Bulk > Absorb > Float questions

[Vic]

Hi open..,

If you set Skip Days,   on a day that is Skipped,   the CC begins in Float-MPPT,   and will never do a Bulk,   or Absorb stage.  When there is enough input power,   after some time,  there will have been enough charging for the battery voltage to reach the Float voltage setpoint,   and will show Float.

The entire rest of that day will be spent in Float,  until there is too little input power for the CC to maintain Vflt.   When this occurs,   the CC will show Float-MPPT,   until the CC rests due to too little input power to run its Converter (the MPPT mechanism that allows the CC to provide power for charging and loads).

In general,   we run Skip Days AND  use  Shunt EA.   Our Absorbs are relatively long,   as the EA setting is far out on the diminishing battery charge current curve,  where it is often difficult to see if the battery charge current (EA)  is diminishing at all (primarily due to WbJr current jitter,  which is often about one Amp Peak to Peak (at about 18 Amps,  on  these days).

SO,   we do avoid unnecessary Absorbs,  and yet,   have some hours in the Absorb stage.

To me,   EA should be set  to a current,   where the rate of current change  is very small.

But,   that's just me.      FWIW,    Vic

[Matrix]

My understanding of skip was on the days the Classic "skips" it skips both bulk and absorb, using only the V float. The times I have tried it with an soc of 88% +/- my system simply floated the batteries back up to full 100%.

[boB]

My bad this time !   Yes, for skip days, Float is the only stage.  Thanks guys !

During days when Bulk/Absorb is happening, Ending Amps will still apply.

So, Absorb should change to Float if Ending Amps or timed Absorb finishes, whichever comes first.

WheW ! 

boB

[Matrix]

 Does the Classic also turn to float when 100% is reached even if it has not timed out or reached end amp? Mine did today.

[Vic]

Does the Classic also turn to float when 100% is reached even if it has not timed out or reached end amp? Mine did today.

I have never seen this happen,   although,   almost always the batteries are cooler than the Reference temperature,  which often means that just before the transition from Absorb to Float,  the  SOC shows as 98 or 99-ish percent ...

Vic

[boB]

Does the Classic also turn to float when 100% is reached even if it has not timed out or reached end amp? Mine did today.

I think the answer to this is yes.  The Classic will reset to 100% State of Charge when going from Absorb to Float for any reason.

This assumes that the method (time and/or ending amps) is setup correctly.

There are probably methods or algorithms to have this done differently but going to Float from Absorb should be pretty darn close.


boB

[Vic]

Does the Classic also turn to float when 100% is reached even if it has not timed out or reached end amp? Mine did today.

I have never seen this happen,   although,   almost always the batteries are cooler than the Reference temperature,  which often means that just before the transition from Absorb to Float,  the  SOC shows as 98 or 99-ish percent ...
Vic

Think what I said above is incorrect.   Temperature should not cause the SOC displayed by the Classic to change   ...   only the Remaining Capacity  (probably,  maybe ...).

Still,  have never seen the above-noted situation where the transition to Float occurs due to SOC reaching 100% before Absorb time,  or an EA setting triggers this transition  ...

FWIW,   Vic

[boB]

Does the Classic also turn to float when 100% is reached even if it has not timed out or reached end amp? Mine did today.

I have never seen this happen,   although,   almost always the batteries are cooler than the Reference temperature,  which often means that just before the transition from Absorb to Float,  the  SOC shows as 98 or 99-ish percent ...
Vic

Think what I said above is incorrect.   Temperature should not cause the SOC displayed by the Classic to change   ...   only the Remaining Capacity  (probably,  maybe ...).

Still,  have never seen the above-noted situation where the transition to Float occurs due to SOC reaching 100% before Absorb time,  or an EA setting triggers this transition  ...

FWIW,   Vic

Correct.  Absorb to Float should not happen  because of SOC becoming 100%...

However, the other way around is true.  SOC becomes 100% because of Absorb going to Float

[Resthome]

Question.  You said in your last reply


So, for example, if you set Bulk Skip Days (which, if I understand correctly what it does, should perhaps be called "Absorb Skip Days")...if you set it to 1, that means that every other day, if and when it reaches the Bulk/Absorb transition voltage, rather than going to Absorb it goes straight to float. Now, are you saying that on THESE days it's not using Ending Amps (which makes total sense), or that when Bulk Skip is set to anything other than 0 the Classic will NEVER use End Amps, and only rely on Absorb Time???

Thanks.



Pax--Paul

Bulk Skip Days does exactly that it skips Bulk and Absorb and starts out in Float for the day that it is skipping.

[Matrix]

The way I'm reading this it would be better to float your batteries with a lower voltage back up to 100% charge if possible, rather than bulk-absorb charge your batteries back up to 100% with a higher voltage. I am guessing that would be one of the benefits of skip days? And I'm assuming this would increase battery life?

[boB]

The way I'm reading this it would be better to float your batteries with a lower voltage back up to 100% charge if possible, rather than bulk-absorb charge your batteries back up to 100% with a higher voltage. I am guessing that would be one of the benefits of skip days? And I'm assuming this would increase battery life?

That's the basic general idea...  To increase battery life...   BUT !!  But you still have to Absorb once in a while to avoid sulfation.

boB

[Matrix]

I should have said ...

it would be better to float your batteries with a lower voltage back up to 100% charge (if possible), rather than bulk-absorb charge your batteries back up to 100% with a higher voltage...

Every Day

But thanks boB,   now back to your regularly scheduled program.