Hi,
I think the Lenmars are generally of crappy build. It seems the Maha, Energizer, and Duracell 2500 mah are the brands you should get. However, the charger is even more important for reliability. Since you only need 4 (SBM-1), I would get the Maha 204-F (i believe that is the model) charger. They have a great conditioning routine as well to optimize battery life (use the cycle once every 15 charges or so). Also, just use the slow (2 hr vs. 1 hr) charge. You will get better battery longevity. My 4 Energizer 2500's will run an SBM-1 for 5 hours easily (more like 6). Go to thomasdistributing.com. Do not try to save a couple of bucks on batteries or the charger, you will pay for it during an important recording! Stick with the above mentioned brands, and MAHA chargers!
Good luck!