need help with solar panel

Thread Starter


Joined Jan 8, 2024
Hey, im new to the forum and semi new to electrical work. i bought a plug and play 40W solar panel to charge a deep cycle battery, it came with a 7amp charge controller.. its worked pretty good this far, but now im trying to run a diesel heater on the same system and it doesnt seem like 1 battery is enough seeing as the heater ran fine for about 2 hours then popped a code for "low power supply".
My question for everyone here is,
1) can i add a 2nd battery to my current setup?
2) what kind of issues am i looking at encountering by adding a 2nd battery?


Joined Oct 5, 2017
You can add a second battery to your system, but in return for getting 4 hours runtime instead of 2, they will take about twice as long to charge from the 40 watt panel.

What capacity is your battery? What voltage? What chemistry? How much electrical power does your diesel heater need? What else is running from the battery? How much sunlight do you get on the panels? How long do you need your system to run when the sun is hidden?