Hello everyone.
I "built" my first solar panel that consists of 30 3x6" cells 0.5V 3.6A each.
Cells soldered in series and put on plexiglass with aluminum frame and encapsulated with epoxy resin (some bubbles left). In theory I had to receive 15V 3.6A and 54 watt as a result. In reality I receive 17.5V 2.7A on the full sun and about 15V 0.5A around 5pm with little clouds (if I measured current properly) with no load.
For my battery bank I have one small 12V 7Ah battery BP7-12
Today I have received cheap chinese charge controller. Description says it protects panel from reverse discharging, so I didn't put diode on my panel.
SITUATION 1
I have connected them all together and put the panel on the sun. There is plenty of space beneath the panel. It gave me nice 14V. After about 30 minutes there was voltage drop, I started receiving only 5-6V out of my panel. When sun went down and it became shady it returned back to 14V.
QUESTION 1: Is it because the panel overheat, therefore increased resistance and as a result voltage drop?
SITUATION 2
Back to the time when I was receiving 14V out of my panel.
For the load terminal I have connected 12V car socket
Checking voltage with multimeter and receiving nice solid 12V. Pluging a plasma ball lamp
and it's working. Plugging car GPS and it looked like it is charging. So I unplugged loads and left the system alone to charge.
In evening, after panel cool down and started producing 12V I plugged GPS to the socket. GPS wasn't charging, controller started blinking. A checked the voltage with multimeter on the socket while gps was plugged, it was 5V, despite battery had 12V. Unplugged gps and voltage went back to 12V.
QUESTION 2: Battery is not fully charged or controller is glitching? I charged the battery several days before I plugged it to my system.
SITUATION 3
I decided to unplug the panel and check the terminal with multimeter. There was 2.5V
QUESTION 3: Is my controller deffective (faulty)? As I understand, since it protects from backflow there must be 0V. Right?
Hope to hear productive answers
Best regards
Ilnar
I "built" my first solar panel that consists of 30 3x6" cells 0.5V 3.6A each.
Cells soldered in series and put on plexiglass with aluminum frame and encapsulated with epoxy resin (some bubbles left). In theory I had to receive 15V 3.6A and 54 watt as a result. In reality I receive 17.5V 2.7A on the full sun and about 15V 0.5A around 5pm with little clouds (if I measured current properly) with no load.
For my battery bank I have one small 12V 7Ah battery BP7-12
Today I have received cheap chinese charge controller. Description says it protects panel from reverse discharging, so I didn't put diode on my panel.
SITUATION 1
I have connected them all together and put the panel on the sun. There is plenty of space beneath the panel. It gave me nice 14V. After about 30 minutes there was voltage drop, I started receiving only 5-6V out of my panel. When sun went down and it became shady it returned back to 14V.
QUESTION 1: Is it because the panel overheat, therefore increased resistance and as a result voltage drop?
SITUATION 2
Back to the time when I was receiving 14V out of my panel.
For the load terminal I have connected 12V car socket
Checking voltage with multimeter and receiving nice solid 12V. Pluging a plasma ball lamp
and it's working. Plugging car GPS and it looked like it is charging. So I unplugged loads and left the system alone to charge.
In evening, after panel cool down and started producing 12V I plugged GPS to the socket. GPS wasn't charging, controller started blinking. A checked the voltage with multimeter on the socket while gps was plugged, it was 5V, despite battery had 12V. Unplugged gps and voltage went back to 12V.
QUESTION 2: Battery is not fully charged or controller is glitching? I charged the battery several days before I plugged it to my system.
SITUATION 3
I decided to unplug the panel and check the terminal with multimeter. There was 2.5V
QUESTION 3: Is my controller deffective (faulty)? As I understand, since it protects from backflow there must be 0V. Right?
Hope to hear productive answers
Best regards
Ilnar
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