FAQs

What size solar system do I need?

Sizing a solar system can be tricky, to say the least. Most online sizing guides are geared toward "on-grid" systems for small cabins or small vacation homes or use the "three day storage rule". In our area of Baja, we rely on solar to live as the power grid may be many many years away. Also, we rarely have a cloudy day here so the sun is plentiful.

Cabo Solar has a free sizing worksheet that will assist you in properly sizing your system for Baja. It takes into account overnight loads (while the sun's not shining) and peak loads to assist in sizing a system that is both practical and economical. Ask us for our worksheet or we'd be glad to size your system for you.

how many solar panels do i need?

Generally speaking - enough to recharge your batteries in a "solar day". A solar day in our area is roughly 6 to 6-1/2 hours long. I know, the sun sometimes is brutally beating down on us for what seems like 14 hours in a day but solar panels loose efficiency when the sun is not hitting them on a direct angle. Also, as a cruel joke to us here in Baja, solar panels become less efficient when they heat up. Solar panels are most efficient in DIRECT sunlight when it's 25ºC or less (not happening here in Baja). That said, if you have a 48 volt battery system that uses 825 Amp Batteries (like the Rolls 6CS-25) you have 39,600 watts of storage (volts X amps) and we don't let the batteries get below 50% depth of discharge so that's 1/2 the total wattage (19,800 watts). We need our panels to produce 19,800 watts over 6-1/2 hours so if you divide 19,800 by 6.5 you come up with 3046 (watts) of panels needed. If you purchased the Evergreen ES-190-RL (190 watt) panel you'd need 16 total panels.

how many batteries do i need?

You can't have too much storage --- or can you? We've seen systems that have huge battery banks and a small amount of panels and little (or no) backup generators. This is a recipe for disaster - or at least for having to replace the batteries every few years. If the battery bank cannot be fully charged by the PV array (and there is not adequate backup power like a generator to automatically charge) and it only gets to 70%-80%-90% full charge it will wear out early. To properly size your battery bank, you need to use a good solar sizing worksheet like the one Cabo Solar offers for free. Don't be misled by someone selling batteries and buy too many batteries for your system. Ask us!

what size backup generator do i need?

Or -- why do I need a backup generator? I often get asked "how many panels do I need to never have to run the generator?". My answer is "you don't own enough real estate to mount that many panels". It's impractical to try to size a system without a backup generator here in Baja. Don't get me wrong, I'd love to sell you a large enough solar system to eliminate the generator (a few of those and I could retire). Generator sizing is based on several factors including peak loads on the system, number of inverter/chargers in the system and you're anticipated lifestyle here in Baja (some folks love to enjoy our little slice of paradise in the comfort of their air conditioned home). The generator has to be big enough to charge the batteries (in the case of those rare cloudy days) while running the house loads (will you be running pool pumps also?) and have a little bit left for a safety/inefficiency factor. Generally the smaller (under 12KW) generators on the market use air cooled engines. These generators are typically loud and do not last long in the Baja intense heat (sort of like running the RPM on your car up to 3600RPM while in park on a hot day for a few hours - you get the picture). We encourage the installation of water cooled generators here in Baja. You'll pay a bit more initially but they will last much longer and they are much, much quieter.

why can't I equalize my batteries?

Under construction.

Why is my battery voltage always low?