Insert blower running off an inverter/battery. How long will it last? Power already flickering here

[Brian26]

Power already flickered here and the storm is just starting. Thinking I will probably loose power.

I have a Walmart deep cycle battery. As well as my tractor battery. It says its rated at 1 amp for 125 hours. So I guess 125 amp hours.

I hooked my killawat up to my blower and on high it draws .83 amps/53 watts.

I own one of those 1000 watt harbor freight cheap 2 cycle gas generators. Rather than run that overnight if needed I think the batteries with a 400w clamp on inverter is a better option. Don't need to worry about fueling it and it would probably get buried in the feet of snow we are supposed to get. I could always use the generator to quick charge my batteries with my charger during the day. They take about 3-4 hours to recharge.

What kind of run times can I expect just powering the blower? So lets round up and say I will have a 1 amp draw. So I can expect 12.5 hours or 125 hours? Thanks.

This is the battery I have,

http://www.walmart.com/ip/EverStart-Maxx-Group-Size-29-Marine-Battery/20531539

The inverter I have.

http://www.harborfreight.com/400-watt-continuous800-watt-peak-power-inverter-61479.html

And worst case scenario I have one of these as well.

http://www.harborfreight.com/900-Pe...zIjoiOTkuOTkiLCJwcm9kdWN0X2lk IjoiOTA1NyJ9

 

[CrufflerJJ]

If you've got jumper cables, and your "deep cycle batteries" are 12 volt, you could probably charge them from your car (as if you were jump starting the batteries). Just an idea....

 

[bholler]

I would let it run on the batteries over night if they go dead it wont be a big deal you wont get as much heat off the insert but it will be fine and will still put off some heat then fire up the genny in the morning and charge the batteries

 

[Dakotas Dad]

Three things..

you don't really want to ever take a lead acid battery below 50% charge, no matter what the type is. Deep cycles handle it "better" but "better" is not the same as "no damage"

Those cheap clamp on inverters are usually less than 75% efficient, so you have about 25% overhead, lost power.

several friends of mine who needed their blowers to run on inserts and stoves during the '09 ice storm discovered the fans wouldn't run on the inverters modified sine wave.

 

[bholler]

several friends of mine who needed their blowers to run on inserts and stoves during the '09 ice storm discovered the fans wouldn't run on the inverters modified sine wave.

Yeah i heard that to but i was assuming that they already tested it and it worked off the inverter

 

[BrotherBart]

Cabled in parallel those batteries should run that blower all night easily. One probably will. Run time calculations on batteries and battery banks are a nice math exercise but inverter loss, battery condition and on and on make it kinda useless.

 

[Brian26]

I already tested the setup and the blower runs with absolutely no difference in sound or performance than when its plugged in regular house current. Those numbers were when the blower was on high. On low the draw is much lower. Without my blower my Drolet 1800 insert just doesn't put out the heat with the blower off.

 

[Dakotas Dad]

I already tested the setup and the blower runs with absolutely no difference in sound or performance than when its plugged in regular house current. Those numbers were when the blower was on high. On low the draw is much lower. Without my blower my Drolet 1800 insert just doesn't put out the heat with the blower off.

Good to know you have tested it BEFORE the need

And also, that "no blower, no real heat" was what our friends experienced. Thankfully, all of them have developed a solution so if we ever have a situation like that again.. they are ready.

 

[ironworker]

If you are home you should keep a nice hot fire going to bring your house temp up, fans on inserts are overrated. I have an insert and don't really need the fan till it drops into the low 30's to upper 20's and even still I can maintain the heat in my house with just a hot fire going.

 

[Grisu]

Pull off the surround and the insert should work fine even without the blower. Of course, that assumes you have a proper block-off plate and you don't lose too much/any heat from the back of the fireplace.

 

[maple1]

If you've got jumper cables, and your "deep cycle batteries" are 12 volt, you could probably charge them from your car (as if you were jump starting the batteries). Just an idea....

I wouldn't do too much of that, if the batteries get discharged too awful much. It's not very good for alternators - I would charge with a charger off a genny. Your alternator might handle it OK, but I wouldn't put it through it any more than I had to.

 

[begreen]

In this circumstance it's worth paying for a bit more efficient inverter/charger. That way when the generator is running the battery can be charging. Don't run the battery down much lower than 11.5volts or it may not recover too well.

 

[iamlucky13]

I suppose the OP's power is already out, but just in case, or for the benefit of future readers:

I hooked my killawat up to my blower and on high it draws .83 amps/53 watts.

Something is off there. 53 Watts on 110 to 120 VAC power should be 0.48 to 0.44 Amps. The KillaWatt is supposed to be good about not getting screwy readings like this from power factors less than 1, so I'm puzzled.

It's minimally relevant though. 53 Watts is the right general ballpark for a small stove blower. Mine draws 70 W on high and 30 W on low.

Keeping in mind the difference between the amp-hour rating of the battery at 12V, and the KillaWatt measurement at 120V, and leaving some room for battery aging (125 Amp-hours sounds a bit high for that size battery anyways) and inverter efficiency, I'd expect to get 10-15 hours out of the battery. Turning the fan down will increase the time - maybe as much as double it.

If you want to manage things carefully, check the battery voltage periodically. 11.5 V is good cutoff. Definitely don't go below 10.8V. Marine batteries usually do better with deep discharges than ordinary starting batteries, although not as well as dedicated deep discharge batteries. Going beyond 50% regularly will wear it out fast, but one or two deep discharges won't kill it. Just shorten the service life somewhat (probably 5-10%). Personally, I'd call the reduced value a reasonable cost for keeping the house comfortable overnight through a power outage, without having to keep an eye on or listen to the generator all night.

If it's a long power outage, charge during the day with the generator. You should be able to run a battery charger and your fan at the same time even with that little generator.

I don't think I'd run the tractor battery in parallel with the marine battery, just because they're fairly different, and because the tractor battery will likely lose more life from being deep cycled. Try to stick to alternating charging / discharging of the marine battery and fall back on the tractor battery if you get desperate.

If you are home you should keep a nice hot fire going to bring your house temp up, fans on inserts are overrated.

My experience plainly contradicts this. Air circulates much more poorly around inserts without fans than free-standing stoves without fans. The less it projects into the room, the worse. It will still provide useful amounts of heat, but not nearly as much. Pulling off the surround should help, but having a fan is the ideal solution.

 

[begreen]

Convection from an insert is going to vary dramatically depending on the design. Flush inserts in general are heavily dependent on the blower for convection. An insert that projects out far onto the hearth will normally convect a lot better naturally than flush units, but often not as well as when the blower is on.