Sizing a Solar Panel for an RV

Start with what the vehicle actually runs

Many of today's RVs have a multitude of appliances that require power. When deciding what size of panels to get for your RV, ensure they are big enough to give you enough electricity. That sounds obvious and it is still the most common mistake — a panel chosen on price will maintain a battery but will never recharge one.

Maintenance versus charging

At 0.29 A optimum operating current, the 5 W BSM005P-T offsets self-discharge on a battery that is not being used. At 1.74 A the 30 W BSM030P is doing real charging work. At 2.56 A the 45 W BSM045P is the largest in this range. The jump from maintenance to charging happens somewhere around 20 W for most leisure installations.

One large module or two small ones

One 45 W module needs one mount set, one cable run and one roof penetration. Two 20 W modules need two of each. Unless roof geometry forces your hand, fewer larger modules is usually the simpler installation.

Match the mounting before you order

Panel and mount are bought together for a reason. Measure the lateral length of the frame and match it to the corner, 180 mm or 530 mm profiles, or choose a kit with the right side bracket length. Getting this wrong is the single most common ordering error in this range.