Reading the Temperature Section of a Battery Manual

Your manual's numbers are the ones that count. General articles, this one included, only tell you what to look for. So let's find them.

Where to look

Start with the manual for your exact product. One maker's guide says to start with the product page or manual for your exact model.¹ It warns against using one model's temperature table for another.¹

Look for a specifications table. If you have the manual as a PDF, search it for the words "temperature", "ambient" and "storage".

If you've lost the manual, try the maker's own support page for your model. A maker's manual is the right source. A shop listing or forum post isn't.

What the lines mean

A spec table may use terms that look alike. Wording differs between makers, so this is a rough guide. Your manual's own definitions come first:

Battery University says batteries can be discharged over a large temperature range, but the charge temperature is limited.² That's one reason a sheet can list two different ranges.

Here's a real example from one maker's published table. It gives discharging as -20°C to 40°C and charging as 0°C to 40°C.¹ Different units will list different numbers.

Watch for these traps

Most mistakes come from reading the wrong line. They're easy to avoid once you know them.

• Charging limits aren't storage limits. The same guide says not to treat a charging limit as a full storage limit.¹
• Units. Some manuals give °C only, others °F only, or both. Check which you're reading.
• Footnotes. Numbers can come with conditions. Read the small print beside the table.
• Several models in one manual. Make sure the column matches your model.
• A missing line. If storage or charging limits aren't given, ask the maker. Don't guess.

What to do with the numbers

Compare each range to the place the battery lives, at its coldest and hottest times of year. Think about the worst week, not the average one. A garage may swing much wider than a hallway does.

One trade article covers long-term storage of lithium-ion batteries. Its advice ends: refer to the battery manual for specifics.³ Take that as a prompt to look for your maker's own storage charge level and range.

The same article notes that battery manuals offer guidelines and maintenance schedules.³ Keep yours somewhere you can find it.

Safety notes

Follow the manual for your own product, including any placement rules it gives for the room, the wall or the outdoor spot where the battery will sit. Simple. If the manual says installation needs a licensed electrician, that's what it means. Don't wire, open or modify the battery yourself.

Rules on where a home battery can go vary by country and region. Ask your electrician, or look at your local authority's published rules, rather than a general article.

The reasoning behind the limits is covered in the opening page. Charging below freezing has a page of its own.