18x34 1 story + loft(s) in the Cariboo

Started by Charlie A, February 07, 2011, 02:41:31 AM

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MountainDon

What is this end?    ???    Guest room (they won't stay long) or batteries, or ?

Just because something has been done and has not failed, doesn't mean it is good design.

Charlie A

#26
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Charlie A

Quote from: MountainDon on February 07, 2011, 08:46:18 PM
What is this end?    ???    Guest room (they won't stay long) or batteries, or ?



LOL. I was going to stick the kids there when they are bad!

Its going to be a utility room.  Batteries/inverter, water heater, electrical panel etc.  I didn't want to look at all that stuff.

MountainDon

I thought batteries. I have built a "energy center" on the end of our cabin.

Are you insulating it? I went back and forth between yes and no for a long time.
Just because something has been done and has not failed, doesn't mean it is good design.

Charlie A

#29
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MountainDon

Lead acid batteries won't freeze when charged up. I forget the numbers, temperature and % of charge. I have them someplace?  Freeze temp on a fully charged battery is very low though.

We use our place every second weekend at most in winter. I leave the charge controller to work its magic all by itself. I do pull the inverter breaker though to fully shut it down. The CC goes through a daily cycle, pumps 200 to 300 hundred KwH of power into the batteries; a brief bulk charge and then most of it in absorb and float. The batteries always check out as fully charged with the temperature corrected specific gravity when we arrive. The winter voltage reads a tad low compared to summer. I fitted more batteries than I would have if there was no winter involved, in order to cover the effective reduced cold weather capacity. Winter here means the occasional drop into the negative F degrees, but more in the 5 to 30 degreesF range. Last week it did drop to -15 F, a new low record at the cabin.
Just because something has been done and has not failed, doesn't mean it is good design.

MountainDon

If I was going to be making much more winter use I'd likely insulate to retain the heat that charging and discharging creates. But when it sits there idle for weeks at a time there is very little heat generated. So it didn't seem worthwhile. If the use pattern changes I can change that though.




"At approximately -22 degrees F (-27 C), battery AH capacity drops to 50%. At freezing, capacity is reduced by 20%. Capacity is increased at higher temperatures - at 122 degrees F, battery capacity would be about 12% higher."

" Battery capacity is reduced by 50% at -22 degrees F - but battery LIFE increases by about 60%. Battery life is reduced at higher temperatures - for every 15 degrees F over 77, battery life is cut in half. This holds true for ANY type of Lead-Acid battery, whether sealed, gelled, AGM, industrial or whatever. "


In very cold climates some batteries can be had with more acid, a greater concentration to compensate.

still looking for freeze info....

EDIT: "At a 40% state of charge, electrolyte will freeze if the temperature drops to approximately -16 degrees F. When a battery is fully charged the electrolyte will not freeze until the temperature drops to approximately -92 degrees F."
Just because something has been done and has not failed, doesn't mean it is good design.

MountainDon

Charlie:  Before your installed the roof metal did you nail steel straps across the peak in place of using collar ties? That's what I did.

Collar ties and rafter ties get confused easily so here's a drawing that explains...


You can still install collar ties but it'll interfere with the cathedral look. ???
The purpose of a collar tie or straps over the peak is to hold things together in times of high winds. The wind flowing over the peak can create lift forces much the same as an aircraft wing. Takes a bit for that to happen, but it can/does.


I also wonder about the two assembled cross beams. A low pitch roof such as yours and mine creates more outward force on the walls than a higher pitch roof. It's not too clear to my old eyes how those are secured to the side walls and rafters. Cross ties like that don't have to be one continuous length but they need to connect securely to the rafter and then the rafter to the wall. Perhaps it is just not clear  to me in the photos.
Just because something has been done and has not failed, doesn't mean it is good design.

Charlie A

#33
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