Current compensated charge controller function

[EW Zuber]

I would like to see a charge controller that has a shunt to monitor current being consumed by loads and has the ability to compensate charge current by adding the amount of load current to the charge current.
Say for instance we have a 5KW solar array charging a 400 AH battery bank with a Midnite controller max charge current set at 40 A for a C10 charge rate.
When a substantial load is put on the system, we'll say 20A DC, it will cut the charge rate to a C20.
I would like to see the controller be smart enough to realize this and compensate, maintaining the C10 rate.
I have been told that this would be prohibitively expensive to engineer and produce. With all the other capabilities of the current model that seems odd.
Maybe I'm missing something?

[TomW]

EW;

I am pretty sure the guys are currently working on just that. My E-panel came with a nice 500 amp shunt in it from the factory.


The MNCSM is mentioned over here:

http://midnitesolar.com/smf_forum/index.php?topic=885.msg6434#msg6434

And here:

http://midnitesolar.com/smf_forum/index.php?topic=885.msg6434#msg6434

Tom

[boB]

Yes, this function will be able to happen with the shunt monitor.  It will be based on the current going into the battery
and will not need to take loads into account...  Just battery current, as long as it's just our charge controller(s) doing
the charging.  Anything above and beyond our chargers charging the batteries will be a separate issue.
Maybe some day, some of those other chargers can also be controlled by our system ?

Also, a bit of a technicality and nit pick, but when you say C20 and C10, I think you really mean C/10 and C/20
which means 1/10 C and 1/20 C Amp-Hour charge rate.

boB

[EW Zuber]

Thats great news.
Eventually I am going to try and install about 20 KW of solar so we can heat the house with solar electricity in the dead of winter on a sunny day. Also on cloudy days where it looks like the sun never came up and we get only ~10% of rated output, there will still be enough power to charge the batteries.
It should totally eliminate the need for a fossil fuel generator.

[Photowhit]

... It will be based on the current going into the battery and will not need to take loads into account...  Just battery current, as long as it's just our charge controller(s) doing the charging....

Heck boB, I don't think you realize, just how good you are!!!

Since the monitor would be measuring current across the shunt into the battery, I would think it would compensate for other charge controllers as well!

Of course it wouldn't be able to control them, but if they were a minor or even a moderate source of energy, I would think the system would work much better, I would think with the system under load, it would increase the Classic's output to properly charge and likely the other charge controller (unless a smart one) would time out.

With no load, would the monitor be confused, or just reduce the output of the Classic so a proper current is reaching the battery?

Trying to think if a smart charge controller looking for end amps would not just shut down early with the classic contributing... It's too late, I'll let you tell me where I went wrong...

Can you tell this has been a much awaited piece of the puzzle! Some of us have been thinking about this for a long time, even thought some guys might have gotten there with the outback CC...lol.

Truely a"Classic"!!!

[Halfcrazy]

Yes the goal would be to have an option to set a second amp limit or current limit using the CSM so if you tell it 60 amps max "Into" the battery the Classic will back off and attempt to follow that. Of course if there are say 3 FM80's and 1 Classic the FM80's will trump but in a normal system this should work swell. Especially for End Amps

Ryan