Freestyle Libre 2

[Robert459]

Helli said "...I usually insert my sensor a couple of days before activating it so it is no longer considered alien whilst it is working..."
At first I thought this was an interesting action, however the battery is designed to last for 8 days and starts working when you complete the circuit by assembling the sensor, whether 'started' or not. Therefore I can't support trying to extend the battery life by assembling the sensor days before starting it. Happy to be contradicted if wrong.

 

[Robin]

Helli said "...I usually insert my sensor a couple of days before activating it so it is no longer considered alien whilst it is working..."
At first I thought this was an interesting action, however the battery is designed to last for 8 days and starts working when you complete the circuit by assembling the sensor, whether 'started' or not. Therefore I can't support trying to extend the battery life by assembling the sensor days before starting it. Happy to be contradicted if wrong.

The battery can’t be designed to work for 8 days, surely, the sensor is designed to produce results for 14 days!
I’ve always put mine on at least 24 hours in advance, and I've never had a problem with it not lasting the full 14 days once started with the reader.

 

[trophywench]

Libre sensors last for 14 days, so sorry, I don't know what you mean.

 

[Robert459]

My apologies, I mixed up 8 hours with the 14 days. The battery starts working when you assemble the sensor and should last for 14 days. The 8 number is the number of hours that it saves data for. Sorry for the mix up. Just trying to help

 

[Robert459]

I was wrong. Happy to say it. Not happy that I was stupid enough to say it. However, I hope that you got the meaning that was trying to convey. L*ve to all you guys

 

[helli]

My apologies, I mixed up 8 hours with the 14 days. The battery starts working when you assemble the sensor and should last for 14 days. The 8 number is the number of hours that it saves data for. Sorry for the mix up. Just trying to help

The battery starts when you activate the sensor, definitely not when you insert or assemble it.
You could assemble and insert it 3 or 4 days before activating (which I have done when I misjudged the timing) and it still lasts 14 days after starting it with the app or reader.
In fact, the battery lasts longer than 14 days after starting. I use an unofficial app which gives me fourteen and a half days of data and then repeats the last 8 hours again and again and again ... ok, I don't know how many times it repeats. As soon as I saw the data repeating, I removed the sensor.

 

[Robert459]

I'm sorry, but if you examine the sensor assembly equipment, the "snap" completes the circuit and positions the "needle". From that point on, the battery is "on-line" and discharging, whether communicating or not I may have got my basic situational math wrong but the battery is connected from that moment on and is discharging. It may well last for a couple of days longer but isn't designed to; and shouldn't be expected to ?

 

[helli]

I'm sorry, but if you examine the sensor assembly equipment, the "snap" completes the circuit and positions the "needle". From that point on, the battery is "on-line" and discharging, whether communicating or not I may have got my basic situational math wrong but the battery is connected from that moment on and is discharging. It may well last for a couple of days longer but isn't designed to; and shouldn't be expected to ?

I have been using Libre as I have described for a couple of years and had no problem of the battery running out before the 14 days of data collection.
This is a very common approach - I didn't make it up - and, as I explained, it overcomes the problem I have of the first couple of days of inaccurate readings.
Unfortunately, if the sensor fails or falls off before the 14 days, I am not able to pre-apply the sensor. In these rare occasions, I notice the inaccuracies for the first day or two.

 

[Robert459]

Helli wrote "The battery starts when you activate the sensor not when you insert or assemble it"

If only physics worked that way. Batteries use a chemical reaction to generate charge. You connect the electrodes and the battery starts to discharge. Maybe one day cold fusion will meet you expectations ?

 

[helli]

Helli wrote "The battery starts when you activate the sensor not when you insert or assemble it"

If only physics worked that way. Batteries use a chemical reaction to generate charge. You connect the electrodes and the battery starts to discharge. Maybe one day cold fusion will meet you expectations ?

As an Electronic Engineer, I understand the chemistry and physics of their working and I also understand empirical evidence.
I bow to your superior understanding of the internals of the sensor applicator.
However, I have proven over 100 times that the battery lasts for at least 16 days after assembling the applicator regardless whether the battery starts at that time or later. I am not overly surprised by this because the battery usage will be very low whilst the sensor is collecting no data and is effectively dormant.
My years of Libre usage have shown that the 14 day count down starts when the sensor is activated and no sensor battery has expired throughout my usage.
Therefore, I find it it beneficial to insert the sensor 1 or 2 days before starting it with the app and have experienced no ill effects of doing so.

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[mark king]

Just to say I too add my FSL2 sensor one day before my existing one runs out then I activate my new one.
I do this in an attempt to get better stability/ accuracy from it as the manufacturer says new sensors take at least 1 day to stabilise.
So far I have had no problems with sensors suffering from battery errors or any errors for that matter.

Best

 

[Lucyr]

I’ve been using the sensors and reading forums on the libre for years and I’ve never heard of a case of someone saying the battery in the sensor ran out early, after they’d applied the sensor early.

 

[PattiEvans]

I’ve been using Libre sensors since they were first released and I had to buy them. I also apply the sensor 24 hours before starting it, except for the current one as I had forgotten to ask for a script, so it only overlapped the old one by 1 hour. I’ve never had a problem with it running out early. In fact I was part of a trial conducted by Abbott where they asked us to insert the sensor 24 hours ahead. So although they don’t specifically recommend it, they clearly know the battery will last.

 

[rebrascora]

I would imagine that those button batteries are not specific to Libre and will most likely last a lot longer than 14 days..... I would be surprised if they couldn't make it to at least double that with some juice left. If I had something which took that size battery, I would test it. I know the Dexcom sensors are only supposed to be used for 10 days but can be unofficially extended by at least another 10 days, so the battery is not the terminating factor. I would imagine the adhesive might be the limiting feature or perhaps the health of the skin/tissue under the sensor going too much beyond 14 days rather than the battery life.

 

[Robert459]

I bow to your experiential knowledge. Was just trying to explain how the sensor assembly works. Of course, I disassembled a used sensor to see how it works, naturally curious. The little white triangle thing that gets inserted into the sensor both completes the sensor circuit and contains the "needle". The battery is already present in the inert sensor but with an open circuit so cannot discharge/operate until the triangle is clicked into place. I have not checked out the battery's specs but was just warning that if stated to last for 14 days, extending that could be a risk. Bowing out of this thread gracefully 🙂

 

[Kaylz]

just because of the doubts I needed to ask and got this reply -

Dear Valued Customer,

Thank you for contacting Abbott's diabetes care division.

Following your enquiry received through a Facebook private message, we can confirm that the FreeStyle Libre sensor starts using the battery when the sensor is activated.

 

[BlueArmy]

just because of the doubts I needed to ask and got this reply -

Dear Valued Customer,

Thank you for contacting Abbott's diabetes care division.

Following your enquiry received through a Facebook private message, we can confirm that the FreeStyle Libre sensor starts using the battery when the sensor is activated.

Starts using yes, but it sounds like the snap connects it to the electrodes so some negligible losses will occur from that point on. And the battery life will be degraded by a bunch of other things also, the main one being ambient temperature. But as these devices are designed to work globally potentially in countries where the temperature effect is much worse than the UK i’d be very surprised if it didn’t last double the 14 days. Ultimately the battery is not the the limitation, the software is - the app will render it useless after 14 days anyway.

As for pain, my arm had a dull ache the day after for both sensors I fitted which is negligible but present.

 

[Kaylz]

Starts using yes

the disagreement was a member stating the battery was activated when the unit was assembled which Abbott have confirmed isn't the case

 

[BlueArmy]

there is a difference between connected and drawing down power. As soon as it connects you’ll get losses in the circuits - the device isn’t using power but it is draining the battery a very small amount. This is based on the previous comment that said the click when you insert it connected the battery to the terminals inside the sensor which makes sense. Abbott can’t have millions of devices sat on shelves for months on end with the batterys connected incurring these losses otherwise the 14 days are at risk.

This is the same “QA” process as getting toys for kids that have a little piece
of plastic poking out the battery compartment you have to pull out when you unbox
it to connect the battery up, however it doesn’t start “using power” until you flick on the switch.

 

[helli]

just because of the doubts I needed to ask and got this reply -

Dear Valued Customer,

Thank you for contacting Abbott's diabetes care division.

Following your enquiry received through a Facebook private message, we can confirm that the FreeStyle Libre sensor starts using the battery when the sensor is activated.

Thanks @Kaylz
The comment from @rebrascora reminds me that there is a hack to extend Libre 1 beyond the 14 days although it comes with an infection warning if you keep a sensor on for too long. I have read of some people extending their Libre to more than 20 days without any battery issues.