Should we have a Hybrid Solar section?
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Remember the voltage under load is different from open circuit. Rolls suggest 50% DOD under load is 46.32volts on 48 volt system. I set my at 47 volts. it hardly reach there but occasionally it went there if I have a cloudy day. so if you set it at 48.8 volts, you will use a lot of the grid power unless your system is grossly over sized. -
Hi wgollie43,
Good, glad we are getting results.
Well, like I said, I don't know the range of voltages that reflect the usable capacity of your AGM's. I do know how the Radian running the GridZero app should work. I would say that if you moved the DoD volts set point from 50V to 49V and the inverter started then the GridZero app is responding to the battery capacity dropping below 100%. I recommend doing some testing. Record the voltage and battery capacity when the inverter cuts off. Then drop the DoD voltage setting again. Record the same again. Try tweaking it until the battery capacity reaches 70%, when the inverter shuts down. Testing will show you where the possible set points really are, whether it is 20, 25, or 30% DoD.
Also, how many KWH's per day average have you been producing since you had your system installed? This has to do with the DoD amps setting, but we'll get into that next time.
RickLeave a comment:
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[QUOTE=Mike90250;131242]As long as you understand the math between buying power from the grid (maybe 30 cents per KWh) and the wear/tear decrease in life of the batteries (you know how much they cost, and that the deeper the discharge, the fewer cycles) for battery replacement costs. So for the $10 you may save in a month on "store bought power", it may cost you $80 in eventual battery replacement costs.[/QUOTE
Hello Mike,
I have to say that if I were buying a standard grid tie system I would consider it an investment and would be calculating a return on investment before I laid out the money to buy it. However, I see a grid hybrid system more as insurance to protect my family and I from something that is less likely to happen. Such as rapidly rising energy costs, long and short term grid failure due to winter storms, tornados, hurricanes, cyber attacks against power utilities, even economic problems, both personal and public. Insurance and investment are two very different mindsets requiring different ways of considering money and resources. Those of us who buy grid hybrid systems want to have the convenience of grid power, while at the same time having the security of a well maintained off grid system available. So I am not adverse to paying a premium for this type of insurance.
RickLeave a comment:
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As long as you understand the math between buying power from the grid (maybe 30 cents per KWh) and the wear/tear decrease in life of the batteries (you know how much they cost, and that the deeper the discharge, the fewer cycles) for battery replacement costs. So for the $10 you may save in a month on "store bought power", it may cost you $80 in eventual battery replacement costs.Leave a comment:
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I have made a change to the DOD per your suggestion. I lowered the DOD Volts to 30%. Now the setting is 49.2. As soon as I made the change the system started using the batteries. Can you explain why all of a sudden it started using the battery when I made this change. I am a EE and feel like a dummy. I understand electronic curcuits but this battery solar stuff has a different twist.
Good, glad we are getting results.
Well, like I said, I don't know the range of voltages that reflect the usable capacity of your AGM's. I do know how the Radian running the GridZero app should work. I would say that if you moved the DoD volts set point from 50V to 49V and the inverter started then the GridZero app is responding to the battery capacity dropping below 100%. I recommend doing some testing. Record the voltage and battery capacity when the inverter cuts off. Then drop the DoD voltage setting again. Record the same again. Try tweaking it until the battery capacity reaches 70%, when the inverter shuts down. Testing will show you where the possible set points really are, whether it is 20, 25, or 30% DoD.
Also, how many KWH's per day average have you been producing since you had your system installed? This has to do with the DoD amps setting, but we'll get into that next time.
RickLeave a comment:
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Thank you for your response. My DOD Volts is 50V and my DOD amps is 12.
The document you referenced above I already have read and used it to program the Radian. When I go up this morning the batteries read 51.9. So I am thinking I should have been using the batteries. What I did not look at was the state of the system this morning. That is was it inverting or passthru. Will check it in the morning and let you know what status is being reported.Leave a comment:
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wgollie43,
Since this is a grid tie mode, the grid is always available to augment or stand-in for the inverter with power up to 15 amps per leg at 240 VAC.
Grid Zero prioritizes battery over grid power, so the inverter will use battery power until it reaches the DOD volts setting.
So, it sounds like your depth of discharge volts setting has been reached, and the inverter is waiting for the batteries to be recharged.
This may be caused by insufficient charging during daylight hours or your loads have taken the batteries down to the DOD volts setting.
This setting is determined by the capacity of your battery bank, the voltage, and how much capacity you want available for backup power.
A lower setting will make more of the battery capacity available for nighttime use. A higher setting will make more capacity available for backup power in case you lose the grid at night.
For your battery bank, three strings of four batteries each for 538 AH at 48 volts, a conservative setting might be what ever voltage represents about 30% DOD on the bank.
I am not that knowledge about AGM lead acid chemistry, so some of the other members of this forum may be able to chime in with that approximate voltage.
Anyway, with this setting (volts equaling 30% DOD) you should have about 150 amp hours for overnight use. About 7 KWH I believe. Obviously this is only true if the battery bank was completely charged by PV during daylight hours.
Should the battery bank be 52 volts at 100% capacity? I can not answer that. You may want to take your DOD volts setting down 1 volt and see what that does.
So...What do you have your DOD volts and your DOD amps set to?
Also, Take a look at this document and then get back to me with those settings. http://www.outbackpower.com/download...BC_2-18-14.pdf
Rick
The document you referenced above I already have read and used it to program the Radian. When I go up this morning the batteries read 51.9. So I am thinking I should have been using the batteries. What I did not look at was the state of the system this morning. That is was it inverting or passthru. Will check it in the morning and let you know what status is being reported.Leave a comment:
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Raj, I done that and have aske questions on the OB forum. But it appears I may be on the bleeding edge for those using GridZero.
Below is the latest of my OB postings:
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I am still trying to determine if my GS4048A is doing what it is supposed to do. I just don't get the feeling the Radian is doing what it is suppose to do in GridZero mode. Total cumulative AH created from my batteries for the last week is 1WK.
In the early mornings, I get up at 4:45 for work, I have a reading light on to read the morning paper. I go out to the garage and the home screen shows that the source is coming from the Grid not the batteries. Batteries are at 100% @ 52V. Why is the system not using the batteries?
Since this is a grid tie mode, the grid is always available to augment or stand-in for the inverter with power up to 15 amps per leg at 240 VAC.
Grid Zero prioritizes battery over grid power, so the inverter will use battery power until it reaches the DOD volts setting.
So, it sounds like your depth of discharge volts setting has been reached, and the inverter is waiting for the batteries to be recharged.
This may be caused by insufficient charging during daylight hours or your loads have taken the batteries down to the DOD volts setting.
This setting is determined by the capacity of your battery bank, the voltage, and how much capacity you want available for backup power.
A lower setting will make more of the battery capacity available for nighttime use. A higher setting will make more capacity available for backup power in case you lose the grid at night.
For your battery bank, three strings of four batteries each for 538 AH at 48 volts, a conservative setting might be what ever voltage represents about 30% DOD on the bank.
I am not that knowledge about AGM lead acid chemistry, so some of the other members of this forum may be able to chime in with that approximate voltage.
Anyway, with this setting (volts equaling 30% DOD) you should have about 150 amp hours for overnight use. About 7 KWH I believe. Obviously this is only true if the battery bank was completely charged by PV during daylight hours.
Should the battery bank be 52 volts at 100% capacity? I can not answer that. You may want to take your DOD volts setting down 1 volt and see what that does.
So...What do you have your DOD volts and your DOD amps set to?
Also, Take a look at this document and then get back to me with those settings. http://www.outbackpower.com/download...BC_2-18-14.pdf
RickLeave a comment:
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Hi wgollie43,
Your system and application is new and under warranty, I suggest you go to the Outback forum, register and ask your questions. They will answer. That is what I did. Here is the link. http://outbackpower.com/forum/
Of course you can also call their support line.
Raj
Below is the latest of my OB postings:
-------------------------------------------------------------------------------------------------------------------------------------------
I am still trying to determine if my GS4048A is doing what it is supposed to do. I just don't get the feeling the Radian is doing what it is suppose to do in GridZero mode. Total cumulative AH created from my batteries for the last week is 1WK.
In the early mornings, I get up at 4:45 for work, I have a reading light on to read the morning paper. I go out to the garage and the home screen shows that the source is coming from the Grid not the batteries. Batteries are at 100% @ 52V. Why is the system not using the batteries?Leave a comment:
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I am a newbie in this Solar stuff but not to electronics. I have 12 Sharp 250w panels. I am using Outbacks batteries 200REs. 12 of them in a 48v configuration. GridZero is Energy Balancing using Advanced Battery Charging. There are a lot of questions I have about what the system is doing when I look at it(Understanding the Mate3 displays).
It would appear that Outback did a great job on the GridZero design but the displays are not intuitive. Then again it could be my lack of understanding what is being displayed.
If anyone knows the GridZero I will post pictures of the Mate3 display for response.
Your system and application is new and under warranty, I suggest you go to the Outback forum, register and ask your questions. They will answer. That is what I did. Here is the link. http://outbackpower.com/forum/
Of course you can also call their support line.
RajLeave a comment:
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Outback Radian GS4048A using GridZero
I am a newbie in this Solar stuff but not to electronics. I have 12 Sharp 250w panels. I am using Outbacks batteries 200REs. 12 of them in a 48v configuration. GridZero is Energy Balancing using Advanced Battery Charging. There are a lot of questions I have about what the system is doing when I look at it(Understanding the Mate3 displays).
It would appear that Outback did a great job on the GridZero design but the displays are not intuitive. Then again it could be my lack of understanding what is being displayed.
If anyone knows the GridZero I will post pictures of the Mate3 display for response.Leave a comment:
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Hybrid is good, I think you should have a separate section for it! I will be Grid tied with battery backup. I have plans
to acquire a better battery setup. Last winter we had 2 ice storms here in TN. Both times we had power outages. For me
the longest was only 14 hours. My biggest concern was heat - I have Gas furnace, but it requires 120 volts to run the blower
fan. That won't be a continuous load and may come on twice in an hour. I can live without hot water, TV, microwave etc. but its
great to be able to supply the power needed to run the minimal few items to make everyone comfortable. Yeah batteries aren't
cheap, but those of that want them will get them! Yeah I have 2 generators, a 5500 watt dual phase and a Yamaha 2000 watt
for small loads! I can improvise if needed! If the power goes out refrigeration, heat would be important. I have a lot of quetions
that I would like to get answered, mostly about batteries! If I where forced into an off grid situation I would make the best
of what I have! Remember with generators, they only work when you have fuel to feed them with! Solar renews itself most every day!
Bill in TN
Batteries on the other hand start to die the minute you put them on the shelf. It is like a leaky faucet. Their life will slowly (or quickly depending on their care) drip away even if you do not put them to use. So their "backup value" slowly erodes over time until when you need them the most they fail.
While a standby generator only needs to be exercised periodically and can be used for many days continuously if and when needed so fuel cost can be minimized. With proper care a gen set will last many times the lifespan of batteries so to me is a better investment as an emergency power backup then batteries.Leave a comment:
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Scenario #1 Winter ice storm.
Lines down, poles snapped off by the hundreds, 2 weeks to truck in new poles Your rooftop panels are coated in 1" of ice, and the weather is forecast cloudy for the next 3 days. Your $12,000 battery bank took over last night keeping the heat pump on for you, but this AM, there is no sun and batteries are 60% depleted (40% remaining) In the next 2 days, your batteries irreversibly sulfate and loose half their capacity. You can run 2 lights for the next 3 days, then the sun comes out, melts your panel ice, and starts charging the batteries (which are now down to about 20% remaining) Just lost 3 years off the 6 year battery life ($6000).
#2, same storm, you have a $3,000 auto-start propane genset, and you hear it start up at 3 am when the batteries get low. You yawn and go back to sleep. The genset runs intermittently the next 3 weeks till the power comes back on, and you continue back feeding the grid. impact to your batteries, nil, propane billl and an oil change $200, and you were mostly comfortable except there was no internet or cable TV for 3 weeks.
You can spend lots more $$ for a larger battery bank, that won't sag below 70% for 3 days.. That's going to cost you a lot more than a $3000 genset and some fuel. And your solar will still not run "everything" for the 3 weeks.
It's all a choice.
If you have a small, expendable battery bank, and just need to keep the beer cold, then there is a lot less skin in the game, and you don't need the generator.Leave a comment:
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Hybrid is good, I think you should have a separate section for it! I will be Grid tied with battery backup. I have plans
to acquire a better battery setup. Last winter we had 2 ice storms here in TN. Both times we had power outages. For me
the longest was only 14 hours. My biggest concern was heat - I have Gas furnace, but it requires 120 volts to run the blower
fan. That won't be a continuous load and may come on twice in an hour. I can live without hot water, TV, microwave etc. but its
great to be able to supply the power needed to run the minimal few items to make everyone comfortable. Yeah batteries aren't
cheap, but those of that want them will get them! Yeah I have 2 generators, a 5500 watt dual phase and a Yamaha 2000 watt
for small loads! I can improvise if needed! If the power goes out refrigeration, heat would be important. I have a lot of quetions
that I would like to get answered, mostly about batteries! If I where forced into an off grid situation I would make the best
of what I have! Remember with generators, they only work when you have fuel to feed them with! Solar renews itself most every day!
Bill in TNLeave a comment:
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Yes by all means the grid tie with generator is the most cost efficient way. But these people are keep beating the dead horse about hybrid solar for reasonable price. I just can't see it even in my circumstances. If the grid is not reliable then go full off grid or grid assist so I call it. (we use off grid and because we have unreliable grid we size the battery bank small and shut off the inverter go back to the grid when battery reach to Low battery cutoff level.)Leave a comment:
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