How to Know If Renogy Panel is Charging Batteries

[Leslie]

I have a 2019 21’ Escape with one 170W solar panel on the roof and 2 stock 12V batteries. I just purchased a Renogy 100W suitcase panel and plugged it into the Zamp sidewall solar port. The numbers on my controller before doing so were 100%, 13.8V, 0.0A. After plugging in the panel, there was no change. I assume because the batteries can’t be any more full than 100%, but how can I be sure that the panel is collecting power and how would you ever know if you don't have a dedicated controller (unless your trailer is under shade and your portable is in the sun)?

By the way, I did have to use the reverse polarity dongle because when I initially plugged the panel in without the dongle, the mode changed from day to night. Any insight would be appreciated.

Thanks,
Leslie

[John in Santa Cruz]

13.8V means you're already 100% charged.

My Renogy 'solar suitcase' has its own integral charge controller, which shows the PV voltage, battery voltage, charging current, and so forth.

[Mike Lewis]

Yeah, drain your batteries and try again. I've noticed that when my batteries approach full, the controller readout shows just a trickle going in from the panels. It made me think there was something wrong as well until I thought it through.

[KirkB]

Early in the morning, your controller should be in bulk mode, trying to charge the batteries at 14.4V for an hour, before switching to float mode (~13.6V). Start the day without your second panel attached. If the main panel has not yet reached 14.4V, check the amps in, then add the second panel. You should see a boost in amps and volts due to the second panel.

If you have a ladder handy, you could also cover the Escape panel so only the portable panel is charging. Again, check it early in the day before the bulk charge has completed.

[padlin]

If needed I'd un my fridge on DC for a few hours with the roof panel covered to create a deficit, plug in the portable and check the voltage.


Good reason for installing a battery monitor.

[Leslie]

Agree about the battery monitor. That's on my list. Thanks!

[Leslie]

Great info @KirkB. I have a lot to learn about solar. Thanks!

[Doug2000]

I learned a lot from this site..

The 12volt Side of Life (Part 1)

Scroll half way down to the chart, it shows voltage percentage levels. That's the most important to understand.

Don't run your batteries past 12.1 V or they won't last long.

[John in Santa Cruz]

Originally Posted by Doug2000

Don't run your batteries past 12.1 V or they won't last long.

Indeed that is a good minimum level rest voltage for a 68 degrees Fahrenheit battery that's at least an hour since it had a heavy load on it or a charger on it and is about 50 to 60% discharge. But the voltage reads quite a lot lower while there's a heavy current load such as an inverter with a heavy AC appliance plugged into it.

If you really want to track the battery status get a Victron BMV-712 battery monitors that have the Bluetooth, and connecting the shunt between everything else and the actual battery so the solar and the DC converter and load all go through the shunt...


(I dictated this host on my tablet, and voice-to-text gets really sketchy, Read between the lines)