Is it OK to replace the CMOS battery?

We just got a Balance 305 and looking around, I see a lot of mentions about problems with the battery dying and causing an issue. We haven’t put the device into service yet but can we replace the CMOS battery to be on the safe side or would that cause issues?

the problem you might find is that when the cmos battery dies or is removed the cmos settings get reset meaning the display doesn’t show anything but squares and the boot order gets messed up (this is on the older models). The password though remains so you can’t change those settings back.

It would be useful if peplink could share the password for the bios as it would allow a lot of the older models to be brought back to life.

What is considered older models? I have a Balance 305 HW 2.

So if a battey dies, it often causes a thousand dollar piece of equipment to be unusable? That not sound right.


As long as you keep it in warranty with Peplink you can get it replaced as an RMA.

That’s a horribly consumer-unfriendly practice. Peplink extended warranties are not cheap. Batteries are. An end user should be able to replace a CMOS battery - a practice that takes seconds and requires no special skill for most products - without it effectively bricking their device.

I wonder if there is a way to provide a continuous power source at the right voltage while making the swap so it never loses power?

That’s what I was also wondering.

What if you replace it while the unit is on – does that make any difference?

I bought the 305 for home use and I cannot afford to buy one new but I still do not like the idea of a $1 battery bricking my system. I would imagine that if a company spent 3k on a system and it stopped working and they found out that it was due to a $1 battery, they would ask their team to find another solution. But what do I know.

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Not necessarily true. I have replaced the battery on a 580 and it boots up perfectly fine. Its been a few months since I started it up, but I don’t think it will have an issue if I do.

The issue @james.webster1, is referring to is that the physical display on the outside of the device will most likely show squares on it, and no longer function correctly by removing that battery. Also on older models it has the potential to cause a boot issue.

I was already experiencing issues on my 580 device (display/temp do not work, and fan is always on high) and it was out of warranty, so I did not mind switching out the battery to see if it would help with another potential issue I was having at the time.

Were you able to resolve the fan issue? Mine is always on high. I bought a new fan that will be here tomorrow to trade it out. There is a dial on the motherboard. I’m not surenehst this or if it would dial down the fan. Mine is spinning around 7000rpm nonstop and very loud.


Good point, the 580, 380 and 305 (HW which can only run 6.3.4) were the models I was thinking of. After a battery change you can get it to boot by connecting a serial cable and skipping the boot selection option. The boot order, serial config (for the LCD) can’t be changed unless you manage to figure out the password for the bios.
The newer models may have a different bios and so boot after a battery change but I guess the serial control for the LCD remains the same.
The older 710 doesn’t even care if a cmos battery is inserted as the display and boot order are default.

I have the HW2 on the 305 running 8.1.2. Does that mean that I can replace the battery without any risk of bricking it?

Or would just waiting until it dies and then replacing it also work with this version?

What this is really about, is consumer “friendliness”. A $1 battery going dead and needing simple replacement should never cause a customer to lose access to their unit, nor should purchase of an extended warranty ever be required in order to do something as simple as allowing a customer to swap out an accessible battery. So… Peplink, please address this. What simple, customer-friendly solution do you propose for this?

No the 2x 580’s I have both have this issue. I have only replaced the battery on one of the devices, and not the fans. They both spin on high, one of the devices has been powered down for a while as the fan sounds like a jet plane taking off when powered on. Only thing I can think of is to disconnect the fan, or swap it with a replacement that can be manually adjusted. I just haven’t given too much time to fixing older equipment as I have already replaced most of it with stuff under warranty.

Mine is running 8.1.1 currently.

You can try @james.webster1’s suggestion of a serial cable/console boot before and after replacing the battery to ensure the device is still working. That’s a little more technical and might require searching the forums for how to do that exactly.

@Madcodger - A simple solution could be a bios firmware patch that be loaded straight to the machine to fix this issue. Unfortunately, a lot of this equipment is outdated, doesn’t receive normal updates, and most likely out of warranty, so the time spent to fix the issue is most likely not worthwhile.

Agree that a bios firmware patch would help. Going forward, a great idea is for companies to never, ever design hardware that can be bricked by something so simple. And when they find that they have and can address it in a relatively easy manner, that they do so. And yet that often doesn’t happen.

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