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Post by Jim on Sept 13, 2018 16:47:50 GMT
I have a similar situation. My storage shed is in a non-leased portion of the backyard of a rental property. So, it is off of the grid. I use it once every week or two to run saws, etc. I also have cameras, internet access, a computer, and amateur radio equipment in the shed for (hopefully) a remote radio station. I have a backup generator. But, I want to be able to turn air conditioning on (500W, 6000BTU unit) remotely for a couple of hours before I arrive and start the generator.
I ended up with a 3000W inverter. I found out quickly that the inverter is the largest power consumer over the long haul.
Currently, I have a 450AH reserve battery, a 40A Renogy MPPT controller, and 8 very old solar panels that a friend found in the garbage. I put new connectors on them and their voltage checks out. They are each about 10x30 inches. In full sun, they each put out about 0.75A at 12V. Not real hot. So, I want to replace them with 100W Renogy panels.
The problem is that half of the shed is shaded in the afternoon. I cannot do much about the shading. So, I would like to install the new Renogy panels in parallel to minimize issues with half of the panels sometimes being shaded. Running large wire is not an issue.
Question: I have room for 8 panels. 8 panels would be capable of producing more than 40A in full sun (mornings.) But, in the afternoon, their combined output would likely 40A or less. Starting 2 hours before sunset, the shade is 80%. -- During the morning, will the controller limit the current to 40A?
Obviously, the alternative is to go down to 4 or 5 panels so that current can never be more than 40A. But, then, afternoon current would be much less.
Jim
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grumpy
Solar Newcomer
Posts: 40
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Post by grumpy on Sept 13, 2018 19:04:59 GMT
I have a similar situation. My storage shed is in a non-leased portion of the backyard of a rental property. So, it is off of the grid. I use it once every week or two to run saws, etc. I also have cameras, internet access, a computer, and amateur radio equipment in the shed for (hopefully) a remote radio station. I have a backup generator. But, I want to be able to turn air conditioning on (500W, 6000BTU unit) remotely for a couple of hours before I arrive and start the generator. I ended up with a 3000W inverter. I found out quickly that the inverter is the largest power consumer over the long haul. Currently, I have a 450AH reserve battery, a 40A Renogy MPPT controller, and 8 very old solar panels that a friend found in the garbage. I put new connectors on them and their voltage checks out. They are each about 10x30 inches. In full sun, they each put out about 0.75A at 12V. Not real hot. So, I want to replace them with 100W Renogy panels. The problem is that half of the shed is shaded in the afternoon. I cannot do much about the shading. So, I would like to install the new Renogy panels in parallel to minimize issues with half of the panels sometimes being shaded. Running large wire is not an issue. Question: I have room for 8 panels. 8 panels would be capable of producing more than 40A in full sun (mornings.) But, in the afternoon, their combined output would likely 40A or less. Starting 2 hours before sunset, the shade is 80%. -- During the morning, will the controller limit the current to 40A? Obviously, the alternative is to go down to 4 or 5 panels so that current can never be more than 40A. But, then, afternoon current would be much less. Jim I have the 40 amp Commander with 5 100 watt panels. This might help: Rated Charge Power 520W @ 12V 1040W @ 24V Max PV Array Power 1560W @ 12V 3120W @ 24V
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Post by Jim on Sept 13, 2018 19:18:16 GMT
I am not following you at all. 12V at 40A is 480W.
You cannot expect more than 425W or so, max, out of five 100W panels. So, it seems like you will never exceed 40A.
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Post by tattoo on Sept 13, 2018 20:48:33 GMT
I ran 8 100w panels with a 40a CC just like yours.... 4 and 4 in series and then them in parallel and it ran just fine... I think the only thing you would have to worry about is in the winter it might charge to much..... But depending on the angle of your panels and the time in the sun because of the shade...
Oh yea you can forget about running the AC off of what your describing... It will be way to much load...
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Post by tattoo on Sept 13, 2018 20:54:28 GMT
I ended up with a 3000W inverter. I found out quickly that the inverter is the largest power consumer over the long haul.
That's what I keep telling people but they seem to incest on running a large inverter for some reason..... You don't need to run/buy an inverter any larger than your system can handle the load.... It's a waste of money and a waste of power.....
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jrh613
Solar Newcomer
Posts: 9
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Post by jrh613 on Sept 13, 2018 21:06:30 GMT
I ran 8 100w panels with a 40a CC just like yours.... 4 and 4 in series and then them in parallel and it ran just fine... I think the only thing you would have to worry about is in the winter it might charge to much..... But depending on the angle of your panels and the time in the sun because of the shade... Oh yea you can forget about running the AC off of what your describing... It will be way to much load... 4 in series and 4 in parallel would cut the current in 1/4. So, that's why you would not exceed 40A in that situation. You will not even exceed 20A. With eight100W panels, why would running a 500W AC for an hour or so each week exceed the capabilities of the system? The battery will certainly handle that much load; I already tested it for 90 minutes without solar panels/controller. And eight 100 watt panels should replenish the battery in an hour or so. (?) Or am I missing something? Jim
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Post by tattoo on Sept 13, 2018 23:02:38 GMT
4 in series and 4 in parallel would cut the current in 1/4. So, that's why you would not exceed 40A in that situation. You will not even exceed 20A. With eight100W panels, why would running a 500W AC for an hour or so each week exceed the capabilities of the system? The battery will certainly handle that much load; I already tested it for 90 minutes without solar panels/controller. And eight 100 watt panels should replenish the battery in an hour or so. (?) Or am I missing something? Jim I said 4 and 4 in series and then those in parallel.... Read what I said...
So you have one battery? What kind? You said it has 450ah what is the CCA?
Most people run the AC more than an hour a week.. You said 2 hours before you got there before, you didn't say you were going to cut it off when you got to the shed.... But you do have a generator to crank up...
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Post by tattoo on Sept 13, 2018 23:14:17 GMT
My storage shed is in a non-leased portion of the backyard of a rental property. So, it is off of the grid. I use it once every week or two to run saws, etc. I also have cameras, internet access, a computer, and amateur radio equipment in the shed for (hopefully) a remote radio station. I have a backup generator. But, I want to be able to turn air conditioning on (500W, 6000BTU unit) remotely for a couple of hours before I arrive and start the generator. Jim Jim in your first post you said you wanted to run all of the above now your focusing on just the AC.... Which is it?
If you think you can run all of that have at it..... At least you have access to a generator.....
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Post by bupkis on Sept 14, 2018 0:12:53 GMT
4 100w panels in series is ~5A x ~60-75v, parallel another 4 in series and ya get ~10A x ~60-70v. Do not confuse input limits with battery charge limits.
An mppt controller takes that ~10A x ~70v and converts it to battery voltage for charging with amps ~45A or so (depending on batt voltage).
Some mppt controllers can be overpowered and the controller clips excess current, ie a 40A controller with 1000w and the controller clips the battery charging current to 40A and the rest is wasted anytime excess is made.
As grumpy showed, that controller can be overpower to 1500w @ 12v.
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jrh613
Solar Newcomer
Posts: 9
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Post by jrh613 on Sept 14, 2018 1:15:50 GMT
My storage shed is in a non-leased portion of the backyard of a rental property. So, it is off of the grid. I use it once every week or two to run saws, etc. I also have cameras, internet access, a computer, and amateur radio equipment in the shed for (hopefully) a remote radio station. I have a backup generator. But, I want to be able to turn air conditioning on (500W, 6000BTU unit) remotely for a couple of hours before I arrive and start the generator. Jim Jim in your first post you said you wanted to run all of the above now your focusing on just the AC.... Which is it?
If you think you can run all of that have at it..... At least you have access to a generator.....
You are not reading carefully... Everything besides the air conditioner runs all of the time. The air conditioner runs for a couple of hours before I arrive and can start the generator. That would happen every week or two. A 500W air condition running for a couple of hours would draw 1KW. It seems that would be quickly replaced in the batteries by 8 solar panels. Please correct me if I am wrong.
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jrh613
Solar Newcomer
Posts: 9
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Post by jrh613 on Sept 14, 2018 1:23:38 GMT
I am sorry; I understood. I just made a typo. And, yes, that cuts your current down by 1/4 of what it would be if all were in parallel. The battery is an Interstate 8 D - M H D. (Sorry for the spaces. The forum program interprets the P/N as a smiley face otherwise.) --- It is a huge battery. 1400 CCA, to answer your question. However, the reserve capacity is the important number for solar. I do not think you will find a larger battery than this. The shed is an hour away. It is well ventilated and insulated with R60 insulation on all 6 sides. So, its inside temperature hovers pretty close to the average 24 hour temperature. (I.e., 80 degree nights and 100 degree days yields a shed that stays around 90.) No need for AC for the electronics. -- Turn the AC on remotely for an hour would get the inside down to 75-80 degrees. Then, I could start the generator when I got there. 4 in series and 4 in parallel would cut the current in 1/4. So, that's why you would not exceed 40A in that situation. You will not even exceed 20A. With eight100W panels, why would running a 500W AC for an hour or so each week exceed the capabilities of the system? The battery will certainly handle that much load; I already tested it for 90 minutes without solar panels/controller. And eight 100 watt panels should replenish the battery in an hour or so. (?) Or am I missing something? Jim I said 4 and 4 in series and then those in parallel.... Read what I said...
So you have one battery? What kind? You said it has 450ah what is the CCA?
Most people run the AC more than an hour a week.. You said 2 hours before you got there before, you didn't say you were going to cut it off when you got to the shed.... But you do have a generator to crank up...
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jrh613
Solar Newcomer
Posts: 9
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Post by jrh613 on Sept 14, 2018 1:26:06 GMT
Ok. This answers my question. Thanks! One followup, though... Grumpy gave numbers for the Commander. But, is the Rover similar? I have the 40A Rover. 4 100w panels in series is ~5A x ~60-75v, parallel another 4 in series and ya get ~10A x ~60-70v. Do not confuse input limits with battery charge limits. An mppt controller takes that ~10A x ~70v and converts it to battery voltage for charging with amps ~45A or so (depending on batt voltage). Some mppt controllers can be overpowered and the controller clips excess current, ie a 40A controller with 1000w and the controller clips the battery charging current to 40A and the rest is wasted anytime excess is made. As grumpy showed, that controller can be overpower to 1500w @ 12v.
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Post by tattoo on Sept 14, 2018 1:29:36 GMT
Ok. This answers my question. Thanks! One followup, though... Grumpy gave numbers for the Commander. But, is the Rover similar? I have the 40A Rover. Yes it will be similar...
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Post by tattoo on Sept 14, 2018 1:32:59 GMT
The battery is an Interstate -MHD. It is a huge battery. 1400 CCA, to answer your question. However, the reserve capacity is the important number for solar. I do not think you will find a larger battery than this. Yep as I thought it's an automotive battery... One battery... But that's fine it's a big one...
It sounds like you have everything figured out....
Hope it works out for you...
Oh by the way they make much larger batteries and more appropriate for solar than yours...
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Post by bupkis on Sept 14, 2018 1:55:41 GMT
Not sure that is confined that it can be overpower like the tracer (commander), ie it is not clear from the manual. A single 8 D is 400ah? more like 220ah. Ok. This answers my question. Thanks! One followup, though... Grumpy gave numbers for the Commander. But, is the Rover similar? I have the 40A Rover. 4 100w panels in series is ~5A x ~60-75v, parallel another 4 in series and ya get ~10A x ~60-70v. Do not confuse input limits with battery charge limits. An mppt controller takes that ~10A x ~70v and converts it to battery voltage for charging with amps ~45A or so (depending on batt voltage). Some mppt controllers can be overpowered and the controller clips excess current, ie a 40A controller with 1000w and the controller clips the battery charging current to 40A and the rest is wasted anytime excess is made. As grumpy showed, that controller can be overpower to 1500w @ 12v.
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