Power Inverter Question

[Eric Johnson]

All this weird weather has me worried about the reliability of the local power grid, which has never let me down. However, if the power does fail in the middle of an ice storm, my boiler is going to overheat. I've avoided addressing this problem for years, and been lucky. I think it's time to be proactive. I think a power inverter and simple battery setup is the best solution.

So, my question is pretty simple: All i want to do is run a few circulators on two circuits (the wood boiler and the gas boiler). By my calculations, if they all ran at once, which is unlikely, the load would be around 500 watts, so I'm thinking a 1,000 watt inverter should be adequate.

My plan was to head down to Tractor Supply after work to buy an inverter and a battery appropriate for the application with the help of the friendly, knowlegeable associates.

Anything special I should be aware of or inquire about when I'm there? Any other considerations come to mind?

Thanks.

 

[Karl_northwind]

an easy solution is to get a computer backup power unit from amazon or somewhere. 1000 watts is not much, and some of them will let you connect an external battery (think 225 ah trolling motor battery) you'll spend a couple hundred bucks, but have automatic changeover, and when your burn is done, it'll run a couple lights and radio for you too. It'll also keep your battery in good health, rather than having a cobbled together unit.

 

[velvetfoot]

How will you know the power went out in the middle of the night so you can rig things up? Maybe an alarm of some kind that will wake you up. You will have to be at home for this to work.
Edit: What he said.

 

[Eric Johnson]

The ones I've been reading about automatically kick on when the power goes out, I believe. Some of them will keep the battery charged as well, I think. That's what I'm looking for, anyway.

I'm intrigued by the idea of a UPS, but I think I'd be more comfortable powering it with a conventional 12-volt battery that I can easily swap out or double up and charge up with my car or truck.

 

[__dan]

The problem is not with the inverters/UPS which are very good. The problem is with the battery.

Even with no usage the battery will have an expected lifetime of three to five years. The quality of the battery and charging system have a lot to do with this. High quality AGM batteries and matched float chargers or matched high quality UPS systems are expensive. Then the run time at load calculation needs to be done. Typical UPS systems are only designed with battery capacity for 10 to 20 minutes. Only enough for orderly shutdown or swap over to generator power. Not a bad scenario except for the cost of repeated battery replacement, which imo would make the plan inadvisable.

A lot depends on how much run time you want on battery. A few minutes to respond to the alarm or eight hours to exhaust the fuel load and run storage down. 8 hours at 500 watts on battery is going to be a big and expensive battery bank, not two deep cycle truck batteries.

In your application a momentary interruption would probably not change anything so you may skip the UPS and go straight to generator power. I would be looking at one of the small inverter gas/propane generators, Honda Yamaha or Yamaha clone, and either a manual or auto transfer as required. The small inverter generator would be more versatile for me and much cheaper to buy and maintain compared to the battery bank, in my opinion.

 

[Eric Johnson]

That's a good point. I do have natural gas, so a nat gas generator would probably make the most sense, but I'm not that ambitious or flush.

As a practical matter, I doubt that whatever I buy and install will ever be used. It would not have been to this point. My main concern is getting the heat from the boiler into the house to avoid an overheat situation, which can lead to melted pex, damaged components, etc. when the pump kicks back on. Even a half-hour outage would cause problems. So, upon further reflection and in light of your information on battery capacity issues, I guess it's more a question of managing an outage, rather than trying to heat through a protracted one. A couple hours, I guess, is what I'm looking to get out of it.

But a small gasoline generator is not a bad idea, considering that it has all kinds of other potential uses in the off season.

 

[blades]

Small gasoline gensets can be coverted to Ng , LPG, propane. some are avaliable as dual fuel units as well. There are conversion kits out there- never used one so buyer beware.

 

[maple1]

Do you have a dump zone? That might not get heat into your house but it would help prevent an overheat.

 

[Karl_northwind]

If you're going the generator way, get a cheap backup UPS, put it on the boiler circ only (or whatever necessary to get rid of the heat from the boiler, let the boiler fan shut down) then you've taken care of the problem. if you're getting a generator the honda 2000 watt inverter generators are great. or you could go this route:
(broken link removed to http://madison.craigslist.org/for/5378026213.html)

I'm searching out a generator/backup option now too. the walk in freezer won't keep forever in a long power outage. something in the 15-30 KW range.

 

[maple1]

I added a UPS to my setup. It's a 2200va model, pretty big, second hand find. It also had the ability to support more batteries being added. I only plug my loading unit into it. I haven't run it right down yet, but I don't think I would count on it for more than one firebox load of wood - say 4 hours. I don't leave the UPS plugged in all the time - it has a fan inside that runs whenever it is plugged in even if it's switched off or nothing is plugged into it. So I only plug it in monthly or so to maintain a charge, and when there's an outage threatening or I'm going out with a fire going.

A cheap UPS I don't think would outlast a load of wood, might not even make it an hour. But it would certainly give you lots of time to get a genny hooked up. As long as you're home. If I was going to get another one, I might get one in the 1500va range, or the biggest I could find that didn't have a fan that runs all the time.

 

[sportbikerider78]

Is your pump DC? It might be very cost effective to have a relay throw the pump into always on in the event of a power failure and then run off a few car batteries on a cheap trickle charger.

 

[Pat32rf]

Or you can buy a UPS that is rated to carry the pump/fan or whatever current but replace the tiny battery in it with a remote mounted deep discharge trolling motor battery. My son used to have a source of old UPS units off of theatre exit lights. After so many years they get tossed so I have three hooked up to various computers/TVs basement lights etc. Each one sits close to a 12 volt battery that will keep power on until I get the genny running...

 

[easternbob]

Eric,
Make sure to mount your inverter away from the boiler. I had mine in the same small room with the boiler and it got cooked from all the heat (or at least that's what I assume happened to the inverter).

 

[timberr]

Eric,

Do your self a favor don't get an inverter that has a transfer switch built-in they don't last. I went through 3 in three years, got one replaced under warranty. I bought a stand alone inverter and transfer switch. Been working great for 3 years. When I get home I can send you the info on the switch. Also you will need a Pure Sine inverter to make the fan on your Eko happy. I think I have a 1500 Watt it runs everything including my Propane Boiler at the same time. I have tested my setup and ran for 6 hrs before I stopped the test. My backup has worked as planned for about 12 power outages.

 

[timberr]

Eric,

Here is a picture of my Transfer switch and Inverter, it is a 1000 Watt not 1500.

Hope this helps

 

[NP ALASKA]

Eric,

Here is a picture of my Transfer switch and Inverter, it is a 1000 Watt not 1500.

Hope this helps

I use the same make but its the 2000 watt, i run my boiler in pellet mode as well as pump with no problems 8 hours.

Didnt think about them being next to noiler, might have to move them.
thanks

 

[Fred61]

I use an AIMS 1500 watt inverter. Bought it from these guys. http://www.theinverterstore.com/?gclid=CKmotZ-cjsoCFckWHwodZmsJCg

Don't see the exact model I have but I've had it for quite some time. It has a built in charger and transfer switch and has served me well.
My first attempt was a 1000 watt square wave unit and on my first test the circulators were humming and the LEDs on the controller were strobing. Unplugged it in a panic and sent it back.

 

[Mauler]

That's a good point. I do have natural gas, so a nat gas generator would probably make the most sense, but I'm not that ambitious or flush.

As a practical matter, I doubt that whatever I buy and install will ever be used. It would not have been to this point. My main concern is getting the heat from the boiler into the house to avoid an overheat situation, which can lead to melted pex, damaged components, etc. when the pump kicks back on. Even a half-hour outage would cause problems. So, upon further reflection and in light of your information on battery capacity issues, I guess it's more a question of managing an outage, rather than trying to heat through a protracted one. A couple hours, I guess, is what I'm looking to get out of it.

But a small gasoline generator is not a bad idea, considering that it has all kinds of other potential uses in the off season.

I'm in the same boat as you. I currently have a portable gas genny that I have to manually turn on, and otherwise works fine, but I want an automatic start to move the heat out of the boiler if I'm not around. I have the outdoor econoburn (passive dump zone not possible) and I'm guessing that I would need to power the econoburn circuit and the oil boiler circuit/zones for my baseboard heating (acting as an active dump zone). The automatic power wouldn't be used for anything else, so its a small load. I'd like to get as much as 4-8 hrs out of it, if I'm not around. Not sure I want to go with a bank of deep cycle batteries to achieve this, but I don't know if I have much choice. I looked at tesla's powerwall but thats way too pricey for such a small need. I can't tell if there are smaller gas run inverters that I could leave connected to a transfer switch and would automatically start if the power went out. I'm guessing not.

I'm kicking myself because I have already melted pex and had a blowout last year due to a power outage and still have not done something about it. fortunately the melt was accessible and easily fixed but that was sheer luck.