Well, to plug in the power supply of the usb hub charger. Its the same inverter I added the picture of before, its the smallest inverter there is, its description says it's rated for 12V battery voltage, 230V AC output voltage 300W of continuous power and 600W short-term peak performance for high starting currents.
Specs say: 220V 230V high frequency inverters with Modified Sine Wave, 300W of continuous power and 5V 2.1A USB load output.
I assumed it wouldn't take up much power? Does it? About the battery, maybe I could use two 12ah batteries, identical models? That would make a nice 24ah. Is there an alternative to the inverter? 4403_1000x1000.jpg
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I would think so.
Always Battery first to Controller, Panels to Controller, then Inverter to Battery . Reverse when disconnecting; Inverter > Panels > Batteries last.
You raised a Red Flag. What Inverter? Houston we might have a problem.
Do not mix batteries. If no 20 AH move up to as high as 25 AH. 17 AH is cutting it close.Leave a comment:
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Understood, the usb hub has an on off switch, I don't think it would drain power even switched off, do you think it would still drain power while switched off? Ohh, and when assembling the system, I should connect the inverter to the charge controller, then the panels and then the battery? Or is there no difference in what order I make it? (Got it off youtube before you told me that youtube is useless).
If I'm getting the same type of batteries, is combining a 17ah one with a 3.2ah a good idea? There just aren't any 20ah ones.Last edited by AllOuT; 04-04-2018, 11:29 AM.Leave a comment:
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OK now that you have a better understanding of what is going on, and I know what you want to do exactly if it were me this is what I would do.
Panel Wattage = 40 to 50 watts
PWM Charge Controller minimum = 5 amps
12 volt battery capacity = 20 AH
The reason it is a little larger than you might be expecting is because of hitting the battery with 150 wh in one singe day. Normally you would limit daily discharge to 20%, but in your case once a week we can push that up to 60 to 70%. So 150 wh / .7 = 215 wh/12 volts = 18 AH plus some wiggle room.
Panel wattage required is just a straight 2 amps x 18 volts = 36 watts. So for the panel look at the Imp and Vmp spec. A 12 volt battery panel Vmp will always be 17 to 18 volts, so zero in on Imp and look for 2 amps or as close as you can get. That is going to be a 40 to 50 watt range. No less than 2 amps, no greater than 3 amps.
As for the controller 5 amp minimum is because I do not think you can find a smaller one than 5 amps. It is not critical as it could be 100 amps, just as long as it is not less than the panel Imp.
Understand everything I just went through? When not in use disconnect the USB charger. Otherwise it just drains the system.Leave a comment:
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Yes, that would be the idea, maybe not all of the 150wh but more or less, maybe around 80-130wh. I also forgot to mention that the usb charger itself is 40w, but then rounding up the battery 17ah and panel to 30w, it doesn't really matter. I'm not sure for how long I would charge these devices, they all have varying battery capacities.Leave a comment:
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I registered to ask this question, but once registered i couldn't create a topic. What i am wanting to do is to put a 12 volt battery in my deer stand, so that my children can watch an ipad pro and charge it while watching. other than that i may charge a cell phone once in a blue moon. also i wanted to run 2 small 12 volt lights in my deer stand for when its dark and im working on firearms or etc. i intend for the bulbs to be green so that they do not bother the animals. can anyone tell me what equipment i need or point me to a specific list of products that i need. i don't want to spend more than i need to. if anyone is willing to help please pm me.Leave a comment:
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Hi, thanks for making it as a task, I had a great time finding the answers.
1. So the daily watt hours should be 30wh because I would use 150wh every 5th day.
2. The battery would be 12V because I for sure will need one small panel, due to to the small daily watt hour requirement.
3. From my calculations I only need a 12.5AH battery, but I'd prefer to size up, not down for energy storage, to a 17AH battery.
4. The charge current would be 1.7A, which means I can have a very small charge controller, but I'll take this 6A since its from the same website as the rest of the components, and has good reviews.
5. Required panel has to be at least 15w, but I'd prefer to get the 30w one. The charge controller will be PWM, so the panel current = 1.7A? It says max 1.69A on the 30w panel though.
Does that mean that a 17AH is too big for a 30w panel?
If I ever get suddenly rich is it a good idea to get a lithium-ion battery?
Thanks for the good advice.Leave a comment:
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That sounds like a yearly average which is used for Grid Tied Systems, not Battery systems. Off grid is designed to worse case Winter Sun Hours. If you look for late December early January I bet it is around 2 to 3 hours, and summer is up around 5 to 6 sun hours.
Because you made the mistake of using AH. You use Watt Hours. Example a 3.6 volt 3.5 AH battery has a wh capacity of 3.6 volts x 3.5 AH = 12.6 watt hours. For a 12 volt battery is 12.6 wh / 12 volts = 1 .05 AH just call it 1 AH.
Your first big mistake, quit watching You Tube. You only got it half right from watching morons on You Tube. True you do not want to take your battery down to more than 50% normally. Problem is what do you do when you get cloudy days. With that logic you go dark after 1 cloudy day and shorten battery life discharging 50% every day, and have to wait for a couple of days to recharge.
The right way is determine how many watt hours you need in a day. Say it is 100 wh. You size the battery for 5 day capacity so you only use 20% on any given day, So 5 x 100 wh = 500 watt hours. So what is the AH? Well at 12 volts is 500 wh / 12 volts = 42 AH. That gives you 3 days run time with cloudy days before you have to shut down and recharge. Additionally any true off-grid system requires a generator for those times when you get a week or two of cloudy days, and perform monthly battery maintenance. At 20% DOD daily triples your battery life.
You Tube idiots. Imagine if pilots learned to fly using You Tube. You would stil have to use a ship to come to the USA.
Not so fast. I am not going to tell you. You are going to tell me. Not trying to be a dick, but I want you to learn and quit watching youtube. Read this sticky and come back and tell me what you are going to do. Then I will give you feed back. Here it is in a nutshell.
1. Determine daily Watt Hours
2. Determine battery voltage. (hint 12 volts)
3. Determine Battery AH capacity. [Daily wh x 5] / Battery Voltage = AH
4. Determine charge current and charge controller size. (Hint C/10)
5. Determine Panel Wattage required. If PWM panel current = charge current
Your turn, go do your homework and come back with answers.Last edited by Sunking; 04-02-2018, 04:14 PM.Leave a comment:
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Okay, that's understandable, I didn't jump the gun with buying anything. Its not that I want an overkill system, I want a system with what I could charge my devices and have a decent amount of power to spare, in case of bad weather, I live in eastern europe in Latvia, we have 4.8 sun hours, I don't know if that's a lot or not but its 5th best for northern europe. Weather in Latvia, especially in the summer and autumn is a lot better than England's
I'm happy that a small panel will do, I was doing these solar calculators which insisted I used big batteries and solar panels, I'm glad I asked real people not calculators.
I still don't understand, if all of the device batteries combined are 30ah, how will a 15ah battery be sufficient enough to charge them in one go?
Sorry if my questions are dumb, its just that a week before I didn't know anything about solar panels or batteries, still learning.
So I need 34wh a day, to be generated, to charge my devices every 5th day, I'd like some energy to spare, just in case as I mentioned.
I've seen people on youtube, and calculators insist that you need a twice bigger battery than your need to charge your load with, with not letting your battery discharge more than 50% you increase its life span dramatically, should I then require an 30ah battery not a 15ah?
Added pictures of every part along with its specs below, please tell me if something is off, and your suggestions on what could be changed, and which charge controller should be chosen.
Thanks for the advice, I'll be impatiently waiting for your response.
AGM 17Ah 20HR 12V - Deep Cycle Solar Battery specs:
System Voltage 12V DC
Storage Capacity (Ah) 17Ah
Capacity at HR1 (C1) 11,1 Ah (11.1A,1.75V)
Capacity at HR5 (C20) 14,5 Ah (2.9A,1.75V)
Capacity at HR10 (C10) 16,5 Ah (1.65A,1.75V)
Capacity at HR20 (C20) 17 Ah (0.85A,1.75V)
Self-Discharge max. 3% (per month / 25 C)
Charging Current max. 5,1A
Load Shedding (no-load) 13,6V-13,8V (-20mV/ C)
Charging Voltage (cyclical use) 14,4V-15V (-30mV/ C)
battery.jpg
30w mono 12v solar panel specs:
System Voltage 12 V
Generator Performance (Wp) 30 Wp
Module Voltage (Vmp) 17,8 V
Max. Current (Imp) 1,69 A
No-Load Voltage (Voc) 21,3 V
Short-Circuit Current (ISC) 1,82 A
max. System power (V) 600 V
Cell Type monocrystal
Degree of Efficiency Cell >18%
Tolerance +/- 3%
Temperatur Coefficiency -0,45% / C
4446_1000x1000.jpg
Inverter: HF12-300 12V 300W 600W voltage transformer modified sine wave
4403_1000x1000.jpg
Charge controller:
Charge Controller Type PWM
System Voltage 12V DC, 24V DC
Charging Current (A) 8A
Deep Cycle Protection 11,2V-11,6V (22,4V-23,2V)
Connection Clamps 4mm2 / 6mm2 - AWG 12 / 9 (fine- / single wire)
Protection IP IP32
Restart Voltage 12,4V - 12,7V (24,8V-25,4V)
Charging Voltage 13,9V (27,8V)
Boost Charging Voltage 14,4V (28,8V)
Self-Consumption Under Load < 4mA
Load Current max. 8A
The only difference between the 8A controller and the 6A was:
Load current max: 6A
No-load voltage solar module < 47V
700_1400x1400_4.jpg
The load:
Input: AC100 ~ 240, 50 ~ 60Hz
Output: DC12V / 2A
71txU99DDJL._SL1500_.jpg
P.S If pictures of products aren't allowed, I'll have no issue of them being removed, or being asked to remove them.Last edited by AllOuT; 04-02-2018, 02:58 PM.Leave a comment:
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OK first understand the battery will not last 10 years.
Your main issue is you pulled the trigger to quickly. All parts of the system need to be matched up to work with each other and sized to support the daily power demand. 175 wh weekly is not a design goal. It is daily usage for an off-grid system. But never mind that for now, you lost that opportunity when you bought the first component.
So what do you have now? Lets work with that. Example lets say you already have a 100 watt panel and are going to use a PWM controller. That dictates everything down stream. With a PWM controller take a look at your 100 watt panel Imp spec (current at maximum power) it should say something like 5.5 amps. If using a PWM controller a 100 watt panel can support a 12 volt battery size as low as 40 AH up to 60 AH. Anywhere in that range. Battery charge current have minimum and maximum amount of current that must be met called C-Rate. The ideal charge rate is C/10 where C = the battery Amp Hour Capacity and the Integer 10 is Hours aka 10 Hour charge/discharge rate aka C-Rate.
Amp Hours = Amps x Hours
Hours = Amp Hours / Amp
Amp = Amp Hours / Hours
So C/10 rate on a 50 AH battery = 50 AH / 10 Hours = 5 Amps. As a general rule of thumb for Pb batteries minimum charge rate is C/12, and max is C/8, and C/10 is ideal. If you were to use a MPPT Controller you would harvest more current. With a 100 watt panel roughly 8 amps which will support a larger battery of 65 to 100 AH with 80 AH being ideal. Understand how I did that?
OK being gin the sunshine capital of the world of good ole England, you have very few sun hours to work with. That means you want to use a C/8 charge rate or as fast as you can charge to make up for short sun hours. My bad the Sun is that bright glowing orb in the sky you see once a week. So if your max charge current is 5 amps x 8 hour charge rate = 40 AH battery. Understand?
Now what can a 100 watt panel with a 40 AH battery generate each day for you? About 150 to 200 watt hours per day. In a week would be 1000 to 1400 watt hours. Way more than you wanted.
But like I said there is no need for solar to do this. It can be done a lot less expensive and works far better by just buying a Battery Charger and Battery. Say a $30 5 amp charger and a $100 12 volt 50 AH battery. You just leave the charge plugged in which keeps the battery charged up. If you loose power, the battery has a capacity of 12 volts x 50 AH = 600 watt hours with 500 watt hours usable. A cell phone stores roughly 10 watt hours. You could charge 50 phones from the battery. Not likely you would have a two month power outage.
So you only need roughly 30 to 50 wh per day if even that much. A 20 to 30 watt panel with the smallest PWM controller you can find charging a 12 volt 15 AH battery would have been overkill. With a 100 watt panel forces you to use at least a 40 AH battery and you can charge cell phones for a month without sun or commercial power Understand?Last edited by Sunking; 04-02-2018, 11:32 AM.Leave a comment:
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I see your point, but the point of this system wouldn't be daily use, plus its not for money saving, or environmental reasons, its for self-sustainability, I calculated my watt hours, and it would be around 170wh that I would use weekly, I live in Europe, and the parts would be shipped to me, no clue about the shipping price though. The battery advertised is rated to work 10 years, the controller is called steca solsum 8.8f, it costs 35 bucks so I assume it is PWM. So what your saying is that a 100w panel is overkill? I'd really like to make this work, as I said, it is necessary for it to be off-grid, the load would be 170wh that'd I'd use on a weekly basis.
Thanks for your input.Leave a comment:
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Lets get a couple of facts straight. Just because you have an 8 amp charge controller does not mean you will have 8 amps of charge current. Charge current is determined by the panel wattage, battery voltage, and charger controller type being used of either PWM or MPPT.
With PWM Controllers Output Current = Input Current. So if you had a 100 watt battery type panel the max Imp (current @ max power) equal roughly 5.33 amps at high noon, something less at all other times. Some quick mat 5.3 amps x 12 volt battery = 64-ish watts from a 100 watt panel for a few minutes around noon.
MPPT Output Current = Panel Wattage / Battery Voltage. So a 100 watts / 12 volts = 8.33 amps. Surprise you actually get close to 100 watts from a 100 watt panel for a few minutes around noon.
If you are looking at a 8 amp charge controller, I am certain you are looking at a Chi-Com PWM controller where the box it comes in is worth more than the controller. Ideally with a Pb battery the optimum charge current is C/10. If charge current is 5.3 amps you are looking at a 50 AH battery, you can figure out on your own if the charge current is 8 amps.
Now this is where things get really funny, educational, and you will just love. Lets say you charge two cell phones each day. Everyday you completely drain your cell phone battery to 0%. A large cell phone battery is 3.6 volts x 3.5 AH = 12.6 watt hours. So to recharge two cell phones requires 25 watt hours to recharge every fricking day. Let say you use a 12 volt 50 AH battery with a 100 watt panel. Such a system is capable of generating roughly 300 to 400 watt hours per day if you used it. That is called full utilization. Enough to charge 16 to 20 cell phones a day or about 5-cents of electricity. A low end 12 volt 50 AH battery cost roughly $100 and will last 2 years at best. 365 days per year x 2 years = 730 days. If you use 25 watt hours per day for 2 years = 730 days x 25 wh = 18.25 Kwh. That means in just battery cost alone you paid $100 / 18.25 Kwh = $5.47 per Kwh. Depending on where you live in the USA electricity cost 8 to 25 cents per Kwh. That means to go solar you are paying up 22 to 68 times more for electricity just in battery cost alone not counting anything else like panels and controller plus all the gas money you spent getting materials home
On the other hand if you could possible utilize every watt hour the panel is capable of generating everyday, impossible to do, would yield 300 wh x 730 days = 219 Kwh. That brings the Kwh cost down to $100 / 219 Kwh = $0.46 per Kwh or 2 to 5 times more than the POCO would charge you. Unfortunately the environment and your children loose because it took 5 times more energy to make the batteries than what you got out of them.
Told you it was funny.Leave a comment:
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No it is not renewable energy, that is a myth with a battery system. It makes you an energy hog and a heavy polluter. The amount of energy t takes to make the battery alone has a negative EROI meaning it will never give you more energy in its lifetime than it took to make the battery. Compound that with the huge amount of energy it takes to make the panels, controller, Inverters, chargers etc is a huge waste of resources that could be better utilized. Two things you cannot do with off-grid is save money or earth. At a small scale like you are going after coupled with poor energy utilization of what power can be utilized from such an inefficient system, you will be paying up 10 to 20 times more for power, and knowing that also means you are pumping out around 10 to 20 times more emissions for the same amount of given power from the POCO. It is a huge looser.
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