# Need help with a Wheelchair Mod project (I'm a beginner)

#### grantschildcare

Dec 16, 2011
2
Hi there, this is my first post on this forum. I am just starting out and trying to build my first big (ish) project a wheelchair upgrade

I have drawn out a circuit diagram to the best of my ability and was wondering if someone could have a look and
a) feedback on whether it looks ok
b) let me know what sort of POT I should use and what value of resistors I should use.
These are the LED's I'm planning on using
c) How I should go about Powering this as it's power supply needs to be different from the chair.

3 Red LED's each front headlight to be run at 2.2V each
LED 5mm high brightness - water clear lens. 476mcd min, typically 1900mcd at 20mA. 1.95Vf - 2.4Vf
Ifmax=30mA

3 Blue LED's each front headlight to be run at 3.1V
5mm BLUE, 8500mcd 3.3Vf, Ifmax=25mA

3 White LED's each front headlight to be run at 3.4V
30000mcd 3.6Vf 50mA
50% power angle 15deg.

This by my calculations works out as a total voltage draw of 25.2V/Front Light therefore around 50 Volts plus the power needed for the horn and the indicators

each indicator 4 LED's to be run at 2.2V
water clear lens. 476mcd min, typically 1900mcd at 20mA. 1.95Vf - 2.4Vf, Ifmax=30mA

=8.8 + 8.8= 17.6 V
Horn to be run at 12V

Total Draw = 80V (Would there be a loss within the circuit as well?)

This is my attempt at the circuit diagramme. I would appreciate your help as I want to make this amazing for this kid.

Thank you,
Grant
http://flic.kr/p/aWpq6T

#### grantschildcare

Dec 16, 2011
2
Power wise I'm just thinking could I use 8 x 23A batteries fitted into a Quad AAA battery holder (working on the basis that 2x23A = same size as a AAA.

What do you think or would I be better building some kind of series of capacitors that can be charged each night from the mains?

#### (*steve*)

##### ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,508
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