OK Jazz. I must learn to use more than 2 fingers when typing .
thejazzpianoma,
Aug 11, 4:41pm
It depends on the refrigerator. A really good 12v refrigerator will have extra insulation and a more efficient compressor design (often danfoss) vs a regular house refrigerator.
So it would depend on what you did your comparison with. If you compared a cheaper/regular 12v refrigerator with a house fridge you would likely only see a slight difference due to inverter losses. However if you compare a regular house fridge with an ultra efficient one designed for solar power (be it 12 or 24v then you will see the difference). It's easy enough to look up the power ratings and compare. Just don't compare the peak wattage as that can be confusing, especially as some of the more efficient designs run their compressors longer than a regular fridge. You want to check average ah ratings.
thejazzpianoma,
Aug 11, 4:44pm
LOL. it will take more than that to catch the pianist/keyboard warrior. It's a dangerous combination. It's good for the OP though to see we are in agreement.
fungles,
Aug 11, 5:26pm
As others have mentioned, take the batteries home, charge them to 16 volts to ensure they are full, then apply a heavy load, I use old car headlights, 4 in parallel will drag around 40 amps. To do this requires a good old fashioned charger, the modern "smart" chargers fail to get the voltage this high. Load them up, then time the discharge cycle. The batteries, if say 150 amp hours each, two in parallel will give 300 AH, so those lights should burn around 7 hours before becoming really dim. Doing this test is murder on the batteries, but there is no other way to get a definitive idea if they are shagged. Good batteries will suffer no damage in a one time test. To the gentleman disparaging Chinese batteries and other solar products, let me say this. China is a world leader in PV panels, Control electronics, and battery manufacture. Yes, some rogue products sneak through, as in all countries., but very few these days. American solar products are over priced and poor value for money, when compared to equivalent Asian products, simply by scale of economy. Chinese have more solar power production than anywhere in the world, the factories produce millions of good product each year. I think the time for random uninformed China bashing is over.
fungles,
Aug 11, 5:56pm
And, re charge controllers. The PWM type being used is fine for that setup. 16 amps from those panels on a winters day, with say 8 hours of daylight is around 120 amp hours, or with a 12 volt system, nearly 1 .5 kilowatts. The fridge would need to draw 62 watts over a 24 hour period continuously to use this energy. very unlikely. So, unless its a very greedy fridge, or a greedy inefficient plasma TV left running. the setup should be fine. Its cheaper now to, rather than spend money on a fancy charge controller, just add another panel to make up the losses, this is a more elegant and cheaper solution now panels are cheap.
pdc1,
Aug 12, 5:39am
good advice from fungles. Also you need to check the voltage at the batteries that the low voltages cut off kicks in at. Report back both the voltage that the cut off switch comes in at, and also the resting voltage of the battery an hour after the power has been cut. I suspect that you will find that it is a combination of the batteries just aren’t being kept fully charged at this time of the year, and that the edge has gone from the batteries now they are 2.5 years old. They are probably a long way from stuffed and will continue to give reasonable service for years. Let us know the batteries and what voltage they are at when the low voltage switch cuts in. This needs to be done when system is not charging. It could well be possible that you could draw more from the batteries without risk of damaging them. Plenty of advice available for deep cycle batteries. Totally agree if system is used daily, however for a weekend retreat, I’m not certain that the extra price of the deep cycle batteries is worth it. I have a similar set up on a boat. I just use two Century N200 starting batteries. The first ones done 15 years service, and now I’m 10 years into the second set and showing no sign of trouble yet.
bigfatmat1,
Aug 12, 6:47am
Just wondering why you have a 20a reg for 520w solar setup? shouldnt you have a 50a one? I know it probably isnt the problem but curious?
fungles,
Aug 12, 2:02pm
The signs of battery problems are quick to charge, quick to discharge indicating lowered capacity. BFM above has a good point, i missed this. those panels can do over 40 amps mid summer. i would suggest a beefier controller for reliability reasons.
snoopy221,
Aug 12, 2:09pm
Yip i saw it too and know my 300 watts of panels can do well over 20 so after the chi nee stuff haters have been then one as always has to go back to the basics of the system is only as good as the knowledge of who ever installed it
muzz67,
Aug 12, 2:59pm
Well, back from the 'Ranch, Disconnected the two 120AH when I got there and replaced them with two mismatched old deep cycle mobility scooter batteries to keep us going for the weekend. After a week in the sun the 2.5yo batts were at 13.2 and 13.5v. After 24hrs they have both dropped 0.22v. Spent a bit of time watching and fiddling with the controller, Found the invertor uses 0.6-0.7A on its own. 4w LEDs are 0.5A each, usually 1 or 2 on at once, and fridge uses 6.5A when running(which isn't often.) None of these loads should be taxing the storage or charging capacity, surely? I suspect the batteries have been cycled to deeply and the controller hasn't been set properly to make use of the panels charging ability. Altered the settings on the controller to charge at 14.4v instead of the 14v it was on (default?) and looked like it charges a lot more before switching to 'top-up' mode(cant remember proper term. ) 20A controller,, these are the panels details , Tech data under standard conditions (AM=1.5, E=1000W/m2, TC=25 degrees C) Rated Power: 260W Closed-circuit Current: 8.44A Closed-circuit Voltage: 30.81V Short-circuit Current: 8.92A Open-circuit Voltage: 38.08V Weight: 19.5 kg Dimensions: 992mm x 1650mm x 40 mm
Is it normal, when the batteries near full charge, that the controller lowers the current (amps?) and raises the voltage. Have noticed the charge voltage nears 35v but amps drop to .5a when batteries nearly full. I could have that completely cockeyed and not be surprised. To be honest,, I didn't know anything about all this stuff when it was set up, and just wanted the simplest, most basic setup, and I guess we had to run with the least expensive option too after dropping 200k on property and cabin. Please be gentle on me!
fungles,
Aug 12, 3:16pm
The problem with using ordinary car batteries is the simple fact of their very low capacity, the average car battery will max out at something like 40 AH Car battery manufacturers quote fantastic CCA figures proudly emblazoned on the case, but conveniently say nothing on the real capacity,
muzz67,
Aug 12, 3:35pm
Both the old and newer battery pairs are deepcycle. Just had newer ones of charger, and get them up to 15.2v. Will leave them till tomorrow evening and check, them put them on to the old Mitzi and leave the headlight on and see what happens.
snoopy221,
Aug 12, 4:11pm
Yeah those specs may be a controller rated at 30 volts as a 20 amp controller
at circa 8 and a half amps a panel which be more ampies at 12 volties
fungles,
Aug 12, 4:52pm
2x 260 12v panels in parallel gives 520 watts, divide that by the 12 volts gives 43 and a bit amps. The controller seems to have coped over the 2 1/2 years, but given the low power useage, it would not have suffered full current for long, the batteries would have been charged in just a few hours. Even so, most, if not all solar controllers have overtemp sensors, they will go into current limit to protect themselves, as I said, the Chinese can make very good stuff. I think what largely fuels the detractors is the cheap looks and appearance of much of what they make, the yanks tend to make the outside look nice, and the general public associate that as a better quality product.which is not necessarily so. The crappy Chinese manuals too make the product look dodgy which also is not necessarily the case. And, when a good kiwi bloke buys aCchinese generator, a tool, a compressor, whatever, and it is Chinese made, its treated with disrespect because its cheap and Chinese., Hell, I repair Chinese generators, most of which are equivalent quality to what the Japanese, produce, many are licenced copies, but they are either left in the rain for weeks, or run with no oil because the owner didnt bother to check. One I recently looked at had hardened concrete that had been poured inside the electrics, the owner said he knew it wouldnt last cause it was a cheap Chinese thing. This China bashing crap drives me nuts.
fungles,
Aug 12, 5:29pm
Muzz, just read your last, . The .7 amp standby load is the parasitic drain of the inverter, this amounts to around 20 amp hours over a 24 hour period. The lights are 1 amp total,, lets say 10 hours if you stay up late enjoying paradise, fridge 6.5 amps when on, lets say it cycles 20 mins each hour, thats near 50 ah over 24 hours, so your total drain in 24 hours is 50+10+20= 80 ah per 24 hour day, or just 2 hours of good sunlight. needed to supply all those needs. Something is dreadfully wrong.
fungles,
Aug 12, 5:37pm
The PWM controller you have supplies full current from the panels until the batteries reach around 13.5 volts, Then the PWM, or pulse width Modulation will reduce the current to maintain the "float" voltage, usually around 14. The low voltage alarm or cutout on the inverter is usually set to around 11.6 to 11.8 volts.Because, and i think i read this right, the battery voltage is rising to 35? , this strongly suggests the controller has pooped itself and just may have fried those batteries.
snoopy221,
Aug 12, 5:42pm
re#41 ya'd know fungles Should it be reading closed circuit voltage of 30.81V and not the 35?
fungles,
Aug 12, 7:44pm
Snoops, thats the weird thing, 12 volt panels should only top out at around 18 to 21 volt, 24 volt panels around 36. so either he has measured it wrong, or the panels are 24 volt types? I really dont know and its hard to diagnose at a distance. I guess firstly to check the batteries are ok and work back.?
Hi intrade, Just like Mercedes, Volkswagen and others, there are companies anywhere in the world attempting to fool the purchaser, it also happens in China. It also happens here in NZ. also I bet I Switzerland where I think you are from. But that doesnt mean all German, NZ or Swiss products or even Chinese products are rubbish, at most it means some could be, the vast majority are not., Think about it. China is the LARGEST industrial producer on the planet, these factories all use Chinese built lathes, milling, punching, CNC machines, welders and foundry equipment, electronics, and computers. If all those tools and machinery were unreliable rubbish, they would not be able to be the industrial powerhouse you see today. NZ importers sell largely by price, and most manufacturers anywhere in the world will try to accommodate a product filling those economic constraints. For an instance,to the general public, two generators will look the same when side by side, and have identical specs, but one will be cheaper, this is the one that they will likely buy. They dont know that it is wound with cheaper aluminium wire, as opposed to more expensive copper. The castings will be thinner, the electrics kept to a bare minimum., and any overload and thermal protection will be neglected. This is where the cost cutting occurs in order for the manufacturer to supply to the importers price constraints. In my opinion. the importer/distributor is the dishonest one here by not disclosing the self imposed limitations of the product he is selling.
comsolve,
Aug 13, 8:42am
I wouldn't personally buy anything from AA Solar.
If you want something tell me what it is and I will advise the best brands.
comsolve,
Aug 13, 8:46am
What is the capacity rating of the batteries? What type of batteries?
Does your "sparky" have any experience in off grid systems? Because it sounds not.
gpg58,
Aug 13, 8:47am
How many spotted neither speedo or rev counter were working.
comsolve,
Aug 13, 8:49am
You could have several things wrong with your system but in any case your controller is one of them. Did you think you would get a free lunch by not buying a Morningstar (the ONLY brand I would advise in small controllers) I suppose you have found out the hard way now. Because your batteries should have lasted a lot longer.
comsolve,
Aug 13, 8:59am
Spend a lot more than $200 on any MPPT worth having.
Special "low power" fridges are false economy. Much better to buy a normal fridge and spend the savings on more solar panels.
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