The key factor in making a truly mobile computer mobile is weight. The lighter the chingarerra is, the simpler the task of making it durable.
Weight is primarily a function of power consumption.
The larger the battery, the heavier the chingarerra will be. Dissipation this high is called for with Pentium IIIs because this is the amount of power they will consume under load. We can use a large battery, thereby achieving long useful life in the field, or choose a small battery, and save weight. Let's pull a dirty trick and make it user's choice. In particular, it can make an excellent substitute for a boot drive .