Going Off-Grid? Please Don’t Make the Same Battery Mistake I Did.

Going Off-Grid? Please Don’t Make the Same Battery Mistake I Did.

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By RICKY RAFFAINI, Tech Support Rep at Wholesale Solar​

I have always been interested in renewable energy, but when I moved into my grandma’s old cabin in Mendocino, CA, it was the last thing on my mind.

Yes, with the cabin came a small off-grid solar setup, but I was more concerned with abstract concepts like “peace” and “beauty.”

So at first, I was happy with the single 12-volt battery I had. It forced me to live a simple life without a bunch of electronics—always a good thing.

With the limited power available I was able to use my laptop, a few lights, a small speaker, and a phone charger. There was no cell service, so my phone never died, and I used kerosene lamps to read most nights.

It turned out to be one of the best experiences of my life.

But eventually, I was ready to upgrade my battery bank—mostly for the experience.

However, I had no idea where to start.

My first thought was, “This can’t be that hard.”

I quickly realized it was more complicated than I thought.

One of the first things I learned: it is so important to have an understanding of how lead acid batteries work before messing around with a battery bank’s wiring.

So I asked around for information, found some basic solar books (mostly outdated books from the local library), and used my phone to research batteries when I was closer to town and had cell service.

I ended up purchasing a couple of cheap marine or “deep cycle” batteries from the local hardware store on the recommendation of a new employee.

I realize now he probably didn’t know the difference between car batteries and the marine batteries they carried… but neither did I at the time, so fair enough. (A car battery’s power is measured in cranking amps, because the battery is designed to offer bursts of energy to start a vehicle—rather than slow discharge needed to run appliances.)

Luckily my limited research helped me decide on the marine batteries, which are designed to have a longer reserve capacity than car batteries.

All that meant in my case, however, was that it took me longer to destroy them.

Knowing what I do now, I’m a little embarrassed to say that I was nowhere near ready to install a battery bank—no matter how small this setup was. Here’s where I went wrong.

The failure happened because I didn’t know the difference between a series connection and a parallel connection.

Diagram showing series wiring versus parellel wiring
Series Circuit Wiring Vs. Parallel Circuit Wiring

In a series circuit, the current through each of the components is the same, and the voltage across the circuit is the sum of the voltages across each component.

Christmas lights are a good example of series wiring. If one light stops working, it blocks the power to the rest of the lights that come after in that circuit.

In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component.

When hooked up in parallel, each light will have its own path to the power source. If one light goes out, the rest will stay on since they are hooked up independently.

In short, series wiring increases the voltage but the amps stay the same. And parallel wiring increases the amperage but the volts stay the same.

And when I got the two new batteries in place, I had no idea what to do.

Now remember, I was working with just one 12 volt battery before, and now I have two 12 volt batteries, which created 24 volts when wired in series.

It’s also important to remember that my inverter (the heart of the system) operates on a 12 volt battery bank. So I’m limited to 12 volts for my battery system.

But wait, you say. You now have a 24 volt battery bank and a 12 volt inverter, that can’t work. Well, yes and no.

The way I wired it, which was in series, was of course wrong. And that’s because I was running a 12 volt inverter with a 24 volt battery bank.

What I should have done was wired the batteries in parallel at 12 volts, allowing my 12 volt inverter to play nice with my battery bank.

Diagram showing the original, wrong, and right way Ricky should have wired his batteries
Ricky's Mistake: Wiring Two 12v Batteries in a Series with a 12v Inverter.

On the flip side, I could have bought a new inverter that was 24 volt rated and would have been fine running with two 12 volt batteries in series (totaling 24 volts), but that would have cost me a lot more to upgrade, when all I had to do was wire my batteries correctly.

I’m still not sure if I caused any damage to my solar equipment. I would be surprised if you told me I didn’t.

My grandma warned me that maybe I shouldn’t attempt to upgrade my system, but of course I didn’t listen. Luckily, she seems to be a firm believer in learning through experience… So the time and money spent were not a total loss in her eyes. (Or maybe she was just trying to make me feel better about destroying her stuff…).

After this experience, I decided to pursue some real education in solar installation.

And I won’t lie—my inspiration came from wanting to make things right at the cabin. (Not to mention wanting to prove to myself that I could figure it out.)

My solar disaster was 100% my fault. And although my grandma has never expressed frustration over the “battery-turned-paperweight incident,” I am sure she would appreciate a more thought out and educated approach to make things right again.

That brings me to Wholesale Solar. I have always had an interest in finding a career path in some sort of industry that supported sustainable living, with solar at the top of that list.

I’ve worked in biodynamic farms in the mountains of Mendocino. I’ve also given water conservation a go with a sustainable plumbing company building rainwater collection systems and gray water gardens in Sonoma.

And as a part of that job I noticed that at every beautiful job site there was a solar array.

I was actively taking classes and pursuing my career, but I’m happy (and lucky) to say I fell into the Wholesale Solar team by chance.

I started working here in July of 2016, and eventually found my way into the technical support department. Which is funny—because I often help folks going through the same kind of failed experiment I did.

Solar takes a lot of time, patience, and effort to install and maintain. That’s something I learned the hard way, and something I hope to teach our customers.

I have so much respect for our customers after battling a tricky installation myself, and I am so grateful to finally be in a position to not only help my grandma, but also many other off-the-grid enthusiasts trying to live in an independent paradise.

Click to download our guide to getting started with solar power

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