Emergency Power

[EmergencyPower]

I want to build an emergency power set up to run off my truck. I need a sinewave inverter capable of running a 2hp well pump.
Any ideas? What size of alternator would I need? Is this even doable? Truck to inverter to house is what I want. Can this be done?

 

[CoolWill]

It's doable, but 2 HP may need a low frequency inverter to get it started. Assuming that the pump runs at full power you'd need to give it about 124 amps. I think a separate battery from the starting battery is prudent. You can charge it through an isolator.

Personally, I just use a small inverter generator.

 

[niktak11]

It's doable, but 2 HP may need a low frequency inverter to get it started. Assuming that the pump runs at full power you'd need to give it about 124 amps. I think a separate battery from the starting battery is prudent. You can charge it through an isolator.

Personally, I just use a small inverter generator.

At 12V I'd expect it to draw closer to 800-1000A at startup. My 3HP well pump pulls about 15kW at startup so a 2HP one is probably around 10kW.

 

[Supervstech]

How big is the battery in your truck?
What voltage is the 2hp pump?
A 12V to 240V inverter capable of starting a well pump is going to be difficult to source.
If you need to run it from the truck alternator, I think you will need a soft starter for the pump, or a low hp lift pump, then a smaller pressure pump...
Look on here for threads addressing the issues and solutions.

 

[HighDesertOffgrid]

How big is the battery in your truck?
What voltage is the 2hp pump?
A 12V to 240V inverter capable of starting a well pump is going to be difficult to source.
If you need to run it from the truck alternator, I think you will need a soft starter for the pump, or a low hp lift pump, then a smaller pressure pump...
Look on here for threads addressing the issues and solutions.

At 2hp, it's most likely a 240v deep well pump. An expensive endeavor to replace the pump. Standard automotive alternators won't be up to the task for long if you can find and inverter to handle the job.

 

[cs1234]

Good advice for you on this thread. Think of the system as independent of the truck. The truck is merely going to be supplying a charge to whatever system you build that is capable of powering the well pump. Whether you choose to let that be removable or attach it permanently to the truck is up to you.

You need enough surge capacity in your inverter/battery( maybe an ultracapacitor if you want to keep the batteries smaller) system to start the well pump (Locked Rotor Amps rating applies here), and then enough battery to sustain it for it's full load rating for whatever length of time you figure it will run. If it's not running nonstop though, you should be able to have the alternator you already have recharge the battery array for the next time the pump starts up again. You could likely get a good 60-80 amps at 12-14v using the existing alternator in your truck if you aren't doing other things in at the same time.

You don't have to use a 12v inverter for the truck, you can always use a dc to dc charger that will charge a higher voltage battery array so you can source an inverter easier, say a 24v or 48v one.

 

[acdoctor]

If the thought was cheap and simple just get a generator and call it a day.

 

[CoolWill]

At 12V I'd expect it to draw closer to 800-1000A at startup. My 3HP well pump pulls about 15kW at startup so a 2HP one is probably around 10kW.

I just meant continuous draw.

 

[Daddy Tanuki]

If the thought was cheap and simple just get a generator and call it a day.

Best answer right here

 

[HighDesertOffgrid]

Best answer right here

If one could define an emergency as 24 hours or more without power, I would definitely concentrate on storing some of that well water above ground.