Hello, I'm a retired Master Electrician who hasn't worked on a solar system since Xantrex was the rage....lots of catching up to do. In 3 mos. I need to have a working solar system for a home I bought in Mexico. Looking to learn from people with real experience. Thank you.
Hello from Mexico
- Thread starter LywWyr
- Start date
Don B. Cilly
Energetic energy padawan
A working solar system? Easy enough. Get a $1 solar lawn light from your local Chinese outlet and you have one.
Now, if you want a "solar system" to do something more than that, and are looking for advice on the best way to do it, it might be a good idea to specify the actual needs ;·)
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Now, if you want a "solar system" to do something more than that, and are looking for advice on the best way to do it, it might be a good idea to specify the actual needs ;·)
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I didn't know if it was ok to post technical questions in a new member intro....
TampaSteve
New Member
- Joined
- Feb 10, 2022
- Messages
- 19
Greetings from Florida! Good luck with your project. As a retired Master Electrician this should be easy for you.
BentleyJ
Solar Wizard
Go ahead and post a few details regarding your electrical needs: Peak KW load & average KWh for daily, montly, seasonal so you can size your inverter(s), I assume you are referring to a standard 240/120V single phase system with neutral.
With the above info we can then size the PV's based on Lat, Lon, orientation, tilt angle and the amount of available space on your roof or if you prefer a ground mount system. Lastly, is your system grid-tie with NET metering or off-grid with batteries or perhaps Hybrid. If batteries will be included then we size the storage capacity based on 80% depth of discharge for the number of days you need if its cloudy.
There are a number of solar calculators Online that will give a very good estimate of electrical output for your location and panel array orientation.
With the above info we can then size the PV's based on Lat, Lon, orientation, tilt angle and the amount of available space on your roof or if you prefer a ground mount system. Lastly, is your system grid-tie with NET metering or off-grid with batteries or perhaps Hybrid. If batteries will be included then we size the storage capacity based on 80% depth of discharge for the number of days you need if its cloudy.
There are a number of solar calculators Online that will give a very good estimate of electrical output for your location and panel array orientation.
Hello,
My home is off grid and yes 120/240 single phase.The home has propane for heating ,cooking and hot water.
My largest load will be a 240v 30k btu ac unit ,manufacturers data sheet says it consumes 3380w, around 11000w at start up.
I estimate a daily usage of 48,000wh for 6 mos of the year,May-Oct, x31days= 1488kwh monthly.
Based upon my current power bill for a similar sized home I'm renting in the area,the other 6 months Nov-Apr will use 12,258 wh daily =380kwh monthly.
PV watts calculator has an avg solar radiation of 6.72 hrs daily, with the months of Mar- Sept ranging from 6.99- 7.87 and Oct at 6.54 with the lowest being 5.11 in Dec.
Location avgs 80% clear skies with the lowest months being Dec-Feb coming in at 68-71% clear skies.
I was thinking about a 7-8k array using 455w 48vdc panels, a pair of stackable 6k inverter/chargers and 6- 5.25kwh 48vdc lithium server rack batteries.
The house is only 1000 sqft in an L shape , so I don't have much room.Hoping to spend less 20k.
Thanks for any constructive input and product recommendations.
My home is off grid and yes 120/240 single phase.The home has propane for heating ,cooking and hot water.
My largest load will be a 240v 30k btu ac unit ,manufacturers data sheet says it consumes 3380w, around 11000w at start up.
I estimate a daily usage of 48,000wh for 6 mos of the year,May-Oct, x31days= 1488kwh monthly.
Based upon my current power bill for a similar sized home I'm renting in the area,the other 6 months Nov-Apr will use 12,258 wh daily =380kwh monthly.
PV watts calculator has an avg solar radiation of 6.72 hrs daily, with the months of Mar- Sept ranging from 6.99- 7.87 and Oct at 6.54 with the lowest being 5.11 in Dec.
Location avgs 80% clear skies with the lowest months being Dec-Feb coming in at 68-71% clear skies.
I was thinking about a 7-8k array using 455w 48vdc panels, a pair of stackable 6k inverter/chargers and 6- 5.25kwh 48vdc lithium server rack batteries.
The house is only 1000 sqft in an L shape , so I don't have much room.Hoping to spend less 20k.
Thanks for any constructive input and product recommendations.
BentleyJ
Solar Wizard
Having the propane really helps reduce the electrical load. Your 2.5 ton AC unit probably draws less than the 3,380W listed on the name plate. I would put a clamp on ammeter on it first thing and find out for sure. If it turns out that it does in fact pull about 3,000 watts that's super high. Means its a like 10 SEER and should be replaced. At the very least a Hyper Engineering Soft Starter should be installed to reduce startup inrush. I'm using a soft starter on a 4 ton Goodman and it works really well.
The estimated 48Kwh daily electricity usage for May-Oct sounds high unless there is a pool or spa with a pump that runs a lot. If its all related to AC I would seriously think about replacing the AC unit AND looking into insulation and better windows or whatever. I say this because its much cheaper to save a KWh than it is to produce one and save it in a battery for later use.
The other conditions you mentioned are very favorable for Solar. An 8K solar array should average 40KWh production per day and 6 batteries gives you 31.5 KWh of storage and 25KWh usable assuming the standard 80% depth of discharge. Even if you do all the installation work yourself, the 20K budget seems like it is going to get stretched really hard. The batteries alone are $10,000.
The estimated 48Kwh daily electricity usage for May-Oct sounds high unless there is a pool or spa with a pump that runs a lot. If its all related to AC I would seriously think about replacing the AC unit AND looking into insulation and better windows or whatever. I say this because its much cheaper to save a KWh than it is to produce one and save it in a battery for later use.
The other conditions you mentioned are very favorable for Solar. An 8K solar array should average 40KWh production per day and 6 batteries gives you 31.5 KWh of storage and 25KWh usable assuming the standard 80% depth of discharge. Even if you do all the installation work yourself, the 20K budget seems like it is going to get stretched really hard. The batteries alone are $10,000.
WYtreasure
It's not happy hour, I'm just like this.
Hello from Wyoming,
Do you want to swap houses for a few years?
Do you want to swap houses for a few years?
Don B. Cilly
Energetic energy padawan
The only problem with your installation really seems to be the A/C.
I have a 70 sqm (so roughly 700 sqft) house. Fridge, washing machine, breadmaker... I don't use electricity for cooking or heating.
I have 220 Ah of lithium batteries (24V). They pretty much never go below 50% SOC - mostly never below 65.
I don't have A/C :·)
So one could theorise that without it, you wouldn't need much more than that. Probably a bit more - I'm really energy-conscious - but not all that much. So we could say you have an A/C... problem. Problems are meant to be solved. I believe there are many ways to tackle that. If you're interested, we could discuss them.
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I have a 70 sqm (so roughly 700 sqft) house. Fridge, washing machine, breadmaker... I don't use electricity for cooking or heating.
I have 220 Ah of lithium batteries (24V). They pretty much never go below 50% SOC - mostly never below 65.
I don't have A/C :·)
So one could theorise that without it, you wouldn't need much more than that. Probably a bit more - I'm really energy-conscious - but not all that much. So we could say you have an A/C... problem. Problems are meant to be solved. I believe there are many ways to tackle that. If you're interested, we could discuss them.
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BentleyJ, and Don B ,
You guys are 100 percent correct. Ac is by far the biggest issue. Six months of the year the low temps are 70- 85 deg. and the highs are 88-98 deg. There is also considerable humidity.
The home will only be occupied by 2 people. The previous owner only used the home in the cooler months so I have no historical data.
I read online that 20btu per sq ft is the recommended amount for cooling needs. The home is 1000 sq ft total and the bedroom has a 12000 btu ac. We will be running the smaller ac unit at night and the larger one during the day but never both at the same time. The bedroom is roughly 200 sq ft. This leaves the 2.5 ton ac in the living room to cool about 800 sq ft.
I am considering purchasing a 48vdc 24,000 btu mini split unit . My reservations are that it will need to be shipped from China , I know nothing about the manufacturer and I'm sure any warranty issues would be a nightmare.
Thoughts?
Thank you
You guys are 100 percent correct. Ac is by far the biggest issue. Six months of the year the low temps are 70- 85 deg. and the highs are 88-98 deg. There is also considerable humidity.
The home will only be occupied by 2 people. The previous owner only used the home in the cooler months so I have no historical data.
I read online that 20btu per sq ft is the recommended amount for cooling needs. The home is 1000 sq ft total and the bedroom has a 12000 btu ac. We will be running the smaller ac unit at night and the larger one during the day but never both at the same time. The bedroom is roughly 200 sq ft. This leaves the 2.5 ton ac in the living room to cool about 800 sq ft.
I am considering purchasing a 48vdc 24,000 btu mini split unit . My reservations are that it will need to be shipped from China , I know nothing about the manufacturer and I'm sure any warranty issues would be a nightmare.
Thoughts?
Thank you
BentleyJ
Solar Wizard
To be perfectly fair, All Chinese products and manufacturers are NOT equal. Many on this forum have had experiences with Alibaba and AliExpress that range from very good to poor. My criteria would be as follows. Ask them for a complete document package on the product that includes an installation/user manual as well as any troubleshooting guides and most importantly a complete, expanded parts diagram. Make sure to ask if all the replacement parts are in fact available and how long that particular model has been in production.
KellyDood
New Member
Welcome, LywWyr - I'm happy you made it to retirement and hope you greatly enjoy it!
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,452
Many ways to build a system, but with 46kwh per day and two days battery back up-92 kWh lithium batterieswhich is like 6 Tesla Powerwalls, I see the cost in the US for me to build from scratch to be in excess of $40 k.
It’s less if you can grid ties and forgo the batteries.
It’s less if you can grid ties and forgo the batteries.
48,000 watts daily
Sorry I hit post early.
My usage is about 48,000 watts daily, in the hottest months, the location has about 300 sunny days per year. The hot months also have 7-8 hrs of usable sun. The cloudy days are in the months that my usage is significantly lower. Around 13kwh .
I have taken the advice of others on this forum and believe I can lower my usage significantly by replacing an old ac unit.
I will also back this up with a 6500w generator.
20-25 k is what I have to work with and I will do all the work myself.
Sounds like it might get kinda sweaty.....
Thanks
Thanks KellyDood!
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,452
Here’ssome data for Puerto Penasco or Rocky Point Mexico. Seems like 15 kw of panels and 96 kwh of batteries will be charged 95% of the time and batteries dead (actually generator coming on) only 1% of the time:
Drop that to 10 kw of panels and you and up having batteries empty 30% of the time. With the 15 kwh of panels, that is three or four days a year of empty batteries. Its not actually dead batteries, but how many times a year your generator needs to be fired up.
The off grid calculator in my signature block you can plug in some data and get customized results.
I find the numbers I put in are fairly accurate for the Phoenix Area I am in at Arizona.
Drop that to 10 kw of panels and you and up having batteries empty 30% of the time. With the 15 kwh of panels, that is three or four days a year of empty batteries. Its not actually dead batteries, but how many times a year your generator needs to be fired up.
The off grid calculator in my signature block you can plug in some data and get customized results.
I find the numbers I put in are fairly accurate for the Phoenix Area I am in at Arizona.
You nailed it! The seer rating for the existing 2.5 ton ac unit is 9.1, and the 1 ton ac in the bedroom is only a 13 seer. I will redo my load calcs based upon new units. Thanks again
Don B. Cilly
Energetic energy padawan
According to my Victron shunt's "history" my average daily consumption is 112Ah (average discharge).
Counting 26.4V average, that's just under 3kW. For 24 hours.
OK, I run cold cycles on the washing machine and switch off lights when not needed.
Say you have a slightly more "can't be bothered" attitude and use four times that. 12 kW.
On top of which, there is the A/C.
Now, the A/C will not only drain you batteries, you will need a bigger inverter to run it. Which, however big, will still huff and puff (make fan noises) most of the time. Make sure you put it outside ;·)
But the point is... if you can reduce the A/C's consumption, you can also save on batteries, inverters, general aggravation.
So, probably worth to do some research - and spend some money - on that.
HVAC pumps sound interesting. Rheem et al. make gas (as in propane/butane/etc, not petrol ;·)-powered air-conditioners. If you have a propane tank, rather than bottles, they might be worth looking at.
Now, I have zero experience with A/C. I actually dislike it, I can take the hot and humid, it's the cold I don't like.
But just saying, if the A/C makes all that difference in what your system needs, it's time well spent to look into it, and money well spent to get a good one.
[EDIT] I forgot. Personally, I think two days of clouds/rain/low-solar "backup" is a bit "overkill". You have a generator, very few of those days...
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Counting 26.4V average, that's just under 3kW. For 24 hours.
OK, I run cold cycles on the washing machine and switch off lights when not needed.
Say you have a slightly more "can't be bothered" attitude and use four times that. 12 kW.
On top of which, there is the A/C.
Now, the A/C will not only drain you batteries, you will need a bigger inverter to run it. Which, however big, will still huff and puff (make fan noises) most of the time. Make sure you put it outside ;·)
But the point is... if you can reduce the A/C's consumption, you can also save on batteries, inverters, general aggravation.
So, probably worth to do some research - and spend some money - on that.
HVAC pumps sound interesting. Rheem et al. make gas (as in propane/butane/etc, not petrol ;·)-powered air-conditioners. If you have a propane tank, rather than bottles, they might be worth looking at.
Now, I have zero experience with A/C. I actually dislike it, I can take the hot and humid, it's the cold I don't like.
But just saying, if the A/C makes all that difference in what your system needs, it's time well spent to look into it, and money well spent to get a good one.
[EDIT] I forgot. Personally, I think two days of clouds/rain/low-solar "backup" is a bit "overkill". You have a generator, very few of those days...
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What's a signature block? Do I just click your user name? That's great info. I'm changing the existing ac units out , they are garbage . Hoping I can get the consumption down significantly. Thanks
Going to replace the ac , it's 12yrs old and has a 9.1 seer rating . I will check that propane ac out , never heard of one. I have heard of propane refrigerators though, so it makes sense. Thanks
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,452
If using a phone, may need to turn it sideways.
BentleyJ
Solar Wizard
You most likely already know this but will mention it in case it helps someone. When you do change out your AC units if you choose an inverter type mini-split (There are several models available where 1 outdoor condenser can service 3 to 4 indoor Evap. units in different rooms) it will solve 2 issues. First will double your present efficiency of 9.1 and second, by virtue of the way an inverter motor operates, will eliminate the need for a soft starter to reduce inrush current.
That's a great idea!
WYtreasure
It's not happy hour, I'm just like this.
Is it possible to do some geothermal to reduce the A/C demand?
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