laptop for fieldwork

I am a field biologist looking to purchase computers to be used for data collection, management, and external device initialization in tropical rainforest settings. Much of the equipment used with the computer requires a PC. Durability is a key issue (and almost certainly SSD). Processor only needs to be fast enough to handle relatively lightweight programs associated with external devices, as well as downloads/uploads/data transfer. Good battery life definitely a plus. Basic word processing and internet needed, but nothing requiring advanced graphics. The ideal budget would run up to ~$800 USD (given usage in rainforest it is expected that the computer will not last forever, so the more replaceable the better! And upgradability probably not critical.).