Configurable Overtemperature Protection
Stop charging when it matters mostβin hot conditions.
Why Heat Kills Batteries
Sometimes, it's better to just stop charging in high temperature situations, like when using your phone as a navigation device on your car dash in hot summer days.
The Heat Problem
In such cases, heat degrades the battery's internal structure more than anything. If exposed to heat for a long time, the battery eventually swells and can ruin your phone or explode.
What Science Says
All phones have some sort of overtemperature protection, but the factory threshold is often set too high to properly protect a battery from premature aging (typically 50Β°C / 122Β°F).
Lithium-ion batteries are very sensitive to heat. A battery dwelling above 30Β°C (86Β°F) is considered elevated temperature. (Battery University, BU-808) Exposing the battery to high temperature while in a full state-of-charge can be more stressful than cycling.
Chargie's Solution
Chargie allows you to charge your phone at much lower temperatures, so that your battery health doesn't degrade as much during long sunny drives or hot summer nights. Automatically.
Navigation & Driving
Protect your phone from heat damage during long road trips with GPS active
Outdoor Use
Stop charging in direct sunlight to prevent thermal stress
Fire Prevention
Eliminate the risk of battery swelling and explosions from heat exposure
Customizable Threshold
Set your own temperature limit for maximum control
Heat roughly doubles ageing every 10 Β°C
Lithium-ion side reactions follow Arrhenius kinetics: the warmer the cell, the faster its capacity fades. Charging while hot is the worst combination because voltage stress and heat stack.
Where the heat comes from
Charging itself dissipates a few watts inside a phone. Add a dashboard in the sun, a navigation app driving the GPU, or a pocket, and the battery can sit at 40β45 Β°C for hours. Manufacturers rate their cells for 0β45 Β°C charging, and every degree above about 30 Β°C measurably shortens life.
What the protection does
Chargie reads the phone's battery temperature through the app and cuts the charging current when it crosses the threshold you set, 35 Β°C by default. Without current flowing the phone cools by several degrees within minutes. Charging resumes automatically once it is back under the limit, so the phone still ends up charged, just without cooking.
Why the threshold is adjustable
Hot climates and car use need a higher setting to charge at all; home overnight charging can use a stricter one. The chart shows why even a few degrees matter: the capacity lost per year at 40 Β°C is roughly four times that at 25 Β°C for a cell kept near full.
Show data table
| Temperature (Β°C) | Held at 100% charge | Held at 40% charge |
|---|---|---|
| 0 | 6% | 2% |
| 25 | 20% | 4% |
| 40 | 35% | 15% |
| 60 | 40% | 25% |
Source: Battery University BU-808, storage-loss table
Show data table
| Situation | Typical battery temperature |
|---|---|
| Car dash, sun | 48 Β°C |
| Navigation + charging | 42 Β°C |
| Pocket, charging | 39 Β°C |
| Desk, charging | 34 Β°C |
| Desk, idle | 28 Β°C |
Source: Chargie app telemetry, median values from user-reported sessions (2024β2026)