Best Inverter Brand for 12v to 110v ?
I really had to decide if I was going with a Pellet stove insert or a wood burning insert for the old fireplace.
With supply/demand/price of pellet fuel in today’s economy, I was leery about relying on future availability, With the supply of “free” wood I had, and will get in the future, I finally bought the Lopi Freedom Bay insert that takes 24″ logs and has a 180 cmf warm air blower.
If there is a power failure to the house, in reading what the Pellet/Corn owners use, they recommend a 12v battery and inverter to power the motors and circuit board for up to 10 hours. Some stove vendors listed their inverters and battery with prices over $500. I’d like to know what brand and size of inverter to be looking for and where it’s sold. Also your thoughts and experience with 12v deep cycle batteries to run the inverter to power the new insert’s blower motors would be appreciated, too.
Thank you,
Bill
Replies
Figure out what the wattage is for the fan and buy a slightly larger (20-50%) inverter. You can find them all sorts of places, including Best Buy, and I'll bet you can find one large enough for under $200.
Keep in mind that the current drain from the battery will be 15-20 times the current drain of the fan, because of the 10x difference in voltage, so calculate the needed amp-hours based on that. Eg, a 120 watt motor would draw one amp, so you'd need 15-20 amps at 12V.
let me skip beyond brands and deal with batteries.. and chargers!
first battery chargers are dangerous to the long term health of the battery.. what you really want is a maintinace charger. They are differant from batterychargers. Battery chargers need to be hooked up, charged and removed when the charge is complete! Maintinace chargers can be hooked to a battery forever.. they measure the state of charge and charge or not as required.. If that's confusing plases ask..
Second batteries will fail when the lead sulfate is deep enough to short between the plates.. Good news! The lead sulfate is removeable.. easily!
Every 3 or 4 years (2 or 3 if exposed to freezing weather) remove the caps on the cells and gently tip the contents into a large glass bowl. What you are pouring out is the acid and water. Let that sit overnight undisturbed.. meanwhile you want to flush out the lead sulfate with fresh water.. keep filling and dumping the contents of the battery untill nothing but pure water comes out. Any white residue is the lead sulfate. If you see some keep flushing. Don't bang the battery around because the plates are vulnerable without the water/acid to protect it.
The next day take a turkey baster and gently suck the water /acid out of the bowl. be carefull not to suck up any of the white residue that will have settled out. (the white residue is lead sulfate)
Chances are you will be short of water/acid so don't fill every cell fully before going on, just fill it until the top of the plates are covered. Then move on to the next cell. any water left should be spread equally among cells.. in all probablity you still won't have the cells completely filled so you will have to add water.. distilled water is best but any drinking water will work.. Now use a PH meter to add the required amount of acid to bring the battery up to the proper reading..
This sounds complicated but it's easy.. plus doing this will take a typical or 4 year battery into a 10 year or more battery.
I used to do this to big forklift batteries and I could take junk batteries that were bought for their scrap value only and get at least a decade or more of life from them.
That's a $4500 battery I paid $300 for and got 10 or more years of use before I'd sell it for scrap and get back my $300.00 Since I charged my batteries with solar collectors that was essentiually a decade of free electricity. My neighbor is still using that system up north to run his cabin.
I've dealt with this issue in off grid homes, and most stoves with an electronic control of any kind, need 'true sine wave' power, which most cheap inverters don't provide. They are out there for a reasonable price, but, by the time you buy batteries, a maintenance charger, and inverter, sized for the stove, $500 might not seem too bad.
up to 10 hours
That infers about a 100-120W load, small motor.
Try a cheap $25 400W Walmart or HF inverter, should work great. More $$ will get you more efficiency, 70-80% eff. is max from a cheapo, delta $$ spent on slightly bigger battery is more cost effective.
Any crappy ol' waveform inverter works OK with most loads as you are talking about.
edit PS: an electronic control of any kind, need 'true sine wave' power -- just read previous post, would be truly amazed if that were the case, any DC derived electronic control I've ever built (and there have been lots on everything from military aircraft to ships) have used a rectifier and power factor correction DC-DC converter first -- don't care about incoming waveform. If you are trying to run a critical chemical process with AC servos, then true sine wave may be needed, but for a woodstove fan??
Edited 12/23/2008 12:33 am ET by junkhound
Agreed. Unless the circuitry is very poorly designed, it doesn't care much about waveform. The juice is converted to DC right off the bat.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
I will concede that the price of inverters has come way down in the last ten years, but they are still a lot of work to install properly, especially the big ones, and for prolonged use without your motor running you really should have a deep cycle battery.
So for 1,000 watts of power, or less, you're probably looking at a few hundred dollars and a few hours of time.
I'd be tempted to take that and invest in a used, small, quiet, Japanese generator.
Scott.
Bill, let's leave the box you have outlined, for a second here.
I would think the best way to approach this, instead, is to locate a 12v fan that will replace the fan on your stove.
No invertor needed, when the power is out, and you are running on a battery.
Easy enough to find a simple transformer for the fan, for when the power is on.
In fact, some of the newer fans at the big boxes have a 'line wart' that plugs into the wall. They are actually 9, 12, 14v DC, etc, and the wart is a transformer. Find one of those fans that can be adapted to your stove, and you are set.
As for batteries...
Get two 6v golf cart batteries. They last several times longer than regular batteries. (Lifetime of the battery.)
Two 6v hooked in series will give you better amps, and longer amp/hours.
Trojan is the best brand that I have heard of, for deep cycle batteries.
For charging the battery when the power is out, get one of those 100 dollar generators at Schucks/Kragen, and a deep cycle battery charger.
Don't charge the batteries directly from the generator. (Any generator.) Even though most generators have a simple adaptor for charging your batteries, you don't want to do that. They are infamous for cutting the life of batteries way down. Get a charger made especially for deep cycle batteries, and run that from the generator.
Just because they want to make it personal,
doesn't mean you have to take it personal.
"Two 6v hooked in series will give you better amps, and longer amp/hours."No when you connect them in series you get the same amps and amp-hours. But you get higher voltage and thus higher watt-hours.But the problem is not just the fan that needs to be powered. But also controls and I would not be surprised for it to have a motor auger feed..
William the Geezer, the sequel to Billy the Kid - Shoe
Bill,
I think the two blower motors, total, will draw less than 2 amps at 110v.
Here's the insert I have, it's only a wood burner.
http://www.lopistoves.com/product_guide/detail.aspx?id=218
Bill
My new forceair furnace blower is a DC motorinstead of AC. Could a DC motor be used insetead?
Tu stultus es
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Look, just send me to my drawer. This whole talking-to-you thing is like double punishment.
Check out computer UPS units. They provide line voltage from built-in batteries and have the circuitry to keep the batteries constantly charged.
Mike Hennessy
Pittsburgh, PA
Like Mike Hennesy said, look at computer UPS systems. I recently bought a 1250VA ups from Wal-Mart for $162. It'll power 3 computers for about 18 minutes. It should run a fan just about forever.
"Like Mike Hennesy said, look at computer UPS systems. I recently bought a 1250VA ups from Wal-Mart for $162. It'll power 3 computers for about 18 minutes. It should run a fan just about forever."The 1250 VA is probably probably only for 5-10 minutes. And the 3 computers are probably drawing only 1/2 of that.But even if it will supply 1250 VA for 18 minutes. That is only 3 3/4 hours at 100 watts. Actually less because of in efficiencies.An UPS would only be practical if it was designed to work with external batteries and you could install a large deep cycle..
William the Geezer, the sequel to Billy the Kid - Shoe
Well, it seemed like a good idea at the time! LOL!
Mike HennessyPittsburgh, PA