Off Grid Home Forums Technical Discussion One system or two/////////Overflow power//////Air conditioning Re: One system or two/////////Overflow power//////Air conditioning


Thanks again! Its funny how things can make more sense and less at the same time.

If I am correct:

1) I would never want 2 systems but 1 system with 2 inverters is a good idea.

2) If I scored an extra pv and extra battery some day, there is no point in leaving them separate as a backup…just connect them into the system…but don’t expand till I have BOTH the pv and battery.

I was thinking if a disaster occurred (the whole thing caught on fire or was stolen while I was on vacation or destroyed by an earthquake etc.) then having a 12v 200 2400 amp watt battery charged somewhere would be nice. Correct me if I’m wrong but if that battery was charged and never used then it would stay charged and last a LONG time with just enough PV to account for the daily drain of 2-3% max = 72 watts / 5 hours = 15 or 20 watt PV. When all hell breaks loose at least I can run a cb radio and keep my fish alive.

3) I will have to look into geothermal cooling more. I have not been to the area for final research yet. I need to get soil and water samples, check ground and surface water temperatures, price a well (might be worth the cost if it gets me my cooling otherwise I would collect the 160 inches of rain we get each year) and figure out how much hydro I can get away with.

4) I don’t think a passive vent pipe in the toilet would work at night or when it was raining. If I’m gonna have a composting toilet I want it to be a nice one…My guest will probably find this more important than me. I am still open to suggestions here but for 10 watts I think I’ll just get a fan

5) Are there cons to the PSW other than cost…i.e. appliances that need MSW

A little about me and the place:

This property is a multiple use property. 1) Its going to be my home for a long time. 2) It will be a mini fruit tree plantation. 3) It will be some of the most remote tourist infrastructure in Costa Rica 4) I’m gonna try and do it with less money that anyone in their right mind would or should to set an example for sustainable design and off-grid livig. 5) The container and the power are the only piece of the puzzle with any serious budget.

If I can develop a DIY hydro or wind turbine/alternator it would reduce the cost a ton, so I am planning a simple starter PV system just to get the ball rolling when I get there. At the same time I am doing the needed research in case wind/hydro doesn’t work out. It sounds like a 400 watt PV and PSW inverter starter system would be a pretty nice one (freezer/computer/aquaponic pump/toilet fan/blender) if I use a generator for the early construction needs and backup.

It will be a VERY modest place built with all local and recycled materials (unmilled timber frame, pallets, earthbags, earthen patio floor and palm thatch outdoor space surrounding/protecting a single container house). It will start with the container. I like the containers because they are easy to secure if I need to abandon the property temporarily. Putting the container under a thatch roof eliminates solar gain and create tons of outdoor living space for very little money. I will also elevate the container off the ground so I can draw cool air in from underneath it. Because I am into aquaponics I’ve decided to put a “creek / pond” around the perimeter of the roof to catch the water and eliminate the potential for roof water leading to erosion. This will act like a swamp cooler if I can keep the sun off it and transfer the heat somewhere (I am thinking with a deep area under the container and/or a waterfall somewhere… a waterfall uses a lot more energy but less than a roof vent) but might just make the place ultra humid if I can’t. I could also lay the air intake pipe below the water but I think it might fill with condensation and need drained periodically.

Does anyone know how a flyroof effects passive cooling…I know it will be cooler under it but it seems like it will disrupt the thermocline in the container. I think it will create the need for a roof vent to power the ventilation in the container. That’s probably a question for another forum but you guys seem knowledgeable about more than just solar.