Electrical questions often appear in Gardening and DIY, if johotech responds I would listen carefully to his advice.
pdc1,
Aug 10, 10:05am
So what have you done so far? First steps, check electrolyte levels in battery and test with a hydrometer. One of the things you are describing sounds to be batteries in a discharged or faulty state. However it could be dirty connections or faulty wiring as well. Check these, with a multi meter by looking that you aren’t getting no voltage drop compared to the battery posts and the regulator while you have a load on. Check the batteries voltages at night with no load and no charging and let us know the resting voltage and the type of battery they are.
I don’t know much about the regulator, but regulator technology has moved on and you will find regulators that will do a better job than that one.
the-lada-dude,
Aug 10, 10:29am
are these japanese or Italian batteries ?
I think fungles is good with this stuff
bitsy_boffin,
Aug 10, 1:19pm
Batteries are stuffed I'd say. Take them home, charge them up on a good quality charger and then load test them.
As for why, well, that depends on what sort of battery exactly for a start, what are the specifications of it and how hard it's cycles are, if it's regularly, getting fully discharged and then recharged (hopefully) that will drastically affect it's life, especially for typical wet/agm types. A 100% discharge on a daily basis would likely kill an AGM deep cycle in a year.
NB: There is a table on this page showing the no load voltage approximating the state of charge for different cell types https://www.energymatters.com.au/components/battery-voltage-discharge/ when it cuts off due to low voltage, if you disconnect the batteries and leave it for a bit then measure, you can see how deeply you are discharging those batteries, maybe your low voltage cutoff is a bit low (obviously you don't want to set the low voltage cut off too high as under load it will drag down but that's not a true indication of state of charge).
serf407,
Aug 10, 3:32pm
What is the sunlight like in winter in the system's location? in some places in nz, wind can be necessary to top up batteries during multiday cloudy episodes if there is some wind blowing. https://www.silentwindgenerator.com/en/ I would have a big question mark over your charge controller. I would not be surprised if the parameters have been fried inside your controller. sniff test? There are a number of alternative charge controllers on the market $200 and upwards. e.g https://www.morningstarcorp.com/products/ecoboost-mppt/ https://youtu.be/HthJ-7I1VkI
thejazzpianoma,
Aug 10, 3:40pm
I wouldn't be surprised if your batteries have died prematurely from running too low overnight with that setup. How many watt hours is your refrigerator drawing overnight when the system is running properly?
Also, how many AH are those batteries rated for?
When replacing the batteries don't rush and get more lead acid style batteries, it's often much better to go Lithium now. One advantage of which is they don't mind being drawn quite low overnight which also means you don't have to have such a large storage amount.
jacinda2059,
Aug 10, 4:22pm
AGM batteries should not be dicharged more than 50%, wet cell can take a bit lower discharge, that is a very cheap controller, might need an upgrade,
thejazzpianoma,
Aug 10, 4:53pm
50% is also too low for a daily cycle if you want them to last a reasonable period of time. When I used them I budgeted on about 20% for a regular daily discharge, leaving a bit extra for the occasional extra drain or day without full recharge.
tony9,
Aug 10, 4:57pm
Agree. My diesel generator starts at 75% calculated capacity.
intrade,
Aug 10, 5:41pm
i told my naigbour in taumarunui . That she should buy stuff thats quality not 2$ shop crap from alibaba. AA solar is the best knowen place to purchase solar equipment. piere sold the business but i guess the next guy wont have gone to stock onhanglow crap. https://aasolar.co.nz/ i got a thred in computing about that nightmare. and she has also got one of the garbage you posted a immage. The one she uses is a different one but same chinesium garbage. mppt and propper brand name from reputable seller is what you want. She has a trace rand unit 12 volt also from ali So its probably just the sticker and the looks thats american trace the inside will be 2$ shop grabage also. People have to stop there delutions that all this cheap crap is any good. its definetly not. i got a lot of cheap car tools and not one of them is remotly any good for real use. if a tool who costs 8 grand can do 90% then a 50$ tool from wish who has the same name can do from 5 to 15% of what the 8 G tool can do and it probably fails after a few uses if it works at all. Single use parts are not as bad like car switches stuff thats not complex.
intrade,
Aug 10, 6:03pm
your discription matches what the naigbours system in taumarunui is doing the batterys are all empty basically and she has had 8 deep cycle truck batterys with 105Amp H the 2$ shop grabage is probably putting 5% of what the solar cell makes in the battery and wastes the rest. its why AA solar only sells mppt not garbage cycle pwm controllers
thejazzpianoma,
Aug 10, 6:23pm
While I agree a cheap PWM charge controller is not ideal, unless it is broken it doesn't sound like the problem in this case.
Ultimately an MMP charge controller just allows you to use the power available from your panels to charge your battery more efficiently. Given this system used to work and from the little information we have does appear to be fully charging the batteries it's not the likely culprit.
To figure out definitively what the problem is we need more information, starting with the size of the battery's and how much current is being drawn overnight. Most of those Chinese charge controllers have a watt hours used function so determining the draw should be easy.
Give us that information and we can guide you from there OP.
In terms of a best guess based on what we know so far, I am expecting the draw to far exceed what those batteries were designed for when it comes to regular discharge ratings. A 240v refrigerator running through an inverter is guaranteed to be very high draw and realistically unsuitable for a small solar setup like this. Electrician or not, the whole thing from the charge controller, to the panel sizes vs the load does not sound well designed at all so I am expecting the battery's to be similarly inadequate.
The best plan in my opinion is to assemble the correct information and start fresh rather than replace items ad hoc.
snoopy221,
Aug 10, 6:31pm
A 240v refrigerator running through an inverter is guaranteed to be very high draw and realistically unsuitable for a small solar setup like this
Yip as much as economics dictate i would be looking for a good second hand 12 volt compressor fridge
ralphdog1,
Aug 10, 6:36pm
Batteries, as JPA says, discharging them by more than 20% of their capacity on a daily basis leads to a short life, I too as others have would guess that your actual issue is that the batteries have died because of the discharge you have been giving them. Have a look at the table under Section 2 on this page to give you an idea: https://www.civicsolar.com/support/installer/articles/battery-life-and-performance-factors LED Lighting = Good. That Regulator = Not suitable in this day and age, be prepared to drop a couple of hundy on a MPPT one, money well spent. 240V Fridge + Invertor = Not good, way too inefficient. I've got a a 12/24V DC compressor fridge, 60L, which has an average power consumption of 14W/hr (approx 1A) compare that to what your invertor is drawing.
Thanks guys. Sounds like batteries are probably toasted. Think the low cutoff is far too low in hindsight. A few points tho,, Cabin is only used one night a week max. Panels are oriented for maximum mid-day winter sun and can do 16amps on perfect winter days. Fridge is only turned on when panels are producing,, and only uses half what they produce for a few minutes an hour. Freezes slikka pads during the day and they keep it cool when not turned on. Only other item that uses much power is a smallish 12v LCD tv. LED lights are 240v 4watt LEDs, usually 1 or 2 on at once. Am heading up there now, will get a bit more info from batteries etc, but not expecting to be able to get through another winter with them.
intrade,
Aug 11, 10:44am
i was thinking we had this conversation once before. And i am pritty sure i posted That i know what i regard as reliable source. That a 12 volt fridge compressor or not is more inefficient then a onhanglow mains voltage fridge. The only advantage would be that you dont need expensive high quality gear in form of a efficient inverter for straight 12 volt. I somhow think stirling on youtube has run thie frige test if i recall correctly. yes it was not a dream https://www.youtube.com/watch?v=SUzbp18L9oc&t=5s
clscmg,
Aug 11, 4:48pm
Are you using the correct type of battery? Conventional vehicle type lead acid batteries are completely useless for a solar application - a vehicle battery is built to deliver a high current at engine turn on then basically idle during charging until the next discharge.
What is needed for a solar installation is a specific battery for the job, this is called a deep cycle battery. If you do any type of research you will be told to use a deep cycle battery ONLY.
These are made differently to a conventional battery and are generally more expensive but you get what you pay for. In my installation I use 4 x 6 volt 225AH batteries (best part of $1200). These are wired in series to give 24 Volts and the 230VAC inverter runs on 24 Volts as well. Also use a MPPT regulator. The batteries should last in excess of 10 years in the installation.
solarboy,
Aug 11, 9:24pm
O P's first post says he's using deep cycle batteries.
thejazzpianoma,
Aug 11, 9:29pm
If using the fridge like that you should be fine, BUT do make sure your batteries are in fact getting fully recovered during the day as charging voltage can be a bit misleading. A good test would be to disconnect the batteries before the sun goes down on your last day when they are supposedly fully charged. Then take a voltage measurement before you reconnect them on your return a week later. They should be at least 12.67 volts after sitting. Usually you would do this test after 24 hours or so but a week is fine if nothing has been connected. If they are not still at that voltage you might need to do the test again with a known good battery as the problem could be with the battery itself or the lack of charging.
Also, your low voltage cutout shouldn't be running at all if everything is sized and running correctly (unless you are using this as your refrigerator disconnect). It should be an emergency only thing. None the less it's a good idea to keep that fairly high.
thejazzpianoma,
Aug 11, 9:34pm
Also. why 240v LEDs? Sounds like you are running an inverter to get the voltage up there only to have the LED's transformer bring it down again. Depending on the size of the inverter and whether it otherwise needs to run this could be wasting far more than what the LEDS actually draw.
You may be able to keep your same LED's but change or remove the transformer/driver to run them directly.
Also, if you are going to replace those batteries I can't recommend enough that you consider lithium. Now remember you size them differently so don't fall in to the trap of looking at the same AH rating as what you have and thinking they will cost you a fortune. There are also a few different cost effective options with lithium batteries. If you want I don't mind helping you to size them correctly.
solarboy,
Aug 11, 9:35pm
I'd suggest swapping your LED lights for 12 volt ones too as you're doing the right thing with the tv already. It's likely using less power than you think as it's label wattage will be what it draws at high/full volume while you're probably using it at lower levels. Though your lights are low wattage, running them through an inverter isn't a great way to go as even the best inverters are quite inefficient on very low loads like that so you're wasting power there.
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