So, What Size Battery Do I Need for My Winch?
Quick Summary:
Minimum Spec: 650 CCA (Cold Cranking Amps) for a 12,000 lb winch.
Best Battery Type: AGM or Dual Purpose (avoid standard Deep Cycle).
Why It Matters: Low voltage causes motor heat, melted wires, and premature winch failure.
First Step: Always check your specific winch manual.
The best place to start is always the manufacturer's website or the user/install manual. In the specification section, locate the Cold Cranking Amperage, or CCA. The CCA is the number of amps a battery can deliver for 30 seconds continuously at 0°F without dropping voltage too low. This rating is extremely important because a winch requires a massive initial surge of power to start pulling.
The next important component is the battery type.
While many people suggest a standard deep cycle battery, I actually recommend a Dual Purpose or AGM (Absorbed Glass Mat) battery. Here is why: a traditional "Deep Cycle" battery is designed for low, steady power (like running RV lights), and it may struggle to provide the high-amperage "surge" a winch needs. A Dual Purpose battery gives you the best of both worlds: the high CCA needed to run the winch effectively, and the deep cycle ability to be recharged and discharged repeatedly without dying.
"What happens if my battery is too small, or I use the wrong type?"
If the battery is too small (low CCA), the voltage will drop significantly when you use the winch. Low voltage forces the winch motor to work harder to compensate. This leads to:
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Excessive heat generation in the motor coils.
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Premature failure of both the winch and the battery.
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Melted wires or electrical fires in extreme cases.
A less common problem you should consider is wire length. Most winches come with the cabling required to hook up the battery, provided the battery is mounted nearby. If you need to extend the wires, you will likely need a thicker gauge wire to combat electrical resistance. The longer the wire, the thicker it needs to be to prevent power loss and overheating.
"But I have never had these problems."
A lot of winch setups make their way onto trailers that do have these issues, and we see the outcomes in the service department constantly. Buyer beware: most trailer dealers do not carry the right battery for your winch.
For context, a typical 12,000 lb winch requires a minimum CCA of 650. If your battery is rated lower than that, you are risking damage to your equipment every time you pull.
Another element to consider is how often you use it. If this is something you plan on using frequently—or even multiple times a day—you definitely want a larger battery (higher CCA and capacity) or a better charging system, which will be covered in a later article.
What about using my truck's battery?
While I would not recommend it, the only time you might get away with a smaller battery is if your system is wired directly to your engine's alternator. However, you must understand that the winch will still draw primarily from the battery.
An alternator only provides a small boost (usually 100–150 amps) relative to the winch’s demand (often 400+ amps). This setup only works if the vehicle is running, and even then, you risk damaging your vehicle's electrical system or finding yourself with a dead truck battery when you’re done winching.
"How did you know all this?"
Jayhawk Trailers has been providing trailer repair services for over 30 years. We make it our goal to provide the best service possible, and we look forward to informing our customers on best practices in their trailer ownership.
Need more information? let me know at Cale@jayhawktrailers.com (or let us know at Sales@jayhawktrailers.com).