Can solar batteries overheat? Will they explode? Is it safe?

Find out what happens when solar batteries overheat. Will they explode if they get too hot and are they safe?

Can solar batteries overheat?

Wall mount home storage batteries can overheat, but only in abnormal conditions. Generally, they will operate as per normal if they are installed correctly and operating in the temperatures and humidity that the manufacturer requires. 

There is a general fear that batteries can overheat which causes damage to our homes or garages. Especially when we have all seen the videos of exploding lithium-ion batteries in phones or tablets. Despite these highly publicised events, home battery storage systems have tended to be quite stable. 

How hot can solar batteries get?

At maximum load, solar batteries can get as high as 50 degrees C to 60 degrees C.

Here are a list of popular manufacturers and their operating temperatures

Manufacturer and productMinimum Operating TemperatureMaximum Operating Temperature
Redback Smart Hybrid-25 degrees C60 degrees C
Tesla Powerwall-20 degrees C50 degrees C
LG Chem High Energy-20 degrees C50 degrees C
BYD HVS-10 degrees C50 degrees C
Sonen Hybrid 9.53-5 degrees C45 degrees C
SENEC Home Hybrid5 degrees C40 degrees C

Here are the sources for the datasheets:

It is also worth noting that the minimum operating temperatures are lower than -20oC and -25oC. If you live in an area with a temperature that is consistently lower than -10oC, then you may be limited to Redback, Tesla or LG Chem only. Even then, you may not be able to get as much out of the battery as others in a warmer climate. 

Does a solar battery get hot while charging?

Yes, it is normal for batteries to get hot while charging or discharging. 

Any time that current runs through the inverter from AC to DC, or back from DC to AC there is a conversion of energy type. This is either electrical energy to chemical, or chemical to electrical. 

Anytime there is an energy conversion, there are losses. No energy conversion conserves 100%.

The lost energy is generally produced in heat. You may also sometimes hear the batteries give off a “hum” sound. This is just another conversion type to sound.

The less heat that is produced means the conversion is as efficient as possible. 

If you place your hand on the battery, at most it should be warm to touch. If it becomes hot, then something could be wrong. 

What is the recommended temperature?

Heat is a major problem for all batteries. 

The hotter the surrounding temperature is, the harder the batteries need to work. 

Almost all battery manufactures have a recommended operating temperature. For example, this is on the spec sheet for the Tesla Powerwall. There is an operating temperature and a recommended temperature.

This is the temperature range that allows the battery to perform at ideal conditions. Once these are not met, the battery output, storage and frequency and all other parameters should act as per normal. 

If the temperatures fall outside of the range, the battery will likely not work as well. 

This is shown in the data sheet for the Redback Hybrid. 

It says anything above 50oC will derate the battery. 

What happens if a solar battery gets too hot?

Although very unlikely, there may come a point when your solar battery gets to above 50oC and potentially too hot to touch. 

This is when there is likely a major manufacturing defect, and your battery has malfunctioned.

Again this is only under extreme conditions, but once temperatures are too hot, the surrounding insulation and protection around the battery may break down or melt. You may notice these from the battery:

  • Bulging
  • Bubbling
  • Emitting gas
  • Sparks 
  • Flames

Do not be alarmed. 

If possible, remove the battery connection to your home or grid. 

Once again, these batteries have been tested rigorously and these conditions are highly unlikely to happen. 

Can batteries explode if they get too hot?

Once again, it is very unlikely that your battery will get to the temperature that exceeds its operating range.

But if it does, it will produce much of what is discussed in the previous section.

It may get to the point that the batteries do explode. 

Again, this probably won’t happen.

How do you keep solar batteries cool?

The first rule is to consider what sort of climate you live in. 

Is your average temperature above the highest recommended temperature? 

Or is it below the lowest recommended temperature?

If you answered “yes” to either of the above, then getting a solar battery right now may not be a good investment. You may need to look at other technologies, or wait until technology catches up. 

Besides the first conditions, the best way to keep it cool is:

  1. Keep the battery indoors
  2. Allow ventilation
  3. Keep the battery away from heat producing appliances.

Keeping the battery indoors

Keeping the battery indoors will help insulate against harshness of temperature changes outside. An ideal location would probably be in your garage. 

On the Tesla Powerwall website, they specifically ask to avoid installing their Powerwall in locations exposed to direct sunlight.

In addition, this will help against other weather elements as well as birds wanting to start a nest above the battery. 

Do batteries need ventilation?

Batteries need a decent amount of ventilation, but you don’t need to go overboard. 

Almost all manufacturers ask for a location with good ventilation. If your battery is located outside, then ventilation is taken care of.

If it is installed inside, then you should probably not put too many things in front of it. For example, installing it inside another cupboard. 

Redback’s spec sheet gives a range of airflow from 30cm3/min to 320cm3/min.

Tesla’s website asks for customers to keep clear of debris. 

Keep the battery away from heat producing appliances.

You should probably put the battery away from other appliances in your home that tends to create heat. 

This could be your heater, hot water tank, pool heater etc. 

You would ideally want to reduce the temperature to around 15 degrees. The closer it is to this temperature, the better your battery will run.

What happens to excess power?

For Lithium-ion batteries, once the battery is full, it will be producing minimal heat, and charging the battery won’t damage it in any way.

There is nothing to worry about if your battery is full. 

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