Crash course solar

[robinredd]

my utilities have been shut off in a attempt to evict. so my knowledge in solar needed to be learned fast..
I have 4x390watt panels wired in parallel to a 80 charge controller with 8x90ah commercials caterpillar deep cell batteries with 2 sets of 4 wired in series then parallel to charge controller 24volt system . I have the charge controller set to shut the pv off to 28.6. it doesnt matter if it is cloudy the panels keep the batteries at 100% Evan with a load during the day .. i just can not figure out when the sun goes down being held at 28.6 all day when the sun goes down it will slowly settle out at like 67% charged and i can only use that down to 50% im only wanting to run 2 laptops and a tv as the moniter for the one laptop no lights nothing 4 of the batteries are new and the other 4 one month old i just dont know i can send pictures

 

[snoobler]

Welcome to the forum.

Terminating utilities to force eviction is illegal in the U.S. in most cases.

The meter that you are reading % from is basing it purely on the voltage of the battery. It has absolutely no meaningful value in most cases. When charging is terminated, voltage drops. A 24V battery will settle to around 25.4 if unused after several hours even though it is fully charged.

The charge controller should be set to something around 28.6 for the boost/absorption voltage, but float voltage should be closer to 27.2. Holding them at 28.6 all day will shorten their life.

 

[robinredd]

is the number that i set the pv to turn off is that what the charge controller basis it percentage of charge on ? if so that's the number of % that im reading off the controller im going to take a picture right now of the screen . now it is really gloomy outside looking like it going to rain. i took 2 pictures because the screen flashes with 2 different readings you see were im getting the 100% reading from and when the sun goes down that percentage drops to like 61% I have 4 of those panels hooked up in parallel. If the panels during the day hold them all day at 28.6 do i have to much panel for the amount of battery i have ? the charge controller says 28.6 my inverter flashes between readings of 60 and 29.3 i know the 60 is what in using and the 29.3 is that supposed to be the battery if so that's different from the 28.6 controller reading

 

[robinredd]

ill change my setting to 27.2 right now i forgot to mention that before i sent the last message.when i lowered it when it was being held at a higher rate you see how it was showing 96% and charging? and 27.0

 

[robinredd]

i just reread your message what number is the float did i change the wrong one

 

[snoobler]

Again, the % meter is completely useless. You should ignore it.

Please link the manual for that charger.

 

[robinredd]

this is the name im still looking for the manual online

OOYCYOO MPPT Charge Controller 80 amp 12V/24V Auto, Renewable Energy Solar Charge Controller​

 

[snoobler]

Can you take a picture of the page(s) that contain the battery settings options?

 

[robinredd]

Can you take a picture of the page(s) that contain the battery settings options?

i can not find the manual so im sorry i guess im out of luck i took a little video

 

[snoobler]

Yeah, that's a mystery to me too. I searched the Amazon listing, and the seller claims it adjusts all those voltages automatically, so PV OFF should be the absorption voltage, 28.6V, or whatever the appropriate voltage is for your batteries.

Back to the original issue:

You need to ignore the % gauge. It is worthless. The only way to get an accurate % reading on a battery is to count the amount of current put into and taken out of the battery. This is accomplished with a battery monitor.

The % reading on your charge controller is just reporting % based on voltage, which is completely unreliable. I wish they would just leave them off. You have no idea how many people come here with this exact issue.

First thing tomorrow morning, right before sunrise - before solar charging starts, with as few loads as possible, you need to check your battery voltage AT the battery with a voltmeter. You want that voltage to be 24.2V or higher.

 

[robinredd]

At the end of the day I noticed that they settle out at 25.8 ok I’m learning thank you and at night I just want to pay attention that it doesn’t run any lower than 24.2? That’s another thing I want to ask how is the charge controller supposed to turn off the load when the batteries get to what you set the charge controller to shut off the load off , when the inverter is connected directly to the batteries not to the load on the charge controller? So I should set my load to shut off at 24.2? And ( what # to turn on?) I’m just don’t know how that supposed to control the inverter when it shuts off and turns on the load to protect the batteries

 

[snoobler]

The charge controller can only turn off anything attached to the load terminals, and you should NOT connect the inverter through the load terminals (if it has them).

Your inverter has a cutoff. It's probably around 21V.

You shouldn't necessarily set your shutdown at 24.2. That's the resting voltage that indicates 50% capacity. You should moderate your power use to ensure you're not driving the battery too low as deep discharges will dramatically shorten their lives.

 

[robinredd]

after reading this you will probably go "OH MY GOODNESS HERE WE GO "
this is what im understanding dont connect to the inverter load .from what i understand that the load connection are for light small stuff light just a light really small stuff, but never the battery bank .you said the inverter has probably a cut off of 21v.
i take it that is a built in like emergency the owner is already not paying attention they have gone well under the red kill your battery zone and im "the inverter" am taking over and shutting off? on my inverter i do not see anything that's adjustable. on a lot of video's they speak a lot about setting the load on to this and off to that and gave me the impression that these settings running the show "saving your batteries" they speak so much about a load connation that most are not even going to be using unless they are going to be out of town and are wanting a light to come on and off ? now that im thinking about that scenario would not even work. im sure their something as to why someone would use the load connection . but with all the emphasis on the internet on the on and off setting i was confused how the charge controller controlled that ? that why i asked last night. a feature more dont use than use that doesnt rank much higher thank the % reading of the voltage? listen to me quite rambling this mourning.. ok back on track i got the 24.2v from when you said by morning time just before the charging kicks in i went my reading to be 24.2v or higher ? so i was understanding that persay a stayed up all night running my laptop that i just needed to keep a eye on the reading that i did not take them under 24.2 before the charging starts all over the next mourning? because last night that made such a beautiful differance in the amount of time that i was able to use the power , it was great i was on the internet at NIGHT TIME a long time, and when i went to bed i still had 25.5v left. and that % icon im supposed to not look at said 42%. i thought i finally figured it out and this was going to work out ok..
then i read this you shouldn't necessarily set your shutdown at 24.2. That's the resting voltage that indicates 50% capacity. You should moderate your power use to ensure you're not driving the battery too low as deep discharges will dramatically shorten their lives. and "You want that voltage to be 24.2V or higher..? my impression was that as long as it have a reading of a settling A 24V battery will settle to around 25.4 if unused after several hours even though it is fully charged. mine settle out at 25.8,, and i dont want the batteries to be lower than 24.2 thats the reading for 50% charge ..so 24.2 is acceptable but really not the best if your wanting a long life out of your batteries every but it not something you want to do all the time? IM GETTING IT?? IF SO WHAT WOULD BE A GOOD HAPPY MEADIUM ON A SAFE DISCHARGE RANGE VOLT , SHIT I FORGOT I HAD THE CAPITALS ON IM GOING TO SEND THIS

 

[snoobler]

I'm not willing to read a wall of text. What is your question?

 

[robinredd]

im sorry i was a little excited at that i was figuring it out ,here my question
my impression was that as long as it have a reading of a settling A 24V battery will settle to around 25.4 if unused after several hours even though it is fully charged. mine settle out at 25.8,, and i dont want the batteries to be lower than 24.2 thats the reading for 50% charge ..so 24.2 is acceptable but really not the best if your wanting a long life out of your batteries every but it not something you want to do all the time? IM I GETTING IT?? IF SO WHAT WOULD BE A GOOD HAPPY MEADIUM ON A SAFE DISCHARGE RANGE VOLT

 

[snoobler]

25.8V is a good "settling" voltage.

24.2V is not a hard limit. AT REST 24.2V is 50%. If you're pulling at load on it, it will be below 24.2V and still be okay. If you're below 24.2V, and you remove the load, and it raises about 24.2V, you're still good.

I recommend you purchase a battery monitor. The % SoC is actually a meaningful number on a device like this:

Off-grid Solar Battery Monitors

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

The "budget" one is about $50 and goes between your main (-) battery terminals and all your loads/sources. It "counts" the An in and out of the battery and calculates a % state of charge. It also "resets" to 100% when you fully charge the battery.

 

[robinredd]

thank you very much you have helped me a lot I have one more concern I think I should mention I’m not sure if it’s normal or not so I’ll ask my inverter right now shows 29.3 in charge controller shows 28.6 on voltage is that normal I’ll take a couple pictures My iPad will not take the pictures of the red numbers it says 29.4 is it normal

 

[robinredd]

Do you see the top of that one battery is it kind of an indication there that maybe 28.6 might be too much for the batteries I don’t know ? Their commercial caterpillar‘s

 

[snoobler]

thank you very much you have helped me a lot I have one more concern I think I should mention I’m not sure if it’s normal or not so I’ll ask my inverter right now shows 29.3 in charge controller shows 28.6 on voltage is that normal I’ll take a couple pictures My iPad will not take the pictures of the red numbers it says 29.4 is it normal

Use a meter to measure:

voltage at main battery terminals.
voltage at inverter terminals.
voltage at charge controller terminals.

They should generally be about the same unless there is a heavy load, or a poor connection.

The charger typically shows higher than a measurement at the battery due to wiring losses between them.
The inverter typically shows lower than a measurement at the battery due to wiring losses between them.

When working:
Your inverter pulls voltage down.
Your charge controller raises voltage

Given your inverter is reporting a HIGHER voltage than the charge controller, I would attribute that specific different to measurement error - most likely on the inverter.

 

[robinredd]

I wanted to thank you so much since you told me how to read the inverter .you have saved me from alot of arguing in my house thank you. one question today i checked the batteries individual voltage not connected to panels , and lowered voltage on some making them all in the same range of 13.32/13.40 range. and when i hooked them back up to the panels and 1 of the 8 shot way up from a 13.32 to a 15.19
and the others holding 14.60 being the highest and lowest at a 13.69
what do i do their do they have something i can hook them up to that will equalize them?