diy solar

diy solar

Way more panels than battery - how does the current flow to inverter

wiseacre

Solar Enthusiast
Joined
Aug 8, 2021
Messages
492
Location
North of the Adirondacks
I set up a small system for my maple sugar shed. Originally it was used to power some lights and an induction hot plate to finish off the syrup. Deciding not to waste potential electrical production during the off season I added an ATS and ran a 120v line to the house and run my aquariums off the solar till the battery hits about 50% DoD (Gel battery) and the switch flips over to the grid.

with (8) 195w panels the ATS flips back to battery around 10am and the battery I guess is fully charged in a few hours more. With only 100Ah 24v the battery understandably doesn't last long once the sun goes down.

What I would like to know is it reasonable to keep adding panels in order to power more appliances?
Does a higher load have a negative effect on the battery the way I'm using the system?
Is the SCC charging the battery the whole time? Or once charged does the current just flow through?

Am I in Weekly World News territory with my thinking?

I plan on upgrading the battery bank with most likely a EG4 24v, 200Ah or SOK 24v, 100Ah and add to them as I can afford.
 
Just keep in mind, now you might be displacing 50¢ electricity per day. How much effort are you willing to spend to save 75¢?
 
Just keep in mind, now you might be displacing 50¢ electricity per day. How much effort are you willing to spend to save 75¢?
I'm not trying to save money. I'm just tinkering around when I have money to spend.

Another thought is when the grid goes down. Being able to power different appliances like a freezer and refrigerator at same/different times when the sun is out is better than nothing. Replacing my well pump with a Grundfos could keep me in water at times and even hooking up my 240v hot water heater with the 120 would provide some limited hot water. Everything wouldn't be run at the same time but the more the merrier within limits.

Over time I'll upgrade the battery bank for sunless periods but I'm thinking sunny thoughts as I build up the system. What I was concerned about was passing all the current through the battery when fully charged.
 
The battery is a buffer during the day, smoothing out the output of the panels. Current would just bypass a full battery.
 
I would be more inclined to get more battery until the aquarium will run all night.
 
I would be more inclined to get more battery until the aquarium will run all night.
Yep, you're right, I've reached a comfortable amount of panels for now so it's time to start upgrading my battery bank.
The world is not all sunshine and roses and I should be prepared for some cloudy days.
 
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