Started by TheWire, June 01, 2008, 12:18:25 PM
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Quote from: TheWire on June 01, 2008, 12:18:25 PM
Quote from: TheWire on June 01, 2008, 02:22:13 PMPEG, Thanks for the feedback. I know I have several spots where a point load "appeared", aka not noticed until the framing above it was complete, that I need to take care of by providing better support underneath. I should make mention also of the lack of a box sill on the gable walls. I used I-Joists and framed the gable walls 11 7/8" higher than the walls the I-Joists sit on. That way I save money on rim board, blocking, etc and the top of the 1st floor gable walls are directly tied to the diaphragm of the 2nd floor deck. I haven't seen any negatives of this approach yet. Any comments?
Quote from: TheWire on July 19, 2008, 08:18:09 AMI'm looking at a solar power system for our cabin. The expected loads are task lighting (LEDs), area lighting (Compact Flourescents CF), RV Type water pump, cell phone & other small battery chargers. It would also be nice for occasional use of a microwave/toaster or other small applicance. I'd like to run the LED task lights and a RV water pump from 12 volts and have the rest of the loads on an inverter that I could keep shut off most of the time. I'd size the solar panels and batteries for a typical weekend use, giving the panels 5 days during the week to replenish the batteries. I'll also have a generator if needed for occasional high use times.I have some questions:Does anyone have experience using the multi-LED lights for task lighting such as reading, bathroom, kitchen? They typically only take 2 to 3 watts but supposedly put out as much light as a incandescent 10 times the wattage.We use them for walkway lights and around the pool as well as a larger patio light around the pool. I also use a 5 led head light when prospecting in old mines. They work fine, but the best description I can give them is that their light is great but vague and disagreeable. I like them for lots of light and small but semi-focused in a small area and rather disagreeable color for general seeing and reading. I suggest you go to Costco or somewhere that carries them and get a headlight to try before you decide. I like CF's best for reading and general use. More agreeable slightly yellow light similar to incandescent.110VAC CF lights are cheaper and easier to find than 12VDC. Any thoughts on 12VDC vs. 110VAC Inverter powered CF's? I'm planning on CFs for lighting large areas because I don't think the LEDs will provide enough light to fix dinner/ play cards/ etc.12v is too much trouble for me - inverters are very efficient now and I won't run back and forth swapping things or pay extra looking for and replacing 12v stuff. It's the pits to have to wait for shipping or find a 12v when the other one goes out. 120v stuff is everywhere.Does it make sense to size the inverter and batteries to handle running a 1200 watt kitchen appliance or to use a remote starting generator to power these loads? Do short periods of high discharge wear out batteries faster? I use mine hard and abuse them - light batteries won't hold up. I suggest minimum 2 L16's for 12 volt, 375 AH. Automotive batts even deep cycle are a wast of time and money. Minimum if you must would be golf cart batteries but they don't have the capacity or longevity of the L16's. We use 12 L-16's and are going to 16 soon. First sets are 4 years old and the Desulfator people claime top be able to increase the life possibly up to 15 years. We'll see. Cycling an L16 hard is not a problem - it kills automotive deep cycles. Running a microwave is a short term thing and not a problem or even that much of a power hog if figured in KWH due to the shorter run times.Any reccomendations for an inverter? (Efficiency, pure sine wave and low idling power seem to be qualities I'm looking for)I haven't used but can safely recommend the Outback Sine wave inverter -big enough to run your microwave. An electrical engineer neighbor tests for them. I use the older Trace inverters and like them but have heard that the Xantrex who took over Trace wasn't quite as reliable - maybe just a rumorhttp://www.partsonsale.com/outbackoffgridsealed.html The inverters with battery chargers built in are more expensive than a standard inverter. I don't plan on charging a lot with the generator, is there anything wrong with using a seperate car battery type charger to charge the batteries with the generator? That could work - more to mess with. I don't think 12v is good if you ever plan to go bigger than one of the above inverters.Some other low end solar systems are using RV/Marine deep cycle batteries in parallel or golf cart batteries in series? Any thoughts on which is better/cheaper/other type of batteries? RV/Marine deep cycle batteries are a waste of money - believe me - I've wasted plenty. I doubt they would make it over a year under heavy use from my experience. The golf cart batteries would be a minimum and I won't use them either. The L16s are cheaper in the long run after you figure destroying or replacing a bunch of the small ones - running out of power etc. A 12 volt inverter will pull a lot of amps to make 120v @ 2000 watts - say.... a microwave and another thing or two. Use heavy cables lik 2/0. Note that low charge for long periods and sulfation are the major problems. MPPT controllers with matched solar panels and PWM chargers (built into the MPPT) as well as equalizing -suggested monthly - water level maintenance - clean terminals and getting the charge back up if run down. It's not a weekend thing with us-- it's the way we live here at the underground command center. Thank you,Jerry
QuoteJohn Mitchell wrote:> > I live in B.C. - same problem. I top up the batteries with watter and charge> them up - slow charge. Then disconnect the + connector. Leave them all winter> - top up with the charger in the spring and reconnect. I have had rv batteries> last 8 years this way.> Hope it helps.> John MitchellIt would actually be better to leave the trickle charger on thebattery. The freezing point of the electrolyte varies directly withthe charge on the battery and therefore the concentration ofsulfuric acid in the electrolyte. At full charge, the freezingpoint is very low, lower than -10 deg F, if my scratchy memoryserves. As the battery (self) discharges, the acid concentration isreduced until at full discharge the concentration is very weak andthe freezing point rises to approach the 32 deg F FP of water. Whenthe freezing point and the outdoor air temperature intersect, afrozen and almost always ruined battery results.Trickle charging does something else useful. It inputs a smallamount of heat to the battery. This allows the battery to withstandeven lower temperatures without freezing. I use the little 1 ampbattery maintainer chargers sold at Wal Mart for my infrequentlyused delivery trucks. Never had a battery freeze plus the trucksare ready to run even after extended idleness. Not that we have hadto worry about freezing for the last couple of "toy" winters. John-- John De Armond