What Type of Battery Do I Need for My Car?

One thing that cars and alternative energy have in common is that they both need batteries to function properly. Many people who have to deal with dead car batteries find themselves asking what type of battery do I need for my car? I’ve had a lot of people email me asking if they can use their old car batteries for their renewable energy applications. Unfortunately, the answer to this question is “NO”. Your car will use a 12v battery but that’s where the similarities end.

Automotive batteries are primarily designed for starting your vehicle. After the engine has started, your vehicle gets all of its needed electrical power from your vehicle’s alternator. Automotive alternators are sized so that they can recharge the energy that was used to start your car as well as power your electrical accessories like lights, radio’s, windshield wipers, and heater blower motor.

When you need to replace the battery in your car, it’s not hard to find out what kind you’ll need. You can simply walk into your local automotive store and tell them the make, model, and year of your car and they will hand you a perfectly sized battery. All cars require what are called 12v “starting batteries”. Batteries uses for renewable energy applications require “deep cycle” batteries. These batteries are specially designed to be able to be deeply discharged multiple times without sustaining damage.

If you drain your car’s battery too low even a few times, your battery will sustain damage. They are really only designed for short bursts while starting your vehicle and for short intervals of using the lights or radio while your vehicle isn’t running.

When it comes to picking a battery for your car, the main thing to keep in mind is that each car will have a slightly different sized battery box and battery hold down system. It’s possible to start your vehicle with virtually any 12v automotive battery so what you really need to keep in mind when replacing an automotive battery is whether the battery will fit into your vehicles battery box and whether the battery hold down system that your vehicle is equipped with will work with the battery that you purchase.

There is another thing to consider when purchasing an automotive battery suggested by a reliable source who work in a Car Service Woolloongabba establishment, that I almost forgot to mention. Some batteries have posts that are used to connect the battery cables to. Others have tapped holes and you bolt your vehicle’s battery wire connectors to the side or top of the battery.

Many people who have power inverters installed in their vehicles destroy their car’s battery in a very short period of time because they allow the battery to drain too far before recharging it. They usually wait until the inverter’s low battery alarm goes off and then they start their car and run the engine for a few minutes and think that this is sufficient to charge the battery.

This is not only hard on the battery, it’s also hard on your car’s alternator. Alternators aren’t really designed to charge a deeply discharged battery. A deeply discharged battery places a very large amperage draw on the alternator. Do this too many times and you’ll find that you’ll not only need to replace your battery but your alternator as well.

So if you find yourself asking what kind of battery does my car need, now you know how to find the exact size your car should use and if you find yourself wondering if you can use your old car battery to power your power inverter, you know that that’s not a good idea as well.

DC to AC Converter for Car

From time to time I get people emailing me with “DC To AC converter for car” in the subject line. This has inspired me to write an article to clear up a commonly confused bit of technology. Many people think they need a “power converter” when what they actually need is a “power inverter”. Let’s take a minute and talk about these two different devices.

A power inverter is a device that takes 12, 24, 36, or 48 volt direct current or DC power and changes it into 120 or 240 volt alternating current or AC power. Most of the time when people are asking for a 12 volt to 110 volt converter, they actually mean that they want a 12 volt to 110 volt inverter.

A device does actually exist that is a 110 volt to 12 volt converter that sort of works in the opposite way as a power inverter works. These devices are also known as transformers or power supplies.

A common reason that someone may want to buy this kind of a device so they can power their 12v electronic devices in their camper or motor home while their RV is plugged into a 110 VAC power source at a campground. A power converter takes the standard 110 volt AC power, steps it down to 12 volts and converts it to DC power.

You might be interested to know that many standard household devices use power converters. Many electronic devices like computers actually need low voltage DC power to operate properly. You probably have dozens of electronic devices around your home that have a large square box as the plug instead if a small 110 VAC electrical plug. These boxes are often referred to as “wall warts” because they are a bit unsightly. These wall warts are actually small AC to DC power converters that change your standard household electricity into something that these devices can actually use.

You see, these devices are similar in the sense that they change electricity from one from to another form but what each device actually does is quite different. Hopefully this article has cleared up any confusion that you might have been having. If you are still confused, please send me an email and I’ll try to answer any specific question that you might have.

How to select a quality power inverter

If you’re thinking about buying a power inverter, you should know that I don’t suggest buying a cheap power inverter that you will typically find in the big department stores. Maybe you’ve wondered what it is that makes one 12v inverter better than another.

Taking the time to become knowledgeable about how to tell the difference between a poorly constructed inverter and a high-quality model will save you a lot of hassle and frustration in the long run.

If you’re looking for a great deal, let me begin by saying that you’ll have to spend money to save money. Allow me to explain what I mean by this statement. When I first started buying power inverters, I convinced myself that I would buy the cheapest unit I could find, and then eventually, I would buy a more expensive model.

What actually happened was that I went through three or four of these “cheap inverters” before I finally decided to lay down the money for a quality unit. You see, I didn’t really save any money at all. As a matter of fact, I probably spent more going this route.

There are some important features that the higher end power inverters have over the entry level models. Let’s take a look at some of the features I look for when I’m purchasing an inverter.

  • A good 12v inverter will have a reverse polarity fail-safe. I once bought a cheap inverter, hooked it up backward and poof, I let the smoke out. There’s a saying when it comes to electronic devices that says, “once you let the smoke out, it’s done”. When electronic components fail, there’s often a brief putrid-smelling puff of smoke.
  • Good 12-volt inverters will be fused. Should something go wrong with the power supply to the inverter, you want the fuse to blow so the sensitive circuitry doesn’t get fried. The fuse should be replaceable by the user as well.
  • A good 12v inverter will be efficient. The high-end units will have an efficiency rating of 90% or better.
  • Good 12-volt inverters will have a very low no-load current drain. I’ve seen cheap inverters that had a 1.5 amp no load draw. This is very bad. Higher-end inverters will draw less than .3 amps when not under a load. Some very nice inverters have zero no-load draws. They have sophisticated electronics that sense when something is trying to draw power from then and automatically turn themselves on.
  • A good 12v inverter will have large ventilation holes and high-quality fans to keep the circuitry cool. The cooling fan is often a week point on cheap inverters. I’ve had two that failed because the cooling fan ceased to function.
  • Good power inverters will have a high voltage overload fail-safe. Usually, if the voltage jumps above 15 volts, the fail-safe will trigger protecting the unit.
  • A good 12v inverter will have a low voltage alarm to let you know to charge your battery because the voltage is getting dangerously low.
  • Good 12-volt inverters will have a low voltage shutdown to keep the inverter from draining the battery so low that it is permanently damaged.
  • A good power inverter will have a high surge capacity. When many electronic devices first turn on, they require a surge of power that is greater than the amount of power need to keep the device running. If your inverter doesn’t have a good surge capacity, it may not operate certain electrical devices. My inverter is rated at 2000 watts continuous and it has a surge capacity of 3000 watts.
  • Good 12-volt inverters will have a decent warranty. The inverter that I’m currently using is made by Go Socket and it has a 2-year warranty. This is the best warranty that I’m aware of.

Look for the features listed above when purchasing your car power inverter if you want to get a good one. If you don’t care about quality, buy one from your local department store but when it fails at the most inopportune time, don’t say I didn’t tell you so.