Saturday, 25 January 2014

Sanyo eneloop - pioneering NiMh batteries with a low self discharge rate







Manufacturer Sanyo
Format
AA
Model Eneloop 1900mAh
Chemistry
NiMh
Compare NiMh batteries
Purchase place Amazon
Buy online
Click here
Our observations
These were the first low self discharge NiMh AA batteries. They've been the best AA NiMh I have ever tested so far:
  • Low capacity
    Although the capacity is a little disappointing compared to other NiMh batteries it remains a very interresting competitor compared to both Alkaline and Nimh batteries 
  • They come pre-charged
    The charge is about 1400mAh / 1700mWh
  • Very low internal resistance
    35-40 miliohm (lower is better)This is great for highly demanding applications (e.g. flash): they will generate less heat and provide more power.
  • Low self discharge rate
    A common problem with NiMh batteries. Most new NiMh batteries now have a lower self discharge rate.
  • Decent price
    Not the cheapest but really good value... when purchased online, they're about twice as cheap as hardware store alternatives such as the Duracell Rechargeable
  • Note on ageing (with the number of discharge/charge cycles)
    It looks like Sanyo has improved how its batteries age with the number of recharge cycles. It looks like more recent batteries handle age much better than older ones (test here). A summery of Sanyo Eneloop's specification can be found here.
Our analysis
Number of discharges
18
Testing period
02/02/2014 - 03/02/2014
Battery cost
Self discharge
Cost of one battery. Since all batteries are not made equal, price alone will not give much info about the value
Percentage of the battery charge lost each year even if you don't use it (lower is better)
2.34 €/battery
?
?
Battery capacity
Energy cost
A higher value indicates the battery containts more energy
This indicates how much you pay for the energy inside your battery (value for money)
1,979 mAh
2,482 mWh
1.18 €/Ah
0.94 €/Wh
Capcity before first charge
Internal resistance
A higher value indicates the battery will last longer before its first charge
A battery with a lower internal resistance will perform better in high drain devices (e.g. camera flashes)
1,410 mAh
1,728.58 mWh
33 mOhm

Legend

   Among the best performing batteries
   Well performing
   Weak
   Among the worst