Re: (ET) How NOT to check your batteries... Battery Charge / Monitor / maintainer

[JBR <reinharj frontiernet net>]

We need to find an 'inspired' Microcontroller Engineer (meaning EE & CS 
skills) who wants to design PIC (or similar) microcontroller into a charge 
controller with real time clock, alarm (piezo buzzer, etc), voltage 
readout,  
and maybe temperature and current monitoring.  [adding more features adds 
some cost in hardware, and tedious software testing]

I know bits and pieces of this (strong enough in hardware part), but am 
far 
too weak in C or Assembly language programming to get it done in timely 
manner.

Maybe we could form an 'Open Source' team to design this - similar to the 
project for PWM motor controllers called OSMC (Open Source Motor 
Controller).
In that case, a few guys collaborated on electrical hardware and software 
design for a microprocessor controlled, Pulse Width Modulated DC motor 
controller, for hobby Robotics competition.  

If we had nothing else to do ... <grin>


John




On Tuesday 07 August 2007 4:30:49 pm Jeremy Gagliardi com wrote:
> I used to dabble in digital electronics myself, back in college in
> *cough*92*cough*, but I'm wayyyy out of practice.  Still, I think a 
> compact
> enough unit could be made to handle this.  I just don't think I could
> relearn enough to get it done in a timely manner myself.
>
> There are really 3 things to be aware of, IMHO...
>
> (1) The original:  If the voltage dips below the setpoint, activate the
> charger.
>
> (2) Timer & voltage detection:  If the voltage does not rise or even
> *drops* over a set period of time, stop the charge and make an LED blink
> incessantly, or just leave a simple 2-pin jumper block for something the
> buyer can insert later, whether it be an LED, a buzzer, or what have 
> you. 
> Activation would simply be to send voltage to jumper "xyz" in a
> repeating-on/off pattern. Stopping this action would be to reset the unit
> by simply removing power to the controller.  Hopefully, upon restoring
> power, the situation will be corrected, and the unit will detect normal
> voltage or it will be desireable to activate the charger once again (such
> as after adding water to the batteries).  By the way, it bears noting 
> that
> the way I have my controller wired is not direct-to- batteries, but 
> rather
> to honor the power cutoff switch on the side of the tractor.  I
> accomplished this by tapping into the leads that go to the 36V power
> accessory outlet on the left, under side of the tractor.  That way, if 
> I've
> tripped the cutoff, the controller will lose power, and it cannot 
> activate
> the charger.  I've often used this to reset the controller, based on the
> below condition (charge starts, cutoff power, correct situation, restore
> cutoff switch, charger stays off)...
>
> (3) Not mentioned yet:  If the voltage dips below the setpoint, wait a 
> few
> seconds and check again; if it's still below, then activate the charger. 
> This simple, check-pause-check-activate/ignore logic would prevent the
> charger from activating for brief power drops.  I've often had these when
> the ET is in the garage, plugged in, and I activate some feature like the
> front lift.  The current controller activates instantaneously after the
> power dips.
>
> If it would save you time, effort, money, etc., I'd be perfectly willing 
> to
> build the circuitry myself, if you provided the parts list, diagram &
> instructions (for a fee?).
>
> --
> Jeremy Gagliardi
> E20
> Potomac, Md
>