Small solar/battery setup ?

[Guest]

If this is not the rite area for this question sorry move it please !

Wanting a backup setup that could power my house furnace blower motor . Furnace is gas just need to power the blower in emergency situations.

What all do I need to achieve this ? I only have $1000 to invest at the time . Will add on later .
Batteries, solar panels etc ?

Thanks for your time

[Wy_White_Wolf]

What's the wattage rating of the fan?

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[Mavmike72]

To be honest I have no idea . I can see if I can get to the motor later when I get home from work .

[Mavmike72]

Looked online it use 500 watts while in use

[lkruper]

Looked online it use 500 watts while in use

If your furnace plugs into an outlet, you can get a handheld Kill-o-watt meter which will give you the actual wattage. Many times the nameplate is higher. The other thing to impact it will be how often the fan runs. I presume it runs more when the furnace is heating which would depend on the outside temperature?

Another thing you may want to consider is whether or not you need solar. If the outages you expect are infrequent and not extremely long in duration, you can charge batteries from your electrical outlet more inexpensively and effectively than solar. That is what I am considering for some areas I want to back up.

500w continuous adds up quickly! For example:

500w X 24 hrs X 1.2 (efficiency) X 2 %DOD = 28800 watt hours
28800 watt hours / 48v = 600 AH

That's a big bank!

But probably your furnace fan is not running 100% and the 500w may be when it surges. That's what you need to find out.

[Mavmike72]

The fan is hard wired in with no plug . The fan doesn't run continuously on when the burners on . I guess the only reason for the solar panels is I really would love one day to run my house on solar with a big battery bank . Just trying to get my feet wet with this setup .

[Mavmike72]

Any and all advice is greatly appreciated ! Thanks

[lkruper]

The fan is hard wired in with no plug . The fan doesn't run continuously on when the burners on . I guess the only reason for the solar panels is I really would love one day to run my house on solar with a big battery bank . Just trying to get my feet wet with this setup .

I have never used one, but I understand you can get a clamp-on amp meter to measure current to the appliance. However, that raises the issue of how you are planning to power it with solar? If it is on its own circuit you could get a manual transfer switch (load side type) where you can activate and select individual circuits to power. They range in price (I have a Reliance 10-circuit from Lowes) that was about $400. If you are handy, you can install it but I paid an electrician. Then the output of your inverter (or generator, etc) can feed that circuit. That takes a big bite out of your $1000 budget.

I suppose alternatively you could also modify your setup to convert the hard-wired fan into a wall socket (that is what is in my garage).

One thing you should know is that supplying your own electricity via solar and using batteries (which will be necessary) will always be way more expensive than utility power. That will be true until (if!) battery backup comes way down in price. But if you want to get experience with solar for fun/hobby, that should not deter you from making a small system. However, depending on how bullet-proof you want your furnace to operate (eg are you away in winter and afraid your pipes will freeze?) you might want to select something that is not a critical system to power for your first experiment.

[Mavmike72]

As far as feeding the fan motor it would be from the batteries and inverter of some sort . Their is a 110 switch beside the furnace that I have taken apart before and on the furnace side of the switch ran those wires to my generator ( if that makes since ) to power the fan . I would wire it similar in an emergency to the inverter I'm assuming.

[lkruper]

As far as feeding the fan motor it would be from the batteries and inverter of some sort . Their is a 110 switch beside the furnace that I have taken apart before and on the furnace side of the switch ran those wires to my generator ( if that makes since ) to power the fan . I would wire it similar in an emergency to the inverter I'm assuming.

I am not an electrician, but make sure you are powering just the furnace and not an entire circuit. Otherwise, potentially you could be back feeding inside your house or even to the grid which is dangerous.

[Mavmike72]

Yep I understand stand what your saying . The hvac guy told me it was ok to do it that way . Once you disconnect the wires at the switch you are not tied to the house any longer .

[Mavmike72]

Any input on solar panels , batteries etc ? Brands ?

[lkruper]

Any input on solar panels , batteries etc ? Brands ?

Hard to do without accurate load defined.

[Wy_White_Wolf]

The fan is hard wired in with no plug . The fan doesn't run continuously on when the burners on . I guess the only reason for the solar panels is I really would love one day to run my house on solar with a big battery bank . Just trying to get my feet wet with this setup .

But you have to plan for worst case when doing things on batteries. And that 600AH turns into 1200AH when you find out that they shouldn't be discharged past 50%.

Best advise - get a generator and rewire the furnace.

2nd best - Build a UPS style system that will allow you run through the night and charge the ups with a generator during the day. Use grid power to keep the batteries on a float charge when it's available. Solar could be added later.

Worst advise - try to charge the batteries with solar only. Take a look at why you loose power. Most likely it's weather. Which means you have very limited solar to recharge the batteries. Also that means the panels are setting there doing nothing the 99% of the time that you do have grid power.

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[Mavmike72]

I've got a generator . Was just trying to plan if I ran out of gas lol