Battery Battle

VRLA batteries aren't living up to the hype created by battery salespeople, and the wireless industry is tired of it.

The problem with VRLA batteries begins with the definition of life. There's design life, warranty life, float life, shelf life, operational life, accelerated life and cycle life. Then there's the actual life that users get out of their batteries.

Each life has different numbers attached to it, from 10- and 20-year accelerated lives to 20-year warranty lives. But the numbers that are causing the battle lines to be drawn are the differences between advertised lives of 10 or 20 years and actual lives of three to seven years.

“This whole design life is a numbers game, quite honestly,” said Allen Byrne, American Power Conversion (www.apcc.com) senior staff applications engineer. “There are two main numbers thrown out. One's a 10-year life design. You're lucky if you get three to five years out of those, even under ideal conditions. And, the so-called 20-year life: Studies have shown that that's probably — I'll be generous — a 7-year battery.”

Battery manufacturers usually base the life of their batteries on accelerated-life tests done by engineers who put batteries in ovens to simulate operational conditions. Those 10- and 20-year numbers have become the industry standard, even though real-life numbers are usually different.

“The reason they use 10 and 20 years is marketing,” Byrne said. “No company's going to say, ‘Well, ours is really a 7-year battery,’ and tell the truth.”

So, battery manufacturers are stuck. They know their batteries don't last as long as the numbers say, but no one wants to be the only one to change its marketing strategy. Meanwhile, carriers are getting more fed up.

“The warranties state 20 years, and people are routinely seeing seven,” said Keith Jungermann, Panasonic (www.panasonic.com) battery business unit manager. “They're frustrated with that, and they should be.”

“(VRLA batteries) have gotten a black eye in the marketplace,” said Steve Vechy, EnerSys director of marketing (www.enersysinc.com).

Promises Made, Promises Broken

VRLA batteries entered the market in the 1980s and were seen as the perfect solution for remote wireless sites. The best telecom battery technology of that time was vented lead-acid batteries, or flooded cells. Central offices relied on flooded batteries to provide their backup power, but flooded cells have many maintenance issues and require a lot of babying.

Because of their liquid electrolyte, flooded batteries usually need a tray for spill control. They can't be mounted horizontally, so they require a large footprint. Other problems include exhaustive maintenance, long delivery times and high cost, not to mention the fact that they vent hydrogen gas and can require special rooms or ventilation.

“You're going to have additional requirements (with liquid cells),” Jungermann said.

On the other hand, because the battery has liquid electrolyte and a see-through case, technicians can monitor the fluid level easily and add to it as needed. It also has been proven to last at least 20 years, maybe longer.

“The main advantage of (flooded) cells is that they're reliable,” Byrne said.

As telephone services migrated out of central offices and into remote sites, carriers began to demand a battery that was smaller, cheaper and easier to maintain than a flooded cell, yet just as long-lived. Battery manufacturers introduced VRLA batteries and touted them as maintenance-free with lives similar to flooded cells.

“The VRLA battery didn't live up to all the hype,” Byrne said. “It proved to be a lot less reliable than the manufacturers made out.”

Learning From Mistakes?

Now that VRLA batteries have been out in the field for a while, it's clear that many in the industry aren't happy with their performance.

Although they work well in remote sites because of their small footprint, they are not maintenance-free, have short lives and require particular temperatures.

“Heat is an extreme killer of a VRLA battery,” said Jim Larmour, CSB Battery (www.csb-battery.com) telecom sales and service manager. “These batteries are made to operate at 77° F. As you go up (in temperature), you start losing capacity, you start losing service life, and you start losing float life.”

Overheated VRLA batteries are also prone to thermal runaway. If a battery takes in too much current, it will get hot, and the gel material in the battery will begin to turn to gas. That will cause the battery to dry out, which will create more heat, causing more gassing. If this overheating sequence continues, it becomes thermal runaway, which can melt battery cases and even cause fires.

Because of carriers' problems with VRLA batteries, manufacturers are trying to educate them about maintenance and temperature, as well as trying to create longer battery life.

Jungermann said it's up to the manufacturer to improve the batteries.

“We've been working on trying to get the reliable life up into the 13- to 15-year range,” he said. “When these are installed at a cell site, there's not a lot that the user can do other than assure that the conditions that the battery operates under, like temperature, are kept at a reasonable level.”

CSB's Larmour disagreed, saying that manufacturers can't be blamed when users abuse the batteries.

“A lot of people are not telling the battery manufacturers how the battery's actually being used,” he said.

Larmour said poor maintenance shortens a battery's life almost as much as heat, so his company is working to educate users.

“It has to do with knowledge,” he said. “It has to do with training the consumers as to what the battery can do.”

Some carriers are so fed up they're looking for alternatives to VRLA batteries. Because most carriers still are familiar with flooded cells, some are leaning in that direction.

Carriers are faced with a dilemma: Do they put flooded cells in remote sites and deal with the footprint and maintenance issues, or do they use VRLA batteries and deal with replacing them every three to eight years?

Flooded, VRLA or Other

Mbr> The decision to use flooded or VRLA batteries isn't an easy one, and it differs from user to user.

Samuel Norman, Delta Telecom Power (www.deltartp.com) sales manager, said a carrier recently told him the company was taking VRLA out of the central offices and some of its wireless applications.

“Their new standard as of this summer will be flooded cells,” Norman said.

Other carriers are doing the opposite. For Alltel (www.alltel.com) the decision to stay with VRLA was clear. After years of frustration with various brands of VRLA batteries, it switched to Panasonic and hasn't looked back.

“We're using valve-regulated in our cell-site applications,” Williams said. “Our switch rooms still have some flooded cells but seem to be going over to valve-regulated because of the quality of Panasonic.”

Before the switch to Panasonic, Williams said Alltel had had numerous problems with VRLA batteries. The seals broke, and the plates swelled, causing batteries to break open and leak chemicals onto the floor.

Williams said that he was pleasantly surprised when the Panasonic VRLA batteries performed so well.

Other carriers are investigating NiCd instead.

“We had a carrier at our spring meeting stand up and literally give us the number of batteries that he expects to die in the next three to five years and what the cost of that is going to be,” Norman said. “His flat-out recommendation was to start looking at NiCd.”

NiCd batteries are much more expensive than either flooded or VRLA batteries, but they last longer than VRLA, are more forgiving in high temperatures and cycle well.

Alternatives to VRLA are out there, but some carriers may prefer to fight, not switch.

“Carriers have come back to lead acid time and time again because, per amp hour, it's the most cost-effective battery you can buy,” said Gary Guagliardi, Delta Telecom Power sales manager. “That's why people put up with it. When it dies, they just replace it.”

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VRLA Vs. Flooded Batteries

Flooded Batteries	VRLA Batteries
Benefits	Benefits
Long life: 20 or more years Time-proven design Fluid can be replenished See-through container	Can be housed near electronic equipment Can be transported safely Easier to install No spill-containment required Minimal ventilation requirements Less expensive Easier to replace More environmentally friendly
Problems	Problems
Usually require spill containment Hazardous to transport and install Exhaustive maintenance Require forced-air ventilation Must be mounted on open-frame racking Long delivery times More expensive	Short life: three to seven years Visual maintenance impossible Susceptible to charging and operating abuse
Source: Allen Byrne, American Power Conversion (www.apcc.com) senior staff applications engineer