OTSC Sport did not start with 3.7 volt rechargeable battery

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Ich hatte meinen OTSC Sport über den Winter mit LI-Akku liegen lassen. Wollte ihn nun wieder aktivieren, leider war der Akku nun tiefentladen (unter 1 Volt). Also hab ich einen neuen 3.7 Volt Akku (14500 Li-Ion Akku 3,7V 900mAh TrustFire mit Schutzelektronik) gekauft. Mit diesen lässt sich der der OTSC Sport aber nicht starten. Akku hat ohne last ca. 4.1 Volt.

Mit einer 1.5 Volt Alkaline Batterie startet er aber sofort beim Batterie einlegen. Ist zwar OK jetzt kurzfristig, aber eigentlich möchte ich lieber Akkus nutzen, wegen Umwelt und ist so in der Anleitung auch empfohlen.

Gibt es da bekannte Probleme mit 3,7 Volt Akkus? Ist irgendwas kaputt im Tauchcomputer?
Kann man den OTSC Sport auch mit 1,5 Volt USB aufladbaren LI-Akkus betreiben?
Starten tut er damit und Aufladbar sind sie auch. Allerdings weiß ich nicht ob die Akkustand anzeige da überhaupt funktioniert, da die vermutlich kaum Spannungsabfall über die Zeit haben.
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I had left my OTSC Sport with LI rechargeable battery over the winter. I wanted to reactivate it, but unfortunately the rechargeable battery was now deeply discharged (below 1 volt). So I bought a new 3.7 volt rechargeable battery (14500 Li-Ion Akku 3,7V 900mAh TrustFire). However, the OTSC Sport does not start with this battery. The rechargeable battery has approx. 4.1 volts without load.

With a 1.5 volt alkaline battery, however, it starts immediately when the battery is inserted. This is OK for the short term, but I would actually prefer to use rechargeable batteries because of the environment and this is also recommended in the instructions.

Are there any known problems with 3.7 volt rechargeable batteries? Is something broken inside the dive computer?

Could the OTSC Sport also be operated with 1.5 volt USB rechargeable LI batteries? It does start with them and they are also rechargeable. However, I don't know whether the battery level indicator works at all, as they have virtually no voltage drop over time.

Firmware: hwOS tech 3.21
Danke / thanks

[jb2cool]

Check the physical length of the new battery you have against the old one that you took out. You may be able to revitalise the old battery in a stand-alone charger rather than trying to charge it in the computer itself.

[heinrichsweikamp]

I also think that the battery does not make contact. If a 1,5V battery works, a 3,6V battery will work, too. Anything between 0,9 and 4,2V is fine for the OSTC sport.

regards,
Matthias

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Yes your right it is a contact problem on the + side.
I tried different bateries and only one worked with a little tip on the top. So I tried soldering a small tip on the 3.7V Li rechargeable battery and now it starts.
Not sure if this is a good solution but I am going on a trip in 2 days.
The 3.7V Li battery is 1 mm longer than the normal AA cell, with the soldering tip it adds 0.5 mm more ... hope nothing gets broken when I close the battery compartment.