Tandem tslim DIY replace battery?

I have a tandem tslim, and it shows malfunction code 4-0x2072 today which is bad battery. I reset the pump and it shows same code again after several hours. I am out of warranty, so i cannot just send it back for a replacement. I cannot afford a new one.

Has anyone replaced the rechargeable battery yourself? How? Thanks.

I’ve done it on computers and cell phones, and I assume the pump would be similar. There’s no seams or screws on the body, so it must be accessed by removing the screen with the help of a heat gun, a suction cup, and a playing card or spudger. There are plenty of videos on YouTube showing you how to do this on a phone, you won’t find anything on a t:slim in particular. I have absolutely no idea what the pump looks like inside, but electronic connections usually snap together like Legos in things like this, so I imagine it wouldn’t be too difficult to figure out.

The problem is, you can’t just buy the replacement part off of eBay. Where would you get a new battery to put in it? Tandem certainly wouldn’t sell you parts, it would be too big of a liability. You’d have to buy someone else’s old pump to strip it for parts, and then risk possible damage to both while attempting the repair. You might as well just buy a used, but still functioning one and use it instead. Maybe Tandem will do out-of-warranty repairs for a reasonable cost? I really don’t know.

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Next time, i won’t buy a rechargable pump. It sounds cool when i bought it, but now i realize that all rechargable batteries have limited life. Once the battery is dead, so is the pump.

Have you contacted technical support, even though out of warranty ? Maybe they would offer replacement at discounted cost or have another solution.

I contacted technical support, they said I have to buy a new one.

May as well crack it open and share images of the inside - I would be interested to see them!

Although as Robyn_H has said you won’t be able to buy a battery specifically marketed for the pump, it almost certainly uses a commodity part that will be available somewhere; Tandem isn’t making enough off these to warrant having cells specifically made for them.

Of course it’s also possible that there’s nothing actually wrong with the battery cell itself, and the fault is with IC that monitors the battery.

I found a link recently that has photos of inner components. It seems that tandem submitted documents to FCC. https://fccid.io/CWO-TWM001/Internal-Photos/internal-photos-1721032

I found that same battery is selling for $5, but it has only one terminal instead of 2 as shown in the photo. I cannot crack it open, i may find a iphone repair guy to open it for me.

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Is your pump an original Tslim like the photos or an X2?
Those photos are comically bad, it’s hard to believe FCC think they are good enough to publish. It’s only barely clear enough that the battery is a 501745 LiPo cell, unusually it says it’s 400mAh, most of these on the net seem to be 360 mAh.

At worst with some soldering skill it should be possible to replace the bare cell, even if the pump doesn’t use the standard snap in connector most of the batteries are sold with. It will either work or not work, if it powers on I would personally be happy to use it for myself (not saying you or anyone else should).

If you do end up getting it cracked open I would be very interested to see some better quality photos, particularly of the battery and the BT chip and antenna.