Wednesday, January 03, 2007

AC Power From Batteries

As you have probably noticed, the Pacific Northwest has had a bunch of storms this year that knocked out the power . There are several solutions and partial solutions to dealing with no electricity. Generators are one solution. Deep cycle batteries and power inverters are another.

For a good discussion of getting AC house power from DC batteries, including how to set up your own system, have a look at Rivrdog's post at Paratus on the subject.


At Wednesday, January 03, 2007 8:46:00 PM, Anonymous akafuze said...

Had a 10 KW diesel gen set on my boat. Went to Alaska for 3 months and would run the generator for hours while watching TV in port and rock videos at anchor. Finally figured out that not a cost efective tactic. Installed a large inverter and never looked back.

Now, as a neighbor to Mr. Completely, I am going back to a 6.6KW diesel gen set for my HOUSE.

At Wednesday, January 03, 2007 9:40:00 PM, Blogger Rivrdog said...

Thank you for your fine write-up of my post. It just occured to me that while I'm using a smallish battery-inverter set to power my computer room, I actually have all the equipment for a much larger, whole-house, battery-inverter set. All I need to do is acquire about 5 more batteries and a heavy steel shelving set to put it all on, right under the service panel in my garage. If I want to splurge on an auto changeover switch, the system becomes perfectly seamless as a UPS. It will even have two legs for the two 110 legs in the panel, one of 1500 watts for the fridges/freezer/microwave leg and an 800-watt leg for the lights. The 1500 will surge to 2300 watts, way more than the Honda EU2000 genset will handle, and the 800 will surge to 1200. I would only be using about 200 watts of the 800 for lighting, and typically, the fridge loop is only running 600-800 watts when two of the four units are running, which isn't often.

If I stay manual, it's a breeze to operate: power goes down, the fire alarm announces the failure through the house security system. Grab the nearest flashlight, head for the garage. Open the panel, trip the red-painted breakers (range, furnace, hot tub, etc, most of which run on 220 and wouldn't energize anyway, then trip the main breaker, then switch on the two inverters, then go back inside and pick up where we left off. We have all the house lights, TV, some plugs (can run the small coffeemaker, start the gas stove, run the blower on the Heatilator fireplace, etc.

I have a remote panel for the 1500 inverter, and could mount that in the kitchen. It tells me what the main battery bank is doing. When the batteries get down to about 65%, I run out the genset and fire off the 40-amp TruCharge battery charger, or start it if I have a continuous load against the batteries of over 40 amps (500 watts draw on the inverter will do that). The genset, pumping only 500 watts, runs at the low "eco-throttle" setting and the gas will last 12 hours before needing a refuelling. With the genset extending the batteries by at least a third, more likely by 2/3, this is an all-night set-up, but on battery alone I will get at least 6 hours before the 50% recharge voltage in the main bank is reached.

...And I LOVE being the only house in my spendy neighborhood with lights, heat, icemaker, cold beer and entertainment.

At Wednesday, January 03, 2007 10:03:00 PM, Anonymous Anonymous said...

Mr. C, sounds like Mother Nature is trying to make an altenativ energy master out of you.

Hope your luck runs better as the year rolls along.

Rivrdog, thats a nice set up.

At Friday, July 13, 2007 2:24:00 PM, Anonymous Anonymous said...

And not legal -or- safe.

You really need a mechanically interlocked transfer switch. You could get a lineman killed or injured if somebody forgets to trip the main breaker and you back feed the line out of your house.

You would be better off building an auxillary panel and running your inverter/gen backed up loads through it, with the transfer switch providing 'shore power' when in normal conditions.


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