EA and ABSORB time settings?

[sigp2101]

Hi guys, this weekend I set my classic to stop BULK charge at 2.2A.  My BB is 225Ah so I calculate 1% and set EA that way just to se what happens.
Then I proceeded to set CHARGE time to be 00:00 but I could get it only down to 00:03 minutes. Could not set it to be 00:00, why? Is this a glitch or it suppose to be that way?

[Vic]

Hello sig..,

What Firmware version are you using in your Classic?

EA  can terminate the ABSORB charge stage,   but,  with any recent Firmware,  you would want to set an Absorb Time that you believe would normally not be reached during Absorb.  It is really there as a backstop,  in case the EA is not reached,   and you would not want the batteries to hang in Absorb all day,  when not really needed.

The proper EA value will depend upon the relative Absorb voltage.  If your Vabs is set relatively high in the range suggested by the battery manufacturer for your batteries,  a bit higher EA will probably be necessary,  and conversely,  if Vabs is set a bit lower in the suggested range,  EA would normally be set a bit lower.

For all of the Flooded battery banks in use here,  have used just a bit below 1%,  with a relatively low Vabs.   These battery banks are now 11 years of age,  so have needed to incrase Vabs somewhat,  and raise the EA,  to about 1.5% of 20 hour Capacity.

FWIW,   Vic

[sigp2101]

Hello sig..,

What Firmware version are you using in your Classic?

EA  can terminate the ABSORB charge stage,   but,  with any recent Firmware,  you would want to set an Absorb Time that you believe would normally not be reached during Absorb.  It is really there as a backstop,  in case the EA is not reached,   and you would not want the batteries to hang in Absorb all day,  when not really needed.

The proper EA value will depend upon the relative Absorb voltage.  If your Vabs is set relatively high in the range suggested by the battery manufacturer for your batteries,  a bit higher EA will probably be necessary,  and conversely,  if Vabs is set a bit lower in the suggested range,  EA would normally be set a bit lower.

For all of the Flooded battery banks in use here,  have used just a bit below 1%,  with a relatively low Vabs.   These battery banks are now 11 years of age,  so have needed to incrase Vabs somewhat,  and raise the EA,  to about 1.5% of 20 hour Capacity.

FWIW,   Vic

Hi Vic, I have latest firmware.
Now you totally manage to confuse me. Isn't that EA are there to end BULK cycle at specified EA value and  to go to FLOAT cycle to slowly trickle charge top up BB as per suggested FLOAT voltage by manufacturer?

Also what do you men by this?

The proper EA value will depend upon the relative Absorb voltage.  If your Vabs is set relatively high in the range suggested by the battery manufacturer for your batteries,  a bit higher EA will probably be necessary,  and conversely,  if Vabs is set a bit lower in the suggested range,  EA would normally be set a bit lower.

EA is specified in Amps not in Volts???

[Westbranch]

EA ends the Absorb cycle. nothing else.
It should be set to a value where you can see that the Amps going unto your battery is 'flat line-ing'
hth

[Vic]

Hello sigp..,

YES,   EA does end the Absorption charge stage.   Bulk on most of the good CCs is not limited in voltage or current.  Bulk puts all available power into charge flowing into the battery.  The only limiting of current is  the ability of the input power source (PV,  Wind Hydro,  etc) to provide this current.   When  the set Vabs is reached,  the Absorb stage begins,  and the battery current tapers,  based upon the battery's ability to Accept current  --  this diminishes as the Absorb stage proceeds.

The charge current that the battery will Accept,  depends upon the voltage applied to the battery.   The higher this voltage,  the greater the current that will flow into the battery.

EA IS a current setting - correct.   But the current that the battery will Accept depends upon the applied voltage.  Therefore,  if one decides/needs to change the Vabs,   the Finishing current (EA)  will change,  somewhat.

EDIT:  Several manufacturers of CCs and Inverter/chargers do choose to allow a Bulk voltage to be set,  just to confuse things a bit ...

This is all that I was trying to say.    FWIW,   Vic

[sigp2101]

It seams that I should have left ABSORB time where it was then.
ABSORB stage will end either when EA value is reached or set timer expires. Right?

Would it be OK then to set ABSOR stage time to as long as possible then?

[Vic]

It seams that I should have left ABSORB time where it was then.
ABSORB stage will end either when EA value is reached or set timer expires. Right?

Would it be OK then to set ABSORB stage time to as long as possible then?

YES,  when an EA value that is not zero has been entered,  then either reaching the EA value,  OR,  reaching the set Absorb time will end Absorb.

Am uncertain the maximum value for Absorb Time in the Classic.   There should be no need to set it to its absolute maximum.   Have set my Classics to about six hours,  but you know your system better than any of the rest of us.

It is good to experiment with EA settings when you have the time to watch the Absorb stage,  near its end.   Forget if you have Flooded batteries ... will look at your Signature.   Using the SG readings to confirm how well a particular EA setting is doing in getting batteries fully-charged can be a large help.

EDIT:  Just to be clear,  you DO have the WBjr set up on your system,  so you are using Shunt EA,  correct ??

Vic

[sigp2101]

EDIT:  Just to be clear,  you DO have the WBjr set up on your system,  so you are using Shunt EA,  correct ??

Vic

NO, I am not using Shunt, system has no loads whatsoever during recharging stage of 5 days. Only INs, nothing OUT.

[Vic]

OK,  that should be fine.   Even with varying loads on a system,  CC EA can be made to work fine,  if one has Flooded batteries,  allowing checking actual SOC.

With NO loads,  you should be able to set a repeatable SOC,  based on your CC EA.

Good Luck,   Vic

[sigp2101]

EA ends the Absorb cycle. nothing else.
It should be set to a value where you can see that the Amps going unto your battery is 'flat line-ing'
hth

Thanks!

Now, how do we establish that value? Do you do that by watching status screen of CC. Which side, left or right, PV or Batt. side or do I have to constantly measure SOC by measuring SG inside batteries cells?
Is it like once I find batteries are full (by measuring SG) then I check Amp value on the screen and that is the number I put for EA or something else.

[Vic]

sigp..,

A good way  to find a reasonable EA value is to watch the battery charge current  --  in your case on the main Status screen of the Classic's MNGP.   As the Absorb stage is nearing its end,  the (in your case)  Classic's output current (on the lower right of the status screen)  will decrease at a lower,  and lower rate.   At some point,  this current simply appears to stop changing.   In this range of CC output current is what you should use for the EA value.

You can then measure SGs of your battery.   Some say that one should really measure SG when the battery has been in Float for several hours,  when possible.

If it appears that your batteries are not quite getting fully-charged,  then you might need to lower this EA setting by a small amount.    One thing that you really do not want to do,  is to set the EA value so low,  that the battery charge current never (or takes a very long time to) get(s) down to that point.

Try this for a week or so to see how this works   ...   looks like you have a variable schedule at your site,  if so,  you may need to intervene on days where there may be loads on the system during the time when Absorb needs to terminate.

Just be certain that you have set the temperature compensation value,  as recommended by the battery manufacturer.

FWIW,  my opinions,   Vic

[sigp2101]

sigp..,

A good way  to find a reasonable EA value is to watch the battery charge current  --  in your case on the main Status screen of the Classic's MNGP.   As the Absorb stage is nearing its end,  the (in your case)  Classic's output current (on the lower right of the status screen)  will decrease at a lower,  and lower rate.   At some point,  this current simply appears to stop changing.   In this range of CC output current is what you should use for the EA value.

You can then measure SGs of your battery.   Some say that one should really measure SG when the battery has been in Float for several hours,  when possible.

If it appears that your batteries are not quite getting fully-charged,  then you might need to lower this EA setting by a small amount.    One thing that you really do not want to do,  is to set the EA value so low,  that the battery charge current never (or takes a very long time to) get(s) down to that point.

Try this for a week or so to see how this works   ...   looks like you have a variable schedule at your site,  if so,  you may need to intervene on days where there may be loads on the system during the time when Absorb needs to terminate.

FWIW,  my opinions,   Vic

Just be certain that you have set the temperature compensation value,  as recommended by the battery manufacturer.

Thanks a lot Vic, I will follow your guidelines.

Thing is, I am at the site only during the weekend. I can't monitor what is happening because I am using energy while I am there. My goal is to tweak CC functionality to be best for batteries while system is in unintended stage and self charging. Having said that I do not want it to overcharge or undercharge, just to get to the optimum. Winter is coming and system will be in unintended stage for few months. With few sunny days during the winter and no discharge at all my hope is that battery bank will survive till spring.

Your contribution is greatly appreciated.

SIGP2101

[Vic]

   ...

Thing is, I am at the site only during the weekend. I can't monitor what is happening because I am using energy while I am there. My goal is to tweak CC functionality to be best for batteries while system is in unintended stage and self charging. Having said that I do not want it to overcharge or undercharge, just to get to the optimum. Winter is coming and system will be in unintended stage for few months. With few sunny days during the winter and no discharge at all my hope is that battery bank will survive till spring   ...
SIGP2101

Hi sigp..,

As you know,  with the addition of a Shunt,  and the WBjr,  you would have the ability to see just what is the battery charging current,  even with loads on the system.   Also,  as you know,  the system could reliably use the EA function even when there are significant,  and varying loads.   The addition of these two items is not very expensive    ...   hope that these items are on your shopping list for the future.

You could possibly Skip several charge days,  in your absence,  depending upon the amount of power that you do use when you are there,  and how well the batteries are being recharged at those times.

Discharging your batteries below 90% SOC is generally better for the batteries,  than is  recharging every day,  when the only discharge has been from battery self-discharge.

FWIW,   opinions,    Vic