All-In-One - Is A Battery Required To Use Inverter?

[nifty-stuff.com]

I have a handful of old solar panels (see attached) and I'd love to use them for emergency daytime power... no battery, etc., just juice right from the panels to run simple 120 volt devices.

... but I don't know how to do this without using a batter.

I see @Will Prowse 's great article here: https://www.mobile-solarpower.com/all-in-one-solar-power-packages1.html
(BTW, the ebay link for the $300 unit now goes to a $9,000 unit?!?)

... and it got me to wondering: Could I just plug these 35v panels into an all-in-one, and then use the 120v output right from the inverter?

Or, do I ALWAYS have to have a battery between the panels and the inverter?

I'd like to have this setup be as simple as possible to get some 120 v power from the sun and these panels. Any ideas would be greatly appreciated!

 

[Ampster]

I don't know how to do it either. Many inverters need some kind of buffer like a battery unless connected to the grid. The issue is their ability to curtail and ramp up power from the panels to match the load.

 

[namesgolden]

to preface this: batteryless setups do exist, but I haven't looked into them.

my plan for my first build (all parts purchased and delivered, working on building a structure out now) is to use a small battery bank as a buffer with a mpp all in one.

the setup will be 8-12 250w panels, a mpp 2424 and 4x 6v golf cart batteries.

I bought the batteries new ($100/each out the door at rural king).

the goal is to only use them as a buffer, then fall over to grid power when they are barely discharged (25% or so)

later I will replace the lead acids with LFP, but I wanna get some experience first.

you'll want enough batteries to handle the amp load you're looking to power, but you don't have to cycle them deep so you can basically use anything.

 

[Ampster]

Or, do I ALWAYS have to have a battery between the panels and the inverter?

After thinking about this, I remember there are pump controllers and other devices that do that. I bought one years ago to run an attic fan off a single solar panel. I am grasping at straws but I think it is some kind of DC to DC converter. I can remember the concept but not the details. Someone with more knowledge or a quicker mind may wish to chime in.

 

[nifty-stuff.com]

Thanks guys! I figured there wasn't an easy way to do this, and it seems that these "all-in-one" systems do, indeed, require a battery to work

Now I'm wondering what happens in a situation where:

1. Battery is full
2. Solar panels are producing 1,000 watts
3. A load is placed on the inverter that is 300 watts

I'm assuming that the battery just remains full to "balance out" the supply if needed, correct? Oh, and where does the "excess" power from the panels go?

 

[mtinbox]

According to MPP Solar's website, they have a model the 5048MG that supports batteryless operation. Found a listing on eBay here. Only issue (at least for me) is that it doesn't appear to support 110V, only 220V. Maybe somebody else here has recommendations on a step-down converter to go from 220V to 110V?

 

[nifty-stuff.com]

Wow, great find, thanks! Very interesting!

I'm surprised they don't have a 110V version.

 

[thedodgersonline]

Hi - I would also recommend you drop a line to sales@mppsolar.com - they might have something in the wings
Otherwise just buy 4 cheap 12v batteries and set it up for solar as a priority and set the cut off voltage at the battery level. This way it would only use solar to power the load and as soon as there was not enough solar it would switch to battery - which would be low - and then it would cut off.
You could add the service lead - that way it would switch back to grid when there was not enough solar.
Regards