Cranking Amps

The Truth About Amps - Cold, Cranking, Starting & Peak

There’s a lot of confusion regarding jump starter specifications and what kind of power they are capable of delivering. Different batteries have different standards - you can’t take the parameters for a lead-acid battery and apply them to a lithium-ion for an apples-to-apples comparison. Each battery serves a different purpose and each battery has different chemical limitations. The main ratings we’ll focus on are Cranking Amps (CA), Cold Cranking Amps (CCA), Starting Amps and Peak Amps Lead Acid Batteries Lead-acid is meant to live under the hood of your car for years, enduring heavy cranks each day, several times a day. In the winter it’s exposed to cold temperatures and the chemicals inside freeze up, which is why having an understanding of it’s cold-crank abilities is important. These batteries degrade over time, so having a high CA & CCA means in 5 years, when it’s operating at less than 50% of its original capability, it’s still able to start your car. That’s why an engine that only needs 120A to start, for example, will have a 500CCA battery under the hood; it’s not that the car needs 500A to start, it’s because in 5 years that battery is only going to be able to give 250A at best. Lead-acid batteries have an industry standard that is tried and true to portray battery capability: Cranking Amps (CA) and Cold Cranking Amps (CCA). To define:
  • CA (lead-acid): the measure of current a battery can sustain at 32*F for 30 seconds
  • CCA (lead-acid): the measure of current a battery can sustain at 0*F for 30 seconds
Lithium-Ion Lithium-ion jump starters, on the other hand, are there for the occasional jump – they only need to cover that 3-second-or-less crank for an instant, and then it goes back into storage. It doesn’t need to live under the hood of a car for years on end, with constant drain and charge, and constant exposure to the elements. The chemistry is different, too; it doesn’t allow you to crank for long periods of time because it’s physically impossible. They simply serve a different purpose but are more than capable of delivering the power needed to jump your engine. For this reason, and because lithium-ion crank times are restricted due to chemistry, these batteries have different standards:
  • Cranking Amps (li-ion): the measure of current a battery can sustain at 72*F for 3 seconds
  • Starting Amps (li-ion): the measure of current a battery can sustain at 72*F for 30 seconds
Peak Amps This is another measurement we’ve heard of, but that didn’t come into play until later and it isn’t regulated in any way. There’s no defined temperature, no defined time duration, that it must measure up to. In fact, peak amps are mainly for marketing purposes. Most people who claim peak amperages (oftentimes 10X or higher than the CA or CCA) are measuring the crank for a few milliseconds. There’s nothing useful you can do during a crank attempt/jump start in milliseconds; it’s simply not enough time to do any work on the engine. You see this rating, though, because a trend started, and competitors had to follow suit to keep up, whether they wanted to or not (Weego included). The numbers to focus on, instead, are the cranking amps. We hope, as always, to help our customers understand the battery landscape better so they can make better-educated decisions when it comes to choosing a portable jump starter!
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