Victron Limited Temp Comp Settings

I am concerned that my Blue Solar 150/70 MPPT will damage my AGM batteries . Through the front panel buttons i have set the parameters without any problems however the Temperature compensation will not allow me to set the temperature compensation more than -35 , which is 42mv on my 24 volt bank .
I have always know temperature compensation to be a value which will be added or subtracted to the charge voltage according to the battery manifactures specifications . The scale of settings on the MPPT only go from -35 to 0 to 35 .so on my 24 volt battery bank that would be a total of 42mv which is almost 30% lower then needed which is 60mv, My Rolls flooded batteries and Triojan AGM all give 0.005mvc/cell , Morningstar products allow for this so its strange that a company as respected as Victron would sell a product that from the start would leave the end user setting the wrong charging voltages at any time other than at 25c .
The temperature here over a year is between 2c and 40c which can change during daylight hours by as much as 8c ( on my 24 volt system that's .06 per degree so less 1.9v to plus .9v .so compensation is necessary , without it my batteries would be ruined very quickly .
Has anyone any knowledge of these controllers and is it a common fault , its an expensive bit of equipment to discard but batteries cost far more .
Morningstar TS-60 Charge Controler
4 x 6v 400 Apm/Hr Trojan L16 AGM
Solener 1500w Pure Sinewave Inverter
Comments
Generally -5mV per Cell per degree C is for flooded cell batteries. AGM tend towards -2.7 or -2.2 mV/C/C.
If you pick an AGM charging profile--The controller defaults (max?) to -65mV/C or -2.7 mV/C/C--- However, that is for a 48 volt bank (24 cell). For a 24 volt bank (12 cell). So, you should be around -32.5 mV/C for a 24 volt bank (assuming -2.7 mV/C/C for AGM).
- -0.0027 V/C/C * 12 cells (aka 24 volt) = -0.0324 V/C = -32.4 mV/C @ 24 volt bank
- -0.0022 V/C/C * 12 cells = -0.0264 V/C = -26.4 mV/C @ 24 volt bank
At least that is how I understand your question and the controller setup--And the temperature offset based on 24 volt / 12 cell battery bank vs the 48 volt / 24 cell example in the manual.https://www.victronenergy.com/upload/documents/Manual-BlueSolar-charge-controller-MPPT-150-70-EN-NL-FR-DE-ES-SE.pdf (controller manual)
https://321166-984045-raikfcquaxqncofqfm.stackpathdns.com/wp-content/uploads/2015/12/6-0101G_Lifeline_Technical_Manual.pdf (Lifetime AGM battery spec).
-Bill
I did not pick a preset charging profile , i selected User so that i could be more precise on every setting , 28.8v Absorption , 27v Float , No Equalization Etc. but the one i could not set to match my Batteries profile was the temperature Compensation , the Charge Controller is limited to a maximum of 0.035 volts per cell for every 1 degree C which would be a maximum of .042 for the complete bank , thats 30% lower than both battery manufactures state which means that from the outset the charging voltage would be wrong , it would only be correct at 25 degrees , once temperature rises or falls then the voltages are out by a progressively greater degree , might as well just make a rough guess at the charges as im going to be undercharging during cold days and over charging on the hot ones .
What i cant understand is why a quality manufacturer would make such a big error , other Charge controller manufactures allow for greater offsets knowing whats required for many or the Major battery manufactures but still limit their own product in this way , i accept my knowledge is pretty basic so im wondering is there something i have overlooked or have not heard off .
Morningstar TS-60 Charge Controler
4 x 6v 400 Apm/Hr Trojan L16 AGM
Solener 1500w Pure Sinewave Inverter
I am not sure if I understand what you are saying--Or if it is just a typo:
- 0.035 V/C/C or 0.0035 V/C/C?
- 0.045 V per degree C / 12 cells per battery = 0.0035 V/C/C
Checking a Trojan manual, you are correct, they ask for -5mV/C/C for their AGM batteries.https://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf (Table 5, page 17)
And it appears that Victron has a limit of -3.5 to +3.5 mV/C/C with -2.7 mV/C/C as the default (and note 2: only battery type 8 can this value be adjusted).
https://forum.solar-electric.com/discussion/357367/victron-limited-temp-comp-settings#latest (page 15-16 tables)
I agree--The programmable range should be to, at least allow -5 mV/C/C (pretty common spec. from what little I have read about lead acid).
Also, the temperature compensation (chart on page 21) seems to a range of 6C to 50C (battery temperature). That seems to be a pretty narrow Temp Comp range too.
Contacting Victron Tech Support?
I am not sure I would get rid of the controller because of these limits. Avoiding overcharging of AGM (and other sealed lead acid batteries) should help extend their life (at least for the catalyst used to convert H2+O2 to H2O).
-Bill
Morningstar TS-60 Charge Controler
4 x 6v 400 Apm/Hr Trojan L16 AGM
Solener 1500w Pure Sinewave Inverter