Planning stage

[swfl_extreme]

Quick question....since I am wanting to run the AC power through a panel, should I feed the panel with 120V or 240V? If 240V, would it be better to get (2) single phase inverters or (1) split phase inverter?

 

[John Frum]

Residential load centers in North America are 120/240VAC split phase.
All things being equal I prefer split phase inverters for larger scale stationary applications.
If you will need more than one they need to be stackable.

How is your energy audit coming?

 

[swfl_extreme]

Residential load centers in North America are 120/240VAC split phase.
All things being equal I prefer split phase inverters for larger scale stationary applications.
If you will need more than one they need to be stackable.

How is your energy audit coming?

Waiting on the meter you suggested to arrive and then I will be filling out the spreadsheet

 

[illushinz]

Sounds like a single 6-12kW hybrid inverter w/ 240V split-phase AC might do the trick for you.

Depending on your budget and comfort level with chinese electronics (and, really, whether you think you might grid-tie this system), there are a lot of choices out there ranging from Growatt, MPP, Sol-Ark, etc. Some sites to check out include: santansolar.com, watts247.com, and signaturesolar.com (there are others, but just to name a few of the popular options here).

Edit: As one example of a more budget-oriented inverter.. these Growatt Hybrid inverters are capable of stacking - so while they're only 120v, they can be paralleled for split-phase 240V: https://signaturesolar.com/growatt-5kw-stackable-off-grid-inverter-spf-5000-es/

Edit 2: I didn't explain above, but a hybrid inverter has the benefit of simplifying a solar system. Otherwise, you'll deal with (at a minimum), a separate MPPT charge controller, and a DC -> AC inverter. Often times you'll need additional parts you might not've, if you had gone with a hybrid inverter

I saw a couple of Will's videos on the Growatt, look like a great product. Because they are stackable for split-phase, would a person be able to run one, wired to one side of a normal residential AC panel, and then at some point add a second for the alternate side of the panel? (Total idiot on terminology, my small AC distribution panel is setup for 120/240, so it has two lugs, each powering alternating contacts for breakers.

 

[swfl_extreme]

So, I received my watt meter and of course the first thing I wanted to measure was my wife's dog grooming blow dryer. To be honest, I haven't really messed with the thing since she got it. I gave incorrect information before, it is only a standard (2) prong plug without a ground. On the dryer itself, it has (2) switches. (1) switch is for the motor and (1) switch is for the heat.

I plugged the watt meter into the GFCI plug in the bathroom that my wife has been using the dryer with. I first turned on the motor switch at full speed and the watt meter was showing right around 1500w as @John Frum had suggested. Then I hit the heat switch for Low heat and the watt meter read 1890w and the screen on the watt meter was flashing OVERLOAD. I turned it all off and told my wife that she should NEVER use the heat function on this thing in the house again.

In summary, I don't know what the power consumption would be with full speed blower motor and HI heat, but it would easily be over 2kW.

Now that I have my watt meter, I will start measuring some of my battery chargers, tools, computer, etc. that will be in my garage. I will have to estimate the garage door opener and lights as none of these are currently present.

 

[MisterSandals]

I will have to estimate the garage door opener and lights as none of these are currently present.

Just to be clear, you need the amount of time each day that these appliances will be running. So a garage door opener, may run 5-10 times a day. Lets say for 15 seconds each way. Lets say 10 up, 10 down, 15 seconds:
20 x 15 sec x (1hr / 3600 sec) = .083h
Guessing 500w x .083h = 41Wh per day (not much)

Whereas a 150W laptop x 5h = 750Wh

 

[400bird]

I plugged the watt meter into the GFCI plug in the bathroom that my wife has been using the dryer with. I first turned on the motor switch at full speed and the watt meter was showing right around 1500w as @John Frum had suggested. Then I hit the heat switch for Low heat and the watt meter read 1890w and the screen on the watt meter was flashing OVERLOAD. I turned it all off and told my wife that she should NEVER use the heat function on this thing in the house again.

In summary, I don't know what the power consumption would be with full speed blower motor and HI heat, but it would easily be over 2kW.

Wow, that's a surprise! And good recommendation for the end user.

I'd want to get real load numbers. You can get a clamp style amp meter and either split an extension cord or somehow clamp a single conductor and run the blow dryer on high.

With real energy numbers, you could cut the plug off the end of the cord and install a properly rated plug and receptacle.

 

[swfl_extreme]

Wow, that's a surprise! And good recommendation for the end user.

I'd want to get real load numbers. You can get a clamp style amp meter and either split an extension cord or somehow clamp a single conductor and run the blow dryer on high.

With real energy numbers, you could cut the plug off the end of the cord and install a properly rated plug and receptacle.

I do plan to do further testing, but I will be doing it on my Generac 5500W generator. My house is a wood farm house built in 1948, so I'm not going to risk running that thing in the house. Thankfully the house has upgraded electrical and plumbing, but still not worth the risk.

 

[swfl_extreme]

Just to be clear, you need the amount of time each day that these appliances will be running. So a garage door opener, may run 5-10 times a day. Lets say for 15 seconds each way. Lets say 10 up, 10 down, 15 seconds:
20 x 15 sec x (1hr / 3600 sec) = .083h
Guessing 500w x .083h = 41Wh per day (not much)

Whereas a 150W laptop x 5h = 750Wh

I appreciate the great advice. To be honest, neither the garage or the other (2) outbuildings will see much daily use. Like, occasionally I will work on projects in the garage, but I'm not in there doing stuff every day. I do store all of my tools in there and 2 cars. The lights, opener, battery chargers, and iMac will get the most action. The chargers and iMac will be in standby most of the time. As this will be an off grid system, I want to oversize it for the days that I am using power tools (drill, saws, dremel, etc.) This is the tricky part of doing an energy audit because it's not routine use of power.

 

[swfl_extreme]

I am currently establishing a baseline. I have the watt meter hooked up in the garage via an extension cable from the house. From the watt meter it goes to a power strip. On the power strip, I have my Ryobi Plus (6) bay charger, (2) Greenworks 60V chargers, a JBL bluetooth speaker, a Craftsman 18V single battery charger, and my battery maintainer for my one car that has the worst battery ever designed for a vehicle. I will check in 24 hours and see what the Wh was. I will also go out and run some power tools tomorrow to get that data into the mix.

 

[MisterSandals]

On the power strip, I have my Ryobi Plus (6) bay charger, (2) Greenworks 60V chargers, a JBL bluetooth speaker, a Craftsman 18V single battery charger, and my battery maintainer for my one car that has the worst battery ever designed for a vehicle. I will check in 24 hours and see what the Wh was.

Those should be pretty constant so getting an hours worth of data is probably sufficient. For some, just the number of momentary watts is usually better than a big glob of things on a power strip.

Things like a refrigerator, that cycle on and off, have defrost cycles... these are the big ticket items to monitor for 24 hours.

 

[swfl_extreme]

Those should be pretty constant so getting an hours worth of data is probably sufficient. For some, just the number of momentary watts is usually better than a big glob of things on a power strip.

Things like a refrigerator, that cycle on and off, have defrost cycles... these are the big ticket items to monitor for 24 hours.

Yeah, I was originally going to get just a snap shot, but I know that the battery maintainer on my car will randomly kick on at some point because that battery is horrible.

 

[swfl_extreme]

Just a quick follow up....When I went out to the garage today I was at 19.5 hours of the watt meter running and had used 0.422kWh. I did some work in the garage where I used an air compressor (about 15 minutes), a wet/dry vac (about 30 minutes), a miter saw (about 10 minutes). I finished up in there and looked at the watt meter and I was at 22 hours and 0.633kWh.

 

[John Frum]

Just a quick follow up....When I went out to the garage today I was at 19.5 hours of the watt meter running and had used 0.422kWh. I did some work in the garage where I used an air compressor (about 15 minutes), a wet/dry vac (about 30 minutes), a miter saw (about 10 minutes). I finished up in there and looked at the watt meter and I was at 22 hours and 0.633kWh.

Consumption over time is one dimension to the problem. The other is instantaneous peak consumption.
Both determine the battery specification.
The latter determines the inverter specification.
Motor loads have use 3 to 7 times the runtime draw to get the rotor spinning.
This peak draw can be a only a couple of hundred milliseconds but still be enough to make an inverter fall over.

 

[swfl_extreme]

Consumption over time is one dimension to the problem. The other is instantaneous peak consumption.
Both determine the battery specification.
The latter determines the inverter specification.
Motor loads have use 3 to 7 times the runtime draw to get the rotor spinning.
This peak draw can be a only a couple of hundred milliseconds but still be enough to make an inverter fall over.

I will be taking individual readings, but I wanted to see a typical "day in the life" kind of picture