# Home Solar Fail: Help!



## proudamericandad (Jul 28, 2014)

I am fairly new to prepping/homesteading so I am need of help on one very important subject: power. I put together a small solar system awhile back and have been disappointed/aggravated ever since. I have read and tweaked and watched videos and tweaked but no matter what I do its not doing what I want it to do. I have three 15 watt panels connected to a Sunforce 7 amp charge controller that is putting about 17.6 volts into a four-battery bank of 12-volt deep-cycle marine batteries connected in series with automotive battery cables. All this is then connected to a 3000 watt inverter. After letting the batteries charge for a day or two I can't power a refrigerator (pulling 230 watts) more than a couple of hours. What am I doing wrong?


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## Wellrounded (Sep 25, 2011)

You're going to need a LOT more panel watts. On my tablet ATM and hate typing, pretty sure another member will show you the math


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## smaj100 (Oct 17, 2012)

proud,

I can feel your pain. I've got a small system on our farm running a fan, small fridge and a heat lamp in the winter for our chickens. I'm running almost 650W of panels and if I get more than 1 or 2 days of cloudy weather. I have to hit my batteries with a charger for 6-12hrs.

Depending on how often your fridge runs let's just make some estimates. fridge runs for 12hrs out of 24. You stated it pulls 235W @ 110v is 2 amps per hour. 2Ah x 12hrs =24A per day.

Your putting in daily;
15Wx4=60Watts at 100%
60W=12Vx Xamps where you are putting 5Amps into the system. Lets also assume you are getting a modest 5hrs per day of great sun. In a perfect system you are putting in 25A and taking out 24. Now lets factor in system inefficiencies and you are no longer putting in 25 and might be taking out more than 24.

I'm going to guess this is harbor freight panel kit? I have a few of those for trickle charging equipment on the farm that doesn't get used very often. I honestly don't think they are good for much else. I have 4 160W Grape Solar panels from Amazon. I love them they are fixed to the roof pointing east, yet they make usable power from sunrise well into sunset. If you search my name you can see some pics of my setup and while my math might be off a bit, i'm sure others who are much more knowledgeable will chime in to correct.

Feel free to PM if I can hep I will.


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## mosquitomountainman (Jan 25, 2010)

First, get a good fast charger (40 amp continuous) and get those batteries up to full charge before you ruin them. Using batteries in a discharged condition shortens their life considerably.

Second, you'll need a lot more charging capabilities which means more/larger panels.

Third, your refrigerator is a power hog. Ours uses half the watts yours does. Get a smaller, more efficient fridge.

General guidelines are that if your battery bank is not charged up by early evening you need more solar panels or to use less electricity.

If your battery bank runs out of power before morning (assuming it was fully charged by sunset), you need more batteries or to use less power during the night.

Your battery bank should have enough capacity to run your appliances for three days of no Sun conditions and five days is much better. If it won't get more batteries.


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## cowboyhermit (Nov 10, 2012)

It's been a long day and good info has already been posted but here's a couple things.

If we say 230W is about 20A @12V Then even the most paltry deep cycle batteries should be able to put that out for 1-2 hours. A GOOD battery will typically have 100Ah storage (@12V), enough to put out 20A for 5 hours until discharged (which of course is a state you never want to reach).

So, either the batteries have very limited capacity, your inverter is extremely inefficient, or (like already mentioned and my guess as well) they are not fully charged to begin with (not enough solar). You can narrow down the problem with some testing but in reality you are most likely going to want to add some real panels. 45W (rated) of solar with a bank of 4 batteries is a bit out of wack for your application imo.

Real panels can be had for around $1/W grab one or several and you will be on the right track.


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## nightwing (Jul 26, 2014)

First the issue is with large appliances sorry but in many cases 
they should be alternative like 12 volt with a propane or natural gas 
ability.

120 was never efficient that is why the Europeans went with 220 volt.

you can run your home from solar if your bill gates or one of the other 
wealthy people that do not need to as they can afford a unlimited bill.

As for the rest of us it is not looking good batteries need to be the same 
if one is lower amperage you will damage it or it will cause they system to think it is all charged and it is either defaulting to the lowest charged or the highest and either is an imbalanced state.

the Amount of batteries and you really need 6 volt in series to make 12 volt and then your inverter need to be expensive to get proper voltage 
to power your electronics or they will burn out,

the battery bank and the panels alone will be a large sum as far as I can see your only paying forward on electrical power divide what it costs 
and then add in replacements as batteries life are not the same as panels 
so you can figure replacing the bank 4 times per the panels and I have no clue about the controller or the sine wave inverter both have to be 
balanced with the total amperage output so the higher the more expensive.

As was already stated if you allow your batteries to fall below 10 volts they probably will die.

the only way I can see a system working is if you have a free source of gas vaporous or liquid and then you have to know how to convert or 
distill or heat treat to extract what I would consider archaic fuels 
they are dangerous and take only a slight mistake and boom 
or control the output of methane ethane butane iso-butane or propane 

I can see a paddle wheel in a creek or a wind vane in a area with a good wind source but batteries will still stomp your bank account flat.
Not to mention all the NEW appliances either specifically 12 volt 
or liquid or vaporous in nature.

I have solar and a battery but only for lighting and that is L.E.D. lights 
and a few computer fans beyond that it is too expensive.
I have hand operated equipment and although they could be run on a gas motor I would not count on them as the new E-85 gas is total crap 
and cannot be stabilized with fuel additives.

That is neither here nor there all the new small or large motors 
have so many sensors or electronics they too are not to be counted on 
in a EVENT the new diesels are junk if you do not have the additive 
the will not start all of them have as many sensors and even fewer mechanics that know how to repair them.

If it cost 20,000 dollars to run your home off the grid and in 5 years 
your going to have to replace the battery bank 5,000 bucks 
then exactly where is the savings ? all you did was pay it forward
if you took that same 20,000 and invested it well you would be broke 
as well because the transition periods between new and old is getting 
smaller each day every month a new phone or app or TV is competing 
for market share and as we see from Government motors if there is a problem they will cover it up and one day your rich the next you cannot
give away the stock.

I see a problem one that will either cost a heck of a lot to fix or it will 
crash around our ankles but I doubt there will be much in between 

it is the life span and cost and as you get older you will not have the 
earning power to replace your system if your over 40 your finding harder
to get a job and make the same if your very lucky for many of us 
if we invest in such things they will far outpace our ability to afford them.

Add it up I did and found it is not all that and a bag of chips.
the only thing we can do is down size and there are not enough young people 
with the credit score to buy all of us out so we can take that save and buy smaller
this is a game of musical chairs those that do not act fast will be left out 
I see today where pay is getting smaller or benefits are thinner to equal out 
the day of every child has a TV and a room is going to come to a halt
in some cities the homeless are increasing at an alarming rate 
the working poor are becoming the masses I do not see it getting better only 
lousy and worse I see where they are going to raise the age for benefits to 69 
but the have money to give to hamas and mexico and all the other South American nations 
but your just crap on their heel.


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## mosquitomountainman (Jan 25, 2010)

nightwing said:


> First the issue is with large appliances sorry but in many cases
> they should be alternative like 12 volt with a propane or natural gas
> ability.
> 
> ...


A number of us live off grid completely and I don't believe any of us are filthy rich. It doesn't take a huge amount of money to do so but it does take some lifestyle adjustment to do so cheaply. I have a chapter in my book (Creating the Low Budget Homestead) that does a good job telling people how to set up an adequate off grid solar power system without breaking the bank. If I ever get caught up on my other projects I'll finish the one I'm writing on how to set up a home power system yourself.

Do you live off grid? I ask because there are a lot of things in your response that don't mesh. Maybe I can get on my computer later to type a better response. My tablet is tedious to type on.


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## hiwall (Jun 15, 2012)

proudamericandad the advice above is good. You're amount of solar panels is extremely lacking. I use solar for my camping RV. I only camp when it is sunny (almost always in AZ). I have 275 watts of solar to run my 120 volt (88 watt) refrigerator and any additional modest items. I am not into all the math like many on here are but when the label on a solar panel says 100 watts that is under ideal conditions with the panel carefully aligned to face directly at the moving sun. I figure if I get half the rated watts on a whole then thats good.


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## smaj100 (Oct 17, 2012)

Mosquito is correct on all accounts. It doesn't take a fortune to setup a system. My small system was setup with providing enough power in a SHTF to my freezers and fridge and recharging other small electronics. I have purchased components to allow for expansion when funds allow it. I've purchased 6V golf cart batteries from a local farm store that regularly has them on sale. They are made by exide and marketed as the store brand. They are flooded which allows for easy maintenance. I check water levels monthly and every 6 months I pull a 12V set and place them on a desulfating charger. 

Our homestead is growing and will have power service hopefully soon. We wanted to avoid it and go solar for total off grid, but the bank requires electric service as a backup for funding to build a house. So I will continue to add to our small system as I can. Once we have power service installed I'll add some grid tie inverters to fully use the panels to our benefit and still have a backup capability. I've purchased all components except the batt's from amazon as a prime member saving on shipping helps keep the price down. 

I've found the $1/watt price mark is available but usually only if you are buying multiple panels from a distributor and then they hammer you on shipping (at least the few I called).


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## mosquitomountainman (Jan 25, 2010)

smaj100 said:


> Mosquito is correct on all accounts. It doesn't take a fortune to setup a system. My small system was setup with providing enough power in a SHTF to my freezers and fridge and recharging other small electronics. I have purchased components to allow for expansion when funds allow it. I've purchased 6V golf cart batteries from a local farm store that regularly has them on sale. They are made by exide and marketed as the store brand. They are flooded which allows for easy maintenance. I check water levels monthly and every 6 months I pull a 12V set and place them on a desulfating charger.
> 
> Our homestead is growing and will have power service hopefully soon. We wanted to avoid it and go solar for total off grid, but the bank requires electric service as a backup for funding to build a house. So I will continue to add to our small system as I can. Once we have power service installed I'll add some grid tie inverters to fully use the panels to our benefit and still have a backup capability. I've purchased all components except the batt's from amazon as a prime member saving on shipping helps keep the price down.
> 
> I've found the $1/watt price mark is available but usually only if you are buying multiple panels from a distributor and then they hammer you on shipping (at least the few I called).


The dollar per watt price can be found on single panels but they are often for odd voltage panels (like 20 volt) that won't work on 24 volt systems but waste a lot of power on 12 volt system. The key to using odd voltage panels is to go with an MPPT charge controller. But they cost more than the older controllers.

Our next system will be using an MPPT controller and higher voltage panels. It cost less per watt if you're going to have 1,000 watts or more. I already have enough controllers for the three systems we currently use.


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## cowboyhermit (Nov 10, 2012)

nightwing, I don't mean to pick apart your post, however there are a few issues I feel compelled to address.



nightwing said:


> First the issue is with large appliances sorry but in many cases
> they should be alternative like 12 volt with a propane or natural gas
> ability.
> 120 was never efficient that is why the Europeans went with 220 volt.
> ...


I kinda lost you in the end but in regards to the long term economic prospects, first of all the biggest reason (for me) to go off-grid is self-reliance and independence. Economics and reliability are secondary for me, although in other circumstances I have installed them they were the primary reason.

The economics really have to be done on a case by case basis, I have no idea whether it would work for you, given the numbers you gave for battery banks and such. On the other hand a more normal size bank that lasts an appropriate length of time has completely different economic realities.

ETA; I really only mention the $1/W because of the insane prices people are paying, sometimes the markup on this stuff drives me crazy:gaah: and makes people discouraged. I should probably say that 12V panels should be *less than* $2/W


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## nightwing (Jul 26, 2014)

your opinion is valid I was looking at a large enough system for my home to remain off the grid then I ran into a real problem home insurance 
look at the rules on being hooked up to utilities

and if you know of batteries that have a longer than 5 year warranty
please post.

all I know for deep charging the Trojan 6 volt are the best price warranty 
and life span because they are basically golf cart batteries.

the iron nickel batteries are great until you break down the price per volt 

I have seen my math and all I could see was I would be paying forward 
my bills are 120 bucks a month under solar I would need a large bank of batteries to run AC I live in Texas so that would be a must at night to 
sleep comfortably and it could not run it 24/7
or run a dryer at the same time as another large load the surge would require 
everything would be upgraded to handle the startup of 2 large amp 
appliances.

I really did look at it and had an solar firm engineer a suitable plan and it was 
just like pre paying my electric bill for 20 years and that was without 
consideration for consumables.
also if anyone has owned a vehicle you will have maintenance 
corrosion and insurance will be more to cover hail or wind damage 
falling limbs etc. 

and I always have a skewed eye for the insurance guy they promise you the 
world and you get the moon ( them bent over showing you their posterior)
Here is the real problem if we do go through a situation you had better be 
very familiar with your system if you loose a panel or a couple of batteries 
your going to have to reconfigure the system and reevaluate the load
/ surge I have my doubts that the solar guys will be online or manning 
the support line WTSHTF. 
I could I have test gear and know how to do a lot of this or could figure it out.
but people bring me a lot of repair jobs and they seem surprised I can 
do so much and since they are not repairing it then either they do not have the time or cannot or do not have the confidence.

Let us remember this is partially low voltage and high voltage and even low voltage with high amperage will have consequences I have seen toenails 
blown off and finger tips.

If it were so easy and no threat of injury or death wally would sell the kits
right? they already sell batteries cables and you can order most any thing 
all you have to do is ask the manager a friend of mine ordered a portable 
hot dog stand.

So you are probably right but the average person would blow themselves to 
bits back feeding or shorting the battery bank.
I have seen this on people jumping their vehicles.
It has been a real eye opener but I know from experience people asking me if 
their GEL battery need water (REALLY) I get a hefty discount on batteries 
and electronic gear as well as many other items and I still will not 
take this on for a myriad of reasons.
you cannot leave the power on of you leave for vacation 
the weather channel is on your 1 click remote.
A brown out or a power failure means you on deck until you fix it.

I am looking at multiple systems to power lights in out buildings and 
also have remote 120 volt for hand tools or small appliances like fans.

should one fail or have an issue or accident I am not in jeopardy 
I have alternatives and that is important in prepping to have alternatives.
or plan B C D just in case all your plans have a turn of fortune.
I would also remind people that solar panels are not exactly covert
I have mine on the back side of a out building in dire times folks will be looking to scavenge useful hardware so your going to have to defend 
external assets 24/7 people are walking up and stealing air conditioners now 
for the copper and aluminum "WHILE ITS RUNNING" a friend has lost 
Thousands of feet of copper cable from a unit that needs external power 
on his ranch and he has dogs and is not installing a sophisticated security 
system.

So to each his own and if you have to bug out it would not be a quick snatch & run.


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## cowboyhermit (Nov 10, 2012)

nightwing said:


> your opinion is valid I was looking at a large enough system for my home to remain off the grid then I ran into a real problem home insurance
> look at the rules on being hooked up to utilities
> 
> and if you know of batteries that have a longer than 5 year warranty
> ...


Solar power has saved me huge amounts of money personally and (in places I have worked on) also provided a much more reliable and safe alternative. Most of the "problems" with alternative energy have simple fixes for anyone who makes the effort and the returns are worth it, IMHO.


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## proudamericandad (Jul 28, 2014)

Thank you all for the sound advice! I am currently shopping for some new panels. This has been frustrating beyond belief! I am determined to put together a system that will work for my family if/when the grid goes down.


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## NaeKid (Oct 17, 2008)

proudamericandad said:


> I put together a small solar system awhile back and have been disappointed/aggravated ever since.


I hear your frustration, and see that the proverbial light has come on. We had another member not long ago with almost the same question - and - doing something very similar.

You can read the whole thing (and there are links to various calculations to tune your system): http://www.preparedsociety.com/forum/f16/i-need-help-please-d-24141/

You will find many more ideas that would help you tune your system to be efficient through-out this section.


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## Viking (Mar 16, 2009)

mosquitomountainman said:


> The dollar per watt price can be found on single panels but they are often for odd voltage panels (like 20 volt) that won't work on 24 volt systems but waste a lot of power on 12 volt system. The key to using odd voltage panels is to go with an MPPT charge controller. But they cost more than the older controllers.
> 
> Our next system will be using an MPPT controller and higher voltage panels. It cost less per watt if you're going to have 1,000 watts or more. I already have enough controllers for the three systems we currently use.


After having a MPPT solar controller on our motor home for a number of years now I wouldn't have anything else. I have learned that having solar panels that have higher cell count that provides higher voltages than is necessary for my battery banks is a real plus on cloudy, hazy days or spring and fall low sun angles when there is less charge time per day. If you have panels that are too close to the battery operating voltage they just won't get enough charge on low sun availability days. The four 100 watt panels we have on the motor home are 44 cell and in full sun generate up to just over 20 volts. I'm thankful I did the research before putting our system together. MPPT's are expensive and we are by no means "Well off.", but I'd rather build up savings or sacrifice on some other things and have a good system to begin with than to spend money later when I've found that the less expensive system is just not up to what I wanted it to do.


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## Viking (Mar 16, 2009)

For our home solar backup power system we bought 20 six volt golf cart batteries, I spent just under $2000 for them at Costco, if I had core batteries to turn in I would have saved around $180. These are very good batteries for the money as we also use them on our motor home. The refrigerator/freezer in our motor home is three way, 120 VAC, 12 VDC and propane. The only time I run on 12 volt is while the engine is running while driving down the road, otherwise because of it being a resistance system it will run the house batteries down in no time at all. The only time we use 120 VAC is at home or a campground. Propane runs it very efficiently, six weeks boondocking out on the hot desert of N. Nevada along with using propane for cooking and we still had about a half tank of propane when we left.


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## zimmy (Aug 17, 2012)

http://www.ebay.com/itm/Tracer2215R...944?pt=LH_DefaultDomain_0&hash=item3a82c36640

I have used these charge controllers with no problems.


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## smaj100 (Oct 17, 2012)

I'll list a few of the components I am currently running on my small solar system below; i can't agree with the other comments about the mppt chargers enough.

http://www.amazon.com/gp/product/B008KWPGAE/ref=oh_aui_detailpage_o06_s02?ie=UTF8&psc=1 I have this 30A and a 20A charger running from 2 sets of panels into my battery bank.

http://www.amazon.com/gp/product/B00GGCK7IQ/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1 I have a set of these, and the smaller 100W panels.

My batteries and wire are all local sourced as well as the breaker panels. Right now I'm running a 2000w modified sin wave inverter from harbor freight. It's presented no problems and run's everything that i've thrown at it so far, fridge, heat lamps, fans, power tools, air compressor and so on.


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## cowboyhermit (Nov 10, 2012)

Viking said:


> For our home solar backup power system we bought 20 six volt golf cart batteries, I spent just under $2000 for them at Costco, if I had core batteries to turn in I would have saved around $180.


Slightly off-topic but unless those are small batteries $180 probably would have been a steal for them. Haven't checked the prices recently but I am sure you could probably get at least $10/each for any "commercial" battery for scrap. Last pick-up truck load I took was well over $1000 for junk batts.


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## Viking (Mar 16, 2009)

cowboyhermit said:


> Slightly off-topic but unless those are small batteries $180 probably would have been a steal for them. Haven't checked the prices recently but I am sure you could probably get at least $10/each for any "commercial" battery for scrap. Last pick-up truck load I took was well over $1000 for junk batts.


They weigh in over 55 pounds each.


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## cowboyhermit (Nov 10, 2012)

Viking said:


> They weigh in over 55 pounds each.


Should be in the $10-15 each range so probably $250 as scrap, not a huge difference but a bit of cash doesn't hurt. I took in a lot of ancient batts from around the farm and the price was way better than the credit they were offering on new ones. But when I took in some deep cycles, agm, and commercial ones:eyebulge:


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## tleeh1 (Mar 13, 2013)

Viking said:


> Propane runs it very efficiently, six weeks boondocking out on the hot desert of N. Nevada along with using propane for cooking and we still had about a half tank of propane when we left.


I'm impressed. :2thumb: What size is your propane tank?


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## Viking (Mar 16, 2009)

I believe the tank holds 8 gallons. One thing I added to the ammonia absorption cooling fin area was a small 12 volt computer fan because I wasn't getting the refrigerator/freezer temps low enough through natural convection. It's amazing what difference that fan made.


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## Tirediron (Jul 12, 2010)

proudamericandad said:


> I am fairly new to prepping/homesteading so I am need of help on one very important subject: power. I put together a small solar system awhile back and have been disappointed/aggravated ever since. I have read and tweaked and watched videos and tweaked but no matter what I do its not doing what I want it to do. I have three 15 watt panels connected to a Sunforce 7 amp charge controller that is putting about 17.6 volts into a four-battery bank of 12-volt deep-cycle marine batteries connected in series with automotive battery cables. All this is then connected to a 3000 watt inverter. After letting the batteries charge for a day or two I can't power a refrigerator (pulling 230 watts) more than a couple of hours. What am I doing wrong?


If that is not a mistype, each battery is only seeing 4.4 volts 
the batteries need to be connected in parallel for a 12V circuit, if 4 are connected in series you are making a 48 volt battery circuit.
(since that is probably mistyped you need more panels and probably need to look into a chest type fridge so the cold doesn't just fall out every time you open it.


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## proudamericandad (Jul 28, 2014)

I really appreciate all the advice but it looks like I'm failing on multiple levels! 
I ordered and hooked up new panels (Two 100 watt monos from Renelogy). I plugged up the fridge and a couple of hours later, the inverter shut off (even though it was still showing 12.10 volts on the readout). After I stopped blessing the thing out, I went over all my connections and then went to get a GFCI tester. Plugging the tester into the outlet on my inverter, all three lights lit up (which isn't even an option on the instructions). I've got negative to negative and positive to positive and I've grounded the inverter. Any suggestions/ideas?


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## smaj100 (Oct 17, 2012)

Proud,

What size watts is the inverter? What size wire are you using to connect the batteries, and then to the inverter? How many watts total do you have in panels? Are they all wired in parallel? Have you checked the voltage coming into the solar controller? What brand model is the controller? Can you post some pictures up? I'd love to help you get the system running right.


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## proudamericandad (Jul 28, 2014)

Its a 3,000 watt Whistler inverter. I have 2-guage battery cables connecting batteries and 10-guage to inverter. I just installed two 100-watt panels. I haven't checked voltage coming into controller but I know I have more than 20 volts coming out. Its a Renology charge controller. I've attached pics.
Thanks so much for any advice. This is driving me crazy!


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## smaj100 (Oct 17, 2012)

Ok 

1st thing I would do is run 0 or at least 2 gauge to the inverter from the batteries.
2nd put a voltmeter to that controller so you know about what you have coming into the controller from the solar panels.
It shouldn't be that big of a deal but I would shorten those wires connecting the batteries up a bit. Mine are just long enough to go from post to post + 1" with the batteries sitting next to each other.
If you have the option since the system isn't playing nice for you anyhow. Take all those batteries home and put each one on a good charger for a few days and make sure they all take a full charge. How do you have the power from the controller to the batteries? I usually place the positive at one end of the battery string and the negative at the other end. This has worked well for my small system. Hopefully some of these tips will help. Keep asking questions, we'll get it solved eventually.

EDITED:
Also just noticed that, the renogy controller is PWM. IF you have the funds or can find a decent one get an MPPT controller. I've never used the pwm but my limited understanding is the MPPT are much more efficient. The 2 controllers I have are both mppt a 20A and a 30A.

Also just looked at the specs and unless someone else can help me confirm. They show 24v input and 24v out. So you have all your batteries wired in parallel for that inverter you are probably overcharging the batteries.


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## mosquitomountainman (Jan 25, 2010)

The PWM controller should be okay if his maximum charge rate of the panels is not over 17 volts. (On a 12 volt system.) He'd gain some power but not enough to justify the expense of a new controller. Now if the panels put out higher voltage and/or he is adding more the extra cost may be justified.


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## NaeKid (Oct 17, 2008)

One thing that I would add to the two previous posts is to use the clamp post of the battery, not the wing-nut connection. For the best flow of power, make sure that the posts are clean, coated with a die-electric grease and that the clamps on the posts are nice and tight.

You can use the wing-nut posts for other things at the same time (like a simple USB connection or a power-port connection that will run on 12-volt only), but, nothing that has a massive power draw.


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## LincTex (Apr 1, 2011)

NaeKid said:


> One thing that I would add to the two previous posts is to use the clamp post of the battery, not the wing-nut connection.
> 
> You can use the wing-nut posts for other things at the same time (like a simple USB connection or a power-port connection that will run on 12-volt only), but, nothing that has a massive power draw.


WOW - if you are drawing THAT much current that you overload the wing nut terminals, you simply do not have a large enough battery bank!


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## NaeKid (Oct 17, 2008)

LincTex said:


> WOW - if you are drawing THAT much current that you overload the wing nut terminals, you simply do not have a large enough battery bank!


On my brother's boat, he hooked all the wiring to the wing-nut terminals and we noticed that the wing-nuts could turn bright orange (and very hot) with sufficient draw. On top of that, when they warmed up (even a bit) the connections would become loose, causing even more chance for loss of power. On a boat bouncing across the waves, it was a chance for the electricity flow to be interrupted.

We re-worked the wiring so that only the low power-draw wiring (10 gauge wires and thinner with ring-terminals) would be connected to the wing-terminals and the the high power-draw wiring (2-guage) would be connected to the posts with good clamps. Never had problems with the electricity after that.

Since then - it has become a standard rule of thumb that any heavy gauge wiring to the battery should always be connected to the biggest post on the battery with proper connectors.


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## Sithigh (Aug 18, 2014)

Maybe I'm missing something here in the math. But I am an Electrician and did well with word problems.

proudamericandad said he was a Newbie that a 7 amp charge controller is putting about 17.6 volts into a four-battery bank of 12-volt deep-cycle marine batteries connected in series. (That's 12.6*4=50.4 Volts) 

This sounds to me like a 12 volt system that requires the batteries to be connected in parallel, preferably with something to isolate the charge and drain of them individually so they work as a set without draining each other in the direct connections. Sure, cable is cheaper to install. But, batteries are expensive.
If series connection is desired for a stronger, higher voltage system. Then the 
system is 48 volts nominal, the unloaded voltage from the charging source (solar panels) needs to be at least 57.6 to 61.6 volts (14.4*4=57.6 to 15.4*4=61.6) to supply the charger with enough voltage to charge the batteries. And even then, the sun should be factored in. I'm not in Arizona (70%). I'm more like Maryland with only 30% Sun at best. So, I'd need at least 775 watts of solar panels or a reflector 250% the size of a 235 watt solar array just to sustain that fridge when the door doesn't stay shut and sealed well.


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## cowboyhermit (Nov 10, 2012)

Welcome to the forum



Sithigh said:


> Maybe I'm missing something here in the math. But I am an Electrician and did well with word problems.
> 
> proudamericandad said he was a Newbie that a 7 amp charge controller is putting about 17.6 volts into a four-battery bank of 12-volt deep-cycle marine batteries connected in series. (That's 12.6*4=50.4 Volts)
> 
> ...


Tirediron mentioned before about the batteries being in parallel too. We mostly just glossed over it but it was just a typo. The picture the O.P posted later shows the batteries are wired in parallel.

Isolating batteries in a bank may theoretically sound like a good idea in reality it just isn't worth it. Having more than one bank and isolating one is more feasible.


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## Viking (Mar 16, 2009)

NaeKid said:


> On my brother's boat, he hooked all the wiring to the wing-nut terminals and we noticed that the wing-nuts could turn bright orange (and very hot) with sufficient draw. On top of that, when they warmed up (even a bit) the connections would become loose, causing even more chance for loss of power. On a boat bouncing across the waves, it was a chance for the electricity flow to be interrupted.
> 
> We re-worked the wiring so that only the low power-draw wiring (10 gauge wires and thinner with ring-terminals) would be connected to the wing-terminals and the the high power-draw wiring (2-guage) would be connected to the posts with good clamps. Never had problems with the electricity after that.
> 
> Since then - it has become a standard rule of thumb that any heavy gauge wiring to the battery should always be connected to the biggest post on the battery with proper connectors.


On our solar system batteries I use a stainless steel hex nut with a stainless steel lock washer, the washer allows for expansion and contraction by keeping a steady pressure on the connections. Using just a wing nut the connection is not often tight enough unless pliers are used to tighten them. Other types of washers that will keep a continuous pressure on the electrical connections are wavy washers or belleville washers, but they need to be made with brass or stainless steel. Through experience regular steel washers will get eaten up even when coated with electrical grease. As to wire size for our 2000 watt inverter/charger I am using 2/0 for the battery connections, this may seem like overkill but there is next to zero voltage drop even at full current load. The shorter the distance between batteries and inverter the better and for solar panel wires I use the largest gauge that will fit right in the connectors, also striving to keep the wires between solar panels, solar controller and batteries as short as possible. The wires from my 100 watt solar panels to the junction box on the roof of our motor home are #8 as is the wire going to the solar controller. Anything that can be done to reduce DC resistance loss is vital to good AC power output.


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## Viking (Mar 16, 2009)

cowboyhermit said:


> Welcome to the forum
> 
> Tirediron mentioned before about the batteries being in parallel too. We mostly just glossed over it but it was just a typo. The picture the O.P posted later shows the batteries are wired in parallel.
> 
> Isolating batteries in a bank may theoretically sound like a good idea in reality it just isn't worth it. Having more than one bank and isolating one is more feasible.


Isolating batteries that are of different types and amp hour ratings is probably a good thing but in using batteries of the same type and date of manufacture you don't need to isolate them, in fact using isolators in a large bank for solar would be very expensive for what little good it would do. One can put newer batteries in a series system if done properly. The only thing I didn't show for adding a new battery was for the single series that I illustrated at the bottom left, if one had a good old battery a new one could be hooked up in a series connection.


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## proudamericandad (Jul 28, 2014)

*Phew!*

Thanks to all of y'all's help, after several tweaks and changes (and cussing fits), my small system has been running my fridge and a charger system for my battery-operated tools for about two weeks now! (I didn't want to say anything about it too soon for fear of jinxing). I plan to add to the system in the future (slowly, cautiously) and hopefully eventually wiring it as a backup system for my home.
Thanks again so much for all y'all's help!:2thumb:


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## smaj100 (Oct 17, 2012)

Proud,

What were the tweaks and changes that you had to make to get it to work right? Was it a component issue, wiring size issue? Just thought some further explanation might help anyone else reading through this thread from preventing the same thing.


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## Viking (Mar 16, 2009)

smaj100 said:


> Proud,
> 
> What were the tweaks and changes that you had to make to get it to work right? Was it a component issue, wiring size issue? Just thought some further explanation might help anyone else reading through this thread from preventing the same thing.


Good post, it would be helpful to others in not making the same mistakes. The trouble is though that a lot of people don't do a thorough research on solar before jumping in with both feet and when things don't work like they think they should they get a bad taste about solar. We did a lot of research, looked at packaged systems and in the end found that it's far less expensive and so much more efficient to build your own. Finding local suppliers for solar panels, inverters, solar controllers and other things needed and picking them up yourself rather than having them shipped can save hundreds of dollars.


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