PPP computer charger

The people pedal powered computer charger is a device that harvests human energy to charge a computer. The energy input comes from an ordinary bicycle in a stand that drives a generator. The energy output is the charging voltage of the computer.

Find the instructions on WikiFab !


DC connectors

Hier documenteren we onze ervaring met verschillende connectoren voor hoge-stroom DC connectoren.
Neutrik : kunnen tot 40A aan, en nog meer, zijn robuust en hopelijk waterdicht. Female plug komt enkel in panel mount uitvoering.
Neutrik Cable Mount Loudspeaker Connector Socket, 4 Way, 40A, Screw Down Termination
RS-stocknr. 464-684
Neutrik Panel Mount Loudspeaker Connector Plug, 4 Way, 40A, Solder Termination
RS-stocknr. 464-690
Ring connectoren : simpele ring connectoren, met nut and bold vastgezet. Kunnen hoge stromen aan, moet bevestigd worden op een support zodat de twee polen niet raken. Minder praktisch om veel contact te lossen of te maken. Risico tot vergissen van polarisatie.
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Wago klemmen : makkelijk voor test opstellingen, beter dan gewone suikertjes. Risico tot vergissen van polarisatie. Komen in verschillende maten, kunnen ook hoge stromen aan.
Wago 221 Terminal Block Connector, 3 Way/Pole, Spring Cage Terminals, 24 → 12 AWG Cable Mount, 450 V
RS-stocknr. 883-7548

Suikertjes : zijn af te raden, want de draad wordt beschadigd. Moeilijk in en uit te nemen.

XLR : hebben we slechte ervaringen mee omdat de connectie makkelijk los kwam, dit was toen de connectoren op de grond terecht kwamen, dus in jouw geval zal dat niet gebeuren. Neem deze met een vergrendeling “mated connectors are secured by a latch”. Kunnen tot 16A aan.
Deze lijken mij solide, we hebben goede ervaring met neutrik, maar met deze connectoren specifiek hebben we geen ervaring.

Neutrik 3 Way Cable Mount XLR Connector, Female, Silver over Nickel Plated Contacts, 50 V
Neutrik 3 Way Cable Mount XLR Connector, Male, Silver Plated Contacts, 50 V
DIN : zijn duur voor wat ze kunnen. Neem deze met twist lock. Ook beschikbaar bij Elak/Cotubex.

RS Pro 71434 Series, 4 Pole Right Angle Din Plug, DIN 41524, 3A, Twist Lock
RS-stocknr. 453-549

automotive : is een goedkope optie die polarisatiefouten vermijdt. Niet praktisch voor prototypage, eens de richting van de stroom vast ligt, kan je de connector niet meer op een andere plaats inzetten.

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male/female classic : zijn af te raden, vervormen snel en verliezen contact. Als je dit gebruikt, maak de contacten geschrankt, dus male-female aan 1 kant en female-male aan de andere.
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male/female spade : hebben we geen ervaring mee.
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Zoals je ziet is het geen eenduidig antwoord. Als je nog in testopstelling bent, zou ik de wago klemmen aanraden. Als je finaliseert, probeer de neutrik xlr connectoren. Als je daar niet blij van bent, ga dan naar de neutrik speakon, en bouw de female plug in de wand in.

Battery selection

First remark : if you can avoid using a battery and work with the people pedal power in stead, this is considerably more interesting for the environment
– car batteries a heavy compared with the energy they can store, they are designed for giving high current.
– deep cycle / cyclic / boat batteries can contain more energy because of the internal structure of the battery technology, allowing a deep discharge.
*input* : user power (ex sound system of 900W peak)
*input* : time of autonomy (ex one hour before charging)
*input* : voltage of the system (ex 12V)
*energy need* = user power * time of autonomy (ex = 900Wh for the sound system)

checking the battery parameters
– Gel and Absorbent Glass Mat (AGM) types of VRLA can be mounted in any orientation, but need to be ventilated.
– the depth of discharge (DOD) of a battery determines the capacity and the number of cycles, 60% is a good value for AGM batteries (check DOD documentation).
– the current of discharging lowers the voltage output, the higher the discharge current, the lower the voltage and the lower the capacity.
*battery voltage at the DOD* > voltage of the system (ex 6 cel Li-ion doesn’t work, ex when discharging in 3h (0,3C), after 3h the battery voltage drops to 11V)
*charge need* (Ah) = energy need / voltage / depth of discharge (ex = 900Wh / 12V / 60% = 125Ah)

ex DAB12-135EV 12V 166Ah 136Ah 342 173 286 B M8 43,3 http://www.dynoeurope.com/assets/dab-ev/DAB12-135EV-TDS-EN.pdf

The number of cycles of a battery is dependent on the depth of discharge.

Traveling trough Brussels with the xyz cargo bike

Preparation : charge the battery, find the keys, checking the brakes, inflate the tires, take a lock, put the saddle at your height.
Planning the trip : avoid steep hills (Mont des Arts, Botanique, Porte de Namur), the elevator at Palais de Justice fits the bike, calculate your time (then add some for surprises and answering curious passengers.
During the trip : start the bike with the front wheel straight and give some power, when standing up on the pedals watch out for your knees, while in traffic take your place in between the cars, don’t hesitate to give a ring but don’t frighten pedestrians.
At the finish : don’t forget to take care of yourself and drink enough water.



Renewable energy – what can you expect ?

People pedal power is a form of renewable energy, but how much energy can a human produce ?

the numbers
1 cyclist = 100W power generated during 5min
= 75W during 15min
= 50W during 1h
sound system energy used = 1/2 of indicated power (more basses is more power, more volume is more power)
For example a 500W sound system uses generally 250W continuously, equivalent to 3 à 4 cyclists.
1 cinéma projection = 4 cyclists
1 coffee = 20 cyclists for heating (or 1h of cycling for your own)
1 pintje = 1h of cycling to burn the calories

The actual system provides place for 4 ordinary bikes to produce the needed power, equivalent to 300W. The peak power comes to 800W. The plugs are standard mains plugs, with the same quality of current as at home.

There is a possibility to set up a low voltage DC circuit, at 12V car cigarate plug or 24V specific plug. This allows the system to be 20% more efficient.

Find the google sheet with calculation tools :

Salary on pedal energy ?
more numbers
1 day of cycling = 50 W x 8 h = 0,40 kWh
1 kWh = 0,20 €
poverty line = $1.90 a day
cyclists salary = 4% of the poverty line

Sources : http://ec.europa.eu/eurostat/statistics-explained




An electronic component able to hold a charge. It can be used in the same function as batteries with the following differences :
+ a capacitor is easier to recycle than most batteries (references will follow).
+ a capacitor can provide and absorb a higher peak power.
– the voltage varies with the charging state of the capacitor (it needs an additional converter to provide the voltage of the system)
– the energy by weight capacity is less interesting than with batteries.
– the cost by energy is higher.
– the lifetime is quasi infinite (1M cycles).

The energy storage of a supercapacitor :
energy = 1/2 * C * voltage difference^2
ex = 1/2 * 500F * (16-12)^2 = 4000J = 1.11Wh = 1 cyclist for 1min20sec



Energy module


The energy module allows to treat the power form the PPP bike generators. It buffers the power to keep the supply-demand in balance and it converts the messy DC power to AC 230V power.



Little battery module

Little battery module

*Little battery module* manuel
1. switch the battery on (middle) -> is the LED screen on ?
2. hook up generator bike (normal mains plug) -> do you feel resistance when pedaling ?
3. plug in the 3D printer (plug) or other device (USB) -> is the device powered ?
4. pedal to provide power (pedals) -> is the battery charge staying steady ?
(when in trouble, call)
– there is not enough power > check the gears of the bike
(in worst case, plug the charger in the regular 220V nuclear)
– the voltage limiter is triggered too often > pedal backward, use more power
(in worst case, unhook the voltage limiter and stay below 50V while generating, material needed : english key 10, multimeter)


top left : converter IN
top middel : busbar between IN – OUT – BATTERY
top right : converter OUT 24V
side left : OUT USB and diverse chargers
middel : BATTERY
side right : battery charger (220V nuclear to 28V)






left backside : bike generation power IN (normal mains plug)
left top : converter OUT (24Vout, 8A, 40Vmax, green LED)
left bottom : voltage limiter (4.7Ohm, 56Vsafety, red LED)
middel top : positive bus bar IN (80A diode) – BATTERY (to 10Asafety, LED screen)- OUT
middel bottom : negative bus bar
right : converter OUT (28Vout, USB, 20A, 55Vmax, blue LED)




left : positive to thyristor (40Amax) and zener (56Vtrigger)
right : thyristor to resistor (4.7Ohm, red LED) – resistor to negative bus bar
*when triggered, ask to pedal backwards before restarting generating on the bike*