All connections seem correct. Firmware updated. Battery set to Lithium
asked
SmartSolar doesn’t charge although the input voltage is 16.45V and battery is 13.12V
Please read the manual, especially the section 6.1 start up.
https://www.victronenergy.com/media/pg/Manual_SmartSolar_MPPT_75-10_up_to_100-20/en/index-en.htm
Extract from the manual.
The solar charger will commence battery charging as soon as the PV voltage is 5V higher than the battery voltage. For charging to continue, the PV voltage must remain at least 1V higher than the battery voltage.
Therefore, to start charging a battery at 13.12V you need a panel at 18.12V.
What is the minimum PV voltage required to turn on charging vs battery voltage?
Thanks a lot. I saw this constraint in the manual but thought that there may be a way around it. Somewhat in contradiction, the solar kicks in for short moments and charges with 0.2-0.3A for a few moments but it will not continue despite the fact that the voltage is indeed 1V higher than the battery. In conclusion, I presume my solar will start charging only when the litium battery is almost empty, i.e., when the voltage drops to say 11V, which will be quite too late. One possible but rather inneficient solution would be to connect the solar to my Pb starter battery and have the Smart Charger (converter) charge the lithium battery.
What is the configuration of your solar panels? If you can reconfigure to at least a 2s configuration then the MPPT will function properly.
One more question. Is the required voltage measured at the open circuit or at the maximum power? I could find one solar battery that specifies 20.7V at open circuit and 17.6V at maximum power. If the requirement >5V relates to the latter case there seems not to exist a sufficiently high voltage solar cell. I hope it is not the case!
20.7 Volts Open Circuit is GREATER THAN ( Battery + 5 volts ) = start charging.
17.6 Volts MPPT is GREATER THAN ( Battery + 1 volt ) = continue charging.
This panel should work, assuming the panel does not get too HOT, causing the PV voltage to DROP.
Thanks again. Your advice is clear. My current config is with a PV that supplies 17.22V in full sun. Since my litium battery stays at 14.18, the MPPT does not kick in. And there is no detectable voltage drop in the installation between the PV and the MPPT. From all the comments I see that I should get a new PV that has voltage-rating of at least 19.5V. In the Swedish climate it is unlikely it will get too hot, I believe. I am not so fond of getting two and coupling them in series. Besides, since the present one is fairly old, I cannot get an identical one.
