can you jumpstart a car with a deep cycle battery

[LaReed]

Yes, you can jumpstart a car with a deep cycle battery, but it's generally not recommended for regular use. A standard starting, lighting, and ignition (SLI) battery is designed to deliver a very high burst of current (measured in Cold Cranking Amps or CCA) for a few seconds to start an engine. A deep cycle battery, in contrast, is built for deep discharges, providing a lower, steady current over a long period, like for powering a trolling motor or RV appliances. Using a deep cycle battery for jumpstarting can work in a pinch, but it may strain the battery and shorten its lifespan if the car's engine is particularly difficult to start.

The key is the battery's ability to deliver sufficient cranking amps. While a deep cycle battery has a high Amp-hour (Ah) rating indicating its capacity, its CCA rating is typically much lower than a dedicated SLI battery. For a successful jumpstart, ensure the deep cycle battery is fully charged and has a CCA rating that meets or exceeds the requirements of the vehicle you're trying to start. The process is identical to a standard jumpstart: connect positive to positive, then negative to a clean, unpainted metal ground on the dead car's engine block. After starting, let the car run to allow the alternator to recharge the main battery.

Battery Type	Primary Function	Key Strength	Key Weakness for Jumpstarting	Typical CCA Range
SLI (Standard Car Battery)	Engine Starting	High Burst Power (CCA)	Poor Deep Discharge Tolerance	400 - 800 CCA
Deep Cycle Battery	Sustained Power	Long Runtime (Ah)	Lower Cranking Amps	100 - 400 CCA
Dual-Purpose Battery	Both Starting & Power	Balanced Performance	Compromise on Both Specialties	300 - 600 CCA

For a single emergency, a healthy deep cycle battery will likely work. However, repeatedly using it for this purpose is inefficient and hard on the battery. If you frequently need to jumpstart vehicles, a compact lithium-ion jump starter pack or a dedicated portable jump starter is a safer, more effective, and more convenient investment.

[DiCassandra]

It'll probably work once if the deep cycle battery is fully charged. Hook it up just like a regular jump: red clamp to the dead battery's positive, the other red to the deep cycle's positive. Then, black to the deep cycle's negative, and the last black clamp to a bare metal bolt on the engine block of the dead car. Start the good car first, then try the dead one. It's a temporary fix, not a permanent solution. Don't make a habit of it.