Deep Cycle Battery Guide

Deep Cycle Battery Guide to learn about the best Deep Cycle Batteries for Solar, Camping, Caravan, Camper Vans, Camper Trailers, Motorhomes, Marine, 4WDs, RV's & Off Grid Solar with the experts at Aussie Batteries -  WWW.AUSSIEBATTERIES.COM.AU - AUSTRALIA WIDE SHIPPING!

This guide provides answers to our customers most frequently asked questions about Deep Cycle Batteries.This guide includes information on how deep cycle batteries work and deep cycle battery terminology. Learn more about the different deep cycle batteries used in renewable energy storage systems and develop your understanding of the different Deep Cycle Battery chemistry types such as Gel Deep CycleAGM Deep Cycle, Sealed Lead Acid Batteries and more! If you need expert, no-obligation advice about Deep Cycle Batteries you can EMAIL or Call 1800 853 315 

Deep Cycle Batteries Guide for Energy Storage - What is a Deep Cycle Battery?

Best Deep Cycle Battery Australia  If you're looking for a battery for solar and renewable energy or a  battery for camping applications nine times out of ten you're looking for a Deep Cycle Battery. A Deep Cycle Battery or AGM Battery is best for Solar, Camping, Caravan, Camper Vans, Camper Trailers, Motorhomes, Marine, 4WDs, RV's & Off Grid Solar because Deep Cycle Batteries are very efficient energy storage units that allow you to store and use power! 

Deep Cycle Batteries work when a chemical reaction occurs that develops a voltage that results in electricity. Deep Cycle Batteries are designed to be 'cycled' (discharged and recharged) many times over, so while a car battery aims to deliver a burst of energy for a short period, a deep cycle battery gives power at a steady rate for an extended period. In the context of renewable energy, batteries usually mean deep cycle batteries.

Getting the best Deep Cycle Batteries means you get a perfect battery solution for a range of recreational and commercial applications such as camping, boating and off grid applications. Aussie Batteries stock Australia's largest range of  Deep Cycle Batteries including Flooded, AGM and Gel batteries built specifically for Australia’s outback environment and Australian operating environment.  Need expert advice - Simply EMAIL or obligation-freecall our team on 1800 853 315 and speak to a Battery expert.

What are the Different Types of Deep Cycle Batteries ?


What is the best deep cycle battery ? Best deep cycle battery for solar energy storage ?


Aussie Batteries and Solar are the experts in gearing you up with a camping power solution that will suit you and the way you like to camp. With decades of experience under our belts, we are all about providing the best deep cycle battery products, best battery prices and free expert battery advice - to help you get the best deep cycle battery for your adventures around Australia!

The best Deep Cycle AGM Batteries use thicker battery plates and denser active internal material. Deep Cycle batteries are designed to withstand repeated charge and recharge cycles and are popular batteries for Australians who are looking for the best reliable energy solutions.  AGM Deep Cycle Batteries are also known as Absorbed Glass Mat (AGM), and they use technology that suspends the free electrolyte within a highly porous (AGM plate) this means the battery is constructed using glass fibre mat separators. AGM battery plates help eliminate the hazards associated with acid spills or leaks and they allow for a sealed maintenance free design that avoids any need for regular topping-up of an electrolyte. Deep cycle battery technology gives a superior performance. Not sure which battery to go for? Try our Deep Cycle Calculator to determine your energy requirements or EMAIL or freecall our team on 1800 853 315  

Best Selling AGM Deep Cycle BatteryWhy the GIANT POWER 140AH is the Best-Selling AGM Deep Cycle Battery in Australia:

  • This 140AH AGM Battery is best for most 12 Volt Setups and power requirements customers ask for and is an Australian Tier 1 top rated deep cycle battery product.
  • The GIANT 140AH is compatible with all major battery boxes on the market.
  • Industry Leading Australian 5 Year Warranty.
  • 140AH AGM Battey has a best-quality 12 Year Designed Service Life.
  • High Quality Bolt Terminal Connections.
  • Aussie In-house Warranty Testing Facility.
  • Australian Owned and Operated Company.
  • Voted best AGM Battery Australia !
  • Aussie Batteries stock the widest range and best quality AGM Batteries in Australia.
  • 5 Star Review  – Customer Feedback that shows why GIANT POWER Batteries are an Australian bestselling AGM Battery - Top Quality Batteries for Solar Power Systems.

Deep Cycle AGM Batteries have several advantages over both GEL Deep Cycle and Flooded Deep Cycle BatteriesDeep Cycle AGM batteries main advantages are; no maintenance, completely sealed against fumes or leakage, non-spilling even if they are broken, and can survive most temperature states.

All Giant Power Deep Cycle Batteries are constructed using battery electrolyte (acid) that is contained in the glass mats (AGM), so they cannot spill, even if broken. This means that they are non-hazardous and there is no liquid to freeze and expand, they are practically immune from freezing damage. Our range of AGM Batteries are "recombinant" - what that means is that the Oxygen and Hydrogen will recombine INSIDE the battery. This recombining is typically 99+% efficient, so almost no water is lost. The internal resistance on AGM Batteries is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents.

  • Aussie Batteries range of AGM Batteries have a very low self-discharge - from 1% to 3% per month. This means that they can sit in storage for much longer periods without charging than standard batteries.
  • Giant Deep Cycle Batteries can be almost fully recharged (97% or better) even after 30 days of being totally discharged.
  • AGM Batteries do not have any liquid to spill, and even under severe overcharge conditions hydrogen emission is far below the 4% max specified for enclosed spaces.
  • The battery plates in AGM Batteries are tightly packed and rigidly mounted and will withstand shock and vibration better than any standard battery.

Browse deep cycle battery types in our online store. Need help getting the Best Deep Cycle Battery for your needs ?

Deep Cycle Batteries DEEP CYCLE BATTERY SALE *** 130AH ECLIPSE BATTERY  LIMITED STOCK AT THIS PRICE WITH FREE GIFT OFFER ! GRAB A DEAL TODAY! For expert, tailored, no-obligation advice about Deep Cycle Batteries EMAIL or call our friendly team on 1800 853 315

Why the cheapest eBay battery is not your best option? We speak to hundreds of customers every year who find out that while eBay may be a great place to get a quick bargain. AGM Batteries are one of the products that you’re better off getting from a retailer like Aussie Batteries who can provide a competitive warranty and exceptional technical support. 

If you need expert, tailored, no-obligation advice about Deep Cycle Batteries you can EMAIL or freecall our friendly team on 1800 853 315 and speak to a Battery and Solar expert about your power needs or order batteries online

AGM Batteries - Deep Cycle Battery Types:

Absorbent Glass Mat (AGM) is a type of  deep cycle battery in which the electrolyte is absorbed into a fibreglass mat. You will find that the plates in an AGM Battery are flat like wet cell lead-acid batteries, or they may be wound into a tight spiral. The internal resistance of AGM Batteries is lower than traditional cells; they can handle higher temperatures and self-discharge more slowly that other types of batteries. AGM Deep Cycle Batteries have a release valve which is activated when the battery is recharged at high voltage. This valve activation allows a small amount of active material to escape, and AGM Batteries typically have gas diffusers built into them that allow for the safe dispersal of any excess hydrogen that is created during charging. The main benefits of AGM Deep Cycle Batteries and the reason for their popularity is that they are classed as maintenance free batteries. Unlike regular lead-acid batteries that should be kept in an upright position avoiding acid spills and to ensuring the plates are sitting in the electrolyte; AGM Deep Cycle Batteries can generally be placed in any orientation, though it always best to speak to an expert to make sure your battery set-up is correct and wont void any warranties. 

What are the benefits of AGM Deep Cycle Batteries?

They are totally sealed and are easy and safe to transport.They never need topping up with water. They can be safely mounted inside a boat, car, caravan, motorhome, or any recreational vehicle. 

 Due to their very low internal resistance AGM Deep Cycle Batteries can fully charge at a lower voltage, and accept a much larger load charge current. Meaning that when charging from a standard car/truck alternator, these batteries may be fully charged, in about three hours! AGM batteries can also be discharged 'deeper' than conventional deep cycle batteries without major damage. For example, AGM Batteries only self-discharge at the rate of up to 3% per month, and even after 12 months sitting idle as long as they have been cared for, they can be recharged and put back into full service without any major damage. AGM batteries were originally developed for the military and becuase of this they are very robust.

Browse our large range of high quality & best priced AGM Deep Cycle Batteries Online.

State of charge to battery voltage chart

Deep Cycle AGM Batteries - State of Charge (Technical Information) Deep Cycle Battery Ratings

Deep Cycle batteries are generally rated in volts and amps.

  • Amp hours (Ah) are the rated capacity available in chemical energy inside a battery that is converted into electrical energy.
  • Amps also refer to the amount of energy that the battery can store, or, it can be called "the discharge rate". The Discharge rate measures the time it takes to discharge a battery before it needs recharging again.

Here are no-load typical voltages vs state of charge

(figured at 10.5 volts = fully discharged, and 25 degrees C). These Voltages are for a 12 volt battery system. For 24 volt systems multiply by 2, for 48 volt system, multiply by 4. These voltages are for batteries that have been at rest for 3 hours or more. Batteries that are being charged will be higher – the voltages while under charge will not tell you anything, you have to let the battery sit for a while. For longest life, batteries should stay in the green zone. Occasional dips into the yellow are not harmful, but continual discharges to those levels will shorten battery life considerably. It is important to realize that voltage measurements are only approximate. The best determination is to measure the specific gravity, but in many batteries this is difficult or impossible. Note the large voltage drop in the last 10%.

Gel Batteries - Deep Cyle Batteries
A Deep Cycle Gel Battery (also called a “gel cell”) is a sealed, valve regulated lead-acid deep cycle battery and uses a gel electrolyte. Like AGM batteries this type of battery will not need to be kept upright. The major advantage of gel cells is that they can eliminate evaporation of the electrolyte, and all testing shows they have greater resistance to extreme temperatures, shock, and vibration. They are often used in automobiles, boats, aircraft, and other motorised vehicles.

Browse our range of Deep Cycle Gel batteries in our online store. Enjoy, discount prices and same day shipping on stocked items! Aussie Batteries are Australias largest battery and solar retailer.

Lithium-ion Batteries the next generation of Solar Batteries
Lithium ion batteries are very different to conventional deep cycle batteries and have created a revolution in both on and off the grid-connected residential energy storage options. Check out our home battery storage options and find out how you can get off the grid electricity and view our range of next-generation home battery systems.

Charging Your Deep Cycle Battery - Browse Our Range of Deep Cycle Battery Chargers

Dependable performance and long service life depend upon correct charging. Faulty procedures or inadequate charging equipment result in decreased battery life and/or unsatisfactory performance. The selection of suitable charging circuits and methods is as important as choosing the right battery for your application.

To obtain maximum service life and capacity, along with acceptable recharge time and economy, constant voltage-current limited charging is recommended.

During charge, the lead sulfate of the positive plate becomes lead dioxide. As the battery reaches full charge, the positive plate begins generating dioxide causing a sudden rise in voltage due to decreasing internal resistance. A constant voltage charge, therefore, allows detection of this voltage increase and thus control of the current charge amount.

Overcharging Deep Cycle Batteries:
As a result of too high a charge voltage excessive current will flow into the battery, after reaching full charge, causing decomposition of water in the electrolyte and premature aging.

At high rates of overcharge a battery will progressively heat up. As it gets hotter, it will accept more current, heating up even further. This is called thermal runaway and it can destroy a battery in as little as a few hours.

Undercharging Deep Cycle Batteries:
If too low a charge voltage is applied, the current flow will essentially stop before the battery is fully charged. This allows some of the lead sulfate to remain on the electrodes, which will eventually reduce capacity.

Batteries which are stored in a discharge state, or left on the shelf for too long, may initially appear to be “open circuited” or will accept far less current than normal. This is caused by a phenomenon called “sulfation”. When this occurs, leave the charger connected to the battery. Usually, the battery will start to accept increasing amounts of current until a normal current level is reached. If there is no response, even to charge voltages above recommended levels, the battery may have been in a discharged state for too long to recover.

Do’s & Donts for proper use of your Deep Cycle Batteries

Alternators & Generators what you need to know about using them with a Deep Cycle Battery

In general car or van Alternators work reasonably well with AGM batteries. They are not battery chargers however, and will never fully charge a Deep Cycle Battery, so it’s best to use a battery charger when main power is available to top up the battery charge and avoid reduced battery life from sulphation.

Note that alternator output voltages are often reduced by cable/wiring runs and Dual Battery systems so care needs to be taken to measure the actual voltage received at the battery across its terminals to ensure its adequate to charge the battery fully.

Conversely for Gel batteries fitted close to the alternator (under-bonnet with a thick gauge cabling) there is a real risk of damage due to over-charging as the alternator output can be too high for the battery. It is for this reason that we highly recommend NOT using GEL batteries with car alternators.

Many Portable Generators do not have battery charging circuitry built-in and should be used with care if they provide a DC outlet (although you could plug a battery charger into the 240V socket, it seems a fairly inefficient way to operate).

The later models (from Honda et al) with the built in chargers can provide a reasonably quick and efficient battery top-up on sites where they are allowed (or when off-site), although some users do grow tired of the noise and migrate to solar over time.

Learn more about The Best Ways to Charge your Deep Cycle Battery

Capacity & Resistance in Deep Cycle Batteries

Amp-Hour Capacity
All deep cycle batteries are rated in amp-hours. An amp-hour is one amp for one hour, or 10 amps for 1/10 of an hour and so forth. It is amps x hours. If you have something that pulls 20 amps, and you use it for 20 minutes, then the amp-hours used would be 20 (amps) x .333 (hours), or 6.67 AH. The generally accepted AH rating time period for batteries for nearly all deep cycle batteries is the “20 hour rate”. A 10Hr rating is widely used in the USA, therefore many batteries can have 10hr, 20hr or both specifications stated. The 20hr rating means that it is discharged down to 10.5 volts over a 20 hour period while the total actual amp-hours it supplies is measured. Sometimes ratings at the 6 hour rate and 100 hour rate are also given for comparison and for different applications. The 6-hour rate is often used for industrial batteries, as that is a typical daily duty cycle. Sometimes the 100 hour rate is given just to make the battery look better than it really is, but it is also useful for figuring battery capacity for long-term applications like backup, solar, and camping amp-hour requirements.

Internal Resistance
Part – or most – of the loss in charging and discharging batteries is due to internal resistance. This is converted to heat, which is why batteries get warm when being charged up. The lower the internal resistance, the better. AGM batteries have resistance levels upto 5 times lower than standard batteries.

Slower charging and discharging rates are more efficient. A battery rated at 180 amp-hours over 6 hours might be rated at 220 AH at the 20-hour rate, and 250 AH at the 48-hour rate. Much of this loss of efficiency is due to higher internal resistance at higher amperage rates – internal resistance is not a constant – kind of like “the more you push, the more it pushes back”.

Typical efficiency in a lead-acid battery is 85-95%, in alkaline and NiCad battery it is about 65%. True deep cycle AGM’s can approach 98%.

Cycles vs Life - Deep Cycle Battery Technology

A battery “cycle” is one complete discharge and recharge cycle. It is usually considered to be discharging from 100% to 20%, and then back to 100%. However, there are often ratings for other depth of discharge cycles, the most common ones are 10%, 20%, and 50%. You have to be careful when looking at ratings that list how many cycles a battery is rated for unless it also states how far down it is being discharged. For example, one of the widely advertised telephone type (float service) batteries have been advertised as having a 20-year life. If you look at the fine print, it has that rating only at 5% DOD – it is much less when used in an application where they are cycled deeper on a regular basis. Those same batteries are rated at less than 5 years if cycled to 50%. For example, most golf cart batteries are rated for about 550 cycles to 50% discharge – which equates to about 2 years.

Battery life is directly related to how deep the battery is cycled each time. If a battery is discharged to 50% every day, it will last about twice as long as if it is cycled to 80% DOD. If cycled only 10% DOD, it will last about 5 times as long as one cycled to 50%. Obviously, there are some practical limitations on this – you don’t usually want to have a 5 ton pile of batteries sitting there just to reduce the DOD. The most practical number to use is 50% DOD on a regular basis. This does NOT mean you cannot go to 80% once in a while. It’s just that when designing a system when you have some idea of the loads, you should figure on an average DOD of around 50% for the best storage vs cost factor. Also, there is an upper limit – a battery that is continually cycled 5% or less will usually not last as long as one cycled down 10%. This happens because at very shallow cycles, the Lead Dioxide tends to build up in clumps on the positive plates rather than an even film.

Why Deep Cycle Batteries are so popular!!

AGM [Absorbed Glass Mat] VRLA
Sealed Absorbed Glass Mat (Ca/Ca) VRLA deep cycle batteries (also known as “starved electrolyte” or “dry”) have a very fine fiber Boron-Silicate glass mat between their flat Lead with Calcium alloy in the positive and Lead with Calcium alloy in the negative plates. The AGM battery was invented in 1980 and first used in military aircraft in 1985.

AGM, or Absorbed Glass Mat Batteries
A newer type of sealed battery uses “Absorbed Glass Mats”, or AGM between the plates. This is a very fine fiber Boron-Silicate glass mat. These type of batteries have all the advantages of gelled, but can take much more abuse. These are also called “starved electrolyte”, as the mat is about 95% saturated rather than fully soaked. That also means that they will not leak acid even if broken.

AGM batteries have several advantages over both gelled and flooded, at about the same cost as gelled:

  • Much safer then wet batteries (due the hydrogen gas recombination during charging)
  • Do not require water
  • Lower self-discharge rate (typically 1%-2% per month)
  • Longer service life (approx. 2-3 times life expectancy of Flooded lead acid)
  • Higher resistance to vibration
  • Lower deep discharge failure
  • Less forgiving when accidentally overcharged
  • Higher bulk charge acceptance rate (which means up to a 15% shorter recharge time and reduced cost than Flooded lead acid)
  • Do not require special hazardous shipping
  • Can be used in saltwater applications
  • Spill proof and can be mounted in virtually any position (because they are sealed)
  • Can be used inside an enclosed area, like the passenger compartment or trunk
  • Greater terminal corrosion resistance

What about Gelled electrolyte
Gelled batteries, or “Gel Cells” contain acid that has been “gelled” by the addition of Silica Gel, turning the acid into a solid mass that looks like gooey Jell-O. The advantage of these batteries is that it is impossible to spill acid even if they are broken. However, there are several disadvantages. One is that they must be charged at a slower rate (C/20) to prevent excess gas from damaging the cells. They cannot be fast charged on a conventional automotive charger or they may be permanently damaged. This is not usually a problem with solar electric systems, but if an auxiliary generator or inverter bulk charger is used, current must be limited to the manufacturers specifications. Better inverters commonly used in solar electric systems can be set to limit charging current to the batteries.

Some other disadvantages of gel cells is that they must be charged at a lower voltage (2/10th’s less) than flooded or AGM batteries. If overcharged, voids can develop in the gel which will never heal, causing a loss in battery capacity. In hot climates, water loss can be enough over 2-4 years to cause premature battery death. It is for this and other reasons that we sell few lines of the gelled cells. The newer AGM (absorbed glass mat) batteries have all the advantages (and then some) of gelled, with none of the disadvantages.

Starting, Marine & Deep Cycle Batteries

Starting (sometimes called SLI, for starting, lighting, ignition) batteries are commonly used to start and run engines. Engine starters need a very large starting current for a very short time. Starting batteries have a large number of thin plates for maximum surface area. The plates are composed of a Lead “sponge”, similar in appearance to a very fine foam sponge. This gives a very large surface area, but if deep cycled, this sponge will quickly be consumed and fall to the bottom of the cells. Automotive batteries will generally fail after 30-150 deep cycles if deep cycled, while they may last for thousands of cycles in normal starting use (2-5% discharge).

Deep cycle batteries are designed to be discharged down as much as 80% time after time, and have much thicker plates. The major difference between a true deep cycle battery and others is that the plates are SOLID Lead plates – not sponge. This gives less surface area, thus less “instant” power like starting batteries need. Although these can be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge.

Unfortunately, it is often impossible to tell what you are really buying in some of the discount stores or places that specialize in automotive batteries. The golf car battery is quite popular for small systems and RV’s. The problem is that “golf car” refers to a size of battery (commonly called GC-2, or T-105), not the type or construction – so the quality and construction of a golf car battery can vary considerably – ranging from the cheap off brand with thin plates up the true deep cycle brands, such as Crown, Powersonic, Trojan, etc. In general, you get what you pay for.

Marine batteries are usually a “hybrid”, and fall between the starting and deep-cycle batteries, though a few (Rolls-Surrette and Concorde, for example) are true deep cycle. In the hybrid, the plates may be composed of Lead sponge, but it is coarser and heavier than that used in starting batteries. It is often hard to tell what you are getting in a “marine” battery, but most are a hybrid. Starting batteries are usually rated at “CCA”, or cold cranking amps, or “MCA”, Marine cranking amps – the same as “CA”. Any battery with the capacity shown in CA or MCA may or may not be a true deep-cycle battery. It is sometimes hard to tell, as the term deep cycle is often overused. CA and MCA ratings are at 32 degrees F, while CCA is at zero degree F. Unfortunately, the only positive way to tell with some batteries is to buy one and cut it open – not much of an option.

Plate Thickness
Plate thickness (of the Positive plate) matters because of a factor called “positive grid corrosion”. This ranks among the top 3 reasons for battery failure. The positive (+) plate is what gets eaten away gradually over time, so eventually there is nothing left – it all falls to the bottom as sediment. Thicker plates are directly related to longer life, so other things being equal, the battery with the thickest plates will last the longest. The negative plate in batteries expands somewhat during discharge, which is why nearly all batteries have separators, such as glass mat (AGM) that can be compressed.

Automotive batteries typically have plates about .040″ (4/100″) thick, while forklift batteries may have plates more than 1/4″ (.265″ for example in larger Rolls-Surrette) thick – almost 7 times as thick as auto batteries. The typical golf cart will have plates that are around .07 to .11″ thick. While plate thickness is not the only factor in how many deep cycles a battery can take before it dies, it is the most important one.

Internal Resistance

Part – or most – of the loss in charging and discharging batteries is due to internal resistance. This is converted to heat, which is why batteries get warm when being charged up. The lower the internal resistance, the better. AGM batteries have resistance levels upto 5 times lower than standard batteries.

Slower charging and discharging rates are more efficient. A battery rated at 180 amp-hours over 6 hours might be rated at 220 AH at the 20-hour rate, and 250 AH at the 48-hour rate. Much of this loss of efficiency is due to higher internal resistance at higher amperage rates – internal resistance is not a constant – kind of like “the more you push, the more it pushes back”.

Typical efficiency in a lead-acid battery is 85-95%, in alkaline and NiCad battery it is about 65%. True deep cycle AGM’s can approach 98%.

The 20-hour rate is the most common for standardising batteries in Australia, while the USA uses a 10-hour rating system.

Lifespan of Deep Cycle Batteries

The lifespan of a deep cycle battery will vary considerably with how it is used, how it is maintained and charged, temperature, and other factors. In extreme cases, it can vary to extremes – AGM’s can be killed in less than a year by severe overcharging. Gelled cells batteries can be destroyed in one day when overcharged with a large automotive charger. Golf cart batteries can be destroyed without ever being used in less than a year because they were left sitting in a hot garage without being charged. Even the so-called “dry charged” (where you add acid when you need them) have a shelf life of 18 months at most. They are not totally dry – they are actually filled with acid, the plates formed and charged, then the acid is dumped out.

These are some typical (minimum – maximum) typical expectations for batteries if used in deep cycle service. There are so many variables, such as depth of discharge, maintenance, temperature, how often and how deep cycled, etc. that it is almost impossible to give a fixed number. But here goes anyway:

  • Starting: 3-12 months
  • Marine: 1-6 years
  • Golf cart: 2-7 years
  • AGM deep cycle: 4-10 years
  • Gelled deep cycle: 2-7 years
  • Telephone (float): 2-10 years. These are usually special purpose “float service”, but often appear on the surplus market as “deep cycle”. They can vary considerably, depending on age, usage, care, and type.
  • NiFe (alkaline): 5-35 years
  • NiCad: 1-20 years

Inverters for Deep Cycle Batteries

An inverter has basically two functions – to provide an alternating current (ac) voltage rather than the direct current (dc) available from the battery, and to raise the voltage up to an average of 240V. There are several types of inverters. The most expensive provide a pure sine wave which is preferred for any sensitive equipment, especially laptops. The cheapest simply provide a square wave ac, which is satisfactory with most motors and some small chargers for cameras, phones etc, but not for most laptop computers. There are also intermediate types, “modified sine wave”, which combine a number of square waves to approximate a sine wave shape. These are usually satisfactory for laptops, but, like the square wave types, often create a lot of radio interference.

Inverters are about 80% efficient. They come in different sizes. A 150W unit will handle most camp requirements, but may have trouble starting a laptop (even though the average drain by the computer is much less than this.) A 300W unit is probably a sensible minimum. Bear in mind that Watts = Volts x Amps, so, if we draw the full 300 watts, we will require 25 amps from the 12volt battery, plus 20% to account for inefficiency. That’s 30 amps. This will draw from the battery in 1 hour about the same as all other loads discussed above take in a day. There are also many larger inverters. A 2000W one will provide enough power to run power tools or even an electric jug, but at full output they will draw from the battery about 150-200 amps. That’s as much current as they winch when fully loaded, and way outside the comfort zone of any deep cycle battery for long periods of time. Most 1500w-2000w applications such as microwaves and electric kettles will only run for a few minutes, this will be fine to use with a 100AH+ battery.

Charging and Deep Cycle Battery Mainenance

• Batteries should not be stored in a discharged state or at elevated temperatures. If a battery has been discharged for some time, or the load was left on indefinitely, it may not readily take a charge. To overcome this, leave the charger connected and the battery should eventually begin to accept charge.

• Continuous over-or undercharging is the single worst enemy of a lead-acid battery. Caution should be exercised to ensure that the charger is disconnected after cycle charging, or that the float voltage is set correctly.

• It is important that a battery be charged within 6 months after receipt to account for storage from the date of manufacture to the date of purchase. Otherwise, permanent loss of capacity might occur as a result of sulfation. To prolong shelf life without charging, store batteries at 10′C or less.

• Unlimited current charging can cause increased off-gassing and premature drying. It can also produce internal heating and hot spots resulting in shortened service life. Too high a charge current will cause a battery to get progressively hotter. This can lead to “thermal runaway” and can destroy a battery in as little as a few hours.

• Caution: Never charge or discharge a battery in an airtight enclosure. Batteries generate a mixture of gases internally. Given the right set of circumstances, such as extreme overcharging or shorting of the battery, these gases might vent into the enclosure and create the potential for an explosion when ignited by a spark. Generally, ventilation inherent in most enclosures is sufficient to avoid problems.

• High voltage strings of batteries in series should be limited to twenty 6 volt or ten 12 volt batteries when a single constant voltage charger is connected across the entire string. Differences in capacity can cause some batteries to overcharge while others remain undercharged, thus causing premature aging of batteries. It is, therefore, not advisable to mix batteries of different capacities, make, or age in a series string.

• Recharge time depends on the depth of the preceding discharge and the output current of the charger. To determine the approximate recharge time of a fully discharged battery, divide the battery’s capacity (amp. hrs) by the rated output of the charger current (amps) and multiply the resulting number of hours by a factor of 1.75 to compensate for the declining output current during charge. If the amount of amp. hrs. discharged from the battery is known, use it instead of the battery’s capacity to make the calculation.

Installing Your Deep Cycle Battery

• Fasten batteries tightly and make provisions for shock absorption if exposure to shock or vibration is likely.

• When installing the battery within a piece of equipment, fix it securely at the lowest practicable point.

• The battery should not be attached to any piece of equipment during “burn-in” testing.

• Do not apply undue force to the terminals or bend them. Avoid applying heat to the terminals through processes such as soldering.

• If soldering to the battery terminals is unavoidable it must be accomplished within 3 seconds, using a soldering iron no greater than 100 watts.

• Do not place batteries in close proximity to objects which can produce sparks or flames, and do not charge batteries in an inverted position.

• Avoid exposing batteries to heat! Care should be taken to place batteries away from heat-emitting components. If close proximity is unavoidable, provide ventilation. Service life is shortened considerably at ambient temperatures above 30°C.

• To prevent problems arising from heat exchange between batteries connected in series or parallel, it is advisable to provide air space of at least 0.4″ (10mm) between batteries.

• Do not mix batteries with different capacities, different ages or different makes. The difference in characteristics will cause damage to the batteries and possibly to the attached equipment.

• Battery cases and lids made of ABS plastic can sustain damage if exposed to organic solvents or adhesives.

• For best results and generally acceptable performance and longevity, keep operating temperature range between -40′C and 60′C.

• It is good practice to ensure that the connections are re-torqued and the batteries are cleaned periodically.

• Do not attempt to disassemble batteries. Contact with sulfuric acid may cause harm. Should it occur, wash skin or clothes with liberal amounts of water. Do not throw batteries into a fire; batteries so disposed may rupture or explode. Disassembled batteries are hazardous waste and must be treated accordingly.

Handling Deep Cycle Batteries

• Always wear insulated gloves when handling batteries; especially when connecting series and parallel groups of batteries.

• If equipment is to be stored for a long period of time the batteries should be disconnected to avoid undue drain on the batteries and any potential for damage to the equipment.