February 5, 2003
Your battery is only one small part of your vehicle, but nothing else has a harder job to do during cold weather. A good battery will supply power to crank over a frozen engine with ease. A poor battery doesn’t survive long in our winter climate, but even good batteries can become weak and need a little extra care. Here are some tips to keep your battery doing its job when the temperature plummets.
Avoid short trips. Each time you start your vehicle you use energy out of the battery. Normally this energy is quickly replaced as the battery is recharged by the vehicle’s alternator, but cold batteries don’t charge well. When the battery temperature drops to -40C, the battery may need to be charged for over 30 minutes just to heat it enough to accept a charge! Frequent starting of the engine uses energy from the battery without ever giving it a chance to recharge.
There are a couple methods of keeping the battery warm so it will accept a charge faster. One way is to install an electric battery blanket. Remove the battery hold down bracket and covers, wrap the plastic covered heating unit around the battery and hold it in place with the supplied twist tie. Reinstall the battery hold downs and covers and route the battery blanket cord out to the front of the vehicle so it can be plugged in. Installing a battery blanket takes only a few minutes on most vehicles but there are a few new vehicle models that pose a challenge in accessing the battery. A battery trickle charger may be a better solution for these vehicles.
A 2 Amp trickle charger can be used all winter long. The power put out by the trickle charger is very low and will just keep the battery warm. Mount the charger in the engine compartment so it will not damage other components and wire the charger positive and negative leads to the battery connections. Most vehicles with batteries that are difficult to access will have auxiliary connection terminals mounted in an easy to find spot. These are good places to connect the charger. Route the power cord so it can be plugged in with your block heater and you are ready to go. The trickle charger could cause a battery drain if left on continuously in the summertime, so disconnect it from the battery during warmer months.
Keeping a charge in your battery means using as little power as necessary from it. Typical winter drivers will have the headlights, rear window defogger, and the heater fan on all the time. The electronic engine controls use power as well. Many drivers will also have the radio and other electric or electronic options turned on. The electricity used by all these devices is more than most charging systems will supply when the engine is idling. The battery supplies what the alternator cannot, and eventually the battery goes dead.
Avoid a discharged battery by turning off all unnecessary electrical devices when the engine is idling. As engine speed increases, so does the output from the alternator and the electrical system places very little demand on the battery, so you can turn accessories back on when driving. If you have noticed the headlights seem to brighten when you turn off the heater fan or increase the engine speed, your battery is possibly becoming partially discharged, or you have poor battery connections.
Keeping battery cables clean and tight is necessary for dependable winter starting. A battery has only 40% of its cranking power available when the temperature drops to -40C but your engine needs 2 to 3 times as much power to crank it over. Improvements in battery materials and connectors have decreased the problems we have with poor battery connections, but a high percentage of vehicles that have slow cranking engines are caused by corroded connections. It takes only a few minutes to have them cleaned and it could save you a lot of frustration later.