Recent content by solvejskovlund

When I started this thread I was hoping someone would respond "Hey, this device does exactly what you need". I'd prefer if there was a device that could be bought ready. The lack off such reply leads me to think this will end up being a DIY thing. Powering with battery would make stuff a lot...

Is it enough to place it in a sealed waterproof box? Or should I cover them in some stuff to keep air out?

These led me to a document called "±480-V isolated voltage-sensing circuit with differential output" https://www.ti.com/lit/an/sbaa321/sbaa321.pdf?ts=1674928488075 Sounds very much like what I've been looking for. I notice they are using a chain of 4 resistors in the divider, just like...

The main benefit is area saving. If you have available area to install PV or thermal, go for PV. If you've run out of installation area, pipes behind may be worth an experiment

Old thread, but still.... I've played with the idea of adding copper pipes on the back of PV panels, and add insulation on the back to keep the heat in. Then circulate water in the pipes. The PV panels do get hot in sunlight. PV panels are more efficient when cold. After all, they have 17-22%...

Thanks. I'll need to look at these.

Oh. I had no clue about that. How do I find a resistors voltage rating? They aren't labeled with anything that could point me to a datasheet. Why is condensation an issue with high value resistors? I thought that would be related to the power passing through (heat), and higher resistor values...

There seems to be a phase-pattern to the solar-ground balancing. Starting at night, there is <5V from the solar. When voltage increase, the negative seems to stay near GND (within 5-10V) until the solar positive reaches battery voltage (near 48V). As the solar voltage continue to increase the...

All though we haven't had a clear sky day yet, I've seen solar negative 96V under GND, with a total solar voltage of 150V. That makes my plan with the INAxxx components fail...

I guess I'll have to measure current, through some resistors. All though technically that is done measuring voltage drop over a small resistor in series with several large ones, as you suggest. The INA219 track led me to INA228/INA229/INA237/INA238/INA239. The potential issue with INA219 is that...

Think I've found the solution: Adafruit INA219 current sensor breakout https://www.adafruit.com/product/904?gclid=EAIaIQobChMIrIfH39fs9gIVmv_jBx24LggDEAQYBiABEgLX0PD_BwE To my understanding this thing can sense current passing through a 0.1ohm onboard resistor. The arduino can be kept...

That might be the easiest way to go. Are you familiar with current to frequency circuits that will work?

House battery is 48V (46-53). I have buck converters that accept 0-90V input. Opto-isolated SPI should work. But how do I convert the voltage reading to a SPI signal? I've been searching for VCO IC's this morning and there is one issue that applies to all models I find. They send out so high...

Measuring the voltage tells quite a lot. If voltage can be measured within 2V accuracy it will tell how much more power the system can handle, or how much power has to be reduced. I that is accounted for how much charging current the battery can handle at the current state of charge, how much...

Inverter is one of the big consumers. If that thing is on at all times, battery won't last a night. Would be quite silly to have any device that doesn't require AC to depend on AC. What can be smarter? Say if the sun is shining and battery is full, then it is nice to run hotwater. That saves...