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Manufacturers have varying methods to specify battery performance. What may seem like unimportant details, can significantly change the perceived performance of a particular battery. This article is in reference to lead acid batteries, but the general principals can apply to other battery types as well. Here are some things you have to consider:

1) Ampere-Hours

The Ampere-Hour or Ah rating of a battery is how they specify the size or amount of energy stored in a battery. It is calculated by multiplying Amperes x Hours at a particular rate of discharge or C-Rate.

2) Watts

Some batteries are only specified in Watts per cell or per block for a specified time. Small batteries may be specified as Watts for 15 minutes down to 1.67 volts per cell at 25degC. This standard was created in the Uninterruptible Power Supply or UPS industry to specify the ratings for UPS batteries. A UPS inverter basically draws a constant watt load, or in other words; the current (amperes) increases as the battery voltage decreases. The more Watts a battery can provide over a short duration the better. This can be achieved by putting more plates and thinner plates inside the battery to reach higher performance. There is no straight forward conversion between Watts and Amperes, but it can be estimated by dividing Watts and the Average Discharge Voltage. The Average Discharge Voltage for a 12V block is around 11.5V or 1.92V for an individual cell.

3) C-Rate

C-rate refers to how fast a battery is discharged and is most commonly specified at 5, 8, 10, 20 or 100 hours. If a battery is rated 100Ah at the C20 rate, this means that it can discharge at 5 Amps for 20 hours. However, if the same battery is discharged at the C5 rate it may only provide 16.5 Amps for 5 hours, or in other words the C5 rate is 82.5Ah. The lower capacity at a faster discharge rate is the result of resistive and chemical losses. So you have to know how much current your application requires and size the battery appropriately based upon the rate of discharge. Just because one battery has a higher Ah rating than another battery, it may not actually have more capacity because of the specified C-Rate.

4) Temperature

Temperature affects the ability of a battery to supply current. Lower temperatures reduce capacity due to reduced chemical reaction. Battery performance is most commonly specified at 20, 25 and 27degC. The battery capacity difference between 20 and 27degC is about 8%. So a 100Ah/20degC rated battery could supply around 108Ah at 27degC, or conversely a 100Ah/27degC rated battery would be only able to supply around 92.6Ah at 20degC

5) End of Discharge Voltage or Volts per Cell

The End of Discharge Voltage or Volts per Cell is the minimum voltage which will still allow the connected loads to operate properly. In a UPS, this could be the point where the inverter has to shut down or in a switchgear system, this could be the point where the motor operators and solenoid coils can still operate. This must be considered in conjunction with C-Rate to properly size a battery. For example, in an application with high discharge current for a short time, the battery will reach a high end of discharge voltage of around 1.90V/cell very quickly. If the equipment will operate down to 1.67V/cell then you can better utilize the available battery capacity. Conversely, if you have a low current load for a long time, the average battery voltage will be quite high and you can effectively utilize full capacity out of the battery.

6) Cycle Life and Depth of Discharge

The Cycle Life is the amount of times a battery can be discharged and charged. One discharge and recharge represents one cycle. It can be specified in a number of ways depending upon the Depth of Discharge (DOD) and C-Rate. Depth of Discharge is the percentage of capacity that is discharged from the battery. Some of the most common methods are 2-hour BCI (effectively C2 rate or around 84% DOD), IEC896 (60% DOD), or possibly a graph based upon DOD. For example, a manufacturer might specify a cycle rating of 1200 cycles for a battery. You have to verify the DOD the 1200 cycles is rated at because that could be at 30% DOD. Conversely, a battery may have a rating of 800 cycles at 80% DOD, but that actually represents much higher performance than 1200 cycles at 30% DOD.

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Charging

1. Myth: Lead acid batteries can have a memory effect so you should always discharge them completely before recharging.

Fact: Lead acid battery design and chemistry does not support any type of memory effect.  In fact, if you fail to regularly recharge a lead acid battery that has even been partially discharged; it will start to form sulphation crystals and you will permanently lose capacity in the battery.

• Myth: The worst thing you can do is overcharge a lead acid battery.

Fact: The worst thing you can do is under-charge a lead acid battery.  Regularly under-charging a battery will result in sulfation with permanent loss of capacity and plate corrosion rates upwards of 25x normal.  Overcharging a battery breaks down any sulfation, but can cause plate corrosion rates to increase up to 3x normal.  With flooded/wet batteries you can always add water.  One concern is overcharging AGM batteries, which already have very little water reserve, and so there is risk of dry-out. However, most chargers sold today are “smart” chargers and will shut off after the battery is fully charged.

• Myth: Any charger should work perfectly okay with any type of lead acid battery.

Fact: There are many different technologies used in lead acid batteries.  For example; many automotive batteries are a flooded/wet design for engine starting, but not designed for deep cycle use.  You can use automotive chargers for these which are either trickle charge or taper charge and normally have higher output ripple current.  You would not want to use an automotive charger for a deep cycle AGM or GEL battery because the higher ripple current would cause water loss and dry-out and a trickle or taper charger may not fully recharge a deep cycle battery.

Visit our Chargers page for Portable and Stationery Chargers

Storage and Installation

• Myth: Never store a battery on a concrete floor because it will suck the energy out.

Fact: There was truth to that 75 years ago when batteries were built in hard-rubber cases because acid would weep through the case into the concrete creating a discharge path.  Nowadays modern plastics are impervious to acid so there is no risk of this happening.

• Myth: It is okay to store lead acid batteries anywhere inside or outside.

Fact:  It is good to store lead acid batteries in cool places because the self-discharge is lower but be careful not to freeze the battery.  Do not store lead acid batteries in hot areas because the heat will cause high self-discharge and will shorten the life.  Do not store lead acid batteries outside because the UV light will damage the plastic case and moisture will corrode the terminals.

• Myth: Battery operating temperatures are not so critical as long as lead acid batteries are not too hot.

Fact:  Individual cell temperatures within a battery bank must be kept within 3°C/5.4°F of each other because the charge acceptance for lead acid batteries varies considerably with temperature.  If the ambient temperature in the battery room varies by more than +/- 10°C/18°F then you should be using battery temperature compensation to automatically vary the charge voltage.

Maintenance

• Myth:  Maintenance free batteries never require maintenance.

Truth:  There is no such thing as a maintenance free battery and IEEE recommends this type of battery should be called valve-regulated lead-acid or VRLA to avoid any confusion.  Even so-called maintenance free automotive batteries should be checked/tested to insure they do not let you down and the terminals should be cleaned to insure a good connection.  Higher voltage stationary banks also need check-ups and cleaning, furthermore; they need conductance testing to determine condition of the plates and discharge capacity testing to verify if they are performing well or need replacement.

• Myth:  Any type of grease is okay to protect battery terminals.

Fact:  In the industry there are many different cleaning and protecting products out there.  Some of these contain harsh chemicals that may actually damage the plastic case, connections, or terminal seals.  One common industry product is NO-OX which is a petroleum based product with corrosive ingredients that keeps the terminals clean by removing the oxide layer.  This is usually okay to use on automotive or less expensive batteries, but when it comes to advanced technology batteries it can often become a problem, not to mention that NO-OX is also toxic, and very flammable.  Electrical grade silicone grease is a much safer alternative to use on all lead acid batteries because silicone is very non-reactive, so it does not damage plastic or rubber terminal seals and also non-toxic.

Ready to put these facts to use? Contact Us to request a quote or learn more about our products and services.

Since our founding in 1988, Advanced Battery Systems (ABS) distributed only the highest quality industrial batteries, chargers and accessories. That’s why ABS has closely partnered with Exide Technologies and GNB Industrial Power to import superior battery systems from Europe.

Exide is a global leader in battery manufacturing that owns several brands, including Sonnenschein, Marathon and Sprinter. ABS imports these brands from Europe due to their superior performance over many other brands.

With the Sonnenschein, Marathon and Sprinter brands all being manufactured in Europe by the same producer, we can strengthen our supply chain resilience and stand behind these high-quality products. For our customers, this means reduced lead times, enhanced shelf and design life, and better recycling capabilities once the product has reached the end of its useful deployment.

Sonnenschein Batteries Carried by ABS

As the inventor of battery gel in 1957, Sonnenschein’s unrivalled Dry Fit Gel Technology sets them apart from the competition, enabling up to 2 years shelf life and 12-20 years design life. Sonnenschein batteries are highly reliable, and resilient to harsh conditions.

Advanced Battery Systems is the Master Stocking Distributor for Sonnenschein in North America and we regularly stock A500 and GF Traction models. We have exclusive supply in North America for all Sonnenschein product lines such as:

• Sonnenschain A400
• Sonnenschein A400 FT
• Sonnenschein A500
• Sonnenschein A600
• Sonnenschein A700 (Replacements)
• Sonnenschein GF Traction
• Sonnenschein Solar

Access our Supply of Marathon and Sprinter Batteries

Marathon and Sprinter are well known brands of batteries manufactured in the USA; however, we import our Marathon and Sprinter batteries from Exide Europe. The models we import are not identical to those manufactured in North America. In fact, they are the superior replacements to North American models.

For example, the European model we stock supply, Marathon L and XL, is a replacement for the GNB USA Marathon M series. We do this because:

1. The European models are superior with a 12-year design compared to the 10-year designs of their North American equivalents
2. The Marathon M (Top Terminal) and FT (Front Terminal) series, and the Sprinter S series are no longer manufactured in the USA, but equivalents are in Europe
3. Exide manufactures high quality Sonnenschein batteries in the same facilities

Like Sonnenschein batteries, ABS carries a range of Exide batteries manufactured under the Marathon and Sprinter brands. Our models currently in supply include:

• Marathon L and XL
• Marathon M FT
• Sprinter P and XP

Buy Exide Brands with Advanced Battery Systems

Advanced Battery Systems (ABS) offers various sizes and models of the Sonnenschein, Marathon and Sprinter batteries that are manufactured at Exide Europe’s plants. Their products are top of the line, and we’re proud to partner with a manufacturer who cares about excellence in both quality and sustainability.

If you’d like a quote on any of our products, please contact ABS through our online form and we will respond the same day.