If you need to replace battery for CED 7000 timer [1] you can either buy a HLP 443450 3.7V 800mAh 2.96Wh accumulator [2] or dedicated inexpensive Power Bank [3] that contains two accumulators inside – one for quick replacement of the timer battery and the other to charge timer over the USB cable – this way you can also safely carry a backup and replacement power source at hand :-) One thing that could be improved here is using both accumulators in the Power Bank so capacity is doubled and both are always charged – that should also prevent self-discharge below safe point of the unused unit.

If you are happy user of DSO QUAD pocket oscilloscope from Seeed Studio [1] then probably after all those years you need to replace the accumulator. Because stock model PL384070 3.7V 1000mAh is not available anymore you can safely use CL404070 3.7V 1300mAh that is only 0.2mm thicker but it also fits the scope very well and you gain 30% capacity. You only have to solder the plug from the old accumulator. Enjoy :-)