Solar Charge Controller and grounding the battery
Only if you want your installation to be code compliant and to minimize the risk of fire and electric shock. What are the odds that you'll &quot;forget&quot; to install the ground later when you expand the system to 10 or 20 panels, and add another 20 or 30 batteries? What if there is a fire? There will be an investigation, and if the insurance company can prove that the installation wasn't to code, they may not pay your claim. If, of course, you're alive to collect on it.

Good habits start early and last a lifetime.
Bad habits start early and last a lifetime. They also tend to shorten your lifetime.