What’s the Difference? Solar Panels: Series or Parallel
The main difference between wiring solar panels in series or parallel is the output voltage and current. When you wire multiple panels in series, their output voltages add together, and their output current remains the same. Conversely, when you wire numerous solar panels in parallel, their output currents add together, but their output voltages stay the same.
Series Solar Panel Wiring
Voltage and Amps in Series
To wire solar panels in series, connect the positive terminal on the first panel to the negative terminal on the next, and so on. The resulting voltage will be the sum of all of the panel voltages in the series. However, the total current will be equal to the output current of a single panel.
For example, in the graphic above, we have four 12-volt, 5-amp panels wired in series. The output voltage is 48 volts (12V + 12V + 12V + 12V = 48V), yet the output current is still 5 amps.
Parallel Solar Panel Wiring
Voltage and Amps in Parallel
To wire solar panels in parallel, connect all of the positive terminals on each panel together and then do the same for the negative terminals. The resulting current will be the sum of all of the panel amperes in the parallel array. However, the total voltage will be equal to the output voltage of a single panel.
For example, in the graphic above, we have four 12-volt, 5-amp panels wired in parallel. The output current is 20 amps (5A + 5A + 5A +5A = 20A), yet the output voltage is still 12 volts.
If you live on a boat (like me) and run a 12v system then whatever amps we use through a given time is what we need to replace from our solar panels, forget watts etc all we do is charge batteries and then either use 12v or invert it to 240v but either way we use amps and it’s these that are important, i’ve seen so many people with 48v panels with 350w thinking they are the best on the market, so why are you only getting 7.2amps from them? Not to mention the size! Our 200w panels are half the size and kick out 12 amps each! So ok that doesn’t sound a lot of difference but due to the amount of daylight hours we get here in the UK you need to maximize on that energy as much as possible, this is also why Lifepo4 cells are so great, they can take any (within reason) amps you can throw at them whereas lead acid won’t, Lead acid or even AGM batteries take less charge as they charge, this is because the resistance inside them gets higher as they get nearer full, ever watched a charger charge a lead acid type, usually it starts with a high amount of current and then slowly goes down to a minimum rate, as the battery get’s near full it’s probably down to 1amp!