Advice and input greatly appreciated...

[Risky Rob]

Thank you for better explaining the purpose of fuses...

Here's another question?? And thank you for being patient with me...

I've seen potable solar panels with only charge controllers attached to them and no batteries being connected from people using them.... with this in mind....

Can I use a cheap SCC, connected only to a 100 watt 12v solar panel with a voc of 24.8 , and as long as the scc can output 12v on the load side. Use this without a battery in direct sunlight for daytime devices??? Or... is there something you'd suggest me doing before trying this out? Any suggestions?? Thank you again.

A Renogy Rover 20A costs only ~$80, and has nice features. You would need a battery, but it could be a used auto battery. That scc has a programmable load terminal, so you could run 12V low-amp devices without an inverter.

 

[chrisski]

Don’t try to run devices without a battery off solar panels.

At the very least it acts as a buffer for clouds to continue to provide energy.

I have a 2000 watt load and 2600 watts of panels. The panels will easily provide enough power to run the lead, but it takes a few seconds to transition from all battery to full panels during which the battery starts providing 100% of the power and at the end of those few seconds, it provides none.

What happens to your equipment if you did only use panels as it cycles on and off on the clouds.

Solar power is the longest existing alternate energy source and noone has been able to develop a good battery-less system in decades.

Many have tried. All have failed. It’s not a challenge.

 

[Doggydogworld]

Can I use a cheap SCC, connected only to a 100 watt 12v solar panel with a voc of 24.8 , and as long as the scc can output 12v on the load side. Use this without a battery in direct sunlight for daytime devices??? Or... is there something you'd suggest me doing before trying this out? Any suggestions?? Thank you again.

As others have said, a battery smooths things out. But there's more to it. SCC is solar charge controller. It's designed to charge a battery. The instruction manual says to connect the battery first, before connecting panels or loads. So the entire idea of running without a battery is contrary to the design and may damage the SCC.

You could ditch the controller and simply use a DC-DC converter. It's not efficient, but if you pay close attention to the details it can work. And without a buffer you may experience a "power outage" every time a cloud passes over or a bird perches on your panel and shades part of it.

This article talks about why a SCC doesn't work. It also mentions the DC-DC converter approach.

Final note. Please keep in mind that a "cheap scc" does not output 12V at the load port. PWMs just pass voltage through to the battery and load. Connecting a panel and discharged battery together via a PWM is the same as connecting the panel directly to the battery.

While charging panels, battery and load are all at the same voltage, usually around 13-14V. It's not until battery reaches 80-90% SOC (about 14.5V for lead-acid) that the PWM controller really does anything to regulate output. And even then, it just very rapidly alternates between shorting the panels directly to the battery and disconnecting them completely. It works, but it's pretty crude.

MPPTs are different. They have a DC-DC converter inside. But they're also designed to charge a battery. And the ones I've seen simply pass battery voltage straight through to the load terminals. The panels will be at a different (likely much higher) voltage, but battery and load are the same. In theory it might be possible for a MPPT to use its internal DC-DC converter to power loads without a battery, but I don't know of any designed to support that.

 

[swhiting8]

As others have said, a battery smooths things out. But there's more to it. SCC is solar charge controller. It's designed to charge a battery. The instruction manual says to connect the battery first, before connecting panels or loads. So the entire idea of running without a battery is contrary to the design and may damage the SCC.

You could ditch the controller and simply use a DC-DC converter. It's not efficient, but if you pay close attention to the details it can work. And without a buffer you may experience a "power outage" every time a cloud passes over or a bird perches on your panel and shades part of it.

This article talks about why a SCC doesn't work. It also mentions the DC-DC converter approach.

Final note. Please keep in mind that a "cheap scc" does not output 12V at the load port. PWMs just pass voltage through to the battery and load. Connecting a panel and discharged battery together via a PWM is the same as connecting the panel directly to the battery.

While charging panels, battery and load are all at the same voltage, usually around 13-14V. It's not until battery reaches 80-90% SOC (about 14.5V for lead-acid) that the PWM controller really does anything to regulate output. And even then, it just very rapidly alternates between shorting the panels directly to the battery and disconnecting them completely. It works, but it's pretty crude.

MPPTs are different. They have a DC-DC converter inside. But they're also designed to charge a battery. And the ones I've seen simply pass battery voltage straight through to the load terminals. The panels will be at a different (likely much higher) voltage, but battery and load are the same. In theory it might be possible for a MPPT to use its internal DC-DC converter to power loads without a battery, but I don't know of any designed to support that.

OK. This does give me a better understanding of how I will tackle this... I am convinced a battery is better suited with an mppt scc and using a small fuse block to output my (3) 12V, 2A , devices. This way. The draw is constant from my battery with or without the panel on cloudy or no sunny days . I've already did a test run on the battery in itself and got 6 days from it without needing to charge it up... so with that in mind, based on a solar panel and mppt charger, I'll be in a good start and still allowing room for expansion without wasting my money. Thank you guys again.. all suggestions and advice I take to heart.