Dexcom tech advice on receiver battery

Need some advice from the Dexcom and tech gurus.

I bought a spare Dex receiver (because these bad-boys are no longer available).

So I will have one just sitting around unused for possibly years until I need it.

If I don’t do anything with it, I am sure the rechargeable battery inside it will be crap when it comes time to use it. So I am guessing I should probably charge it on occasion, right?

Any opinions on the best way to keep a Dex receiver viable for a long time, even without using it? Charge it once-a-month? More? Less?

Don’t really want to use it until my current one dies and I have to switch over to it.

BTW, got it in pink.

Probably charge the same that you should with any other chargeable device…when the battery is nearly dead, or just died. That would be my guess.

So should I leave it on?

I wouldn’t think you would need to do that. Phones and other devices are continuously losing juice from the battery whether it’s on or off. Maybe flip it on once a month to see the charge? The battery lasts 6 months (I’m guessing this is the USED amount of time), so probably a year or longer unused before you may need to recharge it.

Just guessing here, so I may not be right. Of course, I’ve never tested it and I can’t really find any specific info on battery life for an unused (turned off) receiver.

Right! I can’t find any info either. Apparently it’s not a common thing. :grinning:

So I’m wondering if leaving it off and occasionally recharging is better. Or just leaving it on. Or once a month turning it on and recharging it.

I would leave it off and charge every 6-12 months. Try it at 6 months to check the charge level.

If you leave it off, the only drain on the battery is self-discharge which is usually around 2-3% per month on average for a lithium ion battery. Your battery self-diacharge may vary.

The thing that kills the batteries is the charge-discharge cycles so if you minimize the number of dischargea you will extend the life of the battery.


@Eric, it is not good to leave a battery full or empty. Ideally, you should charge it to full, then discharge it to 50%, turn it off, leave it there for a few months (maybe 4-5 months), then check on it, bring it to 50% etc.

Leaving a device with an empty battery is really bad. You will lose a lot of battery capacity by doing that. But leaving the battery 100% full (or even worse, charing all the time) is not that good either.

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So charge it up, leave it on until it gets down to 50%, turn it off, check back a few months later? Is that the scenario?

A bit awkward to go through it since I’m not actually using it. But if that’s what makes it last, I can do it.

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It is the best way but not the most convenient.

What I do most of the time is: I charge an appliance to 100%, then unplug it and keep on using it for as long as it convenient in the time I have, then leave it as is. So it may be at 90% or 80% or 70%. It is a compromise.

In fact, I actually simplified the process I had told you was best. The true best way is:

  • you deplete it until 10%
  • you charge it until 100% and unplug when it hits max
  • you do this cycle a few times. This will allow you to get the battery to charge as high as it can possibly be: each cycle increases it by 2-3%.
  • you charge it to the max again, then deplete it to 50%.
  • you leave it in that state while you don’t use it.
  • every few months, you deplete it to 10%, charge it to the max, then deplete it to 50% and leave it as is

That is the true best way. But it is a real hassle. I only do it when I get a new laptop, the first few days.

But since I’m not actually using it, is simply leaving it on until it depletes sufficient? I guess it should deplete at a somewhat slower rate since it won’t be getting signals or getting calibrations or alarming.

Give it 3 days.

FWIW - I just tried turning on an older G4 receiver (manufacture date on label of April 2013) that was in a drawer. Hard to say how long it was there and powered off in the drawer. A minimum of a year I would guess. It turned on with no issues. Appears to still be fully charged.

I also tried turning on a Seven Plus receiver (manufacture date of Nov 2011). Couldn’t get that one to power up (or charge) but maybe if I had the original AC adapter it would charge.

Interesting charging the G4 and G5 receivers. They seem to not generally like the higher output (2.1 A) adapters. Most devices work fine and simply charge at their proper power level. But these (generally) will simply not charge on the 2.1 A but will charge normally on a 1.0 A charger. Although sometimes they will charge on the 2.1 A. Curious. (And no - it is not the cable - lol. Not my first time around that block.)

Also - be careful with WHEN you choose to turn off the receiver as relates to ending a session. A power off soon after ending a session can kill your receiver. I lost a G5 receiver that way (11 months into the warranty so just under the wire and was able to get it replaced at no charge) and heard a few people on the forums who had this happen also. Normally the receiver is left on continously. Powering it down is not typical so I guess the testing on the power down was lacking. Anyway, best advice is to leave the receiver powered up for a few hours after ending a session and before you are going to put it away for long term storage.

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I am planning on not using this one until the current (old) one dies. So it will never have a session going. I just need to keep the battery viable for as long as I can.

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Hi Eric,
I too am saving a Dex G5 receiver as my spare. This was purchased July '16, dropped it and screwed up the left half of the screen, replaced it and stopped regularly using it Jan '17. Since then I have stored it slightly discharged with no special considerations for the battery. When I have taken it out of storage, it is definitely 100% dead after a few months but I have noticed no degradation of battery ability to take a new charge and only discharging a little bit after 1 day of use. I am pretty good about always having a charger around so I expect I’ll be OK using this old receiver as long as it will still hold a charge for about a half day minimum. It seems doubtful that G5 compatible transmitters will be available forever so I am not sweating it too hard.

I am going to try the methods outlined above and will see how many years I can get out of it. My gut feel is the batteries on these are pretty robust so I am expecting 10 years minimum life…let’s compare notes in 2027!