comments:
Unfortunately, you are not going to find a charger that displays the remaining capacity with more than 4 slots. This is a very good option for bulk charging (charges each cell individually for maximum service life) Assuming you charge them twice week, this comes out to 26 charges every year. Ni-MH batteries can often last 500-1000 cycles so that would equate to around 40 years of service before having to replace them. However, the internal chemistry only lasts around 5-10 years before it starts degrading. I would recommend replacing them every 5 years for peak performance. The biggest issue with this many cells is keeping them from over discharging in storage. For maximum cell life, it is recommended to charge them every 2 months to prevent them from dropping to 0% soc. Another issue with this many cells is making sure to cycle all of them instead of leaving one group sitting while using the rest. I would devise some type of grouping system to make sure all of the cells cycle equally. For your use case, buying high quality AA cells with low self discharge (like enelope) would be the best long term setup and would definitely near the 10 year mark before having to replace. This would remove the need to top off the cells and would also open up the possibility to store them at 60% soc for maximum shelf life.