Battery Capacity

March 16, 2009

Our Tip of the Week concerns the reserve capacity built into your vehicle's battery. It's always given in the spec charts but rarely talked about.

Reserve capacity is the ability of the battery to deliver approximately twenty amps of current which would be required to keep the engine running, the heaters, wiper and defroster going in the event of an electrical emergency on your car. For example, the alternator quits working on your vehicle, with the reserve capacity built into the battery, you could still drive the vehicle off the road to a safe location where it could be repaired.

On this vehicle, for example three different sizes of batteries could typically be fitted into this vehicle and all of them would have enough cranking power to start this engine in sub-zero weather. But the smallest battery might have as little as seventy-five minutes of reserve capacity and the biggest one, this one right here, might have as many as a hundred and fifteen minutes of reserve capacity.

It's that reserve capacity that could run your four-ways if you broke down on the side of the road or allow you to sit somewhere with the ignition on accessory - not wasting fuel - and listen to the radio and still have the wipers working, for example. That reserve capacity is what's going to allow you to run those accessories and still restart the vehicle. The better the battery and the bigger the battery, the more reserve capacity.

That's your Tip of the Week.

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