Have you ever used a portable jump starter only to be frustrated by the fact that it stops working after a few cranks? If you let it sit for a couple of minutes, it will start working again. But having to wait can be annoying. The wait is because of something known as the ‘duty cycle’.
A duty cycle applies to both portable jump starters and battery chargers. According to Clore Automotive, the company behind the Jump-N-Carry and Booster PAC jump starter brands, the duty cycle idea is all about safety.
Generating Power Also Generates Heat
Whether you are jump-starting a car or charging a battery in your garage, the unit you are using doesn’t actually store electricity. It generates electricity as it does its job. Unfortunately, the process of generating electricity also generates heat.
Heat is the number one enemy of both portable jump starters and battery chargers. Excessive heat damages internal components. Specifically where jump starters are concerned, excessive heat can also damage internal battery packs. This creates a situation that is both unsafe and could permanently damage the unit.
What the Duty Cycle Does
A unit’s duty cycle is a measurement of how long it can be safely used before you have to let it rest. Imagine you have a portable jump starter with a 20-second duty cycle. You could attempt to crank your engine for up to 20 seconds before you need to let the unit cool down for a few minutes. You can use one continuous crank or crank twice at 10 seconds apiece.
Older jump-starter technology could not handle automatic duty cycles. It was up to the user to pay attention to the time and then stop cranking when the unit needed rest. Some of the cheapest jump starters on the market today still don’t have automatic duty cycling built in. You need to manage the duty cycle manually.
More expensive units have built-in thermal protection circuits. If a unit gets too hot, its internal circuits automatically shut it off until things have cooled down. You just need to wait until it is sufficiently cool before using it again.
How to Know That a Unit Is Overheating
The duty cycle built into a battery charger is nearly identical to one built into a jump starter. Practically speaking, the two worked the same way. But what if your unit doesn’t have the protective circuitry built-in? How would you know that it is overheating?
For starters, a battery charger or jump starter should never feel hot to the touch. A bit of warmth is normal. But if you touch it and it is uncomfortably hot, the unit is overheating. Shut it off and let it cool down.
Other signs indicating an overheating scenario are as follows:
- Burning Smell – Internal components will start emitting a burning smell if the unit is overheating. You might smell burning plastic or a chemical odor that seems out of the ordinary.
- Warning Lights – Modern units without built-in safety circuits might still have warning lights that flash under excessive heat. Always pay attention to flashing lights.
- Swelling or Deformation – Jump-starters and chargers are usually encased in plastic cases. Excessive heat could cause a plastic case to swell or deform. Both are signs of a serious internal problem.
- Smoke – Any sign of smoke is a clear indication that the unit is getting too hot. Smoke signals an electrical fault which should not be ignored.
Paying attention to a unit’s duty cycle is a safety issue. Do not ignore duty cycles. They exist for your protection.
