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Does my battery work differently on very hot or cold days?

Short answer. Yes, a little. Sigenergy says its system runs from -20 to 55 degrees C, heats the battery before charging below 0 degrees (using some power), and may reduce its output above 40 degrees. GoodWe lists -35 to +60 degrees C and reduced output above 40. On the Northern Rivers, hot afternoons are the more likely case.

Reduced output on a very hot day is the equipment protecting itself, not a fault. It usually comes back as things cool.

Safety first. Never cover, hose or move the unit, and keep it clear of anything stacked against it. Never open a switchboard, remove a cover from your battery or inverter, or touch any wiring. Anything beyond the app, a light you can read from a safe distance, or your own router is a job for a licensed electrician. If you see smoke, smell burning, hear arcing or see water on or near the unit: keep everyone away, switch off at your main switch only if it is safe to do so, and call 000 if there is any fire or smoke.

What the manufacturers say

  • Sigenergy: maximum operating range -20 to 55 degrees C, with 10 to 35 degrees as the recommended best range. Below 0 degrees the battery cannot charge immediately and the built-in heater can switch on, with best charging after heating for less than 2 hours; the heating uses power. Above 40 degrees the equipment may derate (reduce its power), and higher temperatures shorten its service life.
  • GoodWe ESA: working temperature -35 to +60 degrees C, with derating above 40 degrees (datasheet). It is fanless and cools naturally.

What you can do

  1. Keep the area around the unit clear so air can move. Sigenergy asks for clear space around the equipment, and GoodWe lists checking for debris and blocked air paths every 6 months.
  2. Do not move or cover the unit. Its position was chosen to be compliant.
  3. If your app shows lower power on a very hot day and the unit is otherwise fine, wait for the evening.
  4. If it keeps happening, or you see an alarm, call us. Where it is installed may be worth a look.

Heavy shade over the unit, a hot wall behind it or a blocked area can make summer derating more likely. We check battery position on every site visit.

Read more: Sigenergy batteries and GoodWe batteries from Sun Connect Solar

When to call us

If we installed your system, call us on 0483 903 020. Our service help for existing customers is free: we start by working through it with you by phone. If you are not yet a customer, a service call is $250 + GST, which covers one hour on site within 20 km of Mullumbimby; travel further out is quoted separately. Contact us or call 0483 903 020 (Mon-Fri 7am-6pm, Sat 7am-4pm).

Quick questions

Is it normal for the battery to slow down on a hot day?

Both manufacturers say the equipment may reduce output at high temperatures. It is protecting itself.

Do I need to do anything in winter?

The Northern Rivers rarely goes below 0 degrees, but Sigenergy says its system heats the battery in that case, which uses some power.

Can I install a shade over my battery myself?

Please call us first. Airflow and clearances matter, and anything fixed near it should be done by us.

Does heat shorten battery life?

Sigenergy says higher temperatures shorten service life. That is one reason position matters.

Sources

Last checked 6 October 2026. Only the manufacturer’s, the network’s or the government’s own documents are used; app menus change between versions, so if your screen looks different, call us rather than guess.

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