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Guide to Buying SLA Batteries

SLA batteries, also known as sealed lead-acid batteries, are rechargeable and widely used in backup power systems, medical devices, and UPS. They require no maintenance, making them a popular choice for many applications. They are also versatile, durable and cost-effective.

There will eventually be a time when you&#;ll need to buy a battery for a device or purchase a replacement battery. We&#;ve put together a list of things you might need to look at when you&#;re in the market for a replacement SLA battery.

Basics of SLA Batteries

SLA batteries (also known as Sealed Lead Acid batteries) are rechargeable batteries that use lead plates and sulfuric acid as an electrolyte. They are commonly used in backup power systems like UPS devices and generators, as well as wheelchairs and scooters that require reliable power. It&#;s important to understand that there are several types of SLA batteries.

AGM or Absorbent Glass Mat batteries. These are best for applications that require high power density.

Gel Batteries use a gel electrolyte and are suitable for deep cycle applications requiring high capacity and long life.

VRLA or Valve Regulated Lead Acid batteries use a pressure-relief valve to regulate the internal pressure and prevent overcharging. They are low maintenance.

Deep Cycle batteries are designed to provide a steady charge over a long period of time and are suitable for marine and RV use.

High Discharge batteries (often referred to as SLI batteries) provide a high current discharge over a short period of time and are best suitable to starting motors.

When looking for a type of replacement battery, consider its use. Mostly you&#;ll be looking to choose the same type that is currently in use or go with the recommended type.

Size and Capacity

The size of a replacement SLA battery is important usually because there is limited room where the battery is housed. If the battery is a different size, it may be impossible to fit into the allotted space without some significant reworking. The specs usually include the battery size with length x width x height so make sure to measure and choose one with the same dimensions.

Voltage is a unit of power that is always used with SLA batteries. Typically, you&#;ll notice 6V or the more common 12V for most of your equipment and in some cases 24V.

The amp rating is also important. The amps of an SLA battery are commonly expressed in terms of the battery&#;s amp-hour (Ah) rating, which is a measure of the battery&#;s capacity. The Ah rating of an SLA battery is a measure of how many amps the battery can deliver over a certain period. For example, a 12V 7Ah battery can deliver 7 amps for one hour, or 1 amp for 7 hours. The higher the Ah rating, the longer the battery can deliver power to a device.

NOTE: Make sure to consider the terminals of the replacement batteries. Again, you want to make sure they match the current battery.

When looking to replace your SLA batteries, finding one with the same voltage and amp rating is recommended to avoid damaging equipment.

Brand Quality

There are plenty of brands to consider for SLA batteries and not all are created equal. Some brands may have a strong name and as a result will often add a considerable amount to the price. Conversely a lesser-known brand may provide a cheaper product but perhaps with poor reviews. Given the availability of reviews on most websites, there is usually enough information available to determine the quality of a battery and the company behind it. Do your due diligence to prevent any unwanted surprises.

The ability to search online has made it much easier to find an appropriate replacement as well as to comparison shop for pricing.

Charging

There are a few things to consider when charging a battery. Make sure you have the correct voltage charger. A 6V for a 6V battery, a 12V for a 12V battery etc. One thing to note is that if you have 2 12V batteries connected, you should use a 24V charger or charge them separately. Don&#;t overcharge. The general rule for charging your battery is Amp hours multiplied by 1.3 then divided by the charger Amps.

Float charging is a common term in SLA batteries because of the nature of their roles. For things like UPS devices, generators, exit lights, these are all essentially on standby mode for long periods of time. They have a steady low voltage charge aimed at keeping its life expectancy much higher.

A high-rate SLA battery is the opposite of float charging in that they provide a high burst of power for a short period of time. In this instance, the more you discharge the shorter their lifespan. Depending on how often you use them, their lifespan may be much longer.

Installation

Installing a replacement SLA battery should be relatively easy. Essentially look to match the previous configuration and connections.

• Check the connections to make sure they are free of dust, dirt and debris.
• Place the new battery in the allotted housing.
• Reconnect the cables based on the previous configuration

We have a series of installation guides depending on your product needs so feel free to check those out.

Safety

Even though SLA batteries are generally safe because they are sealed, there are still some things you may want to consider. Always with SLA batteries handle carefully and inspect closely. Look for things like swelling or leaking. Do not install if anything looks off. Gloves and goggles may be a good idea especially if the battery is defective. Remove jewelry and watches, again just in case there are issues. Keep your sleeves out of the way, they can sometimes get caught up during installation or torn on some of the cables or connections.

Types and Uses of SLA Batteries

Another important factor to consider when buying SLA batteries are the types of SLA batteries and matching those with what they will be used for. As an example, if you&#;re looking for a battery for a travel trailer, you&#;re going to want to get a deep cycle battery that is suited for longer sustained amount of power. You&#;ll generally find three types of SLA batteries, Deep Cycle, SLI and Dual Purpose batteries.

Deep Cycle Batteries  &#; are designed to be charged and recharged regularly and hold a sustained amount of power. They are best for travel trailers, RV&#;s, marine vehicles and golf carts. They help to power accessories like lights on a boat.

SLI Batteries &#; the acronym stands for Starting, Lighting and Ignition so they&#;re suited best for short bursts of power, particularly for starting an engine like in motorbikes, snowmobiles, ATV&#;s and other powersports equipment.

Dual Purpose Batteries &#; these are able to accommodate both the role of starting an engine and maintaining a long charge. Boats often use these as well as RV&#;s and can be a great option to reduce weight or save money.

CH Tech contains other products and information you need, so please check it out.

SLA Battery Terms

Part of the challenge of buying an SLA battery is getting around all the technical terms associated with them. Our website lists many of them under the &#;Specs&#; tab and terms like Voltage and Dimensions can be a little more obvious than Cold Cranking Amps or Terminal. For most if you are looking at a replacement SLA battery, typically just match the specs that are listed on the current battery and you&#;ll be fine. Other terms like Exact OEM Replacement simply means that it should be compatible with the manufacturers models and others like Maintenance-Free and Factory Activated are unique features of SLA batteries and are self descriptive. We do offer a more comprehensive guide of SLA Battery Technical Terms.

Disposal

When you do finally purchase and install your replacement SLA battery, what do you do with the old one? A little-known benefit of SLA batteries is that they can be recycled, in fact most of its components can either be melted down and reused, or in the case of the lead and sulfuric acid, be used again and again. The EPA notes that SLA batteries are among the most recycled products in the country at around 99%. They can often be dropped off at specific recycling centers or some big box store locations so it&#;s also convenient.

Summary

These days buying a replacement SLA battery is a fairly easy process with the addition of websites like our own that offer affordable and quality replacements at much better rates than the original manufacturers. Many of the specs are clearly listed on the casing so finding something that matches is a lot clearer. Our own Tutorials & Guides section hopefully helps to clarify some of the more obscure and complex things that can often be found when purchasing a replacement SLA battery but understanding the basics of the batteries, key things to look for including potential hazards, correct handling and installation as well as charging techniques and using a company you can trust can go a long way to ensuring a positive replacement battery experience.

Questions to ask when making a battery buying decision.

Because of the growing number of performance rating schemes and/or ways to value your buying decision in the market today, it has become difficult to make a decision that doesn&#;t come with some form of buyer&#;s remorse at a later date. The following are some of the more obvious things to watch out for when buying:

• Some companies rate their Reserve Capacities (minutes that the battery will deliver a discharge current) at 23 amps instead of the industry standard (BCI published) way of establishing Reserve Capacity at 25 amps.
• Amp Hour (AH) ratings can be at 5-hour, 10-hour, 20-hour and even 100-hour rates, so make sure you compare the same rate.
• Cranking Amps (the ability of the battery to deliver a higher starting current over a shorter period for engine starting) are given at different temperatures, so make sure that you compare the published &#;Cranking Amps&#; of each battery at the same temperature. CCA or Cold Cranking Amps at 0°F/-18°C is the industry standard rating. You may see ratings published at CA, MCA, MCCA and HCA. All reputable suppliers will publish the CCA.

Some companies have invented their own rating system by recognizing that the process of comparing deep-cycle batteries should be simplified. An American-based manufacturer of batteries invented a new labelling system incorporating the &#;Lifetime Energy Unit&#; (LEU). This was their attempt to help a buyer determine the lifetime performance and value of any given battery in the market. Simply stated, and in the words of the SANTA FE SPRINGS, CA. Manufacturer,  &#;Lifetime Energy Units " signifies the kilowatt-hours of energy a battery delivers over its lifetime. The bigger the number, the total work the battery can perform. Before introducing LEUs, accurately determining battery performance and value required complex calculations. Engineers compute the true worth of a battery as the total energy it contains, measured in kilowatt-hours (KWH). To derive a number for KWH, they build a curve that profiles the relationship between runtime and the number of cycles. The area under the curve is the total energy the battery delivers over its lifetime. When amp-hours are multiplied by battery voltage, the result is the battery's capacity in watt-hours. The next step - comparing a battery's value - is also simplified. By dividing the LEU by the battery's price, the prospective purchaser obtains a value figure (energy units per dollar) that ensures an apples-to-apples comparison between competing products.&#;

Discover ultimately rejects this position. As with the variations in determining Reserve Capacity and Cranking Amps mentioned earlier, this is NOT a recognized Battery Council International (BCI) method for rating or comparing batteries as suggested by the manufacturer. The manufacturer leaves out the exact method of determining LEUs, for an exact comparison to be done, which was their stated purpose for establishing the rating. This creates a situation where two suppliers could use two sets of methodologies to determine their respective LEUs, making reasonable comparisons impossible. This implies that the LEU idea or concept is simply a marketing tool with no real scientific basis for engineers, as the manufacturer suggests.

LEUs &#; as a way of helping buyers make an informed decision &#; would work very well if the buyer was given some additional pieces of data (data that IS available from other manufacturers and that could be used to make meaningful comparisons):

1. The exact discharge control methods (test procedures) used in determining the battery's &#;Cycle Time&#; (what discharge rate and to what depth is the battery discharged?).
2. Whether or not the batteries can be pre-conditioned before running the procedure.
3. The resulting ampere hours of power discharged per cycle
4. The recharge control methods (test procedures) before the next discharge procedure.
5. The exact control methods used in determining the battery's &#;Life Cycles.&#;
6. The resulting ampere hours of power discharged over the life of the battery.

In addition to the problems listed above for making good performance comparisons amongst different batteries, using the LEU marketing tool to make a serious value comparison is equally flawed. The value comparison requires more detail. Some, but certainly not all, of the issues to be examined and required in determining value are:

1. Time and Supply costs associated with servicing the battery (as recommended by the manufacturer) to ensure it achieves its assumed life cycles.
2. Costs associated with Workers' Safety and Clothing needs (as recommended by the manufacturer).
3. The cost associated with Environmental Issues, Storage and Equipment Damage resulting from the emission of free hydrogen molecules during discharge and recharge.
4. Freight/time costs and/or restrictions related to shipping.

If these data were known, the buyer could then determine the true energy units per dollar or lifetime energy value as suggested by the manufacturer who introduced the LEU calculation.

What to consider when buying a deep-cycle battery

It is our opinion that to determine the actual best &#;bang for your buck&#; for batteries in cycling applications, you should gather the following information and perform the following calculations:

Information gathering before buying? Determine the amount of energy the battery will deliver in its life using test procedures recognized by worldwide manufacturers and published in the BCI technical manual. This information should be available from all manufacturers and should include the following:

• Discharge current used (25Amps, 75Amps, 20-hour rate, etc.)
• Discharge time (Cycle Life) to an effective 100% depth of discharge (1.75 volts per cell)
• Discharge cycles (Life Cycles) achieved before the battery could not deliver at least 50% of its original rated capacity

NOTE: Different types of batteries use test procedures that allow different end-of-life criteria. For example, an electric vehicle or standard deep-cycle product would be considered at its end of life when it could not deliver 50% of its rated capacity. At the same time, a golf cart battery would not be determined to be at its end of life until it could produce at least 1.75 volts per cell during 40 minutes of discharge at 75 amperes. 

Determine the number of times the battery will be serviced in its lifetime, as the manufacturer recommends. It is important to use the manufacturer's recommended service schedule. For time/cost analysis, we recommend you use an average of 10 minutes per service per battery. 

Determine the average per hour/minute labour costs in your organization. This number varies by region and industry - should not include anything but direct labour costs. You can safely use a figure of $18.00 - $25.00 per hour ($.30 - $.42 per minute) ( dollars) without benefits etc. One transit authority stated that their direct labour cost associated with maintaining batteries in each transit bus was $180.00 per year; another stated it was as high as $550 per battery. We suggest using $22.00 as an average hourly cost ($.367 per minute). 

Cost of service materials over the life of the battery, such as; distilled or specially treated water - using a per cell fluid usage by volume of 20% on an average cell volume of 2.35l/80oz and a 75% consumption efficiency or between $.02-$.04 per oz. Battery fluid volumes are as low as 5l/169oz and as high as 16l/540oz; cleaning and neutralizing agents at 1oz per battery or $.25 per battery per service; special clothing; repair and replacement of battery boxes and trays and more.

Cost Per Battery

• Purchase price of the battery
• Freight or handling charges (overland or can they be shipped through courier or air)

Calculating Cost to Own

Estimate the cost of materials used when servicing the battery as the manufacturer recommends. For comparison, it is reasonable to use just $1.70 each time for distilled water, cleaning and neutralizing agents and ignore the other variable costs. Multiply this amount by the years the manufacturer says the battery will last in the application. Multiply the result by the number of times the manufacturer says the battery should be serviced per year to achieve the published life expectancy. Our experience shows that most manufacturers will recommend your service flooded batteries at least once a month. 

Two of the &#;World's&#; leading manufacturers and sellers of Flooded, GEL and AGM Deep-cycle batteries state the following on their websites:  &#;Flooded batteries need water. More importantly, watering must be done at the right time and in the right amount or the battery&#;s performance and longevity suffers. Water should always be added after fully charging the battery. Before charging, there should be enough water to cover the plates.&#; This would suggest that the world&#;s leading manufacturers of flooded deep-cycle batteries recommend that service is required, particularly as the battery ages, BEFORE and AFTER every charge/discharge cycle. In some cases, they suggest that failing to do so will void the warranty. If you cycle the battery two times per week, the battery will last approximately three years following the manufacturer's recommended service procedures. This means your per battery service material costs will be at least $1.70 x 12 services per year x 3 years = $61.20. If you serve as the manufacturers suggest, it will be as much as $1.70 x 104 services per year x 3 years = $530.40. Our experience shows that for a battery to last three years when being cycled two times per week, it needs to be serviced at least once every four cycles or bi-monthly. $1.70 x 3 years x 26 services = $132.60 per battery. Every user of deep-cycle batteries is familiar with dried &#;rotten egg&#; smelling batteries, the result of NOT maintaining a proper service schedule over the battery's life.

NOTE: when asked, more than 80% of equipment managers could not produce or describe a &#;battery service schedule&#; - for equipment under their supervision that uses cycling batteries.

In our opinion, if you were to match a quality flooded battery against a Discover Semi Traction EV Dry Cell AGM or GEL battery of the same size and AH rating for use in the same application, you would find the total cost of ownership to be higher for the flooded battery option. Discover Semi Traction EV Dry Cell AGM or GEL batteries require less service, and as a result, with proper charging methods, Discover batteries will out-value flooded batteries. It is more likely that the standards of service for the flooded batteries will not be met in the real world. Therefore, it will not meet the manufacturer's required levels to achieve maximum life.

Additionally, when considering flooded versus Dry Cell AGM or GEL, one must also consider other inconveniences and/or costs associated with servicing, working with or having sensitive equipment around flooded batteries. These would include, but are not limited to:

• damaged and/or special clothing
• battery compartment repairs
• air quality problems
• workers compensation claims
• occupational health issues
• hazardous materials handling requirements
• shipping restrictions
• damage to service areas from acid and corrosive by-product spills

We feel the more competitive and demanding the channel (jobber/installer/large user/rental equipment), the more compelling and feasible the switch to Discover Semi Traction EV Dry Cell AGM or GEL batteries becomes. The larger the bank of batteries used, the more important costs associated with service and the more compelling and feasible the switch to Discover batteries becomes.

Are you interested in learning more about Lead Acid Replacement Battery(pt,sv,th)? Contact us today to secure an expert consultation!