Winter is almost here

Twigg

Twigg

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Due to an extended stretch of unemployment and now being under employed I was not able to follow through with my origional plan of having a transfer panel installed along with buying a large enough top quality generator to run the house should the power go out for several days again.

On to plan "B".

I'll be buying a cheap generator fron Wal-Mart to run the fridge & freezer for a few hours and to charge one or two deep cycle marine batteries.

I plan to heat the place using an existing pellet stove and to run the stove off the above battey(ies). I intend to place the battery (or batteries in parallel) & inverter in a plywood box mounted to a small hand truck so I can wheel them into the house when needed and back out to the shed for recharging.

According to my Kill-A-Watt meter the stove draws 400 watts when the ignitor is on and settles down to 100 watts once the fire's going and the blower's on it never draws more than 105 watts after that.

I know I need an inverter rated for at least twice the start up draw, my question is if I want this to run the stove for at least 12 hours how big should the batteries be in terms of amp-hours and how does this relate to the power listed for the batteries using: 135 minutes of reserve capacity and 880 cold cranking amps - as an example ?

And a related question which make of inverter is a good one ?
The only thing I'd be running off it would be the pellet stove.
 
I've been researching building a solar generator... Xantrex inverters are supposed to be some of the best, this should suit your needs well: http://www.amazon.com/Xantrex-Techn...f=sr_1_11?ie=UTF8&s=hi&qid=1257879031&sr=1-11

It sounds like that stove will need 1.3 or so kWhr, based on what you said the ingition draw and regular draw is... If my math serves me correctly, you'd want at least 110ah battery... two unless you want to absolutely kill the battery. That die-hard is rated at 68

Perhaps a pair of these?: http://www.atbatt.com/product/5269/sla/power-sonic/12v-110ah/battery
 
OK, a Reserve Capacity is supposed to be rated at a draw of 25 amps. 25 amps times 12 volts is 300 watts. You said you need roughly 1/3 of that, so you should see about 3 times the Reserve Capacity during operation. Or, roughly 6.5 hours.

This of course does not include what the overhead of the inverter is. You'll have to multiply by the efficiency of the inverter you get. So, if the inverter has an efficiency of 85, then you have 85% of the working power. So 6.5 times .85 is about 5.5 hours.

(efficiency generally ranges from 85-95%, but be careful how it is measured.)

Of course, you need to keep in mind that these are optimal numbers and you will likely not achieve such results. (you could get lucky, however)

Also, keep in mind that motors like the auger, blower, and such will run more efficiently on a pure sine wave (up to as much as 20%) and pure sine wave inverters are generally more expensive.

Also, keep in mind that most inverters are the most efficient in the 70-90% load range. The start up wattage you need MIGHT be handled by the surge capacity of a smaller unit. You'll need to research it.

As for brands, the following are known to be some of the best:

Exeltech, Outback Power, Magnum Energy, Statpower, Samlex
 
My buddy ran his off 2 car batteries and a 400 watt walmart inverter during the last ice storm. It worked. Probably not ideal but if your budget is tight I think a couple of the Walmart deep cycles and an 800 watt inverter would do it. Does it need to be on all 12 hrs? Can you crank it up for an hour and then shut it down for 4 or 5 and then crank it up again? That might let you bypass the whole battery thing and just use the genny. Bundle p and shut down part of the house.
 
What are you going to buy for a genset??
I wired the neighbor across the street with a subpanel, an interlok kit, and out side receptacle last weekend for $375.

He has a 6000W genset....runs 70% of his home.
 
on 2000 watts I was able to run the tv's, fridge, heating plant, and lights, but when the burner was on and the fridge kicked in it did cause my yamaha amp to switch off for low voltage when the motor was spinning up.

By the time you buy a cheap wally world generator, and a couple of deep cycle batteries, etc, you are a good way towards a used Honda EU2000 inverter, or if you shop around a new one. You can go into a cheap 5KW generator for the cost of the 2 deep cycle batteries.

A 10 circuit transfer switch at HD is 3 bills, and another C note for incidentals such as an outside box with a flanged inlet, and a run of 10/4 wire
 
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105W for 12h = 1.26kWh

From a 12V Lead-Acid battery, that would ideally be 105Ah of capacity, unfortunately batteries aren't that good. Figure you'd need 120Ah since the battery voltage will drop during discharge.

As mentioned, the inverter efficiency is going to increase your required capacity.

http://www.theinverterstore.com/the-inverter-store-product.php?model=pwrinv400w-top-rgb#
There's a 90% efficiency (95% efficiency at 125W) inverter that can handle a 800W surge and 400W continuous load. That's pretty close to what you'd want to run the stove from battery. For 12h, you'd want about 126Ah of battery storage. 2 68Ah Deep-Cycle Marine batteries should just about do it for you, and the inverter is only $35
 
Too bad you guys don't come up to NH, most affordable quote I had was $600 for an addition to the breaker panel to run 6 circuits and the outdoor hook up.

I want the batteries & inverter so I don't have to run the generator at night. I can't stay up 24/7 to guard it. Generator theft was a big issue here last year during the Ice Storm's aftermath.

Most likely the auger runs on 12v dc but there's the other electronics in the stove too.
I bought this stove used and if I screw it up the closest retailer who might be able to fix it is in either New Jersey or Canada.


Thanks for the suggestions though. I've got enough to go ahead with the project now.
 
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Dennis,

How knowledgeable are you with electrics? Shouldn't be that hard to open up the control section of the stove and see what is AC and what is DC. If, you see the main power cord come in, connect to a transformer, and then everything is run off that, all you need to do is measure the voltage at the back of the transformer and verify it's 12 volts (or close to that) If that's the case, it should be a simple matter of splicing into that point a DPDT switch and adding a 12v connector to the side of the stove to attach your batteries. Then, you'll not only avoid the inverter issue, but eliminate the efficiency loss of the transformer too.

Heck of a lot cheaper than an inverter. And, by eliminating the inverter, you might be in better shape to look at that Honda 2000 generator which will not only run better, but is MUCH MUCH quieter than any WalMart special you might find.

My November is totally booked solid, but if another member here can't help you out, I can arrange to come up Dec 5th and see what we can do. Let me know.
 
Dennis - There's a hot dot stand in Worcester that runs the bigger, 5 KW version of the Honda he's talking about. The generator was running out in the open, but quiet enough that I didn't hear it at all, even with no traffic on the street, while standing on the opposite side of the truck.

It's amazing how quiet they are, and their run time is significantly longer, with significantly higher efficiency, than most of the stuff I've compared.
 

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