No, I just don’t have much insight in this case, so I’m rather cautious .
These would just be my generic concerns apart from a fitting size … There are batteries with a different number of contacts, so the number is important. Where exactly they are placed and with how much space between them may differ, too, so that may be important. And which contact serves which function (sorry, no electrician here) should be important, too, that’s what I meant with wiring, I don’t know whether there is an established standard for that.
The working battery @HermannMeuth found has 3 contacts on the right (labeled) side.
As a company we advice against this. Keep in mind is that you will have to really proper test a battery to ensure for example that the thermistor has the same properties. It has to work well with the rest of the circuit in the FP1 in order to shut down the phone in case the battery pack starts overheating. Otherwise you will have a thermal runaway with catastrophic consequences…
Edit: The more sources I find the more I think that the Samsung EB-F1M7F comes closest to the FP1 battery. Dimensions: 50,5 x 60,5 x 4,45 mm. I wonder whether it would really fit the FP1 and if the temperature monitoring would work (the central pin).
Edit2: There seems to be two batteries that are identical apart from the number of pins. The Samsung EB-F1M7F seems to have 4 of them, while the Samsung EB-L1M7 has only three. Both of them are advertised for the Samsung Galaxy S3 Mini (different flavours admittedly).
The S beam battery looks ok-ish, but it’s also too short. Mind that the batteries could have a much lower capacity, depending on how much time ago they were produced.
I just clicked through the batteries on this page and found the samsung galaxy s3 mini one by chance. I think I got to that page by searching “smartphone batteries dimensions” in duckduckgo.
There are apps that can display the battery temperature. If it shows about 25°C on a freshly booted phone it should work and it should go up to about 38°C when you use 3G for a while (that’s my experience with the original FP1 battery).
When you let the phone lie in the direct sun, it should eventually give you a warning tone and shut down because of overheating.
thanks for sharing, HermannMeuth! I just ordered two of those vhbw batteries and I will try your solution.
Besides, I wonder if the temperature sensor thing is really a problem. There’s a temperature sensor inside the battery and yes, it provides the phone with the information about the temperature. But it would be a high risk to rely on the phone to shut off the battery (a software bug could prevent that from working) in case of overheating. So my guess (just a guess) is that the battery protection circuit takes care of that and just reports the temperature to the phone for additional safety an/or diagnostic measures.
Does anybody have reliable information on this topic?
I will receive one of those batteries tomorrow or on Wednesday and will report back. “Testing for thermal safety” will be done using the app DevCheck. At the moment it displays 27°C for my original FP1 battery, but it goes up to 39°C, when I use 3G and surf the internet for about half an hour. I will compare these values to the ones obtained with the generic HB5N1H battery.
Yup, this is mentioned four posts up in this topic. As far as I know, nobody has ever verified that those actually work (or that there were modifications for the FP1), and they don’t seem to be available any more either.