Here are some of the more frequent questions we are asked by our clients. For more information, we recommend that you consider attending one of our training courses.
Q: What is a battery “string”?
A battery string (i.e. bank) is a series of battery cells connected as a series circuit.
Q: Do batteries fail?
A: Yes, all batteries will age and eventually fail. Having a regimented battery maintenance program in place will dramatically improve the life of any battery system. Batteries cannot simply be relied upon to perform when the time comes without a proactive maintenance plan in place. [learn more about battery preventative maintenance]
Q: What is the difference between a Vented Lead Acid (VLA) and Valve-Regulated Lead Acid (VRLA) battery?
A: There are several differences. In a nutshell, VLA’s are more expensive and take up more space, but the life expectancy and number of discharge cycles is MUCH longer/greater than a VRLA. While VRLAs are significantly cheaper and don’t require as much footprint, they are very unreliable versus VLAs. We strongly recommend that a battery monitoring system be installed on VRLA battery systems. [learn more about battery monitoring systems]
Q: If I have a battery monitoring system, do I still need to do preventative battery maintenance?
A: Absolutely. Installing a battery monitoring system, and walking away is strongly discouraged. Battery Monitoring Systems are excellent to trend and alarm you on battery issues coming near. They lower battery maintenance, but they do NOT replace or eliminate visual and mechanical inspections. A handheld meter (i.e. Cellcorder CRT-400) should be used to conduct annual readings at a minimum, even if a monitoring system is present.
Q: How fast do batteries fail?
A: This answer is “it depends”. Regular IEEE-450 maintenance is adequate, and you will be able to trend a VLA’s performance well. With VRLA (sealed) batteries, it’s a whole different situation. Dry-out is the #1 cause of failure in VRLAs. There is no way to add water to a “sealed” Valve-Regulated-Lead-Acid battery (like a VLA). Quarterly battery maintenance (following IEEE-1188 standard) is strongly recommended to properly trend VRLA performance. Voltage and internal resistance is measured and is the best way, short of a full discharge test, to gauge the condition of the cell inside. A battery monitoring system is strongly recommended for VRLA battery systems.
Q: How long will my battery system last?
A: The timeframe for usable life of a cell depends on many different factors and variables such as, the type of battery, number of discharges and environment. Generally, a VLA can last between 10 and 15 years. A VRLA can last 3-5 years. There are some premium VRLA technologies that can last over 8 years. If your battery room doesn’t have proper ventilation or air conditioning, the lifespan of you battery system will decline dramatically.
Q: How to I calculate how much time my battery will run? Can I calculate this from voltage and resistance preventative maintenance data?
A: Capacity (load, discharge) testing is the only way to calculate the performance and actual runtime (capacity) of a cell, new or old. Under a load a cell is required to demonstrate its true performance and measured and recorded properly. This allows qualified individuals to calculate an exact percentage of rated capacity. [read more about capacity testing]
Q: How often should I capacity (load) test my battery?
A: Depending on the age of a battery, and the most current maintenance data there are many variables that can determine this answer. Some of our clients capacity test their batteries on an annual basis. Some do it every other year. Most times, the decision of frequency is based upon how critical the system is to the company and its operations. With this all being said, it is imperative that newly installed batteries be capacity tested (i.e. acceptance tested) to ensure they have been properly “commissioned” and that baseline performance values are established for future maintenance and warranty records.
Q: How does temperature affect my battery system?
A: Temperature has a significant impact on both the performance and lifespan of any battery cell. Most lead-acid batteries suggest an operating temperature of 77°F. Cells that are warmer will demonstrate slightly increased capacity (runtime), but will age and fail more rapidly, reducing the lifespan considerably. Cells kept cooler will lose some available capacity, but tend to age more steadily and last longer in the grand scheme of things. Generally, it is best if your battery room is slightly too cool than too warm.
Q: What happens if I do not keep my batteries on float charge?
A: Batteries will self-discharge slowly if not maintained on a proper “float charge”. If a battery is out of service or in storage, it should be given a “freshening charge” every few months to avoid internal cell degradation. The length of time a particular cell is able to go without a charge can be found in the manufacturer’s published technical data.
Q: Is it true that one battery (cell) failure affects the entire battery string?
A: Yes. A single cell failure is capable of bringing down the entire battery string. Cells are connected together in series circuit to achieve a desired voltage. Like links in a chain, if a single link is weak and fails, the entire chain will fail and the entire load will be dropped. Regular, frequent, and consistent maintenance and testing will help identify these “weak links” so that the issue can be addressed, and/or the cell replaced, before YOUR critical load is dropped. A battery monitoring system can also lower your battery maintenance cost and send you an alarm when a battery is nearing failure.
Q: How tight should my battery connections be torqued?
A: Tighter is NOT always better. It is very important that you follow all manufacturer’s recommended torque values. Each battery model’s value is different. A calibrated torque wrench should be used as most Lead-acid cells have lead in the posts as well, and some posts are solid lead. Lead and other soft metals (brass inserts, for instance) will deform if too much torque is applied to the bolt connection. This can lead to damaged posts and actually REDUCE the quality of the inter-cell connection, increase the resistance, and – in extreme cases – even cause damage to the cell that can lead to increased leaks, a greater chance of corrosion, or damaged post-seal leaks.
Q: What is “thermal runaway”?
A: Thermal Runaway is a phenomenon most seen with VRLA batteries. If the charging current and temperature on a battery is not monitored, it is possible to build up to a Thermal Runaway situation, which will quickly lead to catastropic battery failure and serious safety issues. VRLA batteries will often physically melt down if this condition is not resolved quickly.
Q: How do you recycle your batteries, and how am I assured it’s done within government guidelines?
A: We guarantee that your spent batteries are taken to a certified smelter and disposed of and recycled properly. A certified “death certificate” is provided to you as well for your files. [more on battery recycling]