Receiving a set of NiCad batteries as a 10 year old (for use in a ‘Knight Rider’ RC car – how awesome was that?!) started a lifelong obsession with rechargeable cells. My interest in batteries started even earlier than this, after being given random lengths of wire, torch bulbs and supposedly dead C cells to ‘play’ with. Well, it kept me quiet 🙂
Some 35 years later and I’m still doing much the same, only with NiMH cells and a Maha MH-C9000 intelligent charger/analyser.
Recently, I’ve switched to so called ‘hybrid’ or Low Self Discharge (LSD) cells as whilst the capacities are lower, I find the low self discharge rate to be more beneficial in the long term.
All cells are new and run through a charge (0.5C) and discharge (500mA) cycle, the average capacity of 4 cells recorded. Capacities are expected to marginally improve over several cycles.
Edit: Some have pointed out that I should a) be testing remaining capacity after 6 or 12 months and b) my tests are not the IEC standard. Firstly, I’m not so interested in specific rates of self discharge (these tests are available elsewhere online). Secondly, I find the standard IEC test (0.1C charge, 0.2C discharge, from memory) entirely unrealistic for my typical workloads such as amateur radio, DSLR, etc. My 500mA discharge rate was chosen as a reasonable average figure for my typical use.
AA Hybrid
| Brand | Type | Rated mAh | Measured mAh |
|---|---|---|---|
| Sanyo | Eneloop Pro (black) | 2400 | 2386 |
| Sanyo | Eneloop (white) | 1900 | 1858 |
| Maplin | Hybrid | 2100 | 2101 |
| Energizer | ACCU Recharge Extreme | 2300 | 2075 |
| Tesco | Hybrid | 2000 | 1880 |
| 7 Day Shop | Good To Go | 2150 | 2220 |
| Duracell | Duralock | 1300 | 1345 |
| Varta | Recharge Accu | 2600 | 2570 |
| Amazon | Basics | 2500 | 2320 |
| IKEA | Ladda | 2450 | 2400 |
| PowerOwl | PowerOwl | 2800 | 1852 |
AAA Hybrid
| Brand | Type | Rated mAh | Measured mAh |
|---|---|---|---|
| Sayno | Eneloop (white) | 750 | 726 |
| Energizer | ACCU Recharge Extreme | 800 | 742 |
| Amazon | Basics | 850 | 840 |
| IKEA | Ladda | 900 | 895 |
| PowerOwl | PowerOwl | 1000 | 729 |
This post will be updated as further brands/types are tested.
Wow, those Tesco hybrids are dire, aren’t they?
Question, though. Why are the capacities expected to improve over cycles?
I’ve re-tested a set of four Tesco Hybrids and the results are much more in line with expectations; I have no idea what happened the first time! The results in the table above have been updated to reflect the new result.
Also, I can’t find a technical explanation but it often seems that battery capacity will increase after the first few cycles. I assume it’s because the batteries have been idle in their packaging for months (potentially years?) and a few cycles has a positive effect on the battery chemistry. However, I’m no chemist and my google-fu is currently failing me 🙁