Questions tagged [solar-energy]

Form of renewable energy emitted by the Sun, coming in two flavours: photovoltaic and thermal. The former, especially, relates closely to electrical engineering since it is traditionally harnessed through semiconductor devices and converted to AC in order to feed the electric grid or individual users' homes.

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898 views

How do I lower current usage on a 12 VDC fan hooked to a battery without a rheostat?

I have a 12 V fan hooked to a battery. I also have a solar charger to charge the battery. The issue I have is that the fan runs very fast when the battery is fully charged and runs the battery down ...
0 votes
1 answer
80 views

Identify round RS485 connector

I'm going to get a solar inverter. It has a RS485 port on a round waterproof male connector: The diameter of the mating female connector shell seems to be about the same as a MC4, or 19mm. I'm ...
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How to slowly store higher voltage from low power source?

I want to use a small solar panel (about 1V 15mA in ambient light) and then boost its voltage to 6V to slowly charge a 6V battery or capacitor. I have experimented with some generic boost converters, ...
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2 votes
1 answer
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Circuit to limit a variable-voltage DC supply to 30V

I want to charge a powerbank which supports 11-30V input with a solar panel with an open-circuit max voltage of 48V (41V under load). I live in a cloudy area, so I don't expect the solar panel to ...
3 votes
2 answers
507 views

Is it safe to connect DC equipment to a charging battery?

I have an off-grid house with a central 24 V setup of batteries and solar panels. During the day, the voltage of those batteries changes quite a lot, based on power consumption and the solar panels' ...
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2 votes
1 answer
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Low-voltage battery cut-off circuit for 3.7 V lithium

I am looking for something even simpler than this, with low power consumption (so no relay): https://youtu.be/8GQrTZb9T_c?t=158 I need a circuit which can be built from basic components which can cut ...
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0 votes
0 answers
35 views

Auto switch between two DC power sources, depending on battery level

I'm looking for a way to use my Raspberry Pi on solar power when my solar-charged battery has enough power, and switch to the usual electric power grid when my battery reaches a certain level. I don't ...
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"Load balancing" a powerbank to power small wireless camera

I'm doing a very small project to power an off-grid wireless camera. I have a 20 Ah powerbank that supports pass-through and I hooked it to a small 5 W solar panel (which looking at this question ...
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4 answers
119 views

Matching generation and consumption in renewables

To balance power generation and consumption, traditional power plants such as thermal and hydro have governors that regulate the steam/water that flows into the turbine. The energy that renewables ...
0 votes
1 answer
54 views

Solar - charge batteries at 24 VDC, use 12 VDC loads

I have solar panels to charge controller to batteries to DC loads. The charge controllers can handle twice the power at 24 VDC as they can at 12 VDC. The loads are 12 VDC (mainly LED lights). Can I ...
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Solar inverter/charger to battery connection protection

I have a solar off grid inverter/MPPT charger and I want to install protection on the link between the unit and the battery. I thought of using a Circuit Breaker like this. But the problem is that DC ...
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Why is my solar charge controller reducing current?

I have a 60 W, 20 V solar panel and I am trying to charge a 12 V, 70 Ah lead-acid battery with a solar charge controller. I set the charging voltage to 14.1 V in the controller but it shows the ...
0 votes
2 answers
137 views

Damage to inverter: Using excess solar photovoltaic to power water heater like trailing edge dimmer

Motivation I know that a similar question has been asked before (control power to water heater,) but prices and technology have changed, and my situation is slightly different so I am asking again. My ...
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Portable Power Station Solar Input Limitations - Workaround?

I'm considering buying this unit for backup energy + solar charging: https://www.ecoflow.com/us/delta-pro-portable-power-station Now, the max input is 1600W with 150V and 15A max. This is acceptable ...
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Looking for an automatic switch to keep my two solar systems completely separate? [duplicate]

Here is a picture of my Queensland, Australian setup. My 4kW off-grid system needs to be completely separate from the house 3kW solar system, and also cannot touch the Energex meter box at all, ...
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Can a higher wattage solar panel in series pick up slack for lower wattage panels?

I have (in series) three 100 W panels and one 175 W panel. The 100 W panels (with bypass diode) are rated at just under 5 amps, and the 175 W panel is rated at 9 amps. From what I have read this means ...
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2 answers
81 views

Can I add a second solar panel to a battery powered gate opener, to get more charging? [closed]

The system is two 12 V batteries in series powering a 24 V motor. Present 24 V solar panel is in parallel to the 24 V battery circuit. Can I add a second 24 V panel in series or parallel, or should I ...
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12V solar panel voltage is not 12V in reality. How do I correct this? (ESP32 solar powered project)

I slapped together a bunch of spare DIY electronics in an attempt to make an automatic plant watering system. The goal was for it to be solar powered, something to set and forget. Just add water. ...
-1 votes
1 answer
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Do static generators maintain a constant voltage at the terminals?

Do static generators maintain the terminal voltage constant like a synchronous generator does? If not, are they at constant current? With static generator I mean photovoltaic systems connected to the ...
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1 answer
54 views

How to get a static generator starting from a synchronous one?

I want to model a static generator (a photovoltaic one) inside a simulation tool. This simulation tool has no static generator (it is quite new and not user friendly). My idea was to model a ...
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3 answers
355 views

Safety of a polarized DC breaker between the battery and the inverter

DC breakers use a magnet to blow the arc into the quenching channel. If the current is flowing in the wrong directly, the arc is pulled into the guts of the breaker and can cause the arc to be ...
2 votes
1 answer
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Off-grid computing

I am designing the electrical system for a school bus to tiny home conversion (skoolie, by jargon.) The current iteration is entirely solar powered, somewhere around 2640 W in panels, and likely 1000 ...
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Small vs large inverter efficiencies

I want to run a 60W device 24/7 through an inverter as efficiently as possible. I see that inverters become very inefficient at low loads relative to their capacity. Is this only because of factoring ...
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2 answers
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Battery capacity and parallel vs. series battery connections

Say you have 4 200 Ah 12 V batteries connected in parallel, this as I’ve come to learn increases the amp-hour value and not the voltage, and say you have another system same as that but connected is ...
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Is 3 amperes at 5V drawing the same power as 3 amperes at 12V?

I know that amperes are volts x watts. If I draw 5V at 3 amperes, is it almost the same as drawing 12V at 3 amperes from a 12V system? I expect the 5V would draw more as there is inefficiency when ...
0 votes
1 answer
337 views

Charging batteries with both an inverter and solar panels

I have an inverter, a battery bank, a PWM solar controller, and some solar panels. The inverter also supports charging the batteries from the mains power. So if I just plug the inverter into a wall ...
2 votes
1 answer
114 views

Frequency reading 180 Hz on only one line to line measurement in three-phase backup 60 Hz LP gas powered generator in idle mode

I am running into an issue I don't understand why is happening. I have found how to "fix" it, but I am interested in ideas on what the actual source of the issue is Short version: I have a ...
0 votes
0 answers
76 views

How to model solar photovoltaic array in spice?

This is the circuit I need to simulate in KiCad and ngspice. simulate this circuit – Schematic created using CircuitLab Can I encapsulate the above circuit into a variable in ngspice so that ...
0 votes
1 answer
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Safety check - Is this Amazon PV combiner box labeled wrong? 15A Vs 32A - 500V vs 1000V

I'm currently working on a solar circuit. I wanted to protect my internal systems from my panels in the event of a surge. I purchased a PV combiner box from Amazon - link to product. It claims to be a ...
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1 answer
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Can I charge a laptop with a solar panel? [closed]

I have bought a 30W solar panel, with output: USB 2.0 : 5V/2.4A USB3.0 (QC3.0): 5V/2.4A, 9V/2A, 12V/1.5A DC: 18V/1.66A (Max) I would like to charge my laptops. I have seen this power bank of 90 W, ...
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1 answer
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Convert kWh during a 1 hour period to average 15 min kW output

If I have a photovoltaic system that outputs 100 kWh from 1PM - 2PM on a given day and I am trying to figure out what the average 15 minute kW would be during that time period, would that be equal to ...
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1 answer
212 views

Balance 3 phase inverter output

I have a 6kw pv solar system with a 3 phase inverter which splits the generated electricity equally across the 3 phases. I can't resell the excess capacity back so I want to make the most use of the ...
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61 views

Using an existing MPPT charge controller and solar panels with new battery pack

I have an off-grid setup at the moment to power most of my DC devices (bulb, router, NAS, NVR, etc.) I'm planning to upgrade my setup to a more powerful AC off-grid system to power my entire house. My ...
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3 answers
150 views

Clear my confusion on PV or PQ nodes of power system with renewables?

A solar PV is connected to a node of the power system through a converter circuit. Is it possible to understand that the solar PV operating at its maximum power point (MPP) is considered a PQ node? Or ...
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2 votes
1 answer
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What variable power electronic to use for boiler heater?

I am running a PV-Solar system together with a heat-pump in Germany. Excess electric power is fed into the grid, however I am only allowed to feed in 70% of the peak capacity. During solar noon, I ...
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1 vote
2 answers
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I am building a small off-grid solar power setup; I need help with the battery size and combination

I have four 12 V large tubular deep-cycle lead-acid batteries and I want to know which one of these is a better set-up and why: combine two batteries to make one 24 V battery; this way I will have ...
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1 answer
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Using 210 V DC to a 220 V AC heater: is it going to work?

I'm considering building an off-grid solar system piece by piece. I can afford a couple of solar panels, after that an inverter, and finally batteries. I was thinking about finding a practical ...
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2 votes
1 answer
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Can I use 10A solar controller with one 445 watt panel

I am wondering if I can use 10A PWM controller with 445 watt or 625 watt solar panel.
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2 answers
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Can I estimate irradiance from photovoltaic panels' output data?

I'm trying to figure out a way to estimate irradiance from the data I get out of photovoltaics panels; irradiance, or any other variable that would be appropriate to my use case/context, which I hope ...
4 votes
4 answers
196 views

Are solar panels ever used to remove energy?

Solar panels convert energy from the sun into electrical energy. Following the first law of thermodynamics, this means they remove some of the solar energy that would otherwise most likely be absorbed ...
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1 answer
62 views

How to factor roof angles and inverter efficiency in sizing a solar PV system?

I want to install a number of Mission Solar 420 W PV panels (pdf) on my roof. By estimating an average of 5 solar hours per day over the course of the year, I believe I need 9 kW of panels. So by a ...
0 votes
5 answers
267 views

Can I use 10A multimeter to test 445 watts solar panel

I want to know if I can use a cheap multimeter, model DT-830D, which has a maximum current rating of 10A to test voltage and amperage of a 445 watt solar panel with the following characteristics: <...
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2 answers
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CN3722 solar controller does not stop charging

I have this custom PCB witha CN3722 module. I charge two 18650 batteries. Resistors XVR7 and XVR6 are calculated for 8.3 volts. The charger charges the batteries and the "done" LED turns on ...
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Solar Battery Charging Circuit

I designed this circuit: to charge my 12 V UPS battery from a 40 W, 18 V solar panel. I specifically included an LM317T adjustable voltage regulator to control the output voltage to about 13.4 V as ...
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How does solar PV modules array Power, Voltage in Series/Parallel affect maximum power efficiency

I have been struggling with my homework on my course (Solar PV Panels) today. Edit : PV Module parameters are below. These are for STC. In our case, it's 650 W/m^2 and 55°C. I have calculated IL and ...
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Grid-tied micro-inverters and lightning risk

Consider a roof-top solar generation plant. Usually here, a bunch of panels are connected in series to a "string" inverter. So, DC voltage goes up to hundreds of volts. I gather that this ...
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120 views

How do DC solar optimizers work in series?

Tigo and SolarEdge both have solar DC power optimizers. These have MPPT built in and optimize the panel. That is, the panel gis connected to them, then the optimizers are hooked up in series to each ...
1 vote
0 answers
63 views

Switching large batteries between 12 V and 48 V connections

I have four 200 Ah batteries that I am using to drive two separate really high current loads. The first load is 12 V at around 400 A and the second is 48 V at around 120 A. I was wondering if I could ...
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Measuring voltage on different ground reference – PV

I have a small solar power installation and I want to monitor all the data from it. My only problem left is that the solar panel input doesn't have common ground with batteries (or atleast there isn't ...
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3 votes
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Wiring different amp hour batteries in parallel

Can I wire 2 lithium batteries of the same make but different amp hours in parallel? I need 300 Ah in my battery bank. Can I wire a 12 V 200 Ah lithium battery and a 12 V 100 Ah lithium battery in ...

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