Quick and maybe dumb question about max charging volts

[Narrowboat boy]

Hi All

Sorry if this is silly question but I set my absorb to 14.4V and float to 13.6 v , Max Volts then defaulted to 14.6 v OK I thought this allows for some temp compensation . My batteries though are currently at 20 degrees so max compensation required is 600mv ( as per battery spec and what I entered in classic for temp comp ) So how come it is absorbing at 14.6v and floating at 13.8 all the time ? do I need to reduce the max volts to get it to hold what I entered for absorb and float ? the max Volts is within manufacturers spec for absorb but its right on the limit and I would rather a lower mid range absorb of 14.4 as I dont want to overcharge the AGM's .

[ClassicCrazy]

Put the max voltage up above what ever your equalize would be ( and if you don't equalize the same as absorb) . You also put the max voltage at the highest temp compensated value it would get at. I would put it up at 15 or 16 volts depending on how cold you area gets. ( temp compensated goes  up as batteries get colder )
You enter the temperature compensation as a negative value. So my battery manufacturer says -3mv  so that is what I put in temp compensation value. The Classic will know how many cells you have.

Larry

[boB]

For AGMs, there should be a maximum allowed temperature compensation voltage limit.  There is a menu for this.  Check the CHARGE    LIMITS menu for this.

I think that's where it is ?  Might be in the T-Comp menu ?

Anyway, that's what that menu item is for.

AGM batteries plump when you cook 'em !   (like the hot dogs)

[Narrowboat boy]

For AGMs, there should be a maximum allowed temperature compensation voltage limit.  There is a menu for this.  Check the CHARGE    LIMITS menu for this.

I think that's where it is ?  Might be in the T-Comp menu ?

Anyway, that's what that menu item is for.

AGM batteries plump when you cook 'em !   (like the hot dogs)

Hi boB is this menu in the local app or only on the classic as my classic is tucked away and not w
Easy to accesss the mgp . I have not seen it on local app . Also I am more concerned that the classic is ignoring my input volts for absorb and float and going straight to max volts even when temp comp is taken into account . I can artificially set a low absorb and float set point but is that the way it should operate ? Or should it be striving to hold the setpoints entered ?

[Narrowboat boy]

Put the max voltage up above what ever your equalize would be ( and if you don't equalize the same as absorb) . You also put the max voltage at the highest temp compensated value it would get at. I would put it up at 15 or 16 volts depending on how cold you area gets. ( temp compensated goes  up as batteries get colder )
You enter the temperature compensation as a negative value. So my battery manufacturer says -3mv  so that is what I put in temp compensation value. The Classic will know how many cells you have.

Larry

Hi Larry

I don’t really understand your answer if I set max volts up that high won’t the classic just try and hit those numbers ? As said it is ignoring my absorb and float setpoints and going straight to max volts even if I set max volts to the same as absorb it is going over by 2volts and it ain’t that cold just 20.4 degrees c today max comp should be 4mv per cell per deg c as set .

No equalise on my agms

[boB]

I am pretty sure that the MAX and MIN  Temperature compensated limits are also available on the Local App...

Go to CONFIG and then ADVANCED and scroll down a bit.  Look for "LIMITS"

You should see minimum volts and maximum volts underneath the current limits settings.

[ClassicCrazy]

Put the max voltage up above what ever your equalize would be ( and if you don't equalize the same as absorb) . You also put the max voltage at the highest temp compensated value it would get at. I would put it up at 15 or 16 volts depending on how cold you area gets. ( temp compensated goes  up as batteries get colder )
You enter the temperature compensation as a negative value. So my battery manufacturer says -3mv  so that is what I put in temp compensation value. The Classic will know how many cells you have.

Larry

Hi Larry

I don’t really understand your answer if I set max volts up that high won’t the classic just try and hit those numbers ? As said it is ignoring my absorb and float setpoints and going straight to max volts even if I set max volts to the same as absorb it is going over by 2volts and it ain’t that cold just 20.4 degrees c today max comp should be 4mv per cell per deg c as set .

No equalise on my agms

I set the equalize the same as my absorb so just in case it ever gets triggered  by accident it won't do any harm. Guess you could set it same as float.
Get a longer cable and remote the MNGP where ever you want that is easy to access.  It is the same as a 6 pin telephone cable so they are easy to find. ( at least by USA standards ) .
Yes there is a place in the local app to set the min and max voltages Config / Advanced
Ryan made a series of   youtube videos explaining in detail all the features and settings in Local App - there are several videos to cover it all.
https://youtu.be/uyPcDvNXMCI

Larry

[Narrowboat boy]

Ok guys I do t think I have. Explained myself well .

I have done all the things outlined above prior to posting .

Absorb is now set to 14.2 , max volts to 14.4 and float to 13.3 all trying to bring down the actual charge voltage . I now get absorb 14.5 and float 13.7 .WHY ?? Temp is 5 degrees under ambient and that should only increase voltage by 600 mv .
Adjustment is 4mv / deg c per cell

Question is why is the classic not trying to hit to the float and absorb numbers I put in and instead no matter of temperature is heading straight for the max Volts number plus temp adjustment

Is there a software bug or are the absorb and float numbers meaningless

Many thanks
Simon

[ClassicCrazy]

did you put a positive or negative 4 mv ?
It should be a negative number put in the setting

Larry

[Narrowboat boy]

did you put a positive or negative 4 mv ?
It should be a negative number put in the setting

Larry

Hi Larry
Def negative setting

[Narrowboat boy]

Still having this issue , instead I am artificially setting my absorb and float set points lower than I want so I actually get what I want . Seems odd I need to do this but it seems to work .

I have another related question that I probably should start another topic for but I will ask here and see . I am only currently discharging the batteries 5-8 % per day as current loads are modest given the summer and daylight time is long so  batteries are staying in float longer . This will change when the seasons change but in the interim I am considering whether I should use a skip day to limit amount of absorb I put the AGMS through with such a light Dod however using end amps the Absorb cycle is only about 30-40mins before it goes to float so is it worth it and will it help with the battery life . I see quite a few posts about skip days on here but all are about FLA batteries not AGM's

[boB]

NBB, do you have more than one charging source or just the Classic ?

I calculate, at 5 degrees C below reference of 25C that the charge voltage should be rising only 150 millivolts...

Usually what happens is that the voltage you see charging at is either AT the voltage or even slightly LOWER than your setting so this is indeed higher than it should be.

Are you reading the voltage from the Classic display or a multimeter ?  Fluke or otherwise ?

[Narrowboat boy]

NBB, do you have more than one charging source or just the Classic ?

I calculate, at 5 degrees C below reference of 25C that the charge voltage should be rising only 150 millivolts...

Usually what happens is that the voltage you see charging at is either AT the voltage or even slightly LOWER than your setting so this is indeed higher than it should be.

Are you reading the voltage from the Classic display or a multimeter ?  Fluke or otherwise ?

No only the solar array , Reading meter on local app where I set the limits . Yes very puzzling it seems to be absorbing and floating 2-3 volts above the setpoints and 1 volt or so above the max voltage limits , if I lower the setpoints etc it does come down but maintains the 2volts above .

[Narrowboat boy]

Hi All

Sorry for long time between posts on this thread , I have a question , regards the above , Should -4mv be entered in the classic as -4 or -0.4 ? I note that Ryan in the tutorial has -0.5 in his settings and refers to it as -5mv / deg c ? if this is the case it goes along way to explaining why my voltages are wrong , Also if this is the case it wont let me set anything below -0.5 as it seems to go up in 0.5 increments ? is this correct ?  I am guessing 1mv per deg c per cell is not the end if the world but I would be interested in your thoughts .

If I put this new setting in the voltage is now reading 0.1 v above float or absorb which is pretty close to 150mv I guess nearest round anyway .

Also another quick question , I calibrated the offset using a multi meter on the input and the classic was reading 0.1v below the battery voltage so I adjusted the offset to 0.1v is this correct ? it should positive right ? It didnt seem to make any difference though do I have to re-boot the classic for this setting to work ?

[ClassicCrazy]

Hi All

Sorry for long time between posts on this thread , I have a question , regards the above , Should -4mv be entered in the classic as -4 or -0.4 ? I note that Ryan in the tutorial has -0.5 in his settings and refers to it as -5mv / deg c ? if this is the case it goes along way to explaining why my voltages are wrong , Also if this is the case it wont let me set anything below -0.5 as it seems to go up in 0.5 increments ? is this correct ?  I am guessing 1mv per deg c per cell is not the end if the world but I would be interested in your thoughts .

If I put this new setting in the voltage is now reading 0.1 v above float or absorb which is pretty close to 150mv I guess nearest round anyway .

Also another quick question , I calibrated the offset using a multi meter on the input and the classic was reading 0.1v below the battery voltage so I adjusted the offset to 0.1v is this correct ? it should positive right ? It didnt seem to make any difference though do I have to re-boot the classic for this setting to work ?

you would put in -4

Larry