Inverter/Battery backup for Harman P68

[anon_ymous]

Hi all,

Great to find you guys!

We recently purchased a home with a 2015 Harman P68 that we'd like to be able to run on battery backup, should we have a power outage. I've been reading the threads, all of which recommend a sine-wave inverter, however, what's unclear to me is why Harman only recommends 2-3 Tripplite units; the APS700HF, APS750 and APS1012SW (with the last being the only sine-wave inverter)?

Do we need to go with one of the Tripplites? What's the most economical way of setting up a reliable backup?

 

[bogieb]

The reason they only recommend a couple is because that is all they tested the stoves with. Perhaps they are partners or they were the only ones to provide test units for free, or they are the only ones they that will guarantee not to change the inner workings without notifying Harman so they can make sure they are compatible.

Last I saw, the newer manuals didn't mention the The APC (American Power Conversion) model #BE750G. Part of that may be because those are no longer made (I don't know why they discontinued that size and now you can only get 650 or 1500 - not in between. But I think they came out of the manual before those were discontinued (maybe they got notice that they would be discontinued?)

I don't use a tru backup, just the UPC that will let the stoves shut down gracefully in case of power failure.

 

[scajjr2]

I put the charger/inverter & batteries I have in place in 2019 when I was still working and I wanted to have something to run the stove for my wife in case the power went out while I was at work as she can't get the generator out and hooked up to the house. Have since retired so it's probably overkill now but it'll run the stove for 10 hours.

note- they weren't cheap 2 years ago, inverter/charger is now $538 was $475 then, batteries still about $180 ea.

sam

 

[Montecarlossfan]

I am using the aps750, I purchased it used for 150 and bought a 200ah battery which I haven’t tested runtime but should be in the 15 hour plus range. I was at 8 hours and called it more than good.

You do need to change a dip switch to have it continue running otherwise on non sine wave the stove begins shutdown.

 

[anon_ymous]

Yea, maybe I need to keep an eye out for a second-hand one. Is there any reason I couldn't purchase something like this? Also sine wave and 1000W, but at a fraction of the cost of the APS1012SW: https://ca.renogy.com/renogy-1000w-12v-pure-sine-wave-inverter/

 

[Ocelot]

My understanding is at least some of the Harman recommended UPS is that they trigger the stove to go into shutdown mode. The consensus is that the stove sees the non pure sine wave and triggers shutdown, along with pulsing the combustion blower to evacuate smoke while shutting down. There is a dip switch setting that will change how that works, but I don't know the details.

That said, I use a larger pure sine UPS and tested it with my Harman P43. It continues to run the stove as if nothing happened. The first UPS I used was a Cyberpower CP1500PFCLCD and simulating a power outage by unplugging it, it ran the stove on low for 35 minutes before I plugged it back in. the display said I sill had 12 minutes left, but I didn't want to run it to empty.

I then got a great $60 deal on a used much more expensive APC SMT1000 that uses larger batteries which I already happened to have a new set of and during simulation, that ran the stove for over an hour before I ended the test. I estimate I could have gotten another 30 minutes. According to the UPS display, the stove was only bouncing between 85 and 120 watts, depending on auger and room fan which I kept on low. I'm sure it would be less if I was running the stove on high.

That's more than enough time for me to start the generator if needed. We fortunately rarely lose power for more than an hour anyway.

Ray

 

[mr meener]

the heck with batteries get a small generator with an inverter

 

[maraakate]

My understanding is at least some of the Harman recommended UPS is that they trigger the stove to go into shutdown mode. The consensus is that the stove sees the non pure sine wave and triggers shutdown, along with pulsing the combustion blower to evacuate smoke while shutting down. There is a dip switch setting that will change how that works, but I don't know the details.

That said, I use a larger pure sine UPS and tested it with my Harman P43. It continues to run the stove as if nothing happened. The first UPS I used was a Cyberpower CP1500PFCLCD and simulating a power outage by unplugging it, it ran the stove on low for 35 minutes before I plugged it back in. the display said I sill had 12 minutes left, but I didn't want to run it to empty.

I then got a great $60 deal on a used much more expensive APC SMT1000 that uses larger batteries which I already happened to have a new set of and during simulation, that ran the stove for over an hour before I ended the test. I estimate I could have gotten another 30 minutes. According to the UPS display, the stove was only bouncing between 85 and 120 watts, depending on auger and room fan which I kept on low. I'm sure it would be less if I was running the stove on high.

That's more than enough time for me to start the generator if needed. We fortunately rarely lose power for more than an hour anyway.

Ray

What's the energy usage of leaving the UPS plugged in all the time since it will have to maintain the battery?

 

[anon_ymous]

The reason they only recommend a couple is because that is all they tested the stoves with. Perhaps they are partners or they were the only ones to provide test units for free, or they are the only ones they that will guarantee not to change the inner workings without notifying Harman so they can make sure they are compatible.

Last I saw, the newer manuals didn't mention the The APC (American Power Conversion) model #BE750G. Part of that may be because those are no longer made (I don't know why they discontinued that size and now you can only get 650 or 1500 - not in between. But I think they came out of the manual before those were discontinued (maybe they got notice that they would be discontinued?)

I don't use a tru backup, just the UPC that will let the stoves shut down gracefully in case of power failure.

Is your UPS non-sinewave, and does it trigger the stove to automatically shut down?

 

[Ocelot]

What's the energy usage of leaving the UPS plugged in all the time since it will have to maintain the battery

Very little. Once the batteries are charged they use very little power and are only maintaining the battery along with whatever power the electronics use. A quick search estimates that a UPS only uses between 3.5 and 10 watts when the batteries are charged and it's just doing it' thing.
Does a UPS increase Electric Bill?

Ray

 

[velvetfoot]

I don't have a pellet stove but I'll add these observations anyway.

If there isn't sufficient draft for the smoke of the dying pellet fire to evacuate, you'd need a ups to shut down gracefully, ie, without smoking up the house.

If you did the dip switch, what happens when the ups runs out of juice? Does it shut down gracefully? Without the sufficient draft, it could smoke up the house if the battery got real low and you didn't realize it, or were out of the house.

If it did get shut down, and you wanted to restart on battery power, (I don't know if this could even be a scenario), but if you used the electric heating elements to start, that would be what, 1200 watts? If you had a small inverter generator, you'd still have to be careful.

 

[Ocelot]

If it did get shut down, and you wanted to restart on battery power, (I don't know if this could even be a scenario), but if you used the electric heating elements to start, that would be what, 1200 watts? If you had a small inverter generator, you'd still have to be careful.

My Harman igniter is only a bit over 300 watts and the UPS would never need the igniter on mine since I only use it on initial startup. To be perfectly honest, I'm not all that concerned with the amount of smoke that would happen. I'd actually be more concerned with the small risk of back burn on my new bottom feed Harman. Years ago, before I used a UPS I had two instances where power was lost during operation. There was a bit of smoke leakage but certainly not enough to fill the house with smoke. The amount of burning pellets in the pot at any given time I could hold in my two cupped hands if I could. I do have a small amount of natural draft, but not enough to remove all the smoke. One of the times the power was only off for about 3 minutes and when it came back on, the stove just started back up and fed pellets and continued. There was a bit of smoke and I could certainly smell it, but not enough to set off smoke detectors. The other time, the fire cooled too much and when turned back on, it just errored out. Heck, back in the day when I was a kid, I've had that much smoke get in the house starting the old stone fireplace.

Edited to add: If the battery wore down, it would just be like what I assume are the majority of pellet stoves out there that don't use a UPS. It would leak some smoke and die out. The amount of time my UPS runs should cover most nuisance power outages of less than an hour. I have the generator after that.

Ray

 

[velvetfoot]

I was thinking the smoke issue was more than it apparently is.
I think my pellet boiler needs more wattage

 

[bogieb]

Is your UPS non-sinewave, and does it trigger the stove to automatically shut down?

Yes it is, as soon as a stove is running of the battery, it will start pulsing the exhasut fan to evacuate the smoke (I guess the pulsing saves some battery charge?), and the stove goes thru the shutdown process. When power is restored, since the stove is on auto, it starts itself back up. I rarely lose power for more than an hour or two, so this works well for me.

I use APC BE750G - which are no longer available.

 

[Havilcek stole the ball]

the heck with batteries get a small generator with an inverter

My approach as well. The leaked smoke is not enough to cause any harm to any people, can't speak for the white curtains though. The generator is right out in the shed.

 

[anon_ymous]

Thanks, all! I've been swayed toward either not bothering with anything at all, or going with a non-sinewave UPS. Would there be any risk in my doing a test? Pulling the plug on the stove while it's running and supervise it burning out naturally? If the smoke starts leaking out, I'd keep the igniter off and everything else off, then plug it back in?

 

[Mt Bob]

That is how I tested my APC, unplugged the APC UPS, and after about 20 minutes became obvious it was not going to go into shut down.

 

[anon_ymous]

That is how I tested my APC, unplugged the APC UPS, and after about 20 minutes became obvious it was not going to go into shut down.

Did you wait until it was entirely cool before starting it again? Wondering whether if I didn't, any residual gasses might ignite.

 

[Mt Bob]

I never let it go out. Unplugged the UPS, it kept running, quite obvious it was not going to go into shut down,which is what I wanted anyway, so flipped switch to MAN, turned room blower to low, because wanted to see how long it would run. When the UPC battery was getting low, plugged it back in. I seem to remember it was over an hour.

 

[anon_ymous]

I never let it go out. Unplugged the UPS, it kept running, quite obvious it was not going to go into shut down,which is what I wanted anyway, so flipped switch to MAN, turned room blower to low, because wanted to see how long it would run. When the UPC battery was getting low, plugged it back in. I seem to remember it was over an hour.

I see. What I would like to do is a bit different; I'm not connected to a UPS. I'd like to find out whether the chimney is sufficiently vented to warrant not bothering with purchasing one. We have the occasional outage, but nothing usually past 4 hours, and the house is double or triple brick—I was pleasantly surprised how well it retained heat when we let the stove run out to clean it on a colder day.

 

[Mt Bob]

Ah. Well if you have any verticle flue at all, I seriously doubt you will get any smoke from a Harman, UNLESS--1 it is running on high when you unplug it, 2- it is a really windy day.

 

[anon_ymous]

Ah. Well if you have any verticle flue at all, I seriously doubt you will get any smoke from a Harman, UNLESS--1 it is running on high when you unplug it, 2- it is a really windy day.

Here's a picture of the flue. Not long, but after the 90º turn, the chimney is LONG—must be [conservatively] 30 ft—would a chimney that long be affected by wind? We do run the blower on high, because we're heating 2800sq ft with it... Think we'd have an issue? Worth pulling the plug and trying?

 

[Mt Bob]

I doubt you get any smoke to amount to anything. But remember, combustion motors are not sealed,on a pellet stove, there is no way to seal them. I have had just a wiff of "burnt wood"smell in my house, on a windy day, when the power went out, from the stove going out.

 

[anon_ymous]

On second thought, we'll get a non-sinewave UPS and let the stove shut down properly. They're not that expensive and since we leave the stove running while we're sleeping, it'll be one less thing to worry about. And if the power goes out for any extended time, we'll connect the modem

Thanks so much for your (and the others) brainstorming this with me!

 

[shtrdave]

Would you really have smoke pouring out of it anywhere? Unless you didn't have a cold/outside air intake on it. I can see if you just use room air the smoke coming out of that intake. other than some leaking around the door seals where would it come from? I would be more concerned about burn back through the auger, to the point if I was home when power went out, I would open the door and scrape everything from the fire pot in to the ash pan, then cover that with ash if there is enough in the pan.

I guess I would like to have something to run the stove just for the heat, at least until I can get a kerosene heater fired up.