Green Mountain Solar

Can Solar Batteries Be Stored Outside or in a Garage in Vermont?

Short answer: No. Find out why, and what the safe alternatives are.

Canva Design DAEV2y9JKIk-1If you’ve been browsing battery backup options, we’d bet you’ve come across more than one photo of a Tesla Powerwall or other energy storage option hanging in a garage or outside in a modern carport. That may work in cozy climates like Arizona, but in frosty Vermont, that isn’t going to fly. Here are the reasons we are selective about where to store your solar battery bank.

Can Solar Batteries Be Stored Outside?

Technically, yes. Consider the rating system on the battery backup storage Green Mountain Solar prefers to use, the Tesla Powerwall. The Tesla Powerwall gets two scores on an IP scale(Ingress protection; how effective this device is from blocking foreign objects) from 0-6, the first number measuring intrusion protection (small sediment) and the second, moisture protection. The Tesla Powerwall is rated IP56 for the wiring component and IP67 for battery and power electronics. Overall, this rating suggests great quality, and resilience against environmental degradation, and is overall outdoor rated.

Keyword: “overall.” Anyone who has lived in Vermont knows that our winters aren’t your run-of-the-mill winters. Due to the cold temperatures Vermont experiences in the winter months, it is not conducive to place a solar battery outside, or anywhere that is not temperature controlled.

Learn About Vermont Utility Battery Backup Programs Here


The Problem with Cold Batteries

It all boils down to optimizing storage capacity and prolonging the integrity of the battery.

Storage Capacity: The temperature of your battery directly correlates with its energy storage capability. Lower temperatures = Low storage capacity.

According to Green Mountain Solar operations manager, Ben McFeeters, “As the temperature of your Powerwall decreases, it will limit the amount of energy you are able to discharge and will begin using a portion of the energy storage to maintain a higher temperature. The optimal operating temperature is 77 degrees Fahrenheit.” Batteries will operate just fine down to around 45 degrees, but after that, the capacity really starts to drop off due to internal heaters and software limits on charge and discharge rates. That means that unheated garages are out of the question in Vermont.

Battery Integrity: Exposing your battery to freezing temperatures could also result in damage to its internal elements. Just as you wouldn’t leave your brand-new computer in the car during a winter storm, your battery shouldn’t be exposed to such frigid temperatures either. Tesla Powerwall comes with a 10-year warranty, but any sign of temperature damage can void the warranty.

Read More on How To Use Solar Backup Batteries in Vermont


Where to Store My Solar Battery Bank

Even though solar batteries are outdoor rated, they are no match for the blistering cold of a Vermont winter. It will always be best practice to protect your Battery Powerwall from the freezing temperatures we experience in Vermont. At Green Mountain Solar we will always recommend placing your solar backup battery in a climate-controlled area, like a basement or heated garage, to ensure you receive the highest battery performance and lifecycle of your investment.

Lilly Baron

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