LCD Fuel Gauge Hacking

underdog

underdog

10 W
Joined
Jul 19, 2013
Messages
87
Location
Norway
Hello.

I am trying to figure out how to best set up a fual gauge on my bike. I like the idea of a analog "voltmeter", but that would not be any good on a bike humping along uneven roads. I have found a digital voltmeter with a "analog reading". http://www.tme.eu/en/details/ema1710/digital-panel-meters/lascar/#t4d07a4a4af8dc0f9233835f56192119b

ema1710.jpg


Meter Specs:

Meter type panel meter
Sampling 10x/s
DC voltage measuring range 0...1V
DC voltage measuring accuracy ±1 segment
Voltage measuring resolution 125mV DC
Dimensions 43.5 x 21.4 x 7mm
Mounting hole diameter Ø5mm
Mounting M5 screw
Power supply 5...12VDC

What I want to achieve:

I am running 20s LiPo, so a "empty-level" of 74volts and a "full-tank" reading at 84volts would be the best.

I understand that I with 84volts on the tap and the right resistance can achieve 1000mV to the gauge, and make it display "full". What is really the problem is figureing out what I need to add of resistance to make 74volts turn in to under 125mV, while the 84v still reads 1000mV...

Any sugestions or pointers in the right direction would be greatly appreciated! :D
 
why drain your battery charge to make lights on a fake gauge when you can use a cycle analyst or wattmeter to accurately track the amount of charge used? the voltage on your meter will change with the load on the motor. they call it the guessometer on the Leaf. no range left when you go uphill, max range when going downhill on regen.
 
dnmun said:
why drain your battery charge to make lights on a fake gauge when you can use a cycle analyst or wattmeter to accurately track the amount of charge used? the voltage on your meter will change with the load on the motor. they call it the guessometer on the Leaf. no range left when you go uphill, max range when going downhill on regen.
Click to expand...

You are absolutly right. Its a stupid thing to make, when the options are so good :) I guess making it is half the fun.. Any sugestions to my problem though?
 
marty said:
Simple ebike 'fuel gauge'
http://endless-sphere.com/forums/viewtopic.php?f=2&t=22675&hilit=fuel+gauge
Click to expand...

Oh shit sorry. Deleting
 
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