What type of battery does your CGMS transmitter use? Are you happy with it?

I would like to know more about what type of battery your CGMS trasmitter (wearable component) uses. I have a few questions:

1. Are the batteries disposable or rechargeable?

2. If they are disposable, how are they replaced? Are they "coin cell" batteries? Does the replacement compromise water tightness?

3. If they are rechargeable, are they recharged by induction or ... how?

I'm interested in learning about the Dexcom, Abbott/Freescale Navigator, Metronic/MiniMed Guardian RT, or any other (are there others?).

Most importantly:

1. What would you like a new product, in final design stages, to use: disposable or rechargeable?

2. If disposable, what type?

3. If rechargeable, what method?

Thank you!


I have the minimed CGM and the transmitter does not you batteries it has a docking station that charges it and the docking station uses a aaa battery that I have yet to change and I got it a yr ago.

The Dex transmitter does not require charging. You wear it for a year or more and then you get a new one - I suppose that makes it disposable… I’ve had mine for 8 months, use it everyday, and have been fine. The receiver, however, does have a rechargeable cell inside. It comes with an adapter to plug it into the wall. I charge mine while I sleep every 3-5 days. I can’t speak for any product besides Dexcom but I highly recommend it - the transmitter is small and sits close to your skin so it rarely gets in the way, and you never have to forgo BG readings to take time to charge anything.

The MM transmitter has a rechargeable internal battery. When the battery gives out, you have to get a new transmitter :frowning:

There is a small blue recharging unit that takes a AAA battery, which you can replace when it goes dead – the unit blinks red at you when it needs a new battery. I don’t know if it’s by induction, because I don’t know what that means!

I have no preference for disposable or rechargeable – they both have their pros and cons. With disposable, you don’t have to buy a new transmitter every year, but disposables do contribute to environmental waste problems.

Induction means theres usually no metal contacts in the charging base and you usually drop it into a base…it uses eddy currents to charge the battery. A crude way to tell if it is induction (after looking to see if there are metal contact points)… is grab the rechargable device and hold it slightly above the charging “dock” You sometimes can feel the induction current field, It will tend to pull or push the device into the charge dock… (A lot of electric toothbrushes use some variant of inductive charging… the original interplak did…

Personally I like the idea of rechargables but the advantage of long term use disposables (the dexcom uses a long term use disposable battery for its transmitter use), makes it a lot more convienent and you dont run into the problems with the charge life shortening due to prolonged use/charge cycles… For the reciever, a user replacable rechargable pack even if its behind a sealed screw-lock door. makes a lot of sense and is enviromentally correct…and relatively convenient.

I use the Freestyle Navigator.

The transmitter uses a 356 coin cell battery. I’ve tried other brands, but Abbott recommends Renata and those really do work the best in it. Other brands will sometimes result in a battery failure.

Some pod users will use pod batteries in their Nav transmitters, but since the battery life reader functions on a timer feature only, I would rather know for certain that I’m putting a fresh battery in. It will always register that the battery you’ve put in has 100% life…that’s insanely stupid to me, as the receiver doesn’t treat its Energizer AAAs that way.

I’m fine with using a disposable battery in a transmitter so that I don’t have to take it off for the time it takes to charge the transmitter.

The water tightness issue has not affected me in the 2 years I’ve worn the Navigator, but I do know that every time I phone Abbott, they ask if I’ve noticed any cracks in the transmitter housing that could lead to water compromising the transmitter. Hasn’t been an issue for me. I open the battery compartment door with a penny (much like you would on a Minimed or Cozmo pump). It has a rubber o-ring that seals around the door.

Hi Melissa,
Thank you. I was expecting the “rubber o-ring” reply in some of the responses, but apparently only the Abbott has a replaceable battery. It certainly is nice to have the system indicate that the battery is at 100%, and so on.

A couple of questions:

  1. How many days does the battery last?
  2. Do you carry a few spare batteries at all times?


Thanks Jake.

Yes, induction is like “wireless” charging. The disadvantage is that it requires recharging only when you’re not wearing it. Plus, it would make the transmitter more expensive and bigger.

Yes, the convenience of never having to replace or recharge batteries is nice. Good idea for the receiver too.

Thanks for the response. How much does a new transmitter cost?

Hi Natalie,


Did you mean to say that the MM transmitter has a “disposable” (or rechargeable) internal battery? So you buy a new transmitter when it gives out?

Med464rescue seems to think the transmitter has a docking station for recharging. Or do you think he means the receiver?

If it’s disposable after several months, I have a couple of questions:

  1. How long does it last?
  2. How much does a new transmitter cost?


Thanks for the response.

Natalie seems to think it’s a disposable transmitter after several months of use. Or does the transmitter have a docking station for recharging?

Does the transmitter have metal contacts for the docking station? Wouldn’t that make it not water proof?

Thanks again,

Another idea for a inexpensive and relatively environmentally correct way would be to use Zinc-Air hearing aid batteries in the transmitter… Since a sensor is used for roughly 7 days. it should be roughly long enough if you dont pull too much current at a time to use one or two batteries per sensor for a weeks worth of power and theres no heavy metals involved… The convienence of not having a rechargable battery that can go dead, and the ability to swap out the battery if it dies without taking off the actual sensor…(if designed right) immediately would be great

A rechargeable internal battery. And yes, when the internal battery gives out, you throw it away and buy a new one. It’s supposed to last about a year, and the new transmitter is not cheap – I think it’s about $500, but I could be wrong. I would much rather have a disposable battery and have the transmitter last a long time, but I was originally attracted to the idea that it communicated directly with my pump, whereas with the Dex, it would be another THING to carry around.

Maybe these things will get better in the future, just like meters have!

Natalie ._c-

I can get about 3 5-day sensor wears out of a battery. Sometimes more. Sometimes less. They ship you 2 Renata 357s in each box of 6 sensors, and Abbott is happy to send you more free of charge if you call and request it (though I don’t think they make that known to most users).

I don’t carry spares with me, no, but I do usually change the battery when the battery life indicator shows in the 25-50% range. The battery cannot be changed while the sensor is in use without disconnecting or you will have to initiate a new warm-up period (which is how one ‘restarts’ the sensor). I have a video on youtube on how to change the transmitter battery: http://www.youtube.com/watch?v=CMFu6iS3BZs

Thank you, Melissa, Natalie, Jake, med464rescue and ClumsyChemist! I’ve learned a lot. I’ll study all of your responses, input & suggestions, and see what we’ll adopt for the Pancreum products.

I agree with Melissa, I also use the Freestyle Navigator (I actually got it after watching Melissa’s video on Youtube, seeing how easy it was to operate) I like the fact that it does not use a rechargeable battery, meaning that the battery will not die in a year or so which would lead to another expense.

Btw, Melissa, do you get Hypo warnings and readings if you sleep on top of the sensor? say its on your arm and you lay your head on it?

Sorry, I also have noticed how old this thread is, oops