New to Solar and Beginner Off-Grid Setup

vickers

Hello everyone.  I have been interested in utilizing solar power for emergency and backup situations and after doing some research, I decided on a small setup to practice on and better learn about this energy source. 

I purchased several components from Amazon.  Here is what I am working with:

ECO-WORTHY 12 Volts 40 Watts Portable Foldable Polycrystalline Solar Panel Kit
One of the reasons I liked this was it was self-contained and includes a 3A solar charge controller pre-wired and alligator clips to charge the battery.  I think I will be limited in terms of expansion, but this looked like a good starter kit.

ExpertPower EXP12180 12 Volt 18 Ah Rechargeable Battery
I know this is a small battery, so I need to keep my expectations in check, but in case I royally screwed something up, I'm only out $30. 

RioRand 2 Wires Digital Voltmeter DC Volt Tester 12V

Black & Decker 200-Watt Inverter
I already had this lying around.

So, I was ready to start my first test.  I checked the battery with my voltmeter, and it came charged with 12.8 volts, which seemed full.  For my first test, I wanted to understand how much I could realistically get from the battery only with AC power, understanding I lose some energy in the conversion (my next test will be with DC power - no inverter)

With the setup in the first image, I ran an AC fan on low (averaging 26.6 watts) for 6 hours.  The voltmeter was hooked up the entire time and read 11.2 volts.  I understand I probably could have taken it lower, but didn't want to fry my battery on the first test. 

After sitting a few hours, I used the voltmeter again, and it read 11.7 volts (an increase of 0.5 volts).  Is this normal?

The battery is charging on the solar panel now.  It is sunny and 21 degrees outside.  As soon as I hooked it up, the voltmeter started ticking back up (after an hour, I'm up to 12.6 volts).  The 3A charge controller is solid green.  Unfortunately it didn't come with instructions on how to read and there is no other display.  I am going to assume when it goes into float mode it will blink green?

So anyway, I wanted to share my first solar setup and look for feedback on my components, setup, and terminology   Am I missing anything major, or not understanding how anything works?

I am sure I will have questions, and look forward to interacting with members of this site. Thank you.

littleharbor2

 I'd say you are taking a good approach to learning how solar works and are asking the right questions. Starting small and relatively inexpensive while knowing your learning curve may cost in battery abuse, etc. When you are ready to expand your starter equipment can still be used for any number of small charging needs like small water pump, 12 volt radios, vhs radio, etc.
 While under load your battery can dip below 12 volts but you should design your system to not go there by defining your loads, creating a battery to give you enough autonomy 2-3 days to no lower than 50% SOC, Design for 20% daily depth of discharge. And then having enough solar to be able replace your daily usage reliably.
 It appears from what I can see from the chart in the first pic that,(I'm guessing here), the led is a tri colored one and will go yellow when your battery starts getting low and red when seriously low. Does the chart not mention or elaborate on this?

vickers

littleharbor2 said:

 I'd say you are taking a good approach to learning how solar works and are asking the right questions. Starting small and relatively inexpensive while knowing your learning curve may cost in battery abuse, etc. When you are ready to expand your starter equipment can still be used for any number of small charging needs like small water pump, 12 volt radios, vhs radio, etc.
 While under load your battery can dip below 12 volts but you should design your system to not go there by defining your loads, creating a battery to give you enough autonomy 2-3 days to no lower than 50% SOC, Design for 20% daily depth of discharge. And then having enough solar to be able replace your daily usage reliably.
 It appears from what I can see from the chart in the first pic that,('m guessing here), the led is a tri colored one and will go yellow when your battery starts getting low and red when seriously low. Does the chart not mention or elaborate on this?

Thanks for the reply littleharbor2.  I just pulled the chart from online for a general guide to 12 volt battery levels.  Unfortunately there were not any instructions with the panels or included charge controller.  I believe it just has a green light, but I may be incorrect.  I reached out to the manufacturer, but no reply as of yet.  I just checked on it, and the charge controller is solid green, and the voltmeter now reads 13.1, but I understand it will read higher while hooked up to the panels. 

Photowhit

The battery being green, is likely all you will ever get from it while charging. It's likely a simple voltage check and the lights will mean little while charging. It's hard to determine the state of charge (SOC) on a SLA (sealed lead acid) battery. As something to play with, I wouldn't worry too much about keeping it in the top 20%. I used a small system while bicycling and often took the batteries to a very low state at night. They lasted the year.


I will be curious to know if the charge controller goes above 13-13.4 volts. It might just regulate the voltage going in and never really go into a 'float' mode. 13-13.4 (roughly) would have a hard time over charging a battery and current would flow enough to get near fully charged. It does appear to have a load feature. You might hook up your inverter through that and it would shut down the battery if it detected low voltage. 

vickers

Photowhit said:

The battery being green, is likely all you will ever get from it while charging. It's likely a simple voltage check and the lights will mean little while charging. It's hard to determine the state of charge (SOC) on a SLA (sealed lead acid) battery. As something to play with, I wouldn't worry too much about keeping it in the top 20%. I used a small system while bicycling and often took the batteries to a very low state at night. They lasted the year.


I will be curious to know if the charge controller goes above 13-13.4 volts. It might just regulate the voltage going in and never really go into a 'float' mode. 13-13.4 (roughly) would have a hard time over charging a battery and current would flow enough to get near fully charged. It does appear to have a load feature. You might hook up your inverter through that and it would shut down the battery if it detected low voltage. 

Thanks Photowhit.  Ill keep an eye on it and report back.  I know its a cheap controller.  You reminded me of another question though.  Should I hook up a load directly to the charge controller, or to the battery, while connected to the solar panels?  Or is there not a difference? 

If connected to the load portion, is the battery bypassed completely, with extra energy not needed for the load diverted to the battery, or can the load leads from the controller also pull from the battery if the solar power is not enough to supply the direct load.  Hope this makes sense. 

Estragon

My guess is the load terminals on the controller don't draw from battery. To find out you could just cover the panels with a small load connected to the controller. If the load shuts off it isn't connected to battery.

vickers

Estragon said:

My guess is the load terminals on the controller don't draw from battery. To find out you could just cover the panels with a small load connected to the controller. If the load shuts off it isn't connected to battery.

So simple.... I should have thought of that.  Thanks Estragon

vickers

Estragon said:

My guess is the load terminals on the controller don't draw from battery. To find out you could just cover the panels with a small load connected to the controller. If the load shuts off it isn't connected to battery.

So what does one usually hook up to the load portion of the charge controller?  I assume it would have to be something on DC, but also something that can tolerate the inconsistent energy.  Like a fan or a light?  Or are there uses I am not thinking of. 

Estragon

Maybe something like a small circulating pump for a pond or solar thermal collector? Maybe to drive a relay to turn lights on (with another power source) at dusk and off in the morning?

littleharbor2

That is a pretty basic controller but typically the load terminals on charge controllers will run off the battery though when the battery is fully charged they simply allow solar power through while keeping the battery full.  Load output on many controllers are usually intended for small loads, up to the amp rating of the controller and can be set to turn on and off for preset hours and will disconnect the load when the battery voltage falls below a set point.

Photowhit

you ca hook up your inverter to it, some have somewhat reduced load/amperage to the load, but I think you should be fine for minimal loads like the fan.

The charge controller will be independent of the load terminals. The load will just shut down the 'load' if the voltage drops too low, usually between 10.5 and 11.2 volts. This is so you don't draw down your battery so low it will cause damage. Here is what Specialty Concepts says, They are a very good small controller so yours may vary. The 10 amp limit is for DC so would cover loads to 100 watts or so;

"LOADS:  System loads such as lights, radios, DC/AC inverters, etc. must be rated for the proper DC input voltage. If the ASC is equipped with low-voltage disconnect (LVD) (Option-E), DC loads not exceeding 10 amps can be connected to the ASC. These loads will disconnect automatically when the battery voltage is low. Higher current loads, or inductive loads such as pumps, motors or invertors should be connected directly to the battery and be properly fused. "


They say to connect the inverter directly to the battery, but I've been okay with hooking to the LVD with small loads. Your mileage may vary...lol.

littleharbor2

Photowhit, Best reread this. "Higher current loads, or inductive loads such as pumps, motors or invertors should be connected DIRECTLY to the battery and be properly fused".

Photowhit

littleharbor2 said:

Photowhit, Best reread this. "Higher current loads, or inductive loads such as pumps, motors or invertors should be connected DIRECTLY to the battery and be properly fused".

I added that it worked for me, last paragraph. I suspect it will work for him for minimal loads...

vickers

Quick update.  I pulled the battery off of the solar panels after 4 hours of direct sunlight.  Voltmeter read 131 volts.  After 3 hours I checked it again and it had stabilized to 12.7 volts.  I think that is a pretty good recharge rate. 

dennis461

Estragon said:

My guess is the load terminals on the controller don't draw from battery. To find out you could just cover the panels with a small load connected to the controller. If the load shuts off it isn't connected to battery.

I have a couple set-ups like yours.  On my boat I have a slightly more sophisticated controller which shows voltage.  The drawback is, the display actually uses some power, so if the goal is to get the most energy from your solar panel, keep what you have.

Now as to load terminals,  the normal (correct?) setup is ONLY the battery gets connected to the battery terminals.
The controller would then automatically disconnect the load from the battery when the battery voltage gets too low.  This should prevent battery damage.

If your fan and battery are connected to the same terminals, the controller has no control, right?
our battery would drain down to zero volts and become a lead paperweight.

Now, I have an inverter that did not behave properly and the inverter vendor told me to connect the inverter directly to the battery, which in my professional opinion was not correct.

My simple setup is similar to yours, except 24 VDC.  I do not run a fan, just a laptop.
Your numbers appear correct as far as watts. hours, and battery capacity.
Also, batteries do tend to recover some voltage when disconnected after a load cycle. That;s normal.

vickers

Now on to the most confusing part of solar power...... The math........  

Just for S&G - using this solar system, what is the largest battery I can go with in terms of AH and still be able to recharge it with the panels.  I was impressed with how quickly my battery recharged today.  I understand it is a small battery though, and that this may be a loaded question.....

Also, the 3 amp charge controller.... That sounds really small to me, but unless I expand the panels that tie into it, that size should be fine, right?

Photowhit

vickers said:

The math........  

Just for S&G - using this solar system, what is the largest battery I can go with in terms of AH and still be able to recharge it with the panels.  I was impressed with how quickly my battery recharged today.  I understand it is a small battery though, and that this may be a loaded question.....

Also, the 3 amp charge controller.... That sounds really small to me, but unless I expand the panels that tie into it, that size should be fine, right?

The charge controller should be fine for that panel, but it may not be a 'true' charge controller, Typically you would expect a charge controller to allow the voltage to increase until it reaches around 14 volts, this would be 'bulk' charging. Then it would hold the 14 volts so your battery isn't damaged by over heating. usually it will stay there for a set time (this is the absorb mode), then it will lower the voltage until it reaches float level usually around 13.2-13.6 volts(float mode).  This is why I asked what the highest voltage was? It might just regulate the voltage going into the battery. It can do that and charge the battery, but missing the mark of fully charged, just residing at a 'float level' which will charge the battery but not reaching full capacity in general.

I think that's a sealed lead acid battery, it might have glass mat separators. Some times these will maintain surface charges for a long period of time, I'm NOT someone who uses or deals with SLA or AGM batteries much, perhaps Marc will chime in? I have seen agm's holding 13 volts over a week!

If you intend to use energy from your battery, you are about the correct size battery, controller and panel. A 40 watt panels should normally produce about 30 watts. it out put's 17.9 volts so it will create about (30/17=) 1.7amps, that is close to 10% of your batteries 18 amp hour capacity. I would NOT use a bigger battery. I would not try to use the fan as long as you did today on cloudy days.

I would do 2 things to improve your system, make hardwire connections to the battery, those clips are less than worthless, they may miss lead you when they don't have a good connection. I would also let the charge controller do it's job and leave it plugged in and charging. You can draw energy while it's charging, no problem. It should not allow the battery to become over charged.

mcgivor

@vickers ,welcome to the forum. 
Nice to see you don't want to learn to swim by jumping into the deep end, what you have is almost what I started with and ironically it still in daily use for led lighting  after 10 years, although with a gel  battery don't expect more than a year or two, they are not made for cyclical use, they are better suited for standby use, but perfectly fine for educational purposes.
The charge controller should get the battery to 14V  then the led should begin to pulse,this pulse rate may increase in speed, try leaving it on charge for a couple of days without load and see if the voltage gets to 14V as this is important so as not to undercharge as this will lead to premature  failure. 
ALWAYS  connect  the inverter directly to the battery NOT the load terminals.
Once you learn the fundementals they can be applied to future endeavors read as much as possible, the host sites learning center is an invaluable source, and never be afraid to ask questions.Have fun.

mike95490

Caution on the Load terminals.
Many times, you must read the controller manual, *most* controllers can only manage a very small Load. Morningstar controllers can generally manage a Load that equals the main controller rating - a 20A controller can manage a 20A load.
Most large, "professional" controllers don't even bother with Load terminals, the system design is supposed to cover all the bases.
 Most inverters will overload the Load terminals and damage the Controller, Fun.

littleharbor2

 Dennis461,      And I quote,     "Now, I have an inverter that did not behave properly and the inverter vendor told me to connect the inverter directly to the battery, which in my professional opinion was not correct." What is your profession? I certainly hope it doesn't have anything to do with electronics, Solar or renewable energy if you are giving out this kind of advice.

littleharbor2

   OK, I need to mention once more as now I've seen two comments from two different posters saying to connect the inverter to the load connections of the charge controller. This has to be confusing to the OP getting conflicting advice here. 

     DO NOT connect your inverter to the load connection on your charge controller. Connect your inverter to your battery and only your battery. Use a properly rated fuse for your inverter cable. Place that fuse on the positive cable and as close to the battery as practical.

vickers

littleharbor2 said:

   OK, I need to mention once more as now I've seen two comments from two different posters saying to connect the inverter to the load connections of the charge controller. This has to be confusing to the OP getting conflicting advice here. 

     DO NOT connect your inverter to the load connection on your charge controller. Connect your inverter to your battery and only your battery. Use a properly rated fuse for your inverter cable. Place that fuse on the positive cable and as close to the battery as practical.

I was wondering about this.  During my research on a set, I was looking through the questions posed, and Renogy advised not to hook an inverter directly to the charge controller.  https://www.amazon.com/forum/-/TxLDA1SDOSG6BR/-/ref=ask_dp_lsw_al_hza?asin=B00E7NDMC4

Photowhit

I only suggested hooking up to the load for his minimal use, Some of the cheap 'car inverters' don't do a good job of protecting the battery. I'll go ahead and agree to hook the inverter to the battery.

vickers

Photowhit said:

I only suggested hooking up to the load for his minimal use, Some of the cheap 'car inverters' don't do a good job of protecting the battery. I'll go ahead and agree to hook the inverter to the battery.

Appreciate the differing opinions and different ways of looking at things.  I also was looking at a few solar forums before I joined one and landed here due to the helpful advice and that people for the most part get along.   

vickers

Ok, now that I have gotten my feet wet and have been a member of this forum, I am beginning to have a bit of buyers remorse.  I think this may be common in the solar world....  lol

I originally bought the Eco-Worthy kit as it was an all in one solution and included all the hardware and cables.  But I am seeing now that if I wish to expand the system I may be out of luck... 

Perhaps a better starter kit would have been the Renogy 50 Watt 12 Volt Monocrystalline Solar Starter Kit currently selling for $134.  It looks like it comes with a better charge controller and is expandable.  I paid $113.99 for my ECO-WORTHY 12 Volts 40 Watts Portable Foldable Polycrystalline Solar Panel Kit. 

Or the Harbor Freight kit..........  Just kidding. 

vickers

mcgivor said:

@vickers ,welcome to the forum. 
Nice to see you don't want to learn to swim by jumping into the deep end, what you have is almost what I started with and ironically it still in daily use for led lighting  after 10 years, although with a gel  battery don't expect more than a year or two, they are not made for cyclical use, they are better suited for standby use, but perfectly fine for educational purposes.
The charge controller should get the battery to 14V  then the led should begin to pulse,this pulse rate may increase in speed, try leaving it on charge for a couple of days without load and see if the voltage gets to 14V as this is important so as not to undercharge as this will lead to premature  failure. 
ALWAYS  connect  the inverter directly to the battery NOT the load terminals.
Once you learn the fundementals they can be applied to future endeavors read as much as possible, the host sites learning center is an invaluable source, and never be afraid to ask questions.Have fun.

I have it back on the solar charger now.  I probably jumped the gun pulling it off.  I was worried it would fry the battery.  I'm going to let the charge controller do its job and report back. 

mvas

vickers said:

Quick update.  I pulled the battery off of the solar panels after 4 hours of direct sunlight.  Voltmeter read 131 volts.  After 3 hours I checked it again and it had stabilized to 12.7 volts.  I think that is a pretty good recharge rate. 

Printed on your battery it states:  
"Standby: 13.5 v - 13.8 v"
"Cycle Use: 14.4 v - 14.7 v"
I seriously doubt that your battery is 100% fully recharged within 3 hours @ 13.1 volts.
Chronic under-charging will allow the sulfate crystals to harden, which will reduce the AH capacity over time.

vickers said:

With the setup in the first image, I ran an AC fan on low (averaging 26.6 watts) for 6 hours.  The voltmeter was hooked up the entire time and read 11.2 volts.  I understand I probably could have taken it lower, but didn't want to fry my battery on the first test.  

I would not have taken it lower, or even that low.
26.6 watts / 12 volts = 2.2 amps x 6 hours = 13 AH consumed.
I would not habitually discharge an 18 AH battery that low = 28% SOC.
9 AH discharge = 50% SOC, is typical.

vickers

Photowhit said:

vickers said:

The math........  

Just for S&G - using this solar system, what is the largest battery I can go with in terms of AH and still be able to recharge it with the panels.  I was impressed with how quickly my battery recharged today.  I understand it is a small battery though, and that this may be a loaded question.....

Also, the 3 amp charge controller.... That sounds really small to me, but unless I expand the panels that tie into it, that size should be fine, right?

The charge controller should be fine for that panel, but it may not be a 'true' charge controller, Typically you would expect a charge controller to allow the voltage to increase until it reaches around 14 volts, this would be 'bulk' charging. Then it would hold the 14 volts so your battery isn't damaged by over heating. usually it will stay there for a set time (this is the absorb mode), then it will lower the voltage until it reaches float level usually around 13.2-13.6 volts(float mode).  This is why I asked what the highest voltage was? It might just regulate the voltage going into the battery. It can do that and charge the battery, but missing the mark of fully charged, just residing at a 'float level' which will charge the battery but not reaching full capacity in general.

I think that's a sealed lead acid battery, it might have glass mat separators. Some times these will maintain surface charges for a long period of time, I'm NOT someone who uses or deals with SLA or AGM batteries much, perhaps Marc will chime in? I have seen agm's holding 13 volts over a week!

If you intend to use energy from your battery, you are about the correct size battery, controller and panel. A 40 watt panels should normally produce about 30 watts. it out put's 17.9 volts so it will create about (30/17=) 1.7amps, that is close to 10% of your batteries 18 amp hour capacity. I would NOT use a bigger battery. I would not try to use the fan as long as you did today on cloudy days.

I would do 2 things to improve your system, make hardwire connections to the battery, those clips are less than worthless, they may miss lead you when they don't have a good connection. I would also let the charge controller do it's job and leave it plugged in and charging. You can draw energy while it's charging, no problem. It should not allow the battery to become over charged.

Thanks Photowhit.  I am noticing the alligator clips are becoming a PITA.  I also have the battery charging again now.  I pulled it off too quick worried about the voltage.  But I'm going to let the controller do its job.

Estragon

You mentioned wanting to use solar for emergency/backup purposes. Before getting to any expansion, it would be a good idea to quantify the loads you want to have backup power for, and how long they need to run on battery power.

vickers

mvas said:

vickers said:

Quick update.  I pulled the battery off of the solar panels after 4 hours of direct sunlight.  Voltmeter read 131 volts.  After 3 hours I checked it again and it had stabilized to 12.7 volts.  I think that is a pretty good recharge rate. 

Printed on your battery it states:  
"Standby: 13.5 v - 13.8 v"
"Cycle Use: 14.4 v - 14.7 v"
I seriously doubt that your battery is 100% fully recharged within 3 hours @ 13.1 volts.
Chronic under-charging will allow the sulfate crystals to harden, which will reduce the AH capacity over time.

vickers said:

With the setup in the first image, I ran an AC fan on low (averaging 26.6 watts) for 6 hours.  The voltmeter was hooked up the entire time and read 11.2 volts.  I understand I probably could have taken it lower, but didn't want to fry my battery on the first test.  

I would not have taken it lower, or even that low.
26.6 watts / 12 volts = 2.2 amps x 6 hours = 13 AH consumed.
I would not habitually discharge an 18 AH battery that low = 28% SOC.
9 AH discharge = 50% SOC, is typical.

Thanks mvas.  I really thought that the low voltage alarm would have gone off when I was getting down to the low 11 volt range, but it never did.  I guess I cant rely on that.  Upon further research, it seems that may not go off until around 10v, which would be harmful to this battery.  Appreciate the advice.   

vickers

Estragon said:

You mentioned wanting to use solar for emergency/backup purposes. Before getting to any expansion, it would be a good idea to quantify the loads you want to have backup power for, and how long they need to run on battery power.

Good idea.  I live in northern Alabama, and we are prone to tornados.  In April 2011, our power was out for 9 days.  Luckily we had a generator, which worked for our needs but really opened our eyes.  The town over still had power so we could drive to Athens and get gas and other supplies.  But I knew not to run it at night and a few days in I was getting worried about it attracting attention as we live in subdivision. 

So really, I would like to use solar power to recharge cell phones, iPads, and mobile hotspots while running some LED lights at night.  We have portable DVD players for the kids we use on car rides to visit family up north, so running though would be nice.  Also some fans in the spring and summer months.  I work from home, so charging my laptop would be helpful.

So here is the list:
-Recharge iphones, ipads, and mobile hotspots
-LED lights at night (even the USB kind) - just some light at night
-Portable DVD players for a few hours a day
-Fans in the summer - hence my first test with an AC fan.  I think I would probably get more run time out of a DC fan though, right?
-Recharge laptop

And of course, during the zombie apocalypse.