Forumslader
avrfan Tools
Pairing the smartphone with the "Forumslader", a bicycle dynamo charger.
- Downloads
- 3.1K+
- on Google Play
- Price
- Free
- No in-app purchases
- Updated
- Aug 31
- 2025 · v2.07.20250828
Screenshots
About Forumslader
Using a bluetooth connection, the Forumslader can be used as a speedometer as well as an altimeter to measure your speed and altitude. It has a high-quality power supply and an easy to use interface to access both operating and internal data.
You may connect additional sensors as well, such as an air pressure sensor (on the circuit) or a thermosensor (external or on the circuit).
The following data can be displayed, evaluated and saved with a connection to your smartphone:
- current speed
- current gradient
- current height
- kilometers travelled
- travel time
- time
- battery charge
- battery power
- used power
- dynamo power
- current
- max./min. gradient and speed (per day and tour)
- travelled height
- last battery capacity
- voltage of every battery cell with an accuracy of 5 mV
The app supports these languages: German, English and Dutch. Other languages can be made available upon request.
Capturing this data is done without a connection to the smartphone and is saved within the Forumslader itself. The Forumslader can store more data than any other device currently available and is built to last.
The radio range of the sender is up to 30 meters, or 1-5 meters when placed in the head tube or the recumbent bike frame tube. If an upgrade for the range is needed, you can add a wireless coupler set with a 25 centimeter cable allowing you to use an external BT-antenna.
The thermosensor is not needed because its usage is only for measuring temperature, but when used it has to be placed in the airstream. The inner temperature of the Forumslader will be measured as well.
For a correct distance computation you must have the correct pole number of the dynamo, as well as the correct tire circumference in millimeters (This may be set under “system”). To get an accurate tire circumference you can use the speedometer or check measured data from a previous ride. The most accurate data is obtainable by recording a long route and comparing your data in relation to the GPS-distance measurement.
Pedal frequency sensors and chest straps can be integrated too using the “connect to FL” option. When connecting these, ensure your sensor has been turned on. The display must be adjusted to display the pedal frequency or the pulse rate within data fields.
You may connect additional sensors as well, such as an air pressure sensor (on the circuit) or a thermosensor (external or on the circuit).
The following data can be displayed, evaluated and saved with a connection to your smartphone:
- current speed
- current gradient
- current height
- kilometers travelled
- travel time
- time
- battery charge
- battery power
- used power
- dynamo power
- current
- max./min. gradient and speed (per day and tour)
- travelled height
- last battery capacity
- voltage of every battery cell with an accuracy of 5 mV
The app supports these languages: German, English and Dutch. Other languages can be made available upon request.
Capturing this data is done without a connection to the smartphone and is saved within the Forumslader itself. The Forumslader can store more data than any other device currently available and is built to last.
The radio range of the sender is up to 30 meters, or 1-5 meters when placed in the head tube or the recumbent bike frame tube. If an upgrade for the range is needed, you can add a wireless coupler set with a 25 centimeter cable allowing you to use an external BT-antenna.
The thermosensor is not needed because its usage is only for measuring temperature, but when used it has to be placed in the airstream. The inner temperature of the Forumslader will be measured as well.
For a correct distance computation you must have the correct pole number of the dynamo, as well as the correct tire circumference in millimeters (This may be set under “system”). To get an accurate tire circumference you can use the speedometer or check measured data from a previous ride. The most accurate data is obtainable by recording a long route and comparing your data in relation to the GPS-distance measurement.
Pedal frequency sensors and chest straps can be integrated too using the “connect to FL” option. When connecting these, ensure your sensor has been turned on. The display must be adjusted to display the pedal frequency or the pulse rate within data fields.
What’s new
Version 2.07.20250828 · Updated August 31, 2025
- for API level 35 - Bluetooth revised - Firmware update revised
User reviews
Well thought out and has many useful features. My only issue is that it often disconnects upon startup failing to recognize itself. More annoying than anything else but, I appreciate the work that went into the application. The Forumslader itself is a fantastic piece of engineering.
Better than all the commercial stuff out there. Best charging solution you can buy for your bike.
The Forumslader is an awesome product, but this app is what sets it apart from other similar products, like the Cinq Plug 5 Plus. It's a pretty simple app, but shows you exactly what you need to see to monitor speed / distance etc. One very minor issue I had was I couldn't change the wheel circumference as it was gr...
The forumslader USB charger is unique . It is a powerful USB charger for your bicycle with a buffer battery capable of charging your mobile phone even a low speed. With the Bluetooth module it uses the dynamo pulse to calculate speed and travelled distance, even with no phone connected, so at all time you know the t...
Top App, läuft sehr stabil, ist übersichtlich und variabel konfigurierbar. Es gibt lediglich zwei Kleinigkeiten, die ich mir noch wünschen würde: - Funktion um den Tageskilometerzähler automatisch jeweils um 0:00 Uhr zurücksetzen zu lassen. - Unterstützung von Splitscreen um die App einfacher gemeinsam mit Navi anz...
Works like a champ!
Alternatives to Forumslader
Looking for apps like Forumslader? Here are 6 similar Android apps on Google Play. All of them are free to download.
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| Forumslader | – | Free | 1,000+ | Aug 31, 2025 | |
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