.
  • Soon, the charger’s BrightZero algorithm recognizes the laptop isn’t in active use, and that the battery is charged.
  • BrightZero cuts power feed to the laptop and sets the charger into deep sleep. This way it improves the office’s fire safety as well as the battery’s health by keeping its electrons “moving” only to power the minimal usage of laptop’s sleep mode over the weekend.

*For more information, here’s an excellent read about the ways that will damage a laptop’s battery.

Do you have patents for your invention?

We have a comprehensive IPR portfolio which is continuously growing. The core patents for our solution cover Charging Control and AC Charging Control.