Leaving the Cabin?

It’s Okay to Turn Off Your Lithium Batteries

Introduction
Why It’s Okay to Power Down
The Ideal Storage State
What About Freezing Temperatures?
Is This True for Any Lithium Battery?
Conclusion

Introduction

I just had a customer call me about his solar system. He was heading out for five weeks and wanted to know what he should do while he’s away, keep the system on so the sun can keep charging the batteries, or shut everything down?

My first question was simple: “Do you need anything to stay on?” Sometimes people want a fridge running, a light on a timer, or maybe a camera system powered up. But in his case, he said no, nothing needed to stay on.

So I told him, “Then just shut everything off, including your batteries.”

Why It’s Okay to Power Down

One of the many advantages of modern lithium batteries like the Pytes V5 which this particular customer has powering his system, is that they can safely be turned off and left sitting for extended periods, even up to six months, without any harm, as long as they’re at about 50% charge when you power them down.

Unlike lead-acid batteries, which can self-discharge and sulfate when left idle, lithium batteries hold their charge very well. When you shut them off using the internal breaker or communication app, they effectively go into a hibernation state. This minimizes any internal chemical activity and preserves both the charge and the lifespan of the cells.

The Ideal Storage State

If you’re closing up the cabin or heading south for the winter, here’s what I recommend:

Charge the batteries to around 50–60%. That’s the sweet spot for long-term storage. Fully charged batteries can slowly degrade if stored at high voltage, while deeply discharged ones may drop below their safe voltage range over time.
Power down the battery bank. With Pytes batteries, you can do this easily from the front switch or through your monitoring system. Make sure all other components, inverter, charge controllers, and any DC loads, are also powered off.
Check back in the spring. When you return, simply turn everything back on. The batteries will wake up and operate as if you never left.

What About Freezing Temperatures?

If your batteries are stored in an unheated space, make sure they’re protected from extreme cold. Lithium batteries should not be charged below freezing, though they can safely sit in sub-zero conditions as long as they’re disconnected and have some charge.

The Pytes V5 batteries, for example, include an internal warmer. Since they would be turned off while in storage, they can sit below freezing without a charge quite safely. When you turn them back on, however, you must ensure that the batteries are above freezing before charging, allowing the internal heater to bring the cells up to a safe operating temperature first.

The V5 heater system operates between about –18 °C (~0 °F) and +10 °C, meaning the heater must function to raise the internal cell temperature before full charging or discharging can occur.

Is This True for Any Lithium Battery?

No matter which brand of lithium batteries you have in your system, it’s always best to check the manufacturer’s specifications for proper storage, shutdown, and restart procedures. Different brands have different temperature limits, and some lithium batteries come with built-in warmers while others do not.

Always make sure you’re dealing with Lithium Iron Phosphate (LiFePO₄) batteries, as these guidelines apply specifically to that chemistry. Other lithium chemistries — such as lithium-ion, lithium-polymer, or NMC — can have very different temperature tolerances and charging requirements, and should not be assumed to behave the same way.

That said, as a general rule, if it’s not freezing, it’s safe to charge LiFePO₄ batteries, including models without internal warmers. Sticking with reputable brands and reading their specifications is the best way to ensure your system stays healthy and performs as expected.

Conclusion

So yes, you can confidently turn off your lithium batteries for the winter. It’s one of the reasons they’re such a great investment for seasonal cabins and off-grid properties. No maintenance charging, no worrying about sulfation, just peace of mind until you return.

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