diy solar

diy solar

Probably dumbest question ever

Ok, now I’m really lost?
Example: I have a solar pump that pulls up water from 400’ with no batteries attached!
Works like a charm, I fill my holding tank during the day, once every 3 days for yrs now?‍♀️
So why can’t I run my MPP LV6048 all day, while the sun is out? I thought the batteries were just backup? I really don’t care if I have electricity at night??
Read the part of my answer in the parentheses. You can use what’s currently being made, so long as that is sufficient to power the load. Having storage smoothes out the power delivery by storing excess while it is there so that it’ll be available when the sun is not available (shady days, rain, night).

Think of batteries like you do your water storage tank. The well pump is the power source, and the water is electricity. The storage tank holds water that was produced in excess of what you needed at the moment it was pumped, so it will be available when the well pump can’t provide it. Batteries work like that.

You can also run your well pump with no storage and just use water as it’s pumped only, but it’s inefficient and wasteful of a resource you’ll need later. Batteries are your storage tank for power, and make your system more efficient and useful.
 
Let's assume that those batteries are 120Ah. Most flooded lead-acid batteries like a charging rate of about 1/8 of C, or in your case 120Ah X 0.125C= 15Amps. With a 48V system charging at 50V during bulk, you need 15Amps X 50V X 1.175fudgefactor = 881W of panels, more or less.

With 16 250W panels, you can make 4000W, so that is grossly excessive for your battery size. Your battery really should be (4000W/50V) X 0.85fudgefactor X 8fold capacity = 544Ah of battery. So, you need 4-5 times the battery capacity for that amount of power.

One important consideration with small batteries is "ripple current", the fluctuations in the DC voltage caused by AC. It can be damaging to your solar electronics if large enough. Read though the attached file for more info on ripple current.

Those batteries are not the best choice, and assume they are not going to last long. I'd start shopping now for potential replacements. This is my battery, which is in the right size range for what you need.
If I went with your rolls batteries, would I be able to add those to what I already have? Mine are brand new, and Basically not really being used because I shut the power off every night when the sun goes down
 
I don’t know the all in one inverter to well. For these Delhi batteries, what is there ratings in amp hours?

Also are the batteries FLA or AGM?
Ah 65...terrible I know, but when the ox is in the ditch you get what you get and you don’t throw a fit ?
 
If I went with your rolls batteries, would I be able to add those to what I already have? Mine are brand new, and Basically not really being used because I shut the power off every night when the sun goes down
Not at all. Batteries should be the same chemistry, the same amphour size, and the same age to charge equally. I'm assuming you shut the system off at night because the batteries are so small they get drained by morning?

This really is the hallmark of mediocre design. Sort of like buying a classic Mercedes and then trying to put a lawn mower engine in it to supply power. I'm not trying to be mean here, but you've been making the classic mistakes of buying stuff before you really know what you need, and then you'll end up paying twice to make something that works the way it is supposed to. We see this here almost every day.
 
Not at all. Batteries should be the same chemistry, the same amphour size, and the same age to charge equally. I'm assuming you shut the system off at night because the batteries are so small they get drained by morning?

This really is the hallmark of mediocre design. Sort of like buying a classic Mercedes and then trying to put a lawn mower engine in it to supply power. I'm not trying to be mean here, but you've been making the classic mistakes of buying stuff before you really know what you need, and then you'll end up paying twice to make something that works the way it is supposed to. We see this here almost every day.
I don’t need your judgment son, I have what I need, it just will take little longer. It took 3 1/2 years for this 73 yr old retired woman, building her last house, living off grid without electricity to save for what I have now.
Pick somebody else to preach to? so when you see my stuff, just fly right on by...? I don’t need your BS?
 
It's your money. If it's your choice to blunder through replacing part after part till you finally get a working system, that's fine. It's a well practiced strategy on this site.
 
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