Do Jump Starters Work in Cold Weather?
4 lessons in this series, 11 min in total
- How Long Does a Jump Starter Hold a Charge? 3 min read
- Can You Leave a Jump Starter in Your Car? 3 min read
- Should You Keep a Jump Starter Plugged In? 2 min read
- Do Jump Starters Work in Cold Weather? 3 min read
This lesson draws on NOCO’s GB40 and GB70 user guides, Clore’s JNC660 manual, Battery University’s BU-502 and BU-410, and AAA Hudson Valley. How we research explains the method.
Operating vs charging temperature
A jump starter has two cold limits, and they are far apart. The operating range is where it may jump a car; the charging range is where it may take a charge.
| Unit | Operates (jump-starts) | Charges | What the maker adds |
|---|---|---|---|
| NOCO GB40 | -4°F to 122°F (-20°C to 50°C) | 32°F to 104°F (0°C to 40°C) | Do not operate outside these ranges |
| NOCO GB70 | -4°F to 122°F (-20°C to 50°C) | 32°F to 104°F (0°C to 40°C) | Same wording as the GB40 |
| Clore JNC660 | Any weather, hot or cold | Built-in AC charger, no range given | Best results if stored at or above 50°F (10°C) |
Some retailer listings and older spec sheets give the GB40 a lower cold limit of -22°F (-30°C). We go by NOCO’s current user guide, which says -4°F (-20°C). Where a parked pack can be stored all winter is a separate question, covered in can you leave a jump starter in your car.
What cold does to a pack
Battery University says cold raises a battery’s internal resistance and lowers its capacity. At -4°F (-20°C), it puts most batteries at about 50% of their normal performance. The loss is temporary: a cold cell recovers once it is back at room temperature.
Charging is different. Battery University says consumer lithium-ion cannot be charged below 32°F (0°C): it may seem to charge normally, but metallic lithium plates onto the anode, a permanent loss of performance and safety. That is why NOCO’s charging range starts at freezing, and why a pack that spent the night in a cold car should warm up indoors before you plug it in.
How lithium and lead-acid packs compare overall is a separate topic: see lithium vs lead-acid jump starters.
Cold engines ask for more current
Cold works against you from both ends. AAA Hudson Valley says that when temperatures drop, an engine may need up to twice the normal current to start. The car’s own battery is weaker at the same moment, which is why a weak battery shows up in cold weather.
So a pack that is half-charged and chilled is meeting the hardest start of the year. Clore’s manual also lists winter cold among the reasons the number of starts per charge varies. If your engine sits near the top of a pack’s rating, size up, as how many amps you need explains.
Two hard stops apply in any weather: both makers say never to jump a frozen battery (when not to jump-start), and the NOCO guides say not to operate the pack outside its range.
A practical winter routine
- Charge indoors. Top the pack up at room temperature, never in a car below 32°F (0°C).
- Check the gauge before cold trips. NOCO notes that an unused pack discharges over time and must be recharged before use.
- Carry it warm. Bring the pack out with you from the house rather than relying on one that sat overnight in a frozen car. Battery University’s figures show a cold cell gives less until it warms.
- Below -4°F (-20°C), wait. Warm a NOCO pack into its operating range before you use it, since the guide says not to operate it outside that range.
- After the jump, warm it, then recharge. Clore says to recharge the JNC660 after every use, and its retry rules are in how to use a jump starter safely.
Which pack for a cold climate
The GB40 suits gas engines up to 6.0L and diesels up to 3.0L, and it is small enough to bring indoors every night. NOCO GB40 vs GB70 compares the two side by side.
The GB70 gives more margin for large engines on cold mornings, rated for gas up to 8.0L and diesel up to 6.0L.
NOCO Boost HD GB70
NOCO's larger lithium jump starter: 2000A peak, rated for gas engines up to 8.0L and diesel engines up to 6.0L.
Key specs
- 2000A peak
- Gas engines up to 8.0L, diesel up to 6.0L
- 12V lithium
Paid link
View on Amazon (opens in a new tab)The lead-acid JNC660 suits a heated garage or shop, where it can sit on its charger above Clore’s 50°F (10°C) storage advice.
Clore Jump-N-Carry JNC660
A heavy-duty 12V lead-acid jump starter from Clore: 1700 peak amps and 425 cranking amps, with 46-inch (117 cm) cables.
Key specs
- 1700 peak amps, 425 cranking amps
- 46 in (117 cm) cables
- 12V lead-acid
Paid link
View on Amazon (opens in a new tab)Sources
Show all 6 sources Hide sources
- NOCO GB40 user guide and warranty (PDF)
- NOCO GB70 user guide and warranty (PDF)
- Clore Automotive JNC660 operator’s manual (PDF)
- Battery University BU-502: Discharging at high and low temperatures
- Battery University BU-410: Charging at high and low temperatures
- AAA Hudson Valley: Cold Weather Is Hard on Your Car Battery
