Author Topic: Kid + Whiz Bang current limit setting?  (Read 27 times)

eddyvanhalen

  • Newby
  • *
  • Posts: 5
Kid + Whiz Bang current limit setting?
« on: September 13, 2017, 03:50:20 PM »
We have an off grid 48V system comprised of a single string of T105s.  The batteries are charged by two banks of panels.  One bank is 480 watts and is charge controlled by a Kid, while the other bank is 610 watts and controlled by an Outback MX60. 

Since the MX60 has a lot of headroom and we can get more or less electrically matched panels, we'd like to add 2 more panels, or about another 600 watts. 

The goal is to improve charging in the winter (we're at 47 degree N, on the Olympic Peninsula in Washington--> very little light in the winter).  The problem is, in the summer, the proposed system will produce too much peak power for the battery bank i.e. too many amps into the battery.  This is the case because each controller is operating in parallel and knows nothing of the other...  each is happily under their respective current limits, but the sum of the currents exceed the max allowable to the battery.

So the question is, if we add a Whiz Bang Jr, can we set the Kid to either limit or cutoff charging if it detects that the overall current into the battery is above a certain limit? 

Alternatively, I thought maybe I could have the Kid do PWM diversion to a dump load if current is above a certain limit.  But isn't that current measured by the internal shunt rather than the Whiz Bang?  Is there any way to have the Kid do dump load diversion based on the current sensed by the Whiz Bang?

Thanks...

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 1325
Re: Kid + Whiz Bang current limit setting?
« Reply #1 on: September 13, 2017, 08:52:11 PM »
On a friends system that has a Classic full and an Outback that has some additional panels , what we did was to set the Outback Absorb voltage lower so as the voltage comes up on the batteries the Outback will drop out of charging and let the Classic finish off the charging .

When one of the controllers goes into Absorb early it will cut back the current so maybe a scheme like that would work for you.


Larry
« Last Edit: September 13, 2017, 08:53:44 PM by ClassicCrazy »
system one
Classic 150 , 20 Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie