I have a strange situation and I am not sure how to do the fault-finding.
I have 2X 150W Solar Flexible Monocrystalline Panels connected to a Victor MPPT Smart Controller 75/15.
Admittedly the panels were cheapies off Ebay for £50 each.
Together with the Victron they connect to 4X Trojan T-105 6V Cells which form a 24V set.
I am using default factory settings for the Victron as the numbers seemed pretty close to the Trojan requirements
It has all been working for about 3-4 weeks and I have been impressed with the system.
This shows the history, all good
Suddenly this weekend, the MPPT is not able to charge the batteries up high enough to transfer from Bulk to Absorption so it just sits there trying to charge.
In this image, this is the highest I could get the battery to (27.06V) I couldn’t get it any higher?
I am concerned that this will damage the batteries as it is still pumping amps into them.
Previously the Max voltage I got out of the two panels was approx. 44-45V, but now it seems to only run at 35V.
My path so far
- I disconnected the MPPT, connected a battery charger and charged the batteries up, then left over night and they held good charge which makes me think its not the batteries
- When I bought the panels I also got cheap PWM controller with them. I swapped out the Victron with the PWM and it appeared to be doing the same ie still runs at about 35V on the Solar and wont get the battery volts any higher
- This leads me to believe I have developed a fault with the Solar Panels.
Am I running enough grunt in the solar panels to do the job?
The Panels are rated at
Optimum power : 152W ± 0.25W
Working voltage: 18.1V±0.3V
Working current : 8.1A ± 0.15A
Short circuit current : 8.3A ± 0.15A
Open circuit voltage: 21V±0.8V
Times Two as they are in Series to drive enough volts to charge 24V system.
The Rating for the Trojan batteries is the 24V column: -
Do I need more panels? AM I short on required power?
Is 150W X 2 enough or do I need higher rating? Or do I just need better quality Panels?
Thanks in advance