Makes sense, Thanks
actii 7392 MPPT
- Thread starter Courter
- Start date
ChronicHydronic
New Member
Can you comment on how this system is working now that you've had it for a while?
Also these comments in the manual put me off. Should I be concerned? It is for heating a cottage where I am away alot especially in the winter.
COMMENT 1
"- The regulator must be absolutely disconnected from the panels when we leave the apartment for more than a day!!!"
COMMENT 2
"ER.1 Means damage to the control transistor, immediately disconnect the regulator and send it back to the service. At the time of displaying this error, the heater is constantly powered from the panels and the regulator is not able to turn it off! Leaving the regulator with this error can lead to its melting and even fire."
Also these comments in the manual put me off. Should I be concerned? It is for heating a cottage where I am away alot especially in the winter.
COMMENT 1
"- The regulator must be absolutely disconnected from the panels when we leave the apartment for more than a day!!!"
COMMENT 2
"ER.1 Means damage to the control transistor, immediately disconnect the regulator and send it back to the service. At the time of displaying this error, the heater is constantly powered from the panels and the regulator is not able to turn it off! Leaving the regulator with this error can lead to its melting and even fire."
efficientPV
Solar Addict
- Joined
- Sep 24, 2019
- Messages
- 1,347
I was in a restroom years ago and it had a recirculating cotton cloth for drying hands. It had a warning sticker on it. DO NOT USE FOR LIFTING MACHINERY. Lawsuits are everywhere and for anything. Although if you use that 1000W 48V heating element it might just happen. Those units are designed for higher voltage lower wattage elements common in Europe. Domestic hot water is normally a closed system so explosion can occur if there is enough power and the system locks on. Vented water heaters are also common in Europe and there is a chance of water evaporation leaving a dry element which burns out. I think elsewhere they mentioned using a separate relay for disconnect.
Heating water with PV is probably the best education in solar you can get. It quickly demonstrates the effects of loading and site conditions. That is why it is uncommon here, it takes too much learning. Out of the thousands of members on this board I am the only one who discusses it. I thought there would be an active community heating water. Here are the production increases over direct connect. That 40 to 80% current is the most important
% Rated Increase over
Panel A Direct Connect
100% 0%
90% 10%
80% 25%
70% 50%
60% 67%
50% 100%
40% 250%
30% 333%
20% 500%
10% 1100%
Yesterday the rain and thunder started at 4:30am and didn't stop. My wife wanted to do the dishes. Yesterday it was sunny, but she has to have it jam packed before she will run it. Finally there was a break at 11am and went out to the power shed to look at tank temperatures. Both tanks were up to 60C and we did the dishes. These tanks are only heated with excess power. That 40% and below still can do a lot of heating.
Unfortunately, you are in Canada which might as well be outer space. The US post office has conspired against me and sending just a circuit board costs $55. A populated board even more. For that price you could have 20 boards made in China, shipped to you in a week and you could mail half the boards to me. I used to be able to send something to Australia for less than $5.
Heating water with PV is probably the best education in solar you can get. It quickly demonstrates the effects of loading and site conditions. That is why it is uncommon here, it takes too much learning. Out of the thousands of members on this board I am the only one who discusses it. I thought there would be an active community heating water. Here are the production increases over direct connect. That 40 to 80% current is the most important
% Rated Increase over
Panel A Direct Connect
100% 0%
90% 10%
80% 25%
70% 50%
60% 67%
50% 100%
40% 250%
30% 333%
20% 500%
10% 1100%
Yesterday the rain and thunder started at 4:30am and didn't stop. My wife wanted to do the dishes. Yesterday it was sunny, but she has to have it jam packed before she will run it. Finally there was a break at 11am and went out to the power shed to look at tank temperatures. Both tanks were up to 60C and we did the dishes. These tanks are only heated with excess power. That 40% and below still can do a lot of heating.
Unfortunately, you are in Canada which might as well be outer space. The US post office has conspired against me and sending just a circuit board costs $55. A populated board even more. For that price you could have 20 boards made in China, shipped to you in a week and you could mail half the boards to me. I used to be able to send something to Australia for less than $5.
ChronicHydronic
New Member
EfficientPV ...thanks for your comments. Could you explain your % example a little more....as I'm a luddite here. Is this showing the improvements of your MPPT controller over just plain old direct connect? And what does each column refer to?
Would your board work with my system? I'd be interested in learning more, if you have any docs to send along and what you estimate finished costs to be. Are you in the States? I can solder components on a board and likely put a system together but being a Geologist I know more about dirt than electronics.
Would your board work with my system? I'd be interested in learning more, if you have any docs to send along and what you estimate finished costs to be. Are you in the States? I can solder components on a board and likely put a system together but being a Geologist I know more about dirt than electronics.
efficientPV
Solar Addict
- Joined
- Sep 24, 2019
- Messages
- 1,347
100% is the panels rated MPP current. The next figure is the percent increase in power over direct connect using a power point controller. Panel are current sources. At 100% current, both methods produce the same power.
EXAMPLE: if a panel/array is rated at 60V 9A the panel produces 40W. The ideal resistance is 60/9 = 6.6 0hms. That is approximately two 4500W 240V elements in parallel.
When the panel only produces 4.5A the power of the panel/array, the power will be 4.5A X 60 = 270W with a power point controller.
Direct connect will be 4.5 X 6.67 ohms = 30V or half the voltage because the panel is a current source. 30V X 4.5A = 135W. A power point controller produces 100% more power than direct connect. At lower currents the increase is even more, but these are lower power levels.
This is the reason having 2X the ideal resistance produces more average daily power in those areas that have more clouds.
It sounds simple, run just one element till 50% current is reached. That will produce more power. A current relay can sense half current and only switch in a second element at 50% current. Immediately when you do that, the power will drop in half. Overall it will produce a little more power. You just can't switch in at 60 or 70% because the panel won't produce that much voltage. Over 50% current has to have at least three more stages. Suddenly you have a lot of hardware to deal with. A simple PWM proportional system is much simpler.
EXAMPLE: if a panel/array is rated at 60V 9A the panel produces 40W. The ideal resistance is 60/9 = 6.6 0hms. That is approximately two 4500W 240V elements in parallel.
When the panel only produces 4.5A the power of the panel/array, the power will be 4.5A X 60 = 270W with a power point controller.
Direct connect will be 4.5 X 6.67 ohms = 30V or half the voltage because the panel is a current source. 30V X 4.5A = 135W. A power point controller produces 100% more power than direct connect. At lower currents the increase is even more, but these are lower power levels.
This is the reason having 2X the ideal resistance produces more average daily power in those areas that have more clouds.
It sounds simple, run just one element till 50% current is reached. That will produce more power. A current relay can sense half current and only switch in a second element at 50% current. Immediately when you do that, the power will drop in half. Overall it will produce a little more power. You just can't switch in at 60 or 70% because the panel won't produce that much voltage. Over 50% current has to have at least three more stages. Suddenly you have a lot of hardware to deal with. A simple PWM proportional system is much simpler.
damo green
New Member
- Joined
- Jan 13, 2022
- Messages
- 75
How has your ACTii controller been doing? I'm considering it. TIA
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