Is there a way to test transmitter battery life w/o starting a session?

So I have quite the collection of expired (low battery) transmitters that I’ve acquired in the past 1.5 years, but until the past 3 months I wasn’t RECORDING the transmitter numbers in my logs…so now I’m in the situation where I have transmitters that I’m unsure whether I’ve used them or not! I am now putting a black marker dot on top of used ones AND I’m annotating the Transmitter numbers in my log book when I have to do actual transmitter change-outs. But I have some previous transmitters that I’m unsure about. And you know how it goes, the more you look at them the more confused you become…so now I’m not sure if the ones I think are the old ones are actually the unused ones or not.

He’s due for a new transmitter soon as I just got the “low battery” warning on the receiver. If I remember correctly, that warning means I have 2 weeks left?

Anyway, I’m wondering if there is a Transmitter battery tester, or method of determining battery life w/o needing to insert it into a sensor and start a session?

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Just a thought, but maybe that information is recorded on the Dexcom servers, might be worth an email to them.

Based on the Dexcom Long Life Thread using xDrip, I don’t think you will be able to measure a voltage difference between a new and used one, so they might be your best shot.

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Where would I find this if it does exist? Online in the Clarity site somewhere? If so, I’ve not seen any info like this.

The receiver should be able to get it from the transmitter. From recollection when working with the Dex Rec and X2, you should be able to move the Dex Rec well out of range of the live transmitter currently being worn.

Then stop session on the receiver. If out of range, this will not really stop on the transmitter. The tranmitter id field on the Dex Rec then becomes enabled. Switch the Trans ID to the transmitter from the shelf you want to test. At this point, it no longer matters if the receiver is in range or out of range of the trans being worn as the receiver does not have the live trans id so can not communicate with the trans being work. Anyway once the trans id of the trans from the shelf is in the dex rec, you might be able to see the start date direct although possible might have to start session. Either way the start date of the trans from the shelf should now be on the dex rec. Repeat for how ever many trans you have on the shelf.

When done, take the receiver well out of range of the trans being worn. Put the live trans id back into the dex rec. start session. now when the rec comes back into range of the trans being worn, it should not impact the live trans but rather should simply join the session in progress.

In theory.


You would have to call Dexcom. CS would have to read all their call logs and see if you mentioned the Tx number, which they typically ask for when they diagnose a Tx issue.

I have sometimes called them to ask when we were on the road, when we had to reinstall the app, early on – but only for the current Tx #. I have never asked for the full history.


Sorry, what’s Tx?

nvm! Transmitter number! I got it.

Hmm. I am questioning this MO.

A new G5 Tx does not activate until bedded into a sensor. And, once activated, it does not shut off, so it has 3 months of life from there on.

[EDIT] I don’t have a fresh transmitter at hand so I can’t test the MO you propose.

@Michel - I have plenty of transmitters and can test it.

Note: I always keep the box that the transmitter comes in. The only time any transmitter is not in the box is if it is being worn or between sensor changeouts. I never throw a transmitter box away. When I take a new transmitter out of the box for the first time, I write with a Sharpie on the box the current date indicating the start usage date of that transmitter.

After a transmitter hits the 115 day mark (or whenever it stops working) then the old transmitter goes back into its box.

So, when I test the procedure, I will already know the status of the transmitter and will be able to positively verify the results are accurate.


So do you see a new transmitter that has not been started yet that way?

No, I don’t think you can find it online, but was taking a shot in the dark that if you email Dexcom, they could go through their records and tell you this info.


No - my thought was the new tran would not show up. But the problem is the really old has an actual dead battery so that doesn’t show up. This might work for the marginal case where it is perhaps the most recently used tran so the Dex Rec/App will not recognize it but the battery actually has physical life left.

So basically it is a useless procedure for any practical purposes.

You could try simply sorting the Trans alphabetically by Trans Id. That may give you what you want.

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Well at the very least I learned a valuable lesson…ANNOTATE, ANNOTATE, ANNOTATE…I have immaculate records with everything else…I just didn’t ever record the Transmitter numbers for whatever reason…but I am starting this now. If you keep old/new transmitters in different places, problem solves…but I happened to have them on the same shelf which isn’t a good idea unless they’re physically marked (as I’m doing now with a sharpie small dot on top when they’re used), but this is only a recent practice I’ve started IN ADDITION to the annotating of Tx numbers when I start a new one.

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Nice, so do we :slight_smile:

I do too. But since I didn’t annotate anything on the actual boxes…they can be confused with one another. My boxes and transmitters look exactly how they were shipped to me …so each transmitter is placed back onto it’s own plastic seating that they are “used”. The marking of boxes/transmitters is the key piece that I have been missing

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Is there a way to check the voltage on the trans I have that is not attached to the sensor? I have been having sensor failures and I’m thinking the problem may be with the battery even though the settings menu says it is OK, it has been used for only 6 weeks. When I put a volt meter on the two battery contact points it show .19 volts but I don’t know if this is a valid way to check voltage.

You may find this discussion helpful.

Do you have G4, G5, or G6 transmitter?

You might be able to read voltage using xDrip, while transmitter not connected. But doubt anyone has tried.

Looks like you’ve got a fully charged battery. If your volt meter/multimeter is set to 2000mV, you should get a reading of 019.

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