I recently upgraded the air conditioner in my small RV from an old 120v unit to a new 12v one. I have three 100w solar panels and a 12v 300ah lithium battery, but I think I might have messed up my calculations. I know it will take at least two days of sun to fully charge the battery. The AC draws between 30-50 amps, and I'm estimating it could run for about 6 hours on high and maybe 10 hours on low. However, when I connect the AC to the solar charge controller, nothing happens. Would upgrading to a 50amp solar charge controller solve this issue? Right now, I'm using a 20amp one, and the solar is dedicated solely to the AC.
3 Answers
Hey! So, first off, your AC shouldn't be plugged into the load terminal of the charge controller. That part is meant for smaller loads that require cutoff regulation. The charge controller is there to manage the battery charging and not power high-demand devices like your AC directly.
Secondly, even if you got a 50amp charge controller, it wouldn't solve your power issue. The problem is that your solar panels can only produce about 25 amps (300 watts at 12v), which is insufficient to power your AC. If you want to run your AC, you’ll need more solar panels to generate enough power.
I get your frustration, but attaching the AC directly to your charge controller's load output isn't ideal. You really should connect your AC directly to the battery instead. Just ensure you put a fuse in line to protect it.
And about the charge controller, increasing to a 50amp controller won't be effective with just 300 watts of solar; you can't power your AC like that. You need to expand your solar array to have a fighting chance against the AC's demand!
Definitely consider getting a bus bar like the Victron Lynx! It'll help you connect everything—AC load, battery, and charge controller—more efficiently. Just make sure to use the right fuses to protect your wiring.
Also, an isolator for the battery would be a great addition to your setup. It helps manage power effectively and keeps your battery safe from potential overloads!