Dear listers, I'm currently working on a project at the Ohio State University in Columbus, and I plan to use the Campbell 21x datalogger to monitor temperature by wiring 8 thermocouples on the panel board.
The datalogger is borrowed from a colleague, and the battery is totally discharged and can not be recharged. So I plan to purchase a motorcycle or car battery to power up the datalogger during the growing season. I found a really nice one with 44 Ahr capacity. The problem is I don't want to recharge the battery in the middle of season because that way I will have to buy two batteries for continuous measurement. Some one also suggested a solar panel but it seems expensive too. So the question is: does anyone know if a battery with 44 Ahr can provide power to the 21x for about 4 month in the field without recharging? Another question is how to retrieve the data. I plan to bring my laptop in the field and download the data every few weeks. But I'm worried about if I can see my laptop screen clearly during a sunny summer day. Is there any alternative method to download data from 21x? Thanks a lot. Jing Luo
