End Amps how does it work

[Eleu]

Hi all, I fully understand end amps and its use. My questions is how the kid monitors end amps.  Specifically towards the end of a day when light conditions are low.   Let me give and example, let's say I set end amps to 5amps.   During the day I get the batteries into absorb but I don't reach the end amp level.  However, at the end of the day the solar panels can only produce 4.9 amps due to the setting sun.  Will the kid see that it is only putting 4.9 amps into the batteries and assume it has hit the end amp level and put the batteries into float and indicate they are fully charged?

[Vic]

Hi Eleu,   Welcome to the Forum.

In order for EA to be used,  the KID must be in Absorb,   because,  EA   IS used to END  Absorb.
If the CC is in Bulk MPPT (this is the probable stage,  if Absorb has not ended,  before the sun fades),   EA is not used.

FWIW,   Vic

[ClassicCrazy]

Two conditions will get the controller to go to Float .
One would be if you have Absorb Time set and it is in Absorb for that time then it goes to float.
The second would be if you have End Amps set - so if it is in Absorb and gets down to the End Amps setting it will go to Float.
But also the Absorb timer works with End Amps - if in Absorb and the timer runs out before End Amps is reached it will go to Float.
You do need a Whizbang installed on a shunt in system for the End Amps to work correctly .


Larry

[Eleu]

Got a reply from Ryan (thanks Ryan!)

If you are in absorb it is impossible for the amps to drop without the battery being full as the array is producing more then the battery needs. So in your example the battery is truly full and has hit end amps.



Look at this in another way. You have a 5 gallon bucket with a ½ hole in the bottom. The amount of water flowing in to keep it full and satisfy the ½ hole is end amps.



If the water slows down due to lack of supply (IE low sun) then the water starts to drop from the top of the bucket and the bucket is not full (This would be BULK MPPT)



If the water is sufficient to keep the bucket full to the rim and satisfy the ½ hole this would be Absorb on the Kid. The amount of water needed to keep the bucket right at the brim and NOT run over is End Amps.



So in a nut shell your battery can not be less than full if the kid is in absorb and doing less than End Amps. In your example you would generally see the kid fall back into Bulk MPPT and then End Amps is non functional

[Vic]

Got a reply from Ryan (thanks Ryan!)

If you are in absorb it is impossible for the amps to drop without the battery being full as the array is producing more then the battery needs. So in your example the battery is truly full and has hit end amps.

Look at this in another way. You have a 5 gallon bucket with a ½ hole in the bottom. The amount of water flowing in to keep it full and satisfy the ½ hole is end amps.

If the water slows down due to lack of supply (IE low sun) then the water starts to drop from the top of the bucket and the bucket is not full (This would be BULK MPPT)
If the water is sufficient to keep the bucket full to the rim and satisfy the ½ hole this would be Absorb on the Kid. The amount of water needed to keep the bucket right at the brim and NOT run over is End Amps.

So in a nut shell your battery can not be less than full if the kid is in absorb and doing less than End Amps. In your example you would generally see the kid fall back into Bulk MPPT and then End Amps is non functional

Hi Eleu,

You are probably replying to Ryan,   and we cannot know what Ryan said.

There have been several descriptions of how EA works on the KID (and this applies to the Classic with WbJr,  as well).

The folks who have offered this description,   really DO know how EA works,   to end Absorb,   and seem to have described it well.

Probably no reason for argument on that.

However,   EA  is a user setting.   It CAN be set high enough,  such that Absorb ends before the battery is "full"  (fully-charged).

For Flooded LA  batteries,   measuring SGs with an accurate Hydrometer (or Refractometer)  will be the ultimate check weather the chosen EA value is sufficient to allow full charge (without excessive extra time in Absorb).

FWIW,   Did not  analyze your water analogy,    as it is clear how the EA function actually works.    Vic

[Vic]

Hi again Eleu,

Will add,   that as our Lead Acid batteries charge the amount of current that they could Accept from the charge sources tapers (becomes smaller),   this is called battery Acceptance.

In the Absorb stage,  where the Absorb voltage is essentially constant,   this tapering current can be used to cease the Absorption stage.   This called the Finishing current,   or End Amps.   This setting is arrived at by experimentation    (watching the Absorb stage,   where the Absorb time is set excessively long)  --  waiting for the WbJr battery charge current to essentially to stop diminishing.  Note how much Absorb time was required to reach this point,    and set the Absorb timer somewhat longer than this value.   And set the EA value in the KID,  to that nominal value.

On the Flooded LA  (FLA)  battery banks in use here,   this EA value will change considerably,   depending upon the Depth Of Discharge (DOD)  of the battery in the previous discharge.   With these batteries,  in their 15 th year of service,   the appropriate EA value is about 1.5% of 20 hour Capacity,  on average.   When the batteries were younger,   this value was smaller.

Monitoring SGs regularly on FLA batteries will help one determine how well the EA setting being used is at getting the batteries fully-charged,  without excessive Absorb time.

Know that you know all about this,   just wanted to make sure that we are on the same page.

FWIW,  Vic

[FNG]

When I said the battery had to be full, I was more meaning the controller would not be in absorb if the battery wasn't very close to full.

A side note calculating end amps is a pain in the but, How I like to do it is:

1- Set absorb time high like 6-8 hrs
2- Wait for the controller to go to absorb
3- Watch the current into the battery every ten to 15 minutes and note it on a piece of paper
4- When that number settles and really doesn't change any more we can assume this is the true acceptance charge or end amps. We would want to set the actual setting slightly higher than that.

[ClassicCrazy]

When I said the battery had to be full, I was more meaning the controller would not be in absorb if the battery wasn't very close to full.

A side note calculating end amps is a pain in the but, How I like to do it is:

1- Set absorb time high like 6-8 hrs
2- Wait for the controller to go to absorb
3- Watch the current into the battery every ten to 15 minutes and note it on a piece of paper
4- When that number settles and really doesn't change any more we can assume this is the true acceptance charge or end amps. We would want to set the actual setting slightly higher than that.

I found that watching the system amps on MyMidnite site graph over time makes it easier to spot where it flattens out. Plus once the history is in the graph I like how you can select just which things you want to display and then as you drag the mouse across the screen you can watch as the charge state changes to Absorb, SOC rises, amps from full counts positive,  the system amps fall , and hopefully when it is all set right you see Absorb end as SOC gets to 100% that the amps from full is all filled up ( plus extra for the efficiency setting ) . But as Vic and others have said it is never a perfect world and even with all the best settings it might not all work out just right every day but is usually pretty close. With my sealed batteries if they are close but less than full they fill up okay via Float the rest of the day.

Larry

[HIsolar808]

when using the KID charge controller do you need whiz bang jr to be hooked up to use the endamps function for ending the absorb stage?  or can you use endamps function without whizbang JR?

[ClassicCrazy]

when using the KID charge controller do you need whiz bang jr to be hooked up to use the endamps function for ending the absorb stage?  or can you use endamps function without whizbang JR?

You could use the end amps without a Whizbang but it won't work right . That is because with the Whizbang it only shows what is going into the battery - meaning it subtracts the loads from the power produced by the solar panels.  So if you had 10 amp produced by solar panels and loads are using 6 amps - the whizbang will show you 4  amps charging the batteries.  So if you set the end amps to 4 then you know that 4 amps is the true  charge on the battery .

Without the Whizbang in above situation  your end amps setting would be seeing the 10 amps produced by the solar .
The only way end amps would work correctly without a whizbang would be if the system had no loads on it so the output of the solar was pretty much the charging into the battery also.

I am relating mostly my experience with the Classic but think the Kid is pretty much the same.
There is a setting you need to change when using Whizbang to tell End amps to use the external shunt where whizbang is installed instead of the internal shunt which reads the output of the controller only ( what the controller is producing for power )

I think I got the explanation correct on that !

Larry