by Jim Kerr

Rrrrrr, Rrrrrrrr,Rrrrrrrrrrr. The sound of a starter slowly cranking over is a common occurrence during the cold winter months. The engine oil is thick and engine friction is high, but often the problem is a weak or undercharged battery. Recently, a reader asked me about a battery life maximizer he found called the Megapulse III. He wondered if this would help during cold starts and truthfully extend his vehicle’s battery life.

The Megapulse III is a new type of battery maintenance accessory. I have also seen this type of device sold under the Solar and Battery Tender brand names as well as a couple others. Do they work? I have two! Here is how they help maintain a battery.

First, lets make it clear that these battery maintainer units are not solar panels that will generate a charge for the battery. They are also not trickle chargers although they look very much like one. These battery maintainers use solid state circuitry to monitor the battery state of charge and keep it at the optimum level.

With all the electronics on modern cars, there is a constant drain on the vehicle’s battery when it is parked. Luxury cars of the late 1980’s and early 90’s had the biggest electrical drains because of the many accessories on them. The newest vehicles may have as many or even more options but computer advances enable the manufacturers to reduce battery drain by commanding the computers to “go to sleep” when not needed. Even when the vehicles are being driven, some computers will be in a low power “rest” mode until they are signalled to do something by another computer. If everything is working properly, a vehicle should be able to sit for a month before the battery becomes low. Let it sit longer and you may need a boost.

Even if the battery will still start the vehicle, letting the battery sit without a full charge shortens its life. The lead on the battery plates slowly changes into lead sulphate as the battery discharges. This process is reversed when the battery is recharged, but if the lead sulphate is allowed to stay on the plates for some time, it hardens in a crystal form that cannot be recharged. Automotive technicians will load test the battery capacity and tell you the battery has sulphated, meaning it has reduced capacity to crank your engine.

Some drivers install trickle chargers to keep the battery charged. A trickle charger puts about 1 to 2 amps of current into the battery when it is plugged in. These chargers are sometimes referred to as taper chargers because the charge rate tapers lower as the battery becomes fully charged, but even when the battery is fully charged there is still current flowing into the battery. This tends to overheat the battery and shorten battery life if the charger is plugged in all the time, especially in the summer.

Battery maintainers such as the Megapulse unit are better at keeping a battery properly charged than a trickle charger is. Electronics in the unit monitor battery voltage and put a small charge into the battery when needed. Typically, these units will supply over 14 volts to bring the battery up to full charge and then drop the charging voltage down to about 12.8 volts to 13.2 volts to maintain the charge. A fully charged battery will provide 12.6 to 12.8 volts and the slightly higher voltage of the battery maintainer overcomes resistance in the cables and connections to keep the battery at its fully charged state without overheating it.

Keeping your battery fully charged all the time will not only ensure you always have the power to start the engine but it also extends battery life. Most batteries will last from five to seven years if used regularly so that they do not sulphate. Let a battery sit partially discharged for even a few days at a time and battery life is shortened greatly. I have seen batteries that lasted only a few months!

Where do I use my battery maintainers? I have one on a motorcycle and another on a collector car. I should probably buy another for my every day vehicle, because it sits for several days at a time. Plugging in your vehicle isn’t just for the winter months. Plug it in for the summer too. It takes very little power to operate a battery maximizer and extend your battery life.

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