There are several potential problems.

First, most NiMH cells should NEVER be run below 0.9 volts per cell. This would mean that the boat comes in with a visibly lower speed than when the charge was full. If this happens very often, the pack will be permanently damaged.

Second, the cells should not be stored discharged, they should be stored charged. If they drop too much when in storage, the pack will be permanently damaged.

Third, the pack should be balanced periodically. This means charging them at 0.5 amps for over 12 hours. This puts the maximum charge in every cell and helps keep the pack lasting longer.

Fourth, the packs are cheap junk to begin with and just are not intended to last long. This is a problem with some of the cheap sport packs sold at RadioShakk, etc. - most people who buy them want the lowest possible cost, and only run their toys a few times anyway. Better quality cells will last a lot longer if cared for as in the above three cases.


.