Off Grid & Having Problems...

offgridderoffgridder Registered Users Posts: 25 ✭✭
Hi,

I have been away from the forum for quite some time. We are totally off grid in New Mexico. I have been having some troubles with our system for a little while now & the last 2 nights the trouble got much worse.

Disregard my signature - need to update the info!

Our set up consists of:
8 - 90 watt monocrystaline panels
Xantrex 60 amp controller
8 - AGM 100ah batteries
Xantrex 1000 watt sine wave inverter
1000 watt cheapie inverter
8awg to the panels

When I upgraded the system last winter to what it currently is I was overwhelmed at the increase of power we had. We had much more than we could use. Just before the monsoon season arrived I noticed a decrease in power & once the rains came we were in trouble. I was only seeing at most 10 amps when the sun did come out, not good. Once the monsoon passed I expected to have a jump in power but it didn't happen.

I had a friend stop by who said it is the charge controller that is the problem but I am not sure. Another friend was just here & while he was here we did some troubleshooting. We decided to hard wire the panels to the batteries directly to see what the results would be under supervision. The 8 batteries never went above 12.9v & the amperage never rose above 9 amps (panels are rated at 5.13 amp). We then started to test the batteries & one looks to be shot for sure, reads 12.0 after a charge. There are 3 others that are reading 12.5 after charging & the other 4 were 12.75. Next we hooked up the 4 good batteries to the panels & got 15volts after some time.

Last night we had the 4 batteries hooked up to the system & they were charged. The charge controller was still disconnected. At dusk the battery voltage dropped like a rock. Was that because the controller was not connected? Can the panels draw power when the are not producing? I hooked up the controller & let the batteries get a fresh charge today.

We saw a good charge today & I was working online when maybe 3 hours after dark again, a quick a serious drop in power sent the inverters into a frenzy along with myself! So now this is where I am at (with generator running) :cry:

I have a controller that is only showing 10 amps & 130 watts of power at most at high noon. I am having quick discharges for no reason. My batteries are all less than 2 years old which really bothers me....

Please any suggestions as to what the heck is going on or what I can do to figure out a solution??

Thanks, Jonathan
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Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Off Grid & Having Problems...

    Let's see.
    800 Amp hours @ 12 Volts?
    720 Watts of array?

    There's your problem: don't expect that array to successfully charge those batteries.
    The rough calculation: 720 Watts @ 77% efficiency = 554 / 12 Volts = 46 Amps which is 5.75 % charge rate at best. Subtract any concurrent loads and you have chronic deficit charging. Remember the hotter the panels get the less power they will produce, making the situation worse. The batteries' actual capacity will steadily decline.

    For that much battery you should have something like this:
    80 Amps peak current (10%) * 14.2 Volts charging = 1136 Watts * 77% efficiency = 1475 Watt array. Or about double what you've got. The Xantrex isn't going to handle that much current either. Without it the batteries will drain through the panels at night.

    In all likelihood you now have ruined batteries that aren't going to perform no matter what you do to them. Time to start over.
  • BB.BB. Super Moderators, Administrators Posts: 29,717 admin
    Re: Off Grid & Having Problems...

    What kind of Charge Controller? MPPT or PWM?

    How are the panels wired? All parallel, series/parallel, (Vmp-array/Imp-array)?

    I would suggest that you look at a reasonably priced (aka cheap) DC Current Clamp Meter from Sears. They are much easier to use to measure/trace down current flow/issues. And much safer too.

    When you have lots of paralleled connections, the DC Current Clamp meter can quickly identify which paths are carrying current and which are not (connection problems, panel/battery problems, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Off Grid & Having Problems...

    sorry to hear you are having trouble. just to be sure you need to clarify some things for us.
    1 which 60a xantrex cc do you have and if it is an mppt style then how are the pvs wired, series/parallel or both?
    2 what gauge wire and their lengths are you using from the pvs to the cc and from the cc to the batteries?
    3 are you using a bts to detect the battery temp?
    4 what charge settings did you use?

    i think 720w of pv is a bit too light for 8 agm batteries, but that has now dwindled.

    if you wire direct from pv to battery with no cc or blocking diode then the power is free to discharge into the pv from the battery when it's dark or shaded. i do not advise you continue to charge the remaining batteries without the cc as agms are prone to overcharge. this will cause it to outgas and you can't replace the water lost in the outgassing so you lose capacity this way. in the future i would suggest a good battery monitor so you won't discharge your batteries too far again which i believe happened and you lacked enough sun to bring them up to full with the undersized array during a dismal period of time. i suggest a backup plan such as a generator and a good 3 stage charger for those times the weather does not cooperate.
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    Let's see.
    800 Amp hours @ 12 Volts?
    720 Watts of array?

    There's your problem: don't expect that array to successfully charge those batteries.

    In all likelihood you now have ruined batteries that aren't going to perform no matter what you do to them. Time to start over.
    Hmmm... NOT what I wanted to hear, but I guess I was and am still a newbie... :cry:

    I guess my best bet right now is to stick with the 4 batteries that are still strong & use just those with the array?

    Thanks, Jonathan
  • BB.BB. Super Moderators, Administrators Posts: 29,717 admin
    Re: Off Grid & Having Problems...

    That will help... But knowing which type/model of solar charge controller you have and how are your panels wired will help us too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    BB. wrote: »
    What kind of Charge Controller? MPPT or PWM?

    How are the panels wired? All parallel, series/parallel, (Vmp-array/Imp-array)?

    I would suggest that you look at a reasonably priced (aka cheap) DC Current Clamp Meter from Sears. They are much easier to use to measure/trace down current flow/issues. And much safer too.

    When you have lots of paralleled connections, the DC Current Clamp meter can quickly identify which paths are carrying current and which are not (connection problems, panel/battery problems, etc.).

    -Bill

    Hey Bill,
    A PWM contoller, 60 amp Xantrex.
    Panels are wired parallel
    Do you have one certain DC Clamp Meter you can recommend (with a link to it maybe)? I looked on Sears and so soooo many....

    Thanks, Jonathan
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Off Grid & Having Problems...
    offgridder wrote: »
    Hmmm... NOT what I wanted to hear, but I guess I was and am still a newbie... :cry:

    I guess my best bet right now is to stick with the 4 batteries that are still strong & use just those with the array?

    Thanks, Jonathan

    Yes. Unfortunately with AGM's you can't take SG readings. And please note what Bill & Niel have said. Keeping the current flow even amongst eight batteries in parallel is very difficult. Wire sizing, length, and connections are critical.

    When I suggested it was time to start over I meant go back to your loads. What are your daily Watt hour requirements and can they be reduced? Maybe you don't need 800 Amp hours of battery (up to 4.8 kW hours) to begin with. That would be a help. If you do need that much you might want to consider a higher system Voltage: it makes it easier.
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    niel wrote: »
    sorry to hear you are having trouble. just to be sure you need to clarify some things for us.
    1 which 60a xantrex cc do you have and if it is an mppt style then how are the pvs wired, series/parallel or both?
    2 what gauge wire and their lengths are you using from the pvs to the cc and from the cc to the batteries?
    3 are you using a bts to detect the battery temp?
    4 what charge settings did you use?

    i think 720w of pv is a bit too light for 8 agm batteries, but that has now dwindled.

    if you wire direct from pv to battery with no cc or blocking diode then the power is free to discharge into the pv from the battery when it's dark or shaded. i do not advise you continue to charge the remaining batteries without the cc as agms are prone to overcharge. this will cause it to outgas and you can't replace the water lost in the outgassing so you lose capacity this way. in the future i would suggest a good battery monitor so you won't discharge your batteries too far again which i believe happened and you lacked enough sun to bring them up to full with the undersized array during a dismal period of time. i suggest a backup plan such as a generator and a good 3 stage charger for those times the weather does not cooperate.

    The PV is parallel
    It is a pwm CC, wired via 8AWG - about 80 foot distance
    No bts - is it possible to feel the heat when a battery warms up?
    Not sure what you are asking on the settings I set...

    Thanks for the info on the discharge. I hooked the CC back up right after drain occured & is still connected.

    As far as a generator I have one & was building on the cabin so the batteries were being charged every time I ran a power tool which was often, & during the monsoon season... helped but never enough. I got desperate & borrowed a second charger which gave me 10 amp service each or 20 amps total. What type or brand 3 stage charger can anyone recommend? I know I need something with a little more power for sure....

    Thanks for all the replies so far! I guess I have a lot to learn & I have made an expensive mistake not to mention I am on a tight budget... :grr
  • BB.BB. Super Moderators, Administrators Posts: 29,717 admin
    Re: Off Grid & Having Problems...

    Sorry, the link got messed up in the previous post (I will fix it next). Here is the correct link:

    http://www.sears.com/shc/s/p_10153_12605_03482369000P

    It is ~$60.00 and about the least expensive version I have seen that is functional.

    You can easily pay $350-$450+ for a very nice Fluke meter--but this will do what you need for debugging your system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    Yes. Unfortunately with AGM's you can't take SG readings.

    Parden my noobism... what is SG?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Off Grid & Having Problems...
    offgridder wrote: »
    Parden my noobism... what is SG?

    In this case Specific Gravity. A measurement of the electrolyte that lets you know much about the condition the battery is in. Since AGM's have just enough to wet the matte and it can't be accessed you can't check it.

    A guide to the many terms used here, the glossary: http://forum.solar-electric.com/showthread.php?t=6136
  • BB.BB. Super Moderators, Administrators Posts: 29,717 admin
    Re: Off Grid & Having Problems...

    Specific Gravity of battery electrolyte (water+sulfuric acid). 1.000 is pure water; ~1.265 is the S.G. of a fully charged battery.

    AGM and GEL batteries have no "free/liquid" electrolyte to measure SG with a standard float type Hydrometer. And all sealed batteries limit access to the electrolyte.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Off Grid & Having Problems...

    if the cc is the c60 then it has settings for you to charge the batteries at. the battery manufacturer will often state the required absorb and float voltage settings for their batteries. if you go too high you outgas and destroy the batteries' capacity. too little causes a deficit charge and sulfation to the plates which also destroys capacity. going too far too long either way can kill the batteries. i believe the majority of your problem was undercharging the batteries due to too little pv with too little sun while continuing to draw loads from them as you indicated they were in operation for about 2 years already.
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...

    ARRRGH... I have to power down for the evening.... Great help from everyone already, I will return tomorrow at sunup!
    :cool:
    Thanks again, Jonathan
  • VicVic Solar Expert Posts: 2,976 ✭✭✭✭
    Re: Off Grid & Having Problems...

    hi offgridder,

    Sorry to hear of your problems.

    For some of my neighbors, C40s and C60s seem to have ruined a number of battery banks. These CCs seem to work OK for several years, seem to go bad, and the user is none the wiser. The Morse code of the lights is difficult to intrepret, and the setings seem limited. A bank of L16s cost $3K or so, but they run a $100ish CC.

    Think thay you have AGMs. As noted above, it is prob not a good idea to charge AGMs directly from the PV array without a CC, or a Process Engineer monitoring state of charge 100% of the time.

    You mentioned getting the AGMs up to 15 Vdc. This seems way too high for this battery construction, unless the batts are very cold (thus raising the terminal voltage).

    Hope that you can get the situation under control, and perhaps get a more advanced MPPT Charge Controller, plus some more solar input, and perhaps a Battery Monitor.

    Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • icarusicarus Solar Expert Posts: 5,355 ✭✭✭✭
    Re: Off Grid & Having Problems...

    Not to beat the dead horse again, but at the end of the day, you a going to have to go back to the drawing board.

    As has been suggested, all design elements stem from the loads. Proper battery size for the load with designed in resve capacity, both for battery life, as well as. Grey day autonomy, coupled with proper PV/CC sizing to properly charge those batteries, coupled with properly sized inverter(s) to power AC loads, all backed up by a properly sized 3 or 4 stage charger and gender.

    You have a considerble investment in PV, it is only wise to make it work properly.

    Sorry for your trouble,, good luck, and keep in touch,

    Tony
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    BB. wrote: »
    Sorry, the link got messed up in the previous post (I will fix it next). Here is the correct link:

    http://www.sears.com/shc/s/p_10153_12605_03482369000P

    It is ~$60.00 and about the least expensive version I have seen that is functional.

    You can easily pay $350-$450+ for a very nice Fluke meter--but this will do what you need for debugging your system.

    -Bill

    Thanks Bill, I will have to pick one up & then...learn how to use it! I am a bit electrilliterate! LOL...
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    niel wrote: »
    if the cc is the c60 then it has settings for you to charge the batteries at. the battery manufacturer will often state the required absorb and float voltage settings for their batteries. if you go too high you outgas and destroy the batteries' capacity. too little causes a deficit charge and sulfation to the plates which also destroys capacity. going too far too long either way can kill the batteries. i believe the majority of your problem was undercharging the batteries due to too little pv with too little sun while continuing to draw loads from them as you indicated they were in operation for about 2 years already.

    I think I have to agree with you as it seemed that this may have been a slow death... I hate that I unknowingly took advice from a few too many that did not know what they were doing...
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    icarus wrote: »
    Not to beat the dead horse again, but at the end of the day, you a going to have to go back to the drawing board.

    As has been suggested, all design elements stem from the loads. Proper battery size for the load with designed in resve capacity, both for battery life, as well as. Grey day autonomy, coupled with proper PV/CC sizing to properly charge those batteries, coupled with properly sized inverter(s) to power AC loads, all backed up by a properly sized 3 or 4 stage charger and gender.

    You have a considerble investment in PV, it is only wise to make it work properly.

    Sorry for your trouble,, good luck, and keep in touch,

    Tony

    Thanks Tony... I am going to need advice on the easiest way to resolve these problems, both financially & labor-wise. I run my online business with this system, the most important use of the array.
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    niel wrote: »
    if the cc is the c60 then it has settings for you to charge the batteries at. the battery manufacturer will often state the required absorb and float voltage settings for their batteries. if you go too high you outgas and destroy the batteries' capacity. too little causes a deficit charge and sulfation to the plates which also destroys capacity. going too far too long either way can kill the batteries. i believe the majority of your problem was undercharging the batteries due to too little pv with too little sun while continuing to draw loads from them as you indicated they were in operation for about 2 years already.

    When I added the additional panels & batteries I installed everything with the new c60 CC. I did set up the CC according to the battery manufacturers specs although it has been quite a while since I last looked at anything I did originally as everything seemed to be working fine. Obviously I was undercharging the batteries as everyone has said & all I can say is d*mmit I screwed up...

    Now the questions is, what can I do right now till I get what I need to correct this?
  • rplarryrplarry Solar Expert Posts: 203 ✭✭✭✭✭
    Re: Off Grid & Having Problems...

    I use agm batteries in my system, and originally had a C60 charge controller. I found that it did not let the batteries charge fully. The C60 only has 2 settings, bulk charge volts and float volts. I found that agm's need to be brought up to the bulk volts and then held there (in my case a couple of hours) until all the amphours used have been returned to the battery bank, and then go to float voltage. Maybe a different type of charge controller would work better for you. I also found that, because the agm's are so much more efficient than fla batteries, that 5% charge capacity was enough to charge my bank.
    Hope this helps,
    Larry
  • BB.BB. Super Moderators, Administrators Posts: 29,717 admin
    Re: Off Grid & Having Problems...

    Keeping the batteries happy is what it is all about... Look into a Battery Monitor--It will really help you understand your loads and charging (battery monitors are not perfect--just a lot easier to use in day to day use).

    In a way, it is like running a car without a gas gauge (been there, done that). A battery monitor totalizes the Amp*Hours in and Amp*Hour out. Sort of like a fuel totalizer would--gallons into and out of the tank through the fuel line.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,842 ✭✭✭✭✭
    Re: Off Grid & Having Problems...

    As Bill wrote, or learn how voltage, load, and current relate.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Off Grid & Having Problems...
    BB. wrote: »

    In a way, it is like running a car without a gas gauge (been there, done that).
    LOL. Me, too. For years I drove without a gas gauge, just using the trip odometer. I never ran out of gas, but I had a few anxious moments out on long lonely Texas highways.
  • icarusicarus Solar Expert Posts: 5,355 ✭✭✭✭
    Re: Off Grid & Having Problems...

    In addition to a battery monitor ( which is essential!) One has to realize tht battery bsed systems (of any sort) need care and attention. For a flooded bttery s ystem, a monthly SG check, water level top up, cable connection checking and tightening etc. Is also essential. Batteries have bad cells, cables get corroded, connectors get loses etc.

    An off grid system is not a plug and play system. Most of us have learned how to "drive" our systems so that they perform as well as they do. Consider this your cost of learning, (albeit steep!) and now strt with a clean sheet of paper, knowing what your loads are likely to be, and as I said before match the battery to the load, and then the charge regime to the batteries.


    Tony
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Off Grid & Having Problems...
    rplarry wrote: »
    I use agm batteries in my system, and originally had a C60 charge controller. I found that it did not let the batteries charge fully. The C60 only has 2 settings, bulk charge volts and float volts. I found that agm's need to be brought up to the bulk volts and then held there (in my case a couple of hours) until all the amphours used have been returned to the battery bank, and then go to float voltage. Maybe a different type of charge controller would work better for you. I also found that, because the agm's are so much more efficient than fla batteries, that 5% charge capacity was enough to charge my bank.
    Hope this helps,
    Larry

    larry,
    those 2 voltage settings are normal for a 3 stage charger as the first one you refer to as a bulk voltage is actually the voltage the absorb stage is held to as technically the bulk stage has no set voltage. the c60 is, in fact, a 3 stage charger. a 2 stage charger does not go to a float voltage, but continues to hold it at the absorb voltage and allows the current to slowly diminish as it continues to charge.
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...
    niel wrote: »
    larry,
    those 2 voltage settings are normal for a 3 stage charger as the first one you refer to as a bulk voltage is actually the voltage the absorb stage is held to as technically the bulk stage has no set voltage. the c60 is, in fact, a 3 stage charger. a 2 stage charger does not go to a float voltage, but continues to hold it at the absorb voltage and allows the current to slowly diminish as it continues to charge.

    Do I need to check & change something on the CC? Is there something I should have been doing since day one that I was unaware of? Cornfused here....
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: Off Grid & Having Problems...

    The issue has nothing to do with the C60, which does do three state charging as the bulk and absorb as the same voltage. The C60 is a PWM, which might not be harvesting as well as an mppt charge would, but the difference is insignificant for this size array as the OP has all the panels in parallel.

    The OP's issue is chronic deficit charging, and for the OP this means your solar is not sized to support your loads properly and possibly other issues.

    For the OP, you need to go add up all you loads, post them here and lots of nice folks will help you work through the process of figuring out how to size what is needed for your installation.

    by your descriptions of the generator usage, your probably off by a factor of 10 on the solar required for your current usage. Good news is solar panels have never been cheaper and are soon going to be the lowest cost of the system!
  • offgridderoffgridder Registered Users Posts: 25 ✭✭
    Re: Off Grid & Having Problems...

    Thanks Solar Guppy... When I mentioned the generator this was used mostly during the monsoon season which was long this year & didn't give much of a break from the overcast days. We had already started seeing a power loss before the monsoon but it was minimal, not enough in my mind to see a problem till about 1/4 of the way into the season.
    You mention: "your probably off by a factor of 10 on the solar required for your current usage." What is a factor of 10?

    What I am concerned with is my CC is only showing about 8-10 amps at high noon, cloudless & clear skies in New Mexico. 8 panels rated at 5.13 amps, obvious problem exists. I am concerned about this number as it is not even close to what is should be, any ideas? Anyone?

    Our loads are not very much, we are very strict with what we use - I will get our daily usage numbers together shortly, it has changed over the last 2 years so I need to update anyway.

    Thanks, Jonathan
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: Off Grid & Having Problems...

    Since you direct connected the solar to the batteries and got similar readings, that rules out the charge controller

    You haven't posted the specs on the solar panels, but yes, if you have 8 working 12V nominal panels in parallel to a battery bank that accepts the load you should be seeing 30+ amps.

    So its either the solar panels OR the battery's are near dead and there is nothing to draw the load from the panels. ( this is my best guess ) One test, is to disconnect the solar, use a amp meter in series with the solar and short the solar, this will let you know if its the solar ( or wiring ) or the batteries

    So for the 10th time in this thread WHAT ARE YOUR LOADS

    A full description of your setup , specifications, operating voltages are needed to help get you on the right path.

    Oh and factor of 10x means 10 times ... so if even a generator, running all day can't support your loads and charge the battery's properly your going to need 10 times more solar, but that's a guess, and providing more information will lead to specific answers
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