In this community and on the Roon forum there have been several questions over time about the Vivaldi backup battery:
Hi Erno,
The Vivaldi range uses a battery backed RAM/RTC to store unit settings, such as volume, balance, filters etc. It also stores the serial number of a unit, and with the Vivaldi Clock it stores the clock calibration data. If the battery is drained, these settings and data will be lost from the unit. This is where a Vivaldi Clock can show “CAL” on the display. None of these stop the Vivaldi DAC, Clock or Transport functioning normally. With the Vivaldi Upsampler, some aspects of the streamer need a valid serial number to fully boot (such as the Roon Ready module).
At the time Vivaldi was designed, there was no suitable battery-less non-volatile RAM available. By the time we had come to design Rossini, suitable RAM was available so was designed in from then on. This includes Vivaldi Transport II, which uses non-volatile RAM for unit settings.
The battery is not drained while the product is powered on or in sleep mode, and is only used when the unit is fully powered off. However, even switched on or in standby, batteries have a finite lifespan, impacted by things like operating temperature. We have been using this particular part since before Scarlatti, and historically they have regularly lasted >10 years, so we were confident they would perform the same in Vivaldi.
The battery is not user replaceable, and does require a service technician to change. Should a Vivaldi unit lose its settings when powered off, this can be easily rectified locally by a dCS service centre / technician, which your dealer will be able to facilitate.
Thanks James for your thorough reply! All questions fulfilled 
Thanks James, this is very helpful and confirms in my case there was a higher drain of the battery when I had switched the systme off for longer time periods. In future I will leave it on standby and hope that this will not shorten the live of other components. It would have been great if the battery with the higher mAh would have been used for myreplacement, would have been no problemto pay the higher price for it.
I still think the battery could be changed by someone who has some experience with electronic parts, however the lost settings of the serial number cannot be done without special dcs know-how.
A rational hope. On the other hand is replacing the battery less costly than a new ( say) control board? I think I can make a good guess 
some info for your guess Pete.:
I paid for the service changing the battery through the distributor GBP 1008.- Maybe the control board is not much more expensive. To be fair dcs discovered that a few pixels on the display of the upsampler did not longer work and I agreed to change it. The invoice does not show separatley the service for the battery and the display.
Anyway it would have been only a tiny expense to get the battery with 3 times higher capacity and much longer life time, but at that time I had no clue what needs to be done. Thank to this threat I know more today and can be more specific.
Interestingly the upgarde of the upsampler to V2 in 2007 was GBP 1 500 pounds, so actually the battery is cheaper than a new control board,
Wolfhart, the upgrade to the Upsampler Plus involved a change in the Mosaic Processor (compute board), not the Control board.
Also, based on what you’re saying, I’m guessing the more significant cost to during the battery servicing was the display replacement, not the battery or the service cost?
Anupc, the invoice did not split it up and the distributor did not give me a cost estimate. Anyway, changing the battery in a Rolls Royce will always be more expensive than in a no name car 
This may be so, but this is more a function of the poor design of the Rolls Royce, the scarcity of technicians, and the desire of such technicians to further bilk the RR owners.
All of these factors are less present when dealing with dCS directly…
; )
fully agree, but they don’t allow that anymore, even when you are living close by
Agreed. Thats just the nature of things.
That said;
James is spot on about the battery they use. My Vivaldi stack is over 10 years old, I’ve never had it completely powered down for more than a couple of days in total, ever; the battery is still perfectly fine (*touch-wood*!! 
).
would have been nice if dcs had written it in the user manual **not to power it down, then even the battery with the lower capacity lasts forever.
Probably for an extended time as I don’t expect any battery to last forever.Entropy will apply.
I do understand the rationale behind this from a manufacturers standpoint, but looking at it from the consumer side I would say the following: you say it can be easily rectified and looking at it I see it is less than 10€/$/GBP for the part, but the fact of the matter is that any dCS user has to pay a quite substantial fee just by submitting the unit to service. Even more than 10 years ago I remember that just sending a unit in would cost GBP600 at that time to look at it regardless of the actual problem (and without shipping). This will now probably be even higher. This probably reflects also the time and costs of troubleshooting and the standard soak test afterwards, but still sometimes it seems like quite large amounts to spend when effectively a battery or a few capacitors get replaced of relatively small value.
It also seems like this battery is the reason for the CAL message on the clock, so in essence the aging/draining of a low cost part will lead to a necessary expensive recalibration?
It used to be that the control board was essentially the same in every series and it is programmable to use it in a specific series. Classic series used to have EEPROMs or I believe programmable Lattice parts before this battery. So does this mean that newer control boards with battery-less non-volatile RAM can replace the control board in Vivaldi if need be?
Even if that were the case this would not necessarily save money. It may even increase the cost. Much of the same processes like shipping, post work testing etc. would be the same. Any replacement board would bear a cost presumably exceeding that of a battery.
As dCS no longer deal directly this may not apply in the same way but when they did there was a minimum fee for all work outside of warranty repairs. Presumably this may now be bundled into the end fee charged by the dealer. I cannot see a workable way out of this given the existing business structure. So I am contemplating a multi box battery replacement at some point 
. I think that dCS and distributors should fix a reasonable price for what is a standard maintenance procedure and not a repair should they not have done so already.
BTW I would not take whaus’ cost quotation at face value for other customers’ purposes as there were further repairs and parts involved. There may also be a question of shipping wherever he is.
Yes, I agree. Given that the battery is prone to fail at some point, and easy to replace it would be nice if dCS and their distributors devise a reasonable price policy for the replacement of this specific part, especially in the case of three/four-stack owners. These are also in Scarlatti and Paganini/Puccini I believe.
After the battery had failed in my upsampler which is about 10 years old and had an upgrade in 2017 I was afraid that my battery in the Vivaldi clock would also go soon. The DAC I had just upgraded to Apex and so it should not have a battery anymore. After reading all the comments here I thought it should be not an issue to change it on my own.
So I ordered the M4T32 Battery with120mAh from ST Microelectronics, not the one dcs is using the M4T28 with only 48mAh. So I guess I will have at least double the life time with the higher capacity one. Price was £10.-. All ther tools I needed (see pic below) I had already, except the special antistatic gloves costing £ 6.-.
The most difficult procedure is how to find out how to open the enclosure of the vivaldi clock. I could find anything in the web, so I just tried to find it out. At the end it’s easy. Clearly first you have to disconnect the device fully from the power,
To open the top you have to first start at the underside. You have to open with a Torx key No T10 the 8 screws which have a black rubber ring. Now you need a bigger normal srewdriver to take out the srews underneath the srews you had just taken out. If you loosened them you can draw them out. They are very long, because they are fixing the cover which you have to move.Then take out the 4 top torx srews on the pack of the device. Now you turn the device around in the normal position and you can move the cover backwards. You can admire the nice layout and the yellow original battery M4T28 will right away catch your eye. You can also see on the pic beneath one of the long srews which are holding the cover. They have been taken out when the device was turned to the other side.
Now you would think you can easily change it, but wait a minute. If you just take the battery out with the extractor, the chip has no power, neither through the outside power nor from the battery. All content gets lost and you cannot load it up on your own and you have to send it to dcs.
So the tricky part is similar like changeing the 12V Battery in a car with a lot of electronic. In this case you have to supply some 12V outside power to the battery connectors, and only then change the battery. This way the car system has power all the time and the electronic did not loose any storage.
So on the dcs clock I connected the device after having opened the cover to the 230V outside power, made sure that all high voltage cables in the enclsosure are safely connected, switched the power on and only then pulled out with the isolated extractor the yellow battery. Clearly at this stage you should wear the gloves. Then I grabbed with the extractor the new battery, made sure it is aligned in the direction like the old one,checked wheter the tiny four contacts of the battery are exactly above the holes of the chip ( use a torch to make sure) and pressed it carefully in. STM says you need about 9 pounds fo move the battery out and 12.5 pounds to insert it.
I disconnected the external power again and build the enclosure together.
All is working perfectly now again, no memory has been lost, cost £ 20.-
I would not recommend to do it if you have no basic experience repairing electronics and opening and closing the housing is not simple.
I know now when the upsampler loses again its battery power how I can fix it. But probably there will be a new Vivaldi system then. But the value of your used equipment with an upgraded higher capacity battery will be higher and one does not have to be afraid to swith it off totally when it is not been used. Would have been nice if the better battery would have been installed by the factory or during my repair of the upsampledr the £5.- more I would have happily spent. Then it would really last over the lifetime of the device but cost savings are everywhere …
Good stuff Wolfhart! For people with the right skills this makes perfect sense given that this is by definition only relevant for units long out of warranty.
But caveat emptor! This looks simple and it is simple, iff you have the right experience. Rule-of-thumb: if you don’t have an anti-static mat (or don’t know what it is), move on!
Undoing Torx fasteners? I’m already out of my depth .
Seriously, be aware of the Dunning-Kruger effect and, as others point out, do not attempt this unless you have ( rather than think you have) sufficient real life experience in this field.
