My system is three years old. I have 6-100 amp Battle Borns in a 12 volt RV system and all other hardware, except solar panels, is Victron.
MPPT is no longer passing enough current to raise voltage above bulk rate.
I have 10-90 watt solar panels. If I cover one at a time at noon, the voltage drops by approximately 90 watts per panel. The total of all 10 is only in the 450 to 600 watt range though?
The batteries are at around 13.5 to 13.7 volts in bulk charge with the current from solar reduced to the approximate 500 watts. This test was in early July at 49 degrees north with clear skies and 80\ degrees f. All other large DC loads are off.
Can the MPPT 150-70 be throttling the current. I used to get over 900 watts in this same situation.
The Multiplus II and 2-30 amp Orions do not do this and charge to 100% going from Bulk-Absorbtion-float. Does the MPPT most likely need replacing?
Sorry for the long question
Over time electrical connections can work loose.
So check all those first.
600 from 900 if they represent one string there could be a fault there somewhere (reverse diode in a panel a problem??)
Something else to check is if it reading the battery voltage correctly?
At 13.5 to 13.7V, you are into Absorption voltage range, and the charge current will have started reducing. Check the battery voltages on the MPPT terminal with an accurate DVM for confirmation.
Also worth checking the Voltage values programmed into the MPPT. Older lead acid batteries tend to sulphate, sometimes this can be reduced by an equalisation charge (15.5V). Otherwise, the do tend to absorb less power at the Abs voltage.
I would assume that you can still get ~850W (-2% per year on the solar panels) when the batteries are at lower voltage and the sun is full on the panels?
Voltage is off GX 70 and verified with Fluke meter
GX 70 says that I am still in bulk charge. The voltage has not gone high enough to move to absorb and time was 8 hours of sunlight. Batteries are 3 year old Battle Born LI.
My problem is that with full sun I am not getting full potential current from the panels to the batteries. Yet when tested individually each panel is putting out nearly its rated amount. Charging parameters are correct when charging from MutiplusII and Orion 30, just not when charging through MPPT150-70