I've purchased a few of each of the low self-discharge NiMH AA batteries I could find.

TPE--Titanium Power Enduro, from Amondotech $2.50
ENL--Eneloop from Thomas Distributing $2.99
HYB--Hybrio by Ultralast from Thomas $2.49
ACC--Acculoop from Thomas $2.74

This posting is the first installment in reporting test results, and addresses initial behavior only--not capacity retained after shelf time.

All charging and capacity measurement is done on a Maha MH-C9000.

INITIAL CAPACITY AS DELIVERED
This category of battery is claimed to be usable right out of the packaging. For the particular samples I got, here was the capacity measured at 200 mA discharge rate:

TPE 894 828 897 1415
ENL 1436 1435 1447 1432
HYB 1590 1599 1603 1684
ACC 1732 1742

All the batteries had useful capacity out of the package--though I'd still advise charging them before significant use. The TPE set had one badly mismatched--oddly it had _more_ capacity than its stablemates. This round goes to Acculoop.

FIRST CYCLE CAPACITY
After the discharge above, all batteries were charged at the 800 mA rate. All terminated normally after net charges of 2069 to 2284 mAHr except for three of the TPE units, which I terminated manually at 2500 mAHr. Failure to terminate on very new batteries is a known vice of the MH-C9000, often curable by using a higher charging rate, or after a few cycles on the new batteries.

After one hour of wait time, the batteries were discharged at the 200 mA rate

TPE 1891 1902 1900 2034
ENL 1987 1980 1987 1967
HYB 2034 2026 2022 2021
ACC 2024 2019

For this round, the TPE set has the poorest within-set matching. The three other sets are each very well matched within set. HYB wins by a nose over ACC on capacity. Since ENL claims only 2000 while the others claim 2100 nominal capacity, ENL comes closest to meeting its claim.

NEXT PLANS

As NiMH batteries often change charging cycle termination characteristics and capacity in the first few cycles, I next plan to do three blind cycles on the MH-C9000 at 1200 mA charge, 500 mA discharge for conditioning. Then I'll do another one hour delay capacity test. Finally I'll get to more interesting tests: one week delay, four weeks delay, and three months delay.

I'll also include four diverse conventional AAs (not new) for comparison.
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new 350D user July 1, 2005