Power Supply and Coal Stokers ?

I'm new here and did a little searching but I did find the answer to my question.
I'll be a "new Harman Mag user" this Fall. We live in a rural setting and experience power outages at times. Not to many extended outages but some for anywhere between 5 min. to an hour. ( I come home from work and see the clocks flashing)
My questions are :
How much of and outage ( duration) can the typical stoker stove tolerate ?
Will the normal sequence of operation "pick up" after a brief outage ?
If there is an outage and the fire dies, when power returns will it just dump all the coal in the pan ?
If anyone knows, how long will the Mag. burn without power ?

These may seem like pretty "basic" questions but I've never been around a stoker in my life...

Any help appreciated.
Mossy Beard

First, Welcome. Do a search on Backup Battery or Inverters, many of us have discussed this many, many times.

First, A stoker will not run at all without electricity. You need the combustion blower and stoker motors working to keep the fire burning.

Very Brief outages (less than 15mins or so), Yes, it MAY re-light, you may have enough heat in the bottom of the coal to re-light once the power comes back on. If you have a direct vent or power vent, it will probably go out much faster. A natural draft chimney may draw a bit more thru the stove and keep it burning a bit longer. Most stokers will shutdown after about 30+ mins or so.

YES, the stove will just push the coal into the ash bin if the power comes back on and you have a Flame-out condition. (Been there!).

A POWER Inverter or backup power supply can suppliment the burn time when power goes out. Most will run 30mins-3+ hours (Depending on batteries and power requirements of the stove). Most people use them to suppliment until they can get a generator online or other source of power. A TRUE SINE Wave Inverter are available from many different sources online, $100-$1200. Then you need at least one good deep cycle battery ($50-200), the more batteries, the longer the time you can run.

Various threads...

Is There a 10 Hour Battery Backup for Stoker Stove?

Inverter for Homemade Battery Backup

Inverter Suggestions for My Channing 3 Stove

The Harman Mag Stoker has a slightly different design grate than most stoker stoves.. the Harman stoker has a slightly deeper fire so I think it will maintain a fire maybe a little longer, providing you have natural draft.

I'd put in a UPS with a bigger than standard battery,, just to be sure that you don't lose the fire.

Greg L

I have a question along these same lines. I'll be power venting a Leisure Line Pioneer (don't have it yet, but it's on order). I was going to put a UPS on the power venter, and not on the stove itself. My reasoning behind this was...if there was a power outage, I want to make sure the exhaust gases still get vented out. I figure the fire will burn for a little while without power, but there would be no where for the smoke to go. And, I could always restart the fire later. Does that seem to make sense?

Harman makes a slick battery back up unit that will run the stove for near 8 hours on a deep discharge battery. Switch over is automatic and upon the power comming back on will switch back to charge mode and recharge the battery.

new2coal, I understand and agree with your thinking, safety first.. but I'd just add a bigger battery to the UPS, and run the whole stove. No reason to have the fire go out, power come back on, and the stoker fill the ashpan with unburnt coal.. I'd just power the whole unit..

Greg L

Thanks for the responses.
What UPS should I be looking at ? (re: reasonable price)
I've looked over Tripplite ( 'don't make the aps512 anymore). The next one I thought about is the aps 750. It's got a bunch of "farkels", ie: built in charger, auto trans, over current protection, etc. All for about 300 dollars...

Someone mentioned the Harman back up. Could you expand on it a little more.

As mentioned, I'd prefer to keep the enitre unit running as opposed to just certain functions.

Thx, Mossy Beard

**Broken Link(s) Removed**

Whould the Harman backup work on a AA130? How much are they?

My gut feeling is no, the Harman unit wouldn't have the capicity. The motors on the Harman are all small fractional shaded pole motors where as the AA uses a high torque 1/2 hp motor. Running both the id fan amd the auger draw quite a lot of load. Not including the battery I believe the Harman unit is a little over $500 bucks.

There was a thread around here where someone researched the Harman unit and found it's just re badge from a different manufacturer. I believe it was quite a bit cheaper of you buy it without the Harman name on it.

I think I've narrowed it down to the Tripplite APS 750. I found it on line for about 250.00 + ship.
All I have to do now is select a decent battery(s).

Mossy Beard

I'd use Marine deep-cycle batteries.. I also like Optima batteries.. expensive but very good.

Greg L

Automotive lead acid batteries are not the ideal choice for a UPS unit. Automotive batteries depend on vibration to shake gas bubbles off the plates. The gas bubbles reduce the batteries capacity. Stationary UPS applications have a specifically designed lead acid battery. There are two styles sealed and valved stationary batteries. Here's a link:

You can use automotive lead acid batteries but you will get better performance from a UPS application designed battery. Clearly the cost of an automotive battery will be less. If you use an automotive one, support it it such a way that you can on occasion give it a kick to jar the plate bubbles loose. When I was still working we had custom designed electric resistance welders that depended on huge truck batteries. They were supported on a low slung rocking cradle which had a long lever arm handle. Each morning the operator was instructed to give the arm a yank which banged the battery cradle against a stop jarring the bubbles free. I'm sure there is more info on USP battery vs. automotive batteries out there, I just haven't found it in a quick search.

Optima batteries use a wet fiberglass mat instead of liquid acid,, maybe the bubbles are not a problem with this design?? you can mount an Optima battery in any postion,, even upside down.

Greg L