There’s 2 different schools of thought for solar panel systems…
A) Figure out your power needs and go from there.
B) Figure out how much roof space, or budget you have for solar, then work backwards from there.
Option B seems to be the simplest and most efficient to me.
Either way, most people are in for a very rude awakening. You need to remember that it’s not as easy as just having enough battery power to handle your desires. You also need a way to replace about 1.5x the power used, back into those batteries. Heating, cooking, refrigeration, and most forms of cooling are best performed with fuel powered equipment that does not require any electrical power.
That doesn’t mean we need to go without, just that we need to do it differently. The RV, marine, and off grid suppliers are great places for inspiration.
I like being prepared, so I have two separate, but interconnected systems. Each will power my van for about a week. When I’m driving, or charging by other systems, the two systems are connected, so both get charged. If not being charged, they are isolated from each other. Both systems are capable of powering my van for either driving or camping. While this doesn’t have anything directly to with solar, the time to consider this stuff is in the design stages before you begin actually building your system.
Many of us feel like solar should be an optional last step… Regardless, solar is just a very expensive battery charger, and the design of your electrical system is what needs the most careful attention, not the solar. What is going to supply your power system, batteries, generator, shore power, or some combination of them. I didn’t include solar here because it only a battery charger, and not a viable source of actually usable power. Any cloud can literally kill anything you have directly hooked up to solar, all your usable power must come from batteries, a generator, or shore power.
Most of us use both a generator or shore power mainly as a battery charger as well. The batteries act as a regulator, to make the power more stable. In cars, the battery supplies the cars power, while the alternator keeps the battery charged, for the very same reason.
The next thing to consider is whether we want a DC only system (the most efficient), or an AC/DC system, and exactly how we’re going to accomplish it. DC alone is pretty straight forward and easy. For AC we have multiple options to consider and explore. Do we want an inverter(s), or do we only want AC when using a genny or shore power, or do we want both, and how are we going to accomplish it.
Notice I said inverter(s) with an “s”. The most efficient use of inverters is to size the inverter according to your load. Oversized inverters can waste a lot of power, so multiple smaller inverters are a better choice, and all inverters should be turned off when not in use.
Now we need to decide where we want our outlets, which type where, and where do we want our switches, fuses, and circuit breakers. This should be given some very serious consideration, because future changes could be very difficult. It’s better to get it right the first time and plan for any possible future expansions.
I’ll call it good for this post, feel free to ask for anything additional, or even challenge me if you think I got something wrong.
"Never drive faster than your guardian angel can fly." ~ Unknown