Battery Capacity Testing

This page contains data on the capacity of various aftermarket batteries for portable MiniDisc units.

This data is derived from user testing on small samples, and will not be 100% accurate! Battery capacity can vary from batch to batch, so your battery might not deliver the same numbers as found here!

If you have multiple batteries from the same brand, mark them in some way and write down the capacity for each battery, don't mix them. I've observed batteries from the same brand with a 50mAh difference in capacity.

Brand Photo Rated capacity Measured capacity (avg.) Batteries tested Notes
Jinmasi 1450mAh 1268.83 6
VapexTech 1450mAh 1247 2
Doublepow 1400mAh 1249.25 6
Original OTB 1350mAh 1223.5 2 Physical tolerances aren't too precise, one of the batteries needs a “firm” hand to get out of the battery compartment.
vhbw 1200mAh 1200 2 Seems to be the same as the Original OTB battery.

The testing done by u/rcboosted and u/Snoo-34188 was done using an OPUS BT-C3100 battery-charger/tester.

  1. Set the mode to Refresh
  2. Insert each battery and set the current to 700mA
  3. The unit starts discharging the batteries
  4. Press the Display button until you see the “Discharged Refresh” mAh counter (while discharging, this will be a counter counting up from 0)
  5. You can basically ignore the data from the initial discharge, as it depends on the charge-level of the batteries
  6. Once discharged, the OPUS starts charging the batteries again (it will do a total of three discharge/recharge cycles in Refresh-mode)
  7. When each discharge-cycle is done, note down the measured capacity

If the battery is new, the capacity should increase with each cycle. Keep running the refresh-program until the discharged capacity remains more or less unchanged. My batteries were used enough to have been “exercised” to full capacity, so the measured discharge was within ~5mAh between cycles. Now we're ready to do the final test:

  1. Take out the batteries
  2. Set the mode to Recharge
  3. Insert each battery and set the current to 200mA (this is a representative load for a portable unit during playback)
  4. Note down the measured discharge at the end of the discharge-cycle
  5. This will take a long time for high-capacity batteries. 1400mAh/200mA=7h!

For increased accuracy, making 2-3 measurements of each battery and averaging for each battery should yield the best results.

You don't need an OPUS BT-C3100 to contribute, but it helps. Any other testing-unit you have that can do the same job is welcome. Please write a how-to for that unit as well. For the numbers, new measured capacity would be:

((Current measured capacity * Batteries tested) + your results) / New number of batteries tested = New measured capacity.

…and remember to update the number of batteries tested!


  • You test two Jinmasi batteries to 1255 and 1247mAh.
  • There are four Jinmasi batteries already tested, for an average of 1273.5mAh.
  • ((1273.5*4)+1255+1247)/6=1266mAh
  • accessories/battery_capacity.txt
  • Last modified: 3 years ago
  • (external edit)