Battery backup for 1 HP 850 CFM blower?

[Badfish740]

In the interest of still being able to get effective heat from my Englander add-on furnace during a power outage I'd like to add a battery backup. It doesn't have to be fancy-just a deep cycle RV battery and an inverter, but the blower motor is fairly beefy, so can anyone recommend a good one? I want to have the ability to run the blower periodically (as dictated by the thermostat) for at least a 24 period if need be. The motor is rated at 12.0 Amps at full load, so startup would likely be at least 13? How can I determine whether or not a particular inverter will be up to the task? Also, what should I look for in a deep cycle battery in terms of reserve capacity and Amp/Hours?

 

[lobsta1]

Since no one else has answered, I'll bring this back to the top for you. Just remember that 12 A @ 120V will come to 1440 watts. That is a BIG load. A large microwave uses 1500 watts. I've included a link to the Xantrex site. If you scroll down, it shows a large microwave on a 8D battery can run for 30 minutes.
Al

http://www.xantrex.com/web/id/724/DocServe.aspx

 

[smokinj]

In the interest of still being able to get effective heat from my Englander add-on furnace during a power outage I'd like to add a battery backup. It doesn't have to be fancy-just a deep cycle RV battery and an inverter, but the blower motor is fairly beefy, so can anyone recommend a good one? I want to have the ability to run the blower periodically (as dictated by the thermostat) for at least a 24 period if need be. The motor is rated at 12.0 Amps at full load, so startup would likely be at least 13? How can I determine whether or not a particular inverter will be up to the task? Also, what should I look for in a deep cycle battery in terms of reserve capacity and Amp/Hours?

Thats a big load for battery

 

[jdemaris]

In the interest of still being able to get effective heat from my Englander add-on furnace during a power outage I'd like to add a battery backup. It doesn't have to be fancy-just a deep cycle RV battery and an inverter, but the blower motor is fairly beefy, so can anyone recommend a good one? I want to have the ability to run the blower periodically (as dictated by the thermostat) for at least a 24 period if need be. The motor is rated at 12.0 Amps at full load, so startup would likely be at least 13? How can I determine whether or not a particular inverter will be up to the task? Also, what should I look for in a deep cycle battery in terms of reserve capacity and Amp/Hours?

A blower motor that big doesn't make any sense - at least not to me. 12 amps at 120 VAC is 115 amps at 12.5 VDC. I've got a large hot-air wood furnace with a three-speed blower. 1/3 - 1/4 - 1/5 and draws 5.9 amps on the highest setting at 120 VAC. Probably draws twice that at startup - i.e. 12 amps.

That being said, most inverters rated 2000 watt full-time and 3000 watts surge will not run most motors with a 12 amp surge-draw. That's what many of my hand-held saws use. A cheap Chinese 3000 full-time inverter will work (like Harbor Freight sells).

A better unit, with a built in battery charger and generator starter (if desired) is a Xantrex/Trace DR2412. Very rugged unit.

Assuming your motor draws 6 amps when running at 120 VAC, that's 720 watts for an hour if running steady with no starts or stops. Two 6 volt deep-cycle Trojan golf-cart batteries will give 1350 watt-hours of reserve at 12 volts and will run your blower for around two hours.

 

[pen]

I am surprised the the electrical costs of running that fan justify it.

That is one monster fan using that much electricity.

pen

 

[Badfish740]

I am surprised the the electrical costs of running that fan justify it.

That is one monster fan using that much electricity.

I think I'm wrong about the amperage-it's most likely what others have said with regard to 12 amps being the startup surge. Thanks for the replies.

 

[Redox]

Is it possible that you are reading a nameplate that says "less than 12 amps"? I think that UL or the NEC used to require that phrase on small permanently connected appliances as a way of saying that it should be on a 15 amp circuit without actually specifying actual current draw. Nowadays they specify full load amps (FLA) and minimum circuit ampacity (MCA). The FLA should be on the motor nameplate if it isn't on the unit nameplate.

1 HP is by definition 746 electrical watts, but with typical motor efficiencies winds up being about 1200 watts. Most blowers capable of 850 CFM would have a motor of about 1/4 HP and really draw between 300 and 600 watts depending on motor type. A direct drive PSC motor would probably peak at about 900 watts to start while a belt drive split phase motor would be even higher than that.

In any event, you are going to need a pretty serious chunk of lead to run that fan for any useful amount of time. I think a generator would be more appropriate.

Hope this helps...

Chris