Confused About Battery Types? Get The Answer Here.
Selecting a battery looks simple at first. It is only when you first start doing some research, that you realize selecting a battery is a much tougher decision than you initially thought.
You are probably already buried in data, not all of which are consistent between different sources. With this article, I hope to give you some more information on how various batteries work, and some guidance on how to get the best out of them.
My aim is to educate you about these batteries without being too technical. There are many articles on the internet nowadays that aren’t always 100% accurate, which doesn’t make choosing a battery any easier. Let me boil it down for you, so your decision is made easier.
Lead acid batteries have been used commercially for more than 100 years. Our great grandparents were using the same chemical principal to store energy that we are using today.
Understanding the basic working of a battery will help you get more from your battery. With this guide, I hope to help you get better performance, reliability, and longevity from your batteries.
Think of a battery as a bank account. If you keep making withdrawals, and not make any deposits, you will soon be left with nothing. With all the complicated and expensive gadgets that need reliable power to run, you need to keep your batteries in good condition. If you don’t, it can lead to expensive electronic components failing. This can be a costly mistake.
The Building Blocks
A lead acid battery consists of lead, plates and lead oxide with a water solution consisting of 65% water and 35% sulfuric acid. This solution is commonly known as electrolyte and is responsible for the chemical reaction that creates electrons.
You can test the sulfuric acid levels in the electrolyte with a hydrometer. If the battery is running low on sulfuric acid, the chemical reaction will not happen. What happened with the sulfur? A process called sulfation leads to the sulfuric acid turning into lead sulfate resting on the battery plates.
Connecting the battery to a charger will convert the sulfate back into lead and sulfuric acid.
NOTE: Leaving a battery discharged for extended periods of time, will cause the lead sulfate to form lead sulfate crystals. This will negatively affect your battery and will reduce its capacity.
Safety when working with batteries
It is important to keep safety front of mind when working with lead acid batteries. Make sure to remove any jewelry. You don’t want to melt the watch you got for your anniversary!
Batteries contain hydrogen gas that can explode covering everything in sulfuric acid which is why safety goggles must be worn when handling batteries. It is also a good idea to disconnect the ground cable when working with car batteries.
Types of batteries
Lead acid batteries can be divided into two types, starting (cranking) and cycle (marine golf cart). Starting batteries deliver a quick burst of energy (like when starting an engine) and has a greater plate count. These thinner plates have a slightly different composition.
Deep cycle batteries don’t deliver as much energy instantly but have better long term energy delivery. The thicker plates can survive a number of discharges.
Using a battery for the wrong application (such as using a starting battery in a golf cart) can lead to battery plates warping and pitting when discharged.
Dual purpose batteries are an attempt to get the best from both worlds, though my recommendation would be to stick with the right battery for the right application.
Wet Cell, Gel Cell, and Absorbed Glass Mat
The wet cell (flooded), absorbed glass mat (AGM) and gel cell are three versions of the lead-acid battery. The wet cell is available in maintenance-free and serviceable styles.
The gel cell and AGM batteries are built for specific uses and can cost twice as much as a premium wet cell battery. These batteries store really well, and they are less likely to sulfate or degrade than wet cell batteries.
The gel cell and absorbed glass mat batteries are also among the safest lead-acid batteries to use, as there is very little risk of the hydrogen gas exploding.
AGM batteries are well suited to marine, RV, audio and standby power, they are used in high-quality solar generating equipment, to name only a few applications. When not in daily use, these batteries hold their charge much better than other batteries. AGM batteries also have a better life span and a greater cycle life span than wet cell batteries. The higher price is justified, as you will save money in the long run.
More about AGM batteries
While the gel cell and AGM batteries both have the acid suspended, technically the AGM can be considered a wet cell. With the AGM, the suspended electrolyte is very close to the active material of the plates. This leads to more efficient discharge and recharge.
To get the longest possible lifetime use from your AGM, make sure to recharge before it drops below a 50% discharge rate. 300 plus cycles can be achieved by never letting the battery drop below 60%.
Gell Cell Batteries
In the gel cell battery, the electrolyte contains silica which turns the electrolyte into a thick paste-like material. This ensures that the electrolyte won’t leak if the battery is damaged, but also leads to a lower recharge voltage. Because of this, gel cell batteries are very sensitive to over-charging. This battery is well suited to hot weather use. It is important to make sure that the correct charger is used, as this can affect performance and might lead to premature failure.
Battery Output: CCA, CA, AH and RC
CCA stands for cold cranking amps and indicates the number of amperes that a battery can deliver at 0 degrees F for 30 seconds while maintaining at least 1.2 volts per cell.
Pay attention to this measurement for starting battery applications and cold weather use. It is not considered to be a valuable tool for evaluating deep cycle batteries.
CA refers to cranking amps which is measured at 32 degrees F. It is also referred to as marine cranking amps (MCA). Reverse capacity (RC) is an important number and refers to how long the battery will be able to deliver 25 amperes at 80 degrees F when fully charged without dropping below 10.5 volts.
Amp Hour (AH) is a measurement usually found on deep cycle batteries. This refers to the amount of energy charge in a battery to provide 1 ampere for a period of 1 hour. Keep in mind that the time for discharge and the load is not a linear relationship. An increased load will decrease your realized capacity.
Regular cleaning with a solution of baking soda and water (a couple of tablespoons per pint of water) will enhance the effectiveness and battery life span. You should also clean and tighten cable connections to prevent problems caused by dirty or loose connections.
If you have a serviceable battery, make sure to check the fluid level regularly. When topping up the fluid, make sure to use distilled water, as it will not have any impurities could contaminate your battery cells. In warmer climates, care must be taken to not overfill the battery cells.
Hot weather can cause the fluid to expand, pushing excess electrolytes from the battery. A little bit of silicone sealer at the base of the post with a felt battery washer can prevent corrosion. Make sure to coat the washer with petroleum jelly, or high-temperature grease before placing and tightening the cable on the post. The exposed cable end should also be covered with grease.
It’s important to maintain a proper level of charge for your batteries, especially if storing for a long period.
Ensure you are using the correct charger for the type of battery you are using. We have reviewed the best battery charger for 18650 battery cells here.
Automotive Battery Testing
There are a few different ways to test a battery. I prefer measuring specific gravity and battery voltage as this considered to be the most accurate method. A digital D.C. voltmeter measures the voltage, while a temperate compensating hydrometer is used to measure specific gravity. A very good tool for testing your car battery is the BT705 by Foxwell.
For testing sealed batteries, I recommend a quality load tester. To get the most accurate results from these measurements, make sure to fully charge the battery and to remove the surface charge.
The battery should sit for several hours (I recommend 12 hours) before you begin testing. Discharging the battery for several minutes (a high beam headlight works well) will remove the surface charge.
State of Charge Specific Gravity Voltage12V 6V100% 1.265 12.7 6.375% 1.225 12.4 6.250% 1.190 12.2 6.125% 1.155 12.0 6.0Discharged 1.120 11.9 6.0
A load test is another way to test a battery.
It works by removing amperes from a battery in the same manner that starting an engine would. Reputable companies will indicate the amp load for testing on the battery label. Typically this will be half of the CCA rating, e.g. a 500CCA battery will load test for 15 seconds at 250 amperes. This type of test must also be performed at full charge, or very near to it.
Testing Household Batteries
There are many gadgets on the market for conveniently testing batteries, some of these are reliable and some are not so good.
We have found that possibly one of the best household battery checkers is a model made by ZTSinc, an American company in Cincinnati, Ohio. They have two very useful models, the ZTS MBT 1 and the ZTS Mini, both of which can be seen here.
Battery life and performance
As typical energy requirements increase year after year, average battery life has decreased.
I often hear complaints about batteries not taking a charge, and batteries not holding a charge. I have seen statistics claiming that less than one-third of batteries last 48 months.
This can largely be attributed to sulfation build-up. This occurs when batteries are left in a discharged state for too long. Proper care, regular charges and not letting batteries discharge completely will prevent your batteries from excessive sulfation.