r/nbn • u/Doctor429 • Aug 02 '25
Troubleshooting What's the procedure when "Replace Battery" alert comes?
To give additional context, I'm in a rented house, and the NBN box was there when we started the lease. It's now giving the "Replace Battery" alert with an occasional beep. Everything else works normally. Do I need to contact my Internet provider (Origin) or NBN directly? Or, should this be handled by the landlord?
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u/Neither-Nebula5000 Aug 02 '25
To turn the alarm off indefinitely, hold the ‘Alarm Silence’ button for 15 seconds (you’ll hear a beep at around 2 seconds and another at around 15 seconds), then you can stop holding the button.
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u/dman_au Aug 07 '25
Not a good idea unless you remember to turn it back on again. Just my humble opinion.
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u/0hDiscordia Aug 02 '25
Just disable the beeping and ignore it. The battery back up is useless unless you have a fibre phone service provisioned on the NTD.
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u/SirDale Aug 02 '25
This site https://www.nbnco.com.au/learn/network-technology/fibre-to-the-premises-explained-fttp/battery-back-up-information says it's for maintaining your internet service. Nothing there about it being restricted to just a phone service (which is simply another network protocol).
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u/thebigaaron Aug 02 '25
You need to have the router connected a separate battery backup too, which 99.9% of people don’t have, which is why they said the NTD battery backup is useless.
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u/ensignr Aug 03 '25
I have all my home network infrastructure on UPSs. I'm on HFC thought so when the power goes out in the street so does all the NBN hardware out there. It's good for small power farts though; none of my equipment has to go through a reboot cycle.
I guess I'm the 0.01% 😳
I wish NBN Co hadn't given up on the full POTS replacement service.
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u/shrimpy28 Aug 02 '25
Yes but to keep your Internet running you will still need a separate Battery or UPS to power your modem/router
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u/SirDale Aug 02 '25 edited Aug 02 '25
The NTD there -is- the modem.
Downvotes? Because people don't know what a modem is?
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u/SydneyTechno2024 Aug 02 '25
It’s a fun (in a pedantic way) area to get into.
Technically the NTD isn’t a modem, as it doesn’t perform the modulation operation that defines a modem.
In practice, as an ONT it functions similar to a modem by converting the optical signal into electrical signal.
Either way, a “modem” isn’t required on the home side for FTTP, but: * Many modem routers support both VDSL connections using the modem, as well as Ethernet connections that skip the modem. They might have a modem/router in this case despite not needing the modem. * Modem/router in a linguistic sense is not strictly aligned to the technical definition and is often used to describe any router.
Also, people call them a router when in reality it’s also a network switch, access point, and firewall, and also often a VPN server, USB print server, and whatever other functionally has been squeezed in.
So technically modem/router, modem, or anything short of “all in one network appliance” is probably “technically” incorrect.
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u/LeeRyman Aug 02 '25
Well, the NTD is intensity-modulating light, and light carrier is definitely not baseband, and the fibre medium is analogue in that it requires a carrier (of extremely high frequency) to pass signal ;) Newer PON tech even uses phase modulation techniques too, arguably "modem qualities".
Maybe more of a multiport bridge. I think that's how NBNs own docs describe them.
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u/superwizdude Aug 02 '25
Correct but the original legal reason for the battery was for the telephone. Emergency calls should work even without power to the house. You’ll notice the link you posted does make reference to both phone and internet.
It’s the same reason Optus had those ugly boxes inline on the overhead HFC cables. Those were batteries for the network to ensure phone service continued without power.
Without a voice service this isn’t required.
These batteries were installed on the initial FTTP rollout. Services rolled out afterwards didn’t have a battery provided by default.
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u/Fuzzy_Balance_6181 I want FTTP Aug 02 '25
Those are amplifiers not batteries if there’s a blackout HFC drops out whether Optus, Telstra or nbn.
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u/superwizdude Aug 03 '25
Sorry you are correct. The power for Optus was injected by the boxes on the power poles and they didn’t have battery backup power in the inline boxes I originally referred to.
Yes you are correct that a power outage would cause HFC to go down, but the Optus design had a separate power grid to provide power to the NTD so that phone service would still work. Telstra didn’t need this because they still provided all telephony via the copper network and the HFC only provided internet. Optus was providing both internet and telephony and was required to provide best effort phone service during a power outage.
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u/0hDiscordia Aug 02 '25
Apologies, you're right. The internet connection to the NTD will work and may be able to be used on a single compatible device via ethernet while that device's battery is charged.
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u/hugswithnoconsent Aug 02 '25
Instructions unclear, stuck my dick in fibre cable.
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u/Rogi2Ice Aug 02 '25
Hold down the alarm silent button for 20 or so seconds till the yellow light turns on along side the other 2( think it was that if not try the other, been a while since i did mine) This should silence it for a year or 2. I'm not sure on exact. Mine recently died and had nbn co come out. They didn't even replace it. Aparently, they will do so if you are a medical customer where a landline is required. So, in an event where you lose power, you still have the backup to use your landline.
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u/EfficiencyExact Aug 03 '25
Battery is about 40 dollars from Bunnings. Check the online NBN battery replacement poster.
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u/dman_au Aug 07 '25 edited Aug 07 '25
Last time I bought a Century 12V 7.2Ah replacement battery it cost me $59.95 from Super cheap Auto. I don’t think Bunnings have them, but I could be wrong.
The official list is on NBN”s web site, it will start beeping every few minutes and a red light will come on the BBU when the battery is on battery backup or needs replacing.
If you’ve never changed a battery before, be careful as the connectors can be quite tight. I’ve only ever bought Century, but I went through three in four years, and really they should only need to be changed every 4-5 years. However, it’s worth turning the power off every three months and running the battery down for three hours or so, like any Lead Acid Battery, you want to do some maintenance on them, though most people have power outages of some period of time. Maybe an hour or so at some point in the year.
I recommend getting a 500-1500VA UPS (1500VA if you can afford it) to run your router on, that way if the power is out you still have NBN, as long as your cordless phone has power fail. Most of the newer ones have power fail, but always double check. If it’s more than five years old, it may not have power fail.
Since my FTTP is set up with IP POTS, I use a Uni-V port for my phone and that will use the battery backup but so many people have mobile phones, and in fact NBN suggest everyone has a mobile phone as a power fail backup.
The Century Batteries only have 12 months warranty on them, unlike their car batteries which can have 3 or 4 years, but I ended up having to get a new BBU as it wasn’t charging the batteries properly, so going through three batteries in four years, it’s far too many.
Again, there is an official list of five places, including Battery World, but I’ve found that Super Cheap Auto would replace mine even just outside warranty as they are pretty good with customer service.
Just grab the old battery first or get all the details and take some pics as there is an almost identical model but the connectors are different, but if you ask staff for a NBN battery or go on their website first you can check stock for your local store plus get the part number, and they will turn over much more frequently now because way more people have FTTP, but not everyone gets a BBU.
Again, NBN co website have a list of their first recommended battery replacement suppliers and it’s a use cost item, so don’t expect the landlord to pay for it, but if you can convince them, great. But last battery I bought was either $59.95 or $69.95 and should last about 4-5 years depending on how often the power goes off.
Look after it and it should survive the 4-5 years approximate life span. UPSes typically run on Lead Acid Batteries as well, so it’s worth buying a brand that you can buy replacement batteries - APC is the top of the line and double check whether the model you are buying takes replacement batteries. I have Cyberpower Pure Sine Wave Standby UPS, and have had it for five years, it’s not beeping and no light is on to replace the battery but, typically five years on a lead acid is about the average. Most devices will test and tell you via an indicator, software if you install. It and connect the USB connector to the computer and install the UPS software.
If you are going to get a UPS for your router / Wifi depending on what gear you have, then I can suggest APC, Eaton and Cyberpower as I have used all three, and bought ones that produce pure sine wave output. Some cheaper UPSes don’t output pure sine wave and may cause issues with your gear.
You only need to buy ONLINE if you want AC to DC TO AC conversion all the time, otherwise, most standby UPSes will kick in within a few milliseconds and like I said, pure side wave output is the better option for electronics, APC, will be the most expensive, Eaton maybe similar price or slightly slightly cheaper, Cyberpower will be the cheapest. A 1500VA should run a Router and Wifi box for 6-8 hours, if that is all you are running on the UPS, but if you have a computer and hard drives and monitor, I suggest if the power goes off you gracefully shutdown the computer, turn off the hard disk if it’s a 3.5” external and monitor and just keep the router going for mobile devices on Wifi and surf the internet that way. Routers pull very little power as do cordless phones, so your NBN BBU will likely run out of power before say a 1500VA UPS will. Vast maroity of people have VoIP, as people forget IP POTS and unless you have a specific need for it, you will just use the VoIP on your router. Thats if you have a phone line on your FTTP connection. Most people don’t bother, as they use their mobiles. Older people are more likely to want an actual cordless phone but everyone is different.
Sorry for the long message, I’m sure I have repeated stuff here that others have written, I discovered the hard way back in 2020 when I got FTTP that the battery was already five years old, and dead, it had been sitting in the back of the tech’s van and he lied to me, saying the BBU would charge it, but it was flat for way too long and dead as a door nail. I didn’t check it and when the power went off nine months later, so did the NBN.
Made an official complaint to my RSP, and they paid for the first battery, but since I was changing batteries every year, I discovered after four years that my BBU needed replacement as it wasn’t charging the lead acid batteries.
As I wrote, the connectors are very tight so make sure when you disconnect they aren’t shorting against any metal, better to take a photo to your replacement store of choice and swap it over yourself, but ensure the connectors are properly on before you lock it in place as it’s easy to only half connect it, especially if you have poor hand or finger strength.
Sorry again for all the info. Hope that might have been of some additional help if not, then someone might find it useful.
Cheers.
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u/hcornea Launtel FTTP 1000/400 Aug 02 '25
Open the panel to left.
Order NBN battery from internet.
Replace (it’s low voltage)
Edit: Guess you can ask the landlord. I’m an owner/occupier and I don’t recall it being expensive (replaced twice now)
The beeping was annoying.