What do I need vs What should I get

[MrSunshine1972]

Hey All,

I know there is probably a million threads that address this problem, but I figured I would put my question up anyway. I want to get into solar, but don't know almost anything about building systems. So I figured I can power my shed that has smokers in it. This is a small shed that I normally will run an extension cord to it and power it, but I would love to put a small solar system inside it. I want to do it right, and cost is not a major issue. Inside my shed I have a shop light (led), and a couple of pellet smokers (https://www.recteq.com/RT-340-Wood-Pellet-Grill). I know I need solar panels, charge controller, battery, inverter, and I am guessing some other wires or connections.
I am kind of handy and work well with techie stuff. I am a computer programmer and I am the one who wired my shed with 3 outlets and the overhead shop light. I figured I need enough power to power my smoker for as much as 12-14 hours sometimes, but I don't do that everyday. I might do it once a week or twice a week. I have no problem taking cells and putting them together as long as I don't kill myself LOL. I love the video's by Will, but sometimes he speaks so fast through watt's, volts, watt hours and all kinds of stuff.

If anyone has a list of things I should get, any help would be appreciated....really lost on battery, as I would love to do LiFePO since they last longer and get a better charge and I want the best price.

Thanks ahead of time,
Sean

 

[snoobler]

Welcome to the forum.

Get a kill-a-watt and see how much energy the smoker actually uses.

 

[45North]

Will this be a year-round operation, or seasonal?
Where are you located? Will low winter sun and cloudy weather impact your plans?

 

[MrSunshine1972]

Hey All,

Sorry for the delay, I guess I want to start off with the bare minimum that I can maybe enhance. So to even run anything in my shed, I will need a battery, and an inverter. I see if I want LiFePO and I am not scared of building anything, what should I get to get the best bang for my buck. I am also assuming I need an inverter to turn that battery power into something I can plug into. So below I am looking for suggesttions:

1) Batteries (LiFePO and will build, but don't know what to get on aliexpress or alibaba?)
2) Something to charge the batteries (I can use shore power since I can power this through my house and eventually get the solar panels)
3) BMS (There are so many, which won is the best bang for your buck?)
4) Inverter (Again, I might want to grow this, but I don't want to break the bank)

Here is some information I found about my smoker:
The typical pellet smoker requires about 30 watts (30W) of electrical power when running, and anywhere from 300-500 watts (300-500W) for the 5-10 minutes during startup when the ignitor is running to light the pellets and the fan is running to build the fire in the fire pot. This is very different from an electric grill or smoker which have between 500-1500W continuous power requirements.

You’re going to need a power supply that can handle a short-term 500W startup need, and can then run a 30W device for at least 12 hours, more if possible. And you’ll need a way to invert the DC power from a battery to the 110V AC power the grill uses.

I live in USA, Georgia to be specific. Like I said above, I have a shop light (LED), and 2 of those pellet smokers. I don't think I will be running them both at the same time, and also if I need something very long or batteries are not going to cut it, I can run an extension cord to my outlet and run it off my house. (This is how I power my shed right now. I plug it in when i am using it.)

 

[snoobler]

Eliminate guessing.

Amazon.com

 

[MrSunshine1972]

So I ran my shed for a smoking and this is what I got:

.78 kilowatts
7 hours and 22 minutes

Does that make sense? Did I read it correctly?

 

[snoobler]

.78 kilowatts or .78kWh (killowatt-hour)?

 

[MrSunshine1972]

.78 kilowatts in 7 hours and 22 minutes (I think I read the thing correctly)

 

[MrSunshine1972]

Hey All,

I ran my shed for another about 13 hours. I clicked each button on the "Kill A Watt" tool and I will upload the pictures so I can make sure I am reading it correctly. But below are the numbers:

119.4 Volt
0.69 Amp
77.0 Watt / 83.7 VA
59.9 Hz / 0.92 PF
1.14 KWH / 1308 clock

I hope this helps

 

[snoobler]

The 1.14kWh is the number you use for energy usage.

1.24 * 24/13 = 2.1kWh/24 hr

 

[svetz]

Use Case: Run smoker in off-grid location for 13 hours, 8 min
Power Consumed: 1.14 kWh

The typical pellet smoker requires about 30 watts (30W) of electrical power when running, and anywhere from 300-500 watts (300-500W) for the 5-10 minutes during startup when the ignitor is running to light the pellets and the fan is running to build the fire in the fire pot. This is very different from an electric grill or smoker which have between 500-1500W continuous power requirements.

1140 watt-hours / 13.133 hours = 86 watts on average. Did you see the majority of the energy expended in the first 10 minutes as expected?

The meter reading shows 77 watts, assuming that was at the end? Did it stay at that value for the majority of the time? If so, the startup power may be 1140 - 77 x 13.133 = 130 watts. As that doesn't match your research I'd say possibly the 77 watts has a duty (that is it cycles on/off at some rate).

The reason why that information is important is to properly size the inverter for the correct number of watts, although if 500W is the maximum, then you're probably fine getting an 500 Watt inverter (or larger). If there's any sort of induction (e.g., a motor) the startup surge can be significant.

How many solar panels do you need?
This depends on where you live, use a solar insolation calculator to get a rough idea. For example, let's assume you're from the south (where all the best food is), but obviously not too far south (if you were in Florida you'd be smoking fish and it would only take a couple of hours, ). So, let's say Birmingham Alabama for this math example (use the calculator to get data for your actual location), so in February with a tilt of 41° you get an insolation of 3.69.

What that number represents is the equivalent number of hours of "full strength" sunlight per day. You need 1140 watts of AC power. Let's say your inverter is 85% efficient,

1140 watt hours AC power needed / .85 inverter efficiency = 1342 watt-hours DC power.
1342 watt-hours / .80 round-trip efficiency = 1677 watt-hours needed from solar
1677 watt-hours / 3.69 insolation = 455 watt solar array

Battery Size
As the sun is providing power during the day the battery only needs to provide power for the low-light conditions (dusk and clouds). Let's say your using a lead acid battery with a maximum depth of discharge (DoD) of 50% and an 80% round-trip efficiency... (change to 80% and 90% for LiFePO4).

A 12V battery big enough to do it all would be 1342 watt-hours DC / .50 DoD / 12V = 224 amp-hours. I'm not sure what the minimum size for that would be, it depends how many hours into dusk you run it.

Parts
Panels->charge controller->battery->fuse->inverter. If you only use it a few days a year, perhaps use anderson connectors so you can pull things apart so they can be stored easily? You can also add on all sorts of other bells and whistles depending on how fancy you get. These threads might interest you too:

• Budget Models with Amazing Future Power; some DIY required
• The Peak Jump Start
• Bob's Duracell Powerpack 600 Jump Starter

Will also recently made videos of assembling a milk-crate systems, a must-watch for DIYers.

Hope that helps! There are a lot more example calculations in the FAQ section, but if you have questions just holler.

 

[MrSunshine1972]

Hey All,

So all of this is so helpful. I am guessing I want to do this piece by piece. What sounds like a great idea:

1) getting/building a battery pack that is 225 amp-hour or more
2) charger (at first I can plug it into the wall to charge the batteries)
3) 500+ watt inverter

Then after I get that going, then I can look into panel's and getting that hooked up. So what is the best way to do all 3 or what are people's suggestions. Now remember I am not running a house, this is a shed and if things break it isn't the end of the world, so I don't need the world's best inverter for a million dollars lol.

Sean

 

[svetz]

Don't forget that 225h Ah calculation has guesses in it that might not be applicable for your location and didn't run numbers for LiFePO4 -- it was just meant to show example math.

That number also represented the maximum power needed (as if the smoker were run at night). If the smoker is primarily running during the day you might be able save a bundle by downsizing the battery (that is cheaper to buy it all at once rather than a battery too big for your needs). For example, your total power needs were 1.14 kWh over 13 hours smoking time. If the panels produce enough power for 8 hours, then you only need battery power for the remaining 5 hours, a substantial reduction in battery costs/weight. Plus the panels can recharge the battery the next day when you're not using the smoker, so you wouldn't need to purchase a special charger for the batteries.

Plan it all out first: where will you keep the batteries, where will you charge them, how will you move them around to be recharged (hand cart or garden wagon? A 12V 250 AH AGM will weigh about 165 lbs, but you could get two 6V 250 Ah for two batteries at half the weight each, or two 12V 125 Ah in parallel, or put 2 in series for 24V, etc.). Knowing those sorts of things will help you pick the inverter, most likely two 12V in parallel will give you the best economics, but knowing your options will help decide what gear (e.g., charger) to get and help when you run into unexpected bargains (e.g., I was all set to buy Brand X panels, but saw my #2 pick steeply discounted at purchase time, because I'd already run the numbers I knew they'd work and how much I'd save so switched, no regrets).

Also run the numbers and decide on lead acid vs LiFePO4. See the Battery FAQ for a number of posts, but the one most applicable is probably https://diysolarforum.com/threads/battery-faq.200/post-1128

 

[MrSunshine1972]

Hey svetz,

Thanks for the reply, let me see if I can answer some of the question:

Plan it all out first: where will you keep the batteries, where will you charge them, how will you move them around to be recharged (hand cart or garden wagon? I am going to build a box inside the shed. The shed is very close to my house and currently I run an extension cord to power the shed. My vision was this is not moving, so I will build a battery box. Think of this as a very small house.

Lead Acid vs LiFePO: I am going LiFePO since from everything I read, it is the best bang for your buck. I saw Ampere Time battery for 200 AH for around $850 and I am ok with that.

I am most worried about the battery since that is most of the cost of the system. I want a good battery, but don't want to spend much more then 1k . I also would be ok with building the battery if I can get it cheaper.


Sean

 

[svetz]

... I am going LiFePO since from everything I read, it is the best bang for your buck...

Not a hardware guy, so can't help with the what vendor. But, can run through the math for the stand-alone battery case for LiFePO4

Use Case: Run smoker in off-grid location for 13 hours, 8 min
Power Consumed: 1.14 kWh
LiFePO4 DoD: 80%
Inverter Voltage: 12 V
Inverter Efficiency: 85% (this is an unknown, once you pick your inverter redo the calculations)
Calculations: 1140 watt-hours / .85 / .8 = 1677 Wh, 1677 Wh / 12V = 140 Ah

I also would be ok with building the battery if I can get it cheaper.

Usually that's the case

Here's Will making a full system

 

[svetz]

Will just did a new video that will interest you:

 

[2009Bounder2020]

if you wanna go cheap get 2 6volt golf cart batterys at costco , and a 500watt quality inverter (like victron) and a charger and. yes you need to check the water level once a month since you probably spend alot of time doing the meats in the shed a few minutes to check water levels will save you enough to fill those smokers many times and you can get a charge controller and a couple panels.