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Jump starters in cold weather
Updated
Cold hits a jump start twice. Engine oil gets thick so the engine is harder to turn, and batteries, including the lithium pack, give less power. That is why our size picker asks for more headroom as the weather gets colder. For a 2.5 liter gas car, the target goes from 3.1 liters in mild weather to 5.0 liters in severe cold.
Why cold is harder
Interstate Batteries explains that cold thickens engine oil and slows the chemistry inside the battery. Its point is that as temperature drops, the starting power a battery can give goes down while the power the engine needs goes up. That is also why car batteries carry a cold cranking amp rating, measured at 0°F.
How much headroom we add
- 2.5L gas / mild3.1 L
- 2.5L gas / cold3.8 L
- 2.5L gas / severe5 L
- 5.7L gas / mild7.1 L
- 5.7L gas / cold8.6 L
- 5.7L gas / severe11.4 L
| Engine and climate | Our picks that cover it |
|---|---|
| 2.5L gas, severe cold | NOCO Boost GB40, NOCO Boost GBX75, GOOLOO A3 with air compressor, GOOLOO GP4000 |
| 5.7L gas, cold | GOOLOO A3 with air compressor, GOOLOO GP4000 |
| 5.7L gas, severe cold | none of our picks |
These multipliers (1.25, 1.5 and 2.0) are our rule of thumb, not a maker figure. Try yours in the size picker.
The pack has a cold limit too
- NOCO's support FAQ says Boost packs work from -4°F to 122°F, and thermal sensors stop the pack outside that range.
- The GOOLOO A3 and GP4000 listings give -4°F to 140°F. The A3 listing says not to charge below 14°F.
- So on a very cold night a pack left in the car may refuse to work. Keep it indoors and carry it out with you. Recharge it indoors.
Picks for cold places
- GOOLOO A3: gas up to 9.0 liters, and the listing states its cold limits plainly. Caveat: some owners say the air compressor stopped working after a few uses.
- NOCO Boost GBX75: gas up to 8.5 liters. Caveat: some owners report units failing after about two and a half years.
More on storage in storage and charging.
Safety: never jump a frozen battery. If the case is bulged or you see ice, do not connect anything. AAA says to check for cracks and bulging before any jump. Wear eye protection and follow your vehicle manual.