If there is one question that I know I receive every week without fail, it’s “what is the best type of battery for me to use”? While I should get tired of answering it, I’m actually glad that so many people ask this question as it takes power to make power and it all starts at your battery. You can spend thousands and thousands of Rand on fancy amplifiers, woofers and splits however if the current supply isn’t up to standard, you may of well have thrown half that money down the drain. A number of folk think that by simply fitting a “bigger” battery than the stock one, their problems will be solved. Sadly what a lot of them don’t know is that too can be a waste of money and I’ll explain why in the article below.
What about race cars? I know they all about weight, but they happen to run large fuel pumps, coil packs and other electronics all of which also needs a beefed up current supply. When they run smaller lead acid batteries, they actually end up doing themselves a huge injustice. Again, read on and find out how exactly do batteries work and what makes up a good battery. This will help you make an educated decision as to what battery you should look at when deciding to upgrade from the OEM one which has just about enough power to run a cars stock electrical system with the addition of maybe a cell phone charger. What we’re about to dive into isn’t only helpful to bass heads. It’s something anyone with a car can benefit from.
How a battery generally works?
If you didn’t already know, a battery is like a reservoir that stores all the current needed to power the starter motor, the lights, and the ignition system of a vehicle’s. It needs to be able to do a bulk discharge to turn the starter motor when starting the car and is then slowly recharged by the alternator. Batteries generally have surplus current to help supply the rest of the electronics after a bulk discharge while the alternator recharges it.
When looking at a battery there are four key things to look at. The first two should not be taken for granted as they can lead to problems down the line and that is the physical size of the batter which includes the pole height as they sometimes sit about the casing and could cause clearance issues. The second is the battery pole positions as there are a number of different options here. With some cars, it doesn’t really matter which side the positive or negative sits or even if they are positioned more towards the top or bottom of the battery however with a number of modern day cars, this can lead to serious problems as a number of these cars have bulky positive battery terminals because they have built-in fuse boxes on them.
The other two important specifications would be the CCA rating as well as the Ah rating. CCA rating is the Cold cranking amperes which is an international standard for measuring the performance of a battery. CCA measures the cranking capacity of a battery at a temperature of -18°C (0°F). To get technical the rating is defined as the number of amperes a lead-acid battery at -18°C can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12 volt battery).
AH stands for Amp Hour. An amp hour (AH) rating tells us how much current can be dispersed from the battery over an hour before the batteries current has fully depleted. Now with this in mind, please note that the type of battery used also plays a vital role here as an AGM battery can dispense a lot more current, faster than a conventional lead acid battery and at the same time, it’s also able to be replenished or recharged much faster than a conventional lead acid battery as well.
Starting Batteries and Deep-Cycle Batteries
The starter battery is designed to deliver quick bursts of energy so generally has more plates in order to have a larger surface area that provides a high electric current for a short period of time. The plates are thinner and have different material composition. The deep cycle battery has less instant energy but greater long term energy delivery. Deep cycle batteries have thicker plates and can survive a number of discharge cycles. You’d find these on boats or campers, where they’re used to power accessories like trolling motors, winches or lights. These are also great for systems that you’d leave pounding all day as these batteries deliver a lower, steady level of power for a much longer time than a starting battery. In the older days it wasn’t uncommon to have a regular starting battery up front and then a deep-cycle battery in the boot to help with the high current demands of massive amplifiers.
Before going on, I’d like to digress a little to make a point. If you asked if it were possible to drive from Cape Town to Johannesburg in reverse I would have to say yes because technically you could. Would it be advisable to do so is a completely different story.
Similarly, you can use a starter battery for deep cycle applications but it’s really not advisable. The reason behind it is that deep cycle batteries can be discharged a lot more than general automotive batteries without damaging the cells. General Automotive batteries should not be discharged more than 75% whereas Deep Cycle batteries can go as low as around 50%.
Different Types of Starting batteries. The next part of our article on batteries and finding the right type of battery for your application sees us looking at the different types of batteries. This is where I want you to pay close attention to the main difference between the three types we discuss. I also want you to pay attention to the tips and graphs at the end of the article as this will help you get a better understanding as to why it’s more important to not only replace the OEM battery with one that has a larger current capacity, but why it’s also important to go with the right type of battery as sometimes that on its own can make all the difference.
The first thing you need to know about these batteries is that the typical charge rate is between 13.8V to 14.2V Max. Should your charge rate be lower than 13.8V, the battery would not be topped up to its full capacity and should the charge rate be higher than 14.2V, it will reduce its amperage storing capabilities and lower the lifespan of the cell. Lead Acid batteries are the oldest type of rechargeable battery that we know of, which is something that should already scare you off using them for high current demanding systems. Aside from their very old technology, they are also the cheapest type of automotive battery which is what makes them attractive for OEM use in motor vehicles especially when manufacturers are trying to keep the cost down. Lead acid batteries are constructed of several single cells connected in series of which each cell produces approximately 2.1 volts. The cells are made up of two lead plates, a positive plate covered with a paste of lead dioxide and a negative made of sponge lead, with an insulating material (separator) in between. The plates are enclosed in a plastic battery case and then submersed in an electrolyte consisting of water and a type of acid.
A Calcium or GEL battery is a still a lead acid battery however these are usually sealed, maintenance free. Calcium replaces antimony in the plates of the battery to give it some advantages including improved resistance to corrosion, no excessive gassing, less water usage and lower self-discharge. Silver is another additive used by some manufacturers. The addition of silver enables the battery to be more resilient to high temperatures. Calcium batteries require a higher charge voltage than conventional Lead Acid batteries. GEL Batteries are rather more efficient than regular Lead Acid or flooded batteries and are a good choice for longer lasting systems.
AGM/AGM+/Start stop Battery
AGM stands for Absorbed Glass Mat and what you need to know about these batteries is that they are far superior than the above mentioned cells, however they do need to be charged differently. Their typical charge rate is between 14.2V to 14.9V for the AGM while the AGM+/Start Stop batteries charge rate can vary between 14.6V and 15.5V. Should your charge rate be lower than indicated, the battery would not be topped up to its full capacity. Like the other cells, if you charge an AGM battery above 14.9V or an AGM+/Start Stop higher than 15.5V, it will reduce its amperage storing capabilities and lower the lifespan of the cell.
Regarding its chemistry, these batteries differ from both types mentioned above as the positive and negative plates are separated by an absorbent glass mat that holds the electrolyte like a sponge as opposed to freely flooding the plates. The very thin glass fibres are woven into a mat to increase surface area enough to hold sufficient electrolyte on the cells for their lifetime. The fibres that compose the fine glass mat do not absorb nor are they affected by the acidic electrolyte. These mats are wrung out 2–5% after being soaked in acids, prior to manufacture completion and sealing. The plates in an AGM battery may be any shape. Some are flat, others are bent or rolled. These battery’s advantages include lower internal resistance and greater plate area for superior starting power, the ability to recharge much faster, and higher voltage characteristics during discharge. AGM batteries are able to supply amperages that would kill the GEL battery. The GEL cannot compete with the AGM construction either as a starting battery or as a deep cycle battery. Basically the jelly or GEL inside a GEL battery will be scarred by high amperage charging or discharging. The AGM battery on the other hand is designed to push the load, no matter the amperage required. AGM batteries also last longer as they have lower internal resistance which makes them slightly more efficient than a GEL battery. GEL Batteries, being rather more efficient than flooded batteries, are a good choice for long lasting systems though. Each of these batteries is designed to recover much of the gassing, and return it to electrolyte inside the operational battery to eliminate maintenance and prolong life. However, the AGM battery is designed to recombine the gases no matter how they originate.
This is where your street pounders and SPL enthusiast would need to pay extra close attention. It’s all good and well having a battery that can supply your audio system with the current it needs, but how quickly is it able to bounce back and recuperate?
I once referenced a regular wet cell to an AGM cell. Nothing scientific or crazy technical. It was just a simple home test involving a meter and a stopwatch. I pushed both equally and both batteries performed similar for the first few minutes. The initial burb using the AGM cell was louder and the amplifier put out a lot more RMS than it did with the wet cell which was the first part of the tests. The second part of the test involved how long it took each battery to register 100% on the intelligent charger. The AGM cell took about an hour to fully recover while the wet cell took the greater part of half a day. Now think about it, do you really have or want to wait half a day for your battery system to recharge before you can pound again? I certainly wouldn’t.
On the topic of recovery rate, have you ever thought about the new generation cars which have Start-Stop technology. In traffic, the car starts every few minutes so naturally the battery needs to have a super-fast recharge or recovery rate. Guess what type of battery they use for this? Absorptive Glass Mat (AGM) batteries.
Point of the matter is that if you’re looking for a good high-performance battery for anything, AGM is the way to go…unless you can afford to go the lithium route, but that’s another story for another day.