Monday, 3 February 2014

Varta power accu 'ready 2 use' (or not)

These AA rechargeable batteries come from a 'Brico' hardware shop in Brussels. The packaging reads 'Ready to use' and I was therefore expecting these AA NiMh to work out of the box.

My first reflex as a battery tester was to use the 'Ultra Smart Charger' (more info here) to discharge whatever energy was stored on these... and to my surprise there was none.

The battery voltages were 0.66V (cell 1) and 0.71V (cell 2) which meant they were both empty.

After three charge/discharge cycles I managed to revive them (but my ultra smart charger would never stop charging it) which means they're all right but were probably damaged (left for too long on the shelf?).

Anyway, the third discharge cycle provided the following results:
  • Capacity: 1999mAh / 2499mWh (@0.9V cut-off) which is fair but still 300mAh below what I'm reading on the packaging
    The charger and batteries I received from
    Varta's customer service
  • Internal resistance: 43mOhm is excellent for AA batteries and will provide good results for high drain devices
  • Self Discharge rate: all tests above were done on freshly charged batteries. The fact that they came fully discharged probably means they stayed a long time on a shelf... and will probably not perform well on low drain devices.
    Note: I have fully charged these and will test them again in 6 months and a year, stay tuned
  • Cost: these come from a pack of two from a hardware store. You can therefore only expect a prohibitive price.

  • Customer service: I contacted their customer service to check what they could do about these deffective batteries. I received an excuse message two hours later. The next week I received a charger (batteries included) and two packs of 2500mAh batteries in my mailbox. Their customer service is excellent.
    Note: I will not be using the charger they sent me as these are notoriously known for destroying NiMh batteries (they have no control system and will overcharge your batteries if you don't stop it).More info on charging NiMh batteries here.
Stay tuned as I will be testing the 2500mAh replacements I received very soon !