NBN customers are becoming increasingly angry that a wall-mounted battery – once compulsory – is dying years earlier than expected, leaving them with a surprise, out-of-pocket maintenance cost.
And battery retailers say the NBN-supplied product is "cheap and inferior", lasting only a tiny fraction of the expected lifespan.
David Romain, an administrative officer from Homebush, was shocked when he was forced to buy a $40 replacement battery for an NBN-supplied power unit, which keeps a telephone line active for a few hours during a blackout.
He was connected to the national broadband network about a year and a half ago, when the back-up battery was compulsory for all fibre-to-the-premise customers.
"It's very annoying it died so soon. I was forced to have it, and now I have to pay for a new one. It's expensive. When I bought a new one, I was told these should last up to five years," Mr Romain said.
Know more? Email us
At present, more than 200,000 fibre-to-the-premises customers across the country have the large, lead battery mounted on their walls. It became an optional feature in October 2014.
Technology expert Angus Kidman, from comparison service Finder, said an estimated 2.4 million homes and businesses would have a fibre-to-the-premises connection to the NBN by 2020, meaning there was a massive cost to the public.
"If half of these properties choose to have the battery box, we can estimate $60 million could be spent collectively on replacing the battery just once," he said.
"If you're lucky enough to have a full fibre-to-the-premises connection, a battery update isn't a massive deal, but it's a reminder the NBN does not come for free."
Over the past year, Battery World in Bankstown has seen the number of disgruntled customers seeking an NBN battery replacement grow to at least 20 a week.
"They're all coming in with the same issue: the battery dying around the 18-month mark. Alarm systems use a similar battery, and you can get five years out of them," manager Mitchell Harris said.
"The customers are not happy NBN is not servicing the product. They believe NBN should be paying for it."
Mr Romain was told by NBN the battery was no longer under warranty. An NBN spokesman told Fairfax Media this was a mistake, as the warranty period lasts 24 months from the day of installation.
An R&J Batteries employee, who asked not to be named, said the NBN-supplied battery was "cheap and inferior".
In 2014, there were no customers seeking NBN replacement batteries. Now there was a constant stream coming in for quality products.
"It can cost about $50 for a quality battery. It's a big shock for someone who's not expecting to buy a replacement after three or six months. They say they're being told the batteries are not covered by warranty," he said.
He added that R&J Batteries' bid to win the NBN's tender to supply the back-up battery was undercut by three-quarters by the eventual winner.
"The tender went to someone with a really, really cheap price. Apparently, we couldn't even bring the product into the country at the price they were selling it for. NBN obviously went for a really cheap product and that's why you're having a lot of fails," he said.
The Australian Communications Consumer Action Network was concerned some people might require professional help when replacing the battery, which would increase costs, a spokesman said.
"[We're also] concerned batteries that need replacing earlier than expected put vulnerable consumers at risk. Battery back-up is very important for consumers in the event of a loss of power who need to continue to use services, such as phones and alarms," the spokesman said.
"No battery back-up, or failure of a battery, can create a potential risk to life and property for some vulnerable consumers."
The battery has been labelled as a "wall wart", and was once the single biggest source of complaints from users in NBN test sites.
An NBN spokesman said the battery, when used properly, would age to about 70 per cent of its original capacity in about three to five years.
"They are a common off-the-shelf battery, the same type used by businesses that want to maintain a power supply in an outage. These same units meet our requirements, too," he said.
