In the wizard, there is an option to set the absorb time. While I am not a fan of using time for absorb, boB has explained to me that it is not practical to terminate using tail current unless the Classic can measure battery current instead of just controller current. That makes sense.
However, yesterday evening I was making some adjustments to the Classic 200 and I noticed under Main Menu->Charge->ChgTime that there are TWO settings for absorb time there: Min Absorb Time and Max Absorb Time.
That raises some obvious questions:
1) Which Absorb time is set in the wizard? (I would guess Max Absorb Time, but I would like to be sure.)
2) In the current firmware, what types of things can cause Absorb to terminate before Max Absorb Time is reached?
3) Does a low tail current cause Absorb mode to terminate in the current implementation? Granted, this is not reliable in the presence of loads, but if a low current is detected between the Min Absorb Time and Max Absorb Time, I would expect the Classic to go ahead and terminate and switch to float. The only real assumption here is that there are are no other charging sources, which is often valid during absorb and the penalty for the assumption being false is pretty low. (In that case, you would terminate absorb prematurely, but if another charger is present, this might be a good idea anyway.)
4) Assuming low tail current can cause Absorb to terminate early, at what current level does it happen? Is it controllable?
5) Can you talk at all about future plans to add a battery current monitor to the Classic? I'd be interested to learn about what and when if you can.
TIA!
Quote from: RegGuheert on March 03, 2011, 06:41:28 AM1) Which Absorb time is set in the wizard? (I would guess Max Absorb Time, but I would like to be sure.)
I will answer my own question here, since I saw the behavior on the unit today. The Absorb time in the wizard sets the Max Absorb Time directly and Min Absorb Time is set to one minute less than Max Absorb Time. Basically it forces Absorb time to whatever is chosen in the wizard.
This is a little different that what is written in the manual:
QuoteAbsorb
This stage means that the Classic will maintain the absorb set point voltage until the batteries are charged or it reach Float stage. At this stage the classic is not putting out maximum current, as that would increase the battery voltage over the Absorb set point. This is also referred to as constant voltage mode. The absorb time is proportional to the bulk time. (i.e. the time bulk takes to reach the absorb voltage.) The battery it's considered "full" at the end of the absorb charge cycle.
I guess this is how it terminates absorb if you choose to make Min Absorb Time and Max Absorb Time different from each other. However, you will not see this behavior if you set up using the wizard and I have not found any mention in the manual about how to set up the items in the Main Menu->Charge->ChgTime menu where these settings are found.
This post is now over three weeks old. Can someone at MidNite please answer these product application questions?
Quote from: RegGuheert on March 25, 2011, 10:23:39 AM
This post is now over three weeks old. Can someone at MidNite please answer these product application questions?
Hi Reg...
The wizard only controls the Maximum Absorb time.
The minimum Absorb would normally just be 0 but this value is more of an advanced adjustment I would say.
boB
Quote from: RegGuheert on March 03, 2011, 06:41:28 AM5) Can you talk at all about future plans to add a battery current monitor to the Classic? I'd be interested to learn about what and when if you can.
I would like to take advantage of this capability when/if it comes available. As such, can you tell me if it will be using a normal 500A shunt? If so, I may go ahead and wire one in when/if I need to change any battery wiring. TIA!
Quote from: RegGuheert on March 30, 2011, 11:03:06 AM
Quote from: RegGuheert on March 03, 2011, 06:41:28 AM5) Can you talk at all about future plans to add a battery current monitor to the Classic? I'd be interested to learn about what and when if you can.
I would like to take advantage of this capability when/if it comes available. As such, can you tell me if it will be using a normal 500A shunt? If so, I may go ahead and wire one in when/if I need to change any battery wiring. TIA!
Yes, that is the shunt that it will use. The industry standard that is built into most boxes like E-Panels and OutBack Balance Of Systems Flexware, etc etc.
boB