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charger Status project

Posted: Sun Mar 23, 2014 5:27 am
by skooks
Hi all, first time here and a fairly fresh electronics learner with a few questions to get me started in a project.

A month ago I bought the freetronics eleven starter kit and have done all the examples in the book and a few extra's but now its time for me to branch out and do something relevant for my every day and a good chance to learn as I go along. My project I have in mind is possibly quite simple but I need some guidance to steer me in the right direction please.
I work as a mechanic on a tropical island where we have a bunch of 48volt DC golf buggies ( mostly 8 x 6volt deep cycle batteries). When charging these buggies they draw 20 amps and slowly drop to 3 amps the more they get to fully charged and the charger cuts out when it reaches 60vdc.
What i'd like to do as a learning curve is be able to add my freetronics eleven to a lcd shield and a amp sensor shield and be able to detect when the charger is plugged in, then beep twice then show on the LCD screen the word "charging" when the amp meter gets a signal. Then roughly 10 seconds later have the display show the actual amps during the charge cycle. Once fully charged beep 3 times and show the voltage of the battery pack.

Now the sketch I can deal with as I go cause its the part I should pick up on easier but as for what parts I will need to intergrate it into a potentially 60volt DC system and do as described above has me scratching my head. Any suggestions on parts I am likely to need (and a reason for that part) would be appreciated.

Obviously my eleven board will be used and piezo buzzer, was thinking the LCD and keyboard shield and that's where I start to burn brain cells working out what I need to read those amps and volts without frying stuff :)


Re: charger Status project

Posted: Sun Mar 23, 2014 10:11 pm
by andrew
You'll need a DC high-current sensor, a quick search found this: ... vAod00gAJA

It gives out a small voltage which is proportional to the current (40 mV/A) - you can measure that small voltage with the Eleven's analogue input and go from there. There may also be other options on the market.