We have recently found out that in a batch of classic bttns produced and shipped between June and August 2016, there is a chance that certain AA battery makes/models can start heating up upon inserting them. Although it is very rare, the chance is there and we want to fix it.
Mechanical cause:
The issue is caused by a mechanical problem in the metallic battery contact sheet used in classic bttns shipped between June and August 2016. The issue is not in the bttn electronics.
The battery contact sheet can in rare cases, with some battery manufacturers' models, simultaneously touch both the - pole and the + connected body of the battery. This causes the battery to short circuit and heat up when you insert it.
- Not all batteries are affected. For example Duracells have such design that short circuit is not possible.
Checking if your bttn is affected:
Open the battery compartment and look at the metallic battery contact sheet. If the two contacts closest to the micro-USB connector are clearly pointing towards the center and have a J-shaped bend at the end, your bttn has the issue. See photos below.
Options for fixing the issue if your bttn is affected:
1) Apply a simple mechanical fix yourself (see attached pdf document for step-by-step guide with photos), or
2) Write us at support@bt.tn, stating your order number and address, and we will send you a new battery contact sheet as replacement.
We are sorry for the inconvenience and will naturally ship the replacement part free of charge.