diy solar

diy solar

Need help diagnosing problem after 6 months with first system. (cant piece the logic together)

SolarSamSurfer

Here to learn.
Joined
Apr 24, 2022
Messages
83
Hey guys, I am having some issues with my system thats fully offgrid and im not sure if i have the settings set up wrong or if my batteries are just very low quality and failing already.
Equipment: 2x 385 panels in series 8 AWG cable 20 meters from inverter, inverter growatt SPF 3000TL LVM48v, batteries lead acid 4x LTH 205AH 12v in series to make 48v with 6 AWG wire.
Growatt settings: 1-SBU 2-60A 3-N/A 4-off 5- FLD 6-on 7-off 8-120v 9-60hz 10-4 11-30a 12-NA 13- 54v 14- only solar 15-on 16-on 17-on 18- disable 19- 58.4v 20-54v 21-42v 22-enable
Locatation- 15N 96W very light rain season
I installed my system in October 6 months ago, for the first week i didn't have anything heavy connected just maybe 20w worth of LEDS. After a week i connected a fridge and was having low voltage problems straight away, i checked the batteries one by one and two out of four where not holding charge. No problem trip to the supplier and they where changed with the warranty they came with. Now 6 months have passed and last week at 6am my system alarm went off for low voltage (44v), this week i have been having to unplug the fridge so that the alarm doesn't go off. When i checked in the night time one is dead only 10.3 while others are 12.5. the battery that's only reading 10.3 is one that was replaced already and since i claimed the warranty i don't get any on this one so i will need to buy a new battery. I got a new battery a few weeks ago and noticed that in the evening the voltage number where a little lower then before i started having an issue but not low enough to trigger the alarm until 1 week had passed. Before having a problem as well the batteries would normally finish charging at 2pm and i would notice every afternoon for a few hours the growatt making a clicking sound. when i would try to see the error message it would be gone until after months i finally saw it number 3 for over charge. I'm guessing that after fully charging the growatt kept trying to charge them then over load protection went off for a few months everyday causing my damage to my batteries causing one to die. After replacing the battery i have been checking the system between 12-4 pm most afternoons to see what's going on to make sure its not setting the overload protection off on repeat again, it isn't overcharging anymore but its failing to get to the Contest Voltage charging stage some days. Important note about the fridge, i have the growatt data from the dongle so i can see the watt output throughout the day and the fridge turns on an hour then off an hour approx. to maintain temperate. Since changing the battery the data is showing the fridge on constantly, ive made a few tests: if i turn the thermostat inside the fridge down it turns off for a little while before turning back on to cool down again. I've thought about it and the fridge is making noise a lot more lately. This could also be because spring/summer is coming and its getting hotter but i live in the tropics so i don't really have a change

Need help understanding if its a system problem or if its the fridge. i understand that the growatt over charging the batteries for a few months would do a lot of damage to them but that isn't happening any more. Maybe i need to change the settings, i did recently learn that there are settings for the flood batteries to stabilize them settings numbers 43, 44, 45, 46, 47, 48. anyone have recommendations on them because i have it turned off at the moment

If you arrived here thanks very much for taking the time for reading this and if you need any other information please ask.
 
Last edited:
Welcome to the party SolarSamSurfer.

Do your 6 awg wires get warm? Wire size seems small to me.
I do not know what "LTH" is in reference to your batteries.
If you can charge each battery individually, you may learn something new about your system. Just guessing there.
 
Welcome to the party SolarSamSurfer.

Do your 6 awg wires get warm? Wire size seems small to me.
I do not know what "LTH" is in reference to your batteries.
If you can charge each battery individually, you may learn something new about your system. Just guessing there.
no the wires dont get warm, batteries dont get warm, its 33°c everyday so they are room temp. yes i could take them to a mechanic to do that but they are all .1 of each other
 
Welcome to the party SolarSamSurfer.

Do your 6 awg wires get warm? Wire size seems small to me.
I do not know what "LTH" is in reference to your batteries.
If you can charge each battery individually, you may learn something new about your system. Just guessing there.
LTH is the brand, local Mexican battery company
 
Are your batteries lithium or lead acid?
A lot of off the shelf lithium batteries can't be hooked up in series. They will not charge or discharge equal and you will not get the capacity out of them.
 
Are your batteries lithium or lead acid?
A lot of off the shelf lithium batteries can't be hooked up in series. They will not charge or discharge equal and you will not get the capacity out of them.
lead acid ops forgot to say
 
205ah batteries so you'll be lucky to get 100ah of power out of them. My residential refrigerator in my motorhome pulls about 8amps of power so in 10 hours that's 80ah that you need to be replacing with your solar.
 
205ah batteries so you'll be lucky to get 100ah of power out of them. My residential refrigerator in my motorhome pulls about 8amps of power so in 10 hours that's 80ah that you need to be replacing with your solar.
this fridge is putting 4 amps
 
205ah batteries so you'll be lucky to get 100ah of power out of them. My residential refrigerator in my motorhome pulls about 8amps of power so in 10 hours that's 80ah that you need to be replacing with your solar.
this fridge is putting 4 amps
 
What have you done to help diagnose the problem?

Any new information?
I wish I was where you are. We had a 36 hour long blizzard starting Friday. I'll come check it out for food, cervesa & a bed.
 
Last edited:
What is the background consumption of that particular Growatt? Some of these inverters consume about 100W of power just being left on, so you can expect 2400Wh of power consumed just left on.

With just two 385W panels, even with southerly location with ~6sunhours per day, I'd expect you to make 385W X 2panels X 6sh = 4620Wh of power. That should cover both the inverter and the frig under perfect conditions, but you mention light rain, so I'd expect your panel output to drop down to about 10-20% of normal, or maybe at most 4620Wh X 20% = 925Wh. That is not enough to keep the system running.

For a 205Ah battery, you want 1/8C of charging, so what you should have is 205Ah X 0.125C X 50Vcharging X 1.175fudgefactor = 1505W of panels, about double what you have now.

In the short term, turn off both the refrigerator, and the inverter, and try to get the batteries charged as quickly as you can. If you don't have enough solar for that, is there a generator available? Those batteries need charging NOW, assuming they aren't already ruined. Do you have a battery hydrometer available? That's the very best way to determine a lead-acid battery's state of charge.

In the long-term, you need at least twice as many panels to generate the level of power you need, and maybe more for the winter months when it's cloudy and raining.
 
4 amps from the battery? That's a 48W fridge... nice. Are you sure? Most are around 200W
How are you coming up with 48W? 4A X 48V = 192W. That number is in line with what I would expect for a refrigerator. The OP didn't say but is this an AC or DC frig? I'm assuming it's AC because that's why he has the inverter?
 
How are you coming up with 48W? 4A X 48V = 192W. That number is in line with what I would expect for a refrigerator. The OP didn't say but is this an AC or DC frig? I'm assuming it's AC because that's why he has the inverter?
Yeah, I skipped over the massive block of text and made assumptions... my bad.
 
What have you done to help diagnose the problem?
im that new to solar im not sure what to be doing to diagnose the problem. ive checked battery voltage and thats it so far.
Yeah, I skipped over the massive block of text and made assumptions... my bad.
I dont think i need more panels, the system has the batteries fully charged by 2pm. I live in the tropics so theres no rain in winter at all. Infact i dont have winter
 
I dont think i need more panels, the system has the batteries fully charged by 2pm. I live in the tropics so theres no rain in winter at all. Infact i dont have winter
I'd say yes, you need more panels. My system is fully charged at around 10:00am. If it takes till 2pm to be charged, your solar is inadequate.
 
I'd say yes, you need more panels. My system is fully charged at around 10:00am. If it takes till 2pm to be charged, your solar is inadequate.
sorry if i sound naive, could you please explain to me how more panels will improve my battery life because it doesnt make sense to me? in 24 hours i consume just under 3kWh. Around 8AM the PV is strong enough to cover the load and start charging batteries. 2pm batteries are full and at around 5-6PM is when the PV isn't enough for load and they start from batteries. At 8PM is when the sun goes and its 100% batteries. where i live there's 12-13 hours of sunlight the whole year and maybe only 21 days of rain maybe 30 cloudy.
 
How sweet it would be. Torture me with a sunburn, tequila and a warm ocean.

I can see from your other thread:

that folks are suggesting a thorough check of your batteries. I agree 100%. Take them to the mechanic and hopefully you will get good answers.

If you can continue to provide "VERY SPECIFIC INFORMATION", I bet we can help resolve the problem with minimal costs and time down.

I do not see where anyone has specifically addressed your charge controller settings. I can not help you there.

A few photos of your system, wiring and batteries would really help.
 
Back
Top