# Re: [EVDL] PLC based charger



## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*

Can't say that I have done this in the past tense, but it is my plan 
to use one PLC for both monitoring and charging my pack. As soon as 
work calms down, I will get going on it and share the results. What 
you describe below will work, but the power factor resulting from just 
a plain old rectifier circuit will be very poor. I plan to use a PFC 
circuit on mine.




> Stephen Chapman wrote:
> 
> > Has anyone built a custom charger using a PLC for the programmable
> > brains?
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*

Isn't the power factor just a function of the transformer inductance? Isn't
a good PF just a matter a choosing wisely on the transformer and adding
capacitance to clean up the difference?



> Roger Heuckeroth <[email protected]>wrote:
> 
> > Can't say that I have done this in the past tense, but it is my plan
> > to use one PLC for both monitoring and charging my pack. As soon as
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*

No. Its a mater of having the current waveform be proportional to the  
voltage waveform throughout the entire cycle. A simple rectifier will 
have 0 current until the voltage rises above the threshold voltage of 
your output (the battery voltage). Then there will be a short spike 
in current until the voltage once again falls below the threshold. A 
PFC circuit uses a switching circuit and an inductor to keep the 
current flow proportional to the voltage throughout the cycle.



> Stephen Chapman wrote:
> 
> > Isn't the power factor just a function of the transformer
> > inductance? Isn't
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*

Thanks, I never thought about the diode threshold voltage and the effect on
current lag.

Stephen Chapman



> Roger Heuckeroth <[email protected]>wrote:
> 
> > No. Its a mater of having the current waveform be proportional to the
> > voltage waveform throughout the entire cycle. A simple rectifier will
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*

I have a PLC running in my car. I used a cheap Automation Direct PLC and a
touchscreen I got off Ebay. My setup is mostly focused on monitoring
individual batteries and providing a readout for pack voltage and current.
My charger is an old DC drive setup to control voltage. All the PLC does
in terms of charging is turn the charger on when it sees AC power and turn
it off once the charging current drops below a threshold. I plan to use
the PLC for balancing individual batteries but it doesn't do that just yet.


I haven't bothered to try and control voltage from the PLC since it wouldn't
serve much purpose for lead acid. The way my system works is that the drive
has a maximum current control (overload) and maximum voltage control
(speed). Upon initial power on, it goes to full current (based on pot
setting that I manually chose to prevent tripping my breaker). Once the
pack voltage starts to rise, it eventually hits the voltage I have it set to
control to and amps drops off to control volts. If I want to tweak my max
voltage, I do that on the speed pot on the drive. However, I could easily
control that from the PLC if I wanted to.

There is a lot more complexity to the system (power factor correction,
isolation for analog inputs, switching batteries that are monitored). If
you are interested in more details, feel free to ask. If you have
experience with Koyo or Automation Direct I can send you the PLC program
also.

Steve




> Stephen Chapman <[email protected]> wrote:
> 
> > Has anyone built a custom charger using a PLC for the programmable brains?
> > It seems that a powerful programmable unit could be built using a
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*

Steve

I'd be interested in more details. I have no background with PLCs but
did buy a basic stamp starter kit to play with. I'm a programmer by
trade and would love to tinker with this kind of stuff. Even details
like what components you are using, model numbers, etc. would be
interesting. Something to point me in the right direction.

Thanks

Dave Cover

PS Any chance you're on the Least Coast and can make it to Power of DC
this weekend?



> Steve Skarda <[email protected]> wrote:
> > I have a PLC running in my car. I used a cheap Automation Direct PLC a=
> nd a
> > touchscreen I got off Ebay. My setup is mostly focused on monitoring
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*

Hi Steve,
Thanks for posting. I have several questions:
-How did you isolate the pack from the PLC common?
-If using the PLC to monitor multiple batteries, how did you handle the
analog isolation?
-What drive did you use? This is a very interesting approach!

I am sure I will have more questions if you do not mind answering...

Stephen Chapman



> Steve Skarda <[email protected]> wrote:
> 
> > I have a PLC running in my car. I used a cheap Automation Direct PLC and a
> > touchscreen I got off Ebay. My setup is mostly focused on monitoring
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*



> Stephen Chapman <[email protected]> wrote:
> 
> > Hi Steve,
> > Thanks for posting. I have several questions:
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*



> dave cover wrote:
> > I'd be interested in more details. I have no background with PLCs but
> > did buy a basic stamp starter kit to play with. I'm a programmer by
> > trade and would love to tinker with this kind of stuff. Even details
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*



> Lee Hart wrote:
> >
> > What language do you like to program in? Pick a computer that is
> > suitable for use in a car, and that runs that language.
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*



> mark at evie-systems wrote:
> > I haven't tried one yet, but this looks like a neat computer that might be
> > suitable for a car:
> >
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*



> Lee Hart wrote:
> >
> > Looks nice, but I don't see any real specs on it; just marketing
> > eyewash. How much power does it use, can it run on 12vdc, what is its
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*



> mark at evie-systems wrote:
> > This is all I was able to find:
> > http://www.fit-pc.com/web/fit-pc2/fit-pc2-specifications/
> > http://www.fit-pc.com/web/fit-pc2/fit-pc2i-specifications/
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] PLC based charger*

I use mp3car.com as a resource for all things car-computer related
though just Googling for "car pc" will find you more options than you
can possibly work your way through.

--Rick



> mark at evie-systems wrote:
> >
> > Lee Hart wrote:
> >> Looks nice, but I don't see any real specs on it; just marketing
> ...


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