Has anyone else had their t:Slim experience the power source error that fools the pump into thinking the battery isn’t charging or the battery level jumps from full to basically dead? My pump has had this error three times in the past 2 years I’ve had it and Tandem tells me it’s a very rare error.
My pump shut down on Monday morning because of this error.
I have been on a Tandem since ~April. It has occurred 3 times. Each time it occurred, my pump was showing charged at 90-95%. After plugging it in (say before a shower), I returned to the pump and it showed the pump discharged at anywhere from 0-15%. I have ignored the issue each time, and the pump recovered to show 100% charge within maybe ~30 minutes. My pump has never shutdown, but has alarmed low battery.
Since the three occurrences, I have allowed my pump to discharge across several days to 25%, then charged, and now only charge when my pump displays <85% charge. No issues since.
Thanks for sharing. I tried changing outlets, but it completely shut down before the requisite 30 minutes which is supposed to clear the error. Plugging it into my laptop a second time magically fixed it.
It’s been a while since I’ve had an issue with charging, and I believe it was when I was using a Dexcom G4 CGM rather than the G5 (I know you’re referring to your pump but this might hold true here as well) but tech support suggested I use the charging cable that came with the device. I generally use whatever cable has the right jack and don’t have issues - but it might be worth a shot to try the one that came with your pump if you’re not using it already. Having said that, if your pump is shutting down with little or no warning, I’d look into getting a replacement if you’re still in warranty.
I’ve never had an alternate cable to charge with, so it’s always charged on the original cable and wall adapter. Tandem just sent me a new wall adapter, so we’ll see if that keeps it from doing that error again over the next year. 
The Tandem rep said if it does happen again with the new wall adapter, that they’ll look into replacing the pump.
Thanks for sharing - it’s always good to go through the process of elimination. I wonder if your doctor might be able to intercede to get a replacement without having to see if it happens again? I’ve rarely had issues with my devices but when I have they replaced them quickly.
I think if it does happen again I’ll demand a new pump, either through my doc or directly from Tandem. I did that with Medtronic when one of my Paradigm pumps kept giving me motor errors and the rep was asking me to do basic troubleshooting I’d already done. Tandem’s customer support by comparison is much better.
Tech support told me that a loose/intermittent connection between the pump and charging cable can make the battery seem to lose charge, even when it’s fully charged. Switching to my extra, unused Tandem charging cable solved my problem.
I experienced this problem yesterday. Really awful to suddenly lose pump (and it ended my Dexcom session as well). Customer support got everything up running again after a half hour charge, during which the pump continued to jump between 5% and 100%. AND I had already charged it while in the shower that morning–using the tandem cord–and with what had to be more than 50% charge. I was told this is rare and that “if it happens again” they will have to look into replacing the pump. If it happens again??? This doesn’t seem like good support to me. If this is in fact a more regular problem I’d like them to be upfront about this.
Hi @elizabethm I haven’t heard it to be a regular problem but battery and charging systems fail. If it doesn’t level out. If you see the percent charge move in an unexpected way, I would advise to call them back and arrange for a new pump. Sometimes help-desk needs help in the form of guidance but it’s ok to insist as well. Good luck 
From what I understand from speaking with Tandem Technical Elizabeth @elizabethm , this is not a common issue with the Tandem pumps. As you see, this Topic has been posted here since August 2019 and only two Members have noted this issue; and on a daily basis, we usually see about 3.000 people using/reading postings.
I have not had a battery/charging issue with my Tandem t-Slim, but I did experience a “Data Dump” and “Shutdown” last June. Tandem Technician Marty helped me through that and got my pump back working through the internet by doing a reset and reinstall procedure. I was asked to keep in touch, and if issue reoccurred, a new pump would be sent immediately. It is my belief, that Tandem stands closely behind its product and will keep the user’s safety first.
Hi @Dennis . I’m not familiar with a data dump and shutdown. Logically it sounds like something that would happen if someone didn’t upload their pump data periodically - is that what happened? I like to keep caught up on terminology. I’m guessing that’s a rarity since I haven’t seen it before. Thank you and take care.
My t:slim has gotten really warm even hot when I’ve used a phone cord. Doesn’t happen using cord that came with the pump.
Dorie @wadawabbit , the data dump is not affected by uploading to the Tandem cloud, tConnect uploads continuously. Thankfully, the tech reloaded all my data and history after pump repair.
The principal problem was a complete shutdown of my pump no insulin delivery. And I was on my morning walk, a few miles from home.
Henry @Hen51 many phone courds are the 4 wire 1996 standard . The Tandem and dexcom courts are 9 wire. Advanced data capability.
My pump doesn’t heat up.
Yikes! Thankfully you have plenty of experience and know how to handle the unexpected.
Since I stick to original cord – no heat either.
@Dennis if I didn’t say it before I’ll say it now - you have an amazing body of knowledge on not just diabetes but any number of subjects! If you said I’ve for gotten but do you/did you work in a scientific field? Your analytical skills are of the charts😳. Thanks as always for sharing your knowledge.
My pump once got really hot charging to my MacBook. I was told by customer support that its ok to charge to a computer, but that the pump has to “work harder” to do so. I’ve been using the Tandem cord and block since then.
Thanks, Joe. I was promised a follow-up from Tandem. In any event, and definitely if it happens again, I’ll follow up and insist on a new pump. I’d like to avoid that if this is just something that can happen if it gets below 50% or if it isn’t plugged securely into wall or something else that I could then work to avoid. What I can’t have is not knowing if my pump is going to shut down unexpectedly for no good reason.