I need to provide some airflow to reduce ground moisture levels in some dead areas in my subfloor (think old double brick house with single brick internal walls that extend all the way to the ground ... built when noone really cared much for subfloor ventilation) and was thinking it would be reasonably appropriate to power some fans with a solar panel but wasn't sure of the pros and cons of a direct connection between fan(s) and panel.
I was thinking of something like a 12V 7W 12cm axial fan (or, perhaps 3 for a 20W panel) (similar 4.5W version) to connect to a solar panel (eg 10W for $50 or 20W for $100).
- Does anyone know what sort of voltage / current variation these sort of DC fans can happily withstand? ie can I directly connect to a solar panel?
- How well matched would the panel and fan power ratings need to be to prevent damage?
- If I need to regulate voltage to something the fan is happier with, is there a decent hack that lets me do it cheaply or reuses parts from other broken things?
I've researched myself into thinking that I should be extracting the air from the subfloor, but can't help thinking that if I can draw dry air in that would be better (since removing air implies replacing with air from various locations/moisture levels). I know hot air can hold more moisture so perhaps there's a risk of condensation or increased moisture forming when the air is cooled as it enters the subfloor...but if this argument really holds, then I should be looking to move air on cold days.
- Should I extract the air and continue to let most replacement air enter from the cool south side of the house?
- Should I force in air from the likely driest location? I guess that just because the air is hot doesn't mean it will have more moisture (if it hasn't had a chance to pick it up). The north side of our house has a cement/tile patio and there air here is much warmer than on the south side, but I would assume much the same (or possibly lower) moisture content) ??? Any expertise appreciated here.
We have a pretty old house (1930?) and, apart from insulation problems especially on the south side, if we can solve this moisture / rotting problem we will have increased its longevity by another 20 years.