HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

tvtechtvtech Registered Users Posts: 9
Im just more of a backyard hobbyest i guess u could say.

Anyway here is what im starting out with, a very small system.

I have 6 15watt pv,s on my roof giving me 90watts total running into a small charge controller and from it to 4 of these type batteries that i got new but real cheap as they came out of stock rotation from a warehoue and are 2-3 years of age each but were near fully charged when i hooked them up.

Here is the batteries for spec info
http://batteriesasap.com/417.html

Specs
Volt 12
Amps 134
Length 13.57
Width 6.76
Height 10.93
Terminals TI
Weight (100)
Manufacturer C&D
Model # UPS12-490MR Replaces UPS12-475FR C&D 12 Volt 134AH Battery

I have a vector 750 watt inverter w/a surge supply of 1500watt peak.
I have played around with it some like running a 19 inch tv that is drawing 75watts from the inverter and i have run it from like 10am to 5pm this way and when i shut the inverter off the pv,s will usually bring the batteries up to full in less than 90minutes.

Now i have a digital volt meter inside that i monitor when running this tv on the system, i can watch the voltage gradually drop from 13,6 volts down to say 12.4 and thats where i shut the system down as i dont want to take a chance on pullin the batteries to far down.

So the question i have is how far down can i pull the batteries before i hit the danger zone?

And are these batteries pretty good?
I paid only $35 each plus dud plus tax

Comments

  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    tvtech wrote: »

    I have 6 15watt pv,s on my roof giving me 90watts total running into a small charge controller

    So the question i have is how far down can i pull the batteries before i hit the danger zone?

    So you have 90w of PV, *.8 = 72 w harvest at optimum alignment. As panels heat up, their power output decreases about 20%.
    72W x 5 hours = 360WH There is only about 5 or 6 good solar charging hours in a day. So 360W is about all you can hope to harvest for reuse. Then you have battery recharge efficiency of about 80-90%

    What is your controller Mfg & model ? That's the only thing we don't know yet

    Give the battery FAQ a quick read, http://www.windsun.com/Batteries/Battery_FAQ.htm it will cover the depth of discharge vs battery lifetime. (the deeper you discharge the batteries, the shorter the lifetime)
    BV.jpg 25.8K
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • tvtechtvtech Registered Users Posts: 9
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    mike90045 wrote: »
    So you have 90w of PV, *.8 = 72 w harvest at optimum alignment. As panels heat up, their power output decreases about 20%.
    72W x 5 hours = 360WH There is only about 5 or 6 good solar charging hours in a day. So 360W is about all you can hope to harvest for reuse. Then you have battery recharge efficiency of about 80-90%

    What is your controller Mfg & model ? That's the only thing we don't know yet

    Give the battery FAQ a quick read, http://www.windsun.com/Batteries/Battery_FAQ.htm it will cover the depth of discharge vs battery lifetime. (the deeper you discharge the batteries, the shorter the lifetime)


    The charge controller is just a small sunforce 7amp unit here>
    http://www.streetprices.com/Alternative_Energy/Charge_Controllers/UPC-8-34319-00066-2-SP8176659.html
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    there is no way that your little array recharged the batteries to full in an hour and a half after draining down from 7hrs of watching a 19in tv. that tv would minimally be about 50w draw and most likely more due to the inefficiency of the inverter. 1.5hrs of 90w pv is 135wh and you withdrew at least 350wh. it doesn't add up and i doubt you'll see anywhere near full output from hf type 15w pvs. you better recheck what is going on there.
  • tvtechtvtech Registered Users Posts: 9
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    niel wrote: »
    there is no way that your little array recharged the batteries to full in an hour and a half after draining down from 7hrs of watching a 19in tv. that tv would minimally be about 50w draw and most likely more due to the inefficiency of the inverter. 1.5hrs of 90w pv is 135wh and you withdrew at least 350wh. it doesn't add up and i doubt you'll see anywhere near full output from hf type 15w pvs. you better recheck what is going on there.

    What i say is 110% the truth!!

    Now please understand that when the digital meter says im down to around 12.3-12.4 volts that i shut the inverter off as i dont want to pull the batteries down to far but as someone earlier in this thread showed a graph with the voltage readings of a battery and their percentage.
    And from that graph it appears that when i drop down to 12.3-12.4 volts that im only pulling the battery down to the 70-80% range.
  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    To properly read the CHART, you need to allow a couple of idle hours for the battery to stabilize, and it's only valid at one temperature, corrections needed for other values.
    Simple logic disproves what you are reporting @ 110% There is something else happening, you meter calibration, temperature, surface charge effects...
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • tvtechtvtech Registered Users Posts: 9
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    mike90045 wrote: »
    To properly read the CHART, you need to allow a couple of idle hours for the battery to stabilize, and it's only valid at one temperature, corrections needed for other values.
    Simple logic disproves what you are reporting @ 110% There is something else happening, you meter calibration, temperature, surface charge effects...

    Ok, well i guess that ends this discussion.
    Just a note, am an an eletronic tech for 30 years now and use only fluke dvm,s and they dont lie.
  • WindsunWindsun Solar Expert Posts: 1,164 ✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    tvtech wrote: »
    Ok, well i guess that ends this discussion.
    Just a note, am an an eletronic tech for 30 years now and use only fluke dvm,s and they dont lie.

    Meters do lie. Especially if they are not used correctly.

    There is no way that your numbers can be correct.

    That inverter is 80% efficient (at best) at a 75 watt load. That translates into 75/.8, or 94 watts actual battery draw.

    10 am to 5 pm is 7 hours. 7 x 94 = 658 watt-hours. 658/12 volts = 55 amp-hours used.

    You are using those Harbor Freight type solar panels, which are rated at .9 amps in full sun, x 6 = 5.4 amps, under perfect conditions.

    So under perfect conditions you would need a minimum of 10 hours of full 100% sun to recharge the batteries, and unless you are keeping the panels at 70 degree temperature, have no clouds or haze, and the sun is at high noon for 10 hours per day - it ain't happening.
  • tvtechtvtech Registered Users Posts: 9
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    Windsun wrote: »
    Meters do lie. Especially if they are not used correctly.

    There is no way that your numbers can be correct.

    That inverter is 80% efficient (at best) at a 75 watt load. That translates into 75/.8, or 94 watts actual battery draw.

    10 am to 5 pm is 7 hours. 7 x 94 = 658 watt-hours. 658/12 volts = 55 amp-hours used.

    You are using those Harbor Freight type solar panels, which are rated at .9 amps in full sun, x 6 = 5.4 amps, under perfect conditions.

    So under perfect conditions you would need a minimum of 10 hours of full 100% sun to recharge the batteries, and unless you are keeping the panels at 70 degree temperature, have no clouds or haze, and the sun is at high noon for 10 hours per day - it ain't happening.

    Well as i said I DONT LIE and i honestly dunno why all here are finding this so hard to believe.
    The only thing i can see is that you all are missing the point that the solar panels are running the majority of the needed power during the whole day and pulling hardly anything off of the batteries.

    Right now its 2pm cst here and the sun is shining almost straight down on the panels, BOTH fluke meters are showing at the input side of the inverter 13.49 volts and is actually climbing in the past 30 minutes from 13.21.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    75 Watt TV measured on a Kill-A-Watt meter or by the data plate?

    You're probably witnessing a phenomenon of slow discharge. The TV is using up ~50 Amp/hrs per day and you're replacing most, but not all of it. This happens more often than you think, as people frequently buy huge battery banks and expect to charge them off one small panel. Eventually the batteries are trashed, but it takes a while before this problem shows up. In the meantime, the voltages appear 'normal'. Don't get too hung up on voltages: AAA batteries and D cells are both 1.5 Volts.

    Rough estimate: in 160 days of such usage the batteries will be significantly depleted.
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    tvtech wrote: »
    The only thing i can see is that you all are missing the point that the solar panels are running the majority of the needed power during the whole day and pulling hardly anything off of the batteries.

    I was thinking that as well.

    Gents, I think he's gotcha on that one.
  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    dwh wrote: »
    Gents, I think he's gotcha on that one.

    90W of panel, = 72 w harvest at optimum alignment

    Unless there is magic grease on the glass, 72W is only 72 W.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    Originally Posted by tvtech viewpost.gif
    The only thing i can see is that you all are missing the point that the solar panels are running the majority of the needed power during the whole day and pulling hardly anything off of the batteries.

    dwh wrote: »
    I was thinking that as well.

    Gents, I think he's gotcha on that one.


    actually he just admitted the batteries are not fully charged when he said the pvs gave "the majority" of what was used and what he didn't say or need to say was that the rest was made up by the battery power.:cry:
  • tvtechtvtech Registered Users Posts: 9
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    niel wrote: »
    Originally Posted by tvtech viewpost.gif
    The only thing i can see is that you all are missing the point that the solar panels are running the majority of the needed power during the whole day and pulling hardly anything off of the batteries.





    actually he just admitted the batteries are not fully charged when he said the pvs gave most of what was used and what he didn't say or need to say was that the rest was made up by the battery power.:cry:

    Oh boy, anyway now the 2 fluke meters are showing that the voltage coming in is at 13.72 volts but will soon start dropping as the sun moves of course.

    THE Batteries at this moment are right at fully charged as i can shut the inverter off thats running the tv and the voltage will jump up to 13.98 volts and 3 mins later the voltage climbs to 14.2 volts and the charge controller kills the voltage from the panels as the batteriesm are full..

    OK this is enuff of this as the majority of you guys are not here to help but instead to dissprove facts from another.
    ADIOS!!
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    Without measuring the actual amperage going in to and out of the batteries the amount of power supplied by the PV's vs. the batteries remains unknown; voltage alone doesn't tell the story.

    Sad to say it looks like Harbour Freight has claimed yet another victim with its unrealistic advertising.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    you do not need to leave just because i disagree with you. you say i will not help? gee, i didn't see anywhere that you asked for help. what do you need help with?
    also, note that nobody ever said you were lying about anything, but i do think you are overlooking or misinterpreting something.
    never can watts out be more than watts in let alone equal due to losses and efficiency factors.

    do you know the exact draw of the tv by any chance as i estimated the draw based on my 20in tv and they should be similar? i get roughly 45-55w if i remember rightly and an inverter will have conversion losses added to the tv draw so my estimate may be low.
  • homerramirezhomerramirez Solar Expert Posts: 102 ✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    Ha!!!!, this already happen to me with my 1300w of pv and 400ah agms, I thought I had enough to run my fridge and tv's, when the batteries were new it seems to handle it well, after a while will catch up with you, Math, Math, will work as 1+1=2......keep up your hope , in a way we all keep our hopes up, eventually we get more realistic.

    good luck ;)

    hasta la vista.
  • tvtechtvtech Registered Users Posts: 9
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    Ok, I found my watt meter that i plug into the inverter and then any a/c appliance i want to into it and it gives me the voltage/amps being pulled and watts being pulled.

    With the b4 mentioned tv im running is showing its pulling 28-31 watts depending on the brightness of the scenes, of course the brighter the scens the more wattage it pulls, really needless to say as it only bouces around 3 watts up from a pretty steady 28 watts.
    So again, back to those saying its impossible for me to run this tv from 11am in the morn till around 4pm in the eve where i shut it all down and then watch the batteries goto full charge w/in 90 minutes, well its still doing it and so far the live voltage i watch during this tv watching time of the batteries never drops below 12.3 volts as the pv,s again as i said are supplying the majority of the power needed.

    Now in my orig post here in this thread I asked about the 4 batteries im using and the story on them and still no one has given me any info that i requested about them and if they are good batteries for this application, are they good batteries at all etc:confused:

    AGAIN- here is the specs and info on the batteries

    Here is the batteries for spec info
    http://batteriesasap.com/417.html

    Specs
    Volt 12
    Amps 134
    Length 13.57
    Width 6.76
    Height 10.93
    Terminals TI
    Weight (100)
    Manufacturer C&D
    Model # UPS12-490MR Replaces UPS12-475FR C&D 12 Volt 134AH Battery
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    armed with that info i do see it as possible to do and i apologize for any of my wrong assumptions. that is a low draw for a tv and you will do well to use it until you can no longer as the newer flat screens will tend to draw a bit more than that.

    as to the c&d batteries, they are good batteries that probably came from telecom use. they are agm type. used, as with any battery, is a chance one takes. agms do have less self discharge, but depending on how long they have been out of service could have some negative effects on battery life.
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    Welcome back!

    Sorry, I have no real opinion on the batteries (they seem like decent AGMs to me)...but, two things to note from the page you linked to:

    "Battery Reminder: The average life expectancy of most standby batteries is between 3-5 years."

    and

    "Batteries may still read the proper voltage with a volt meter when under charge or off charge even when they are bad. To properly test a battery it should be done with either a load on it or by using battery-testing equipment."


    I noticed that most of your statements refer to voltage, so maybe you'll get a more accurate estimation of the batteries' true status from a full load test.
  • tvtechtvtech Registered Users Posts: 9
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR
    dwh wrote: »
    Welcome back!

    Sorry, I have no real opinion on the batteries (they seem like decent AGMs to me)...but, two things to note from the page you linked to:

    "Battery Reminder: The average life expectancy of most standby batteries is between 3-5 years."

    and

    "Batteries may still read the proper voltage with a volt meter when under charge or off charge even when they are bad. To properly test a battery it should be done with either a load on it or by using battery-testing equipment."


    I noticed that most of your statements refer to voltage, so maybe you'll get a more accurate estimation of the batteries' true status from a full load test.

    Thanks, i have a brand new heavy load tester that i used on each battery and actually kept it on almost double the time it says to be sure and on each one the batteries didnt budge on the power ond the tester was literally smoking red hot lol
  • tvtechtvtech Registered Users Posts: 9
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    oK, now another question, how far down can i pull these batteries down to and be safe?

    According to this chart http://www.windsun.com/Batteries/Battery_FAQ.htm
    it goes into the yellow meaning caution i guess at 11.9 volts or 40%

    Is that the cutoff point?
    Or should i not even pull them down that far?
  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    For flooded cell batteries... If they are stored below ~75% State of Charge (down 25%)--they start sulfate hardening--which reduces capacity. Sulfates begin to harden within hours or a day.

    If the battery is drawn below ~50% regularly, its overall life begins to be shortened significantly... Add to the fact you don't want to sit for days or weeks below 75% state of charge--ends up being a place you do not like to take/leave your battery.

    Drawing a flooded cell down to 20% or below, you run the risk of killing the battery outright. One of the failure modes is that battery cells are not always perfectly balanced (each series cell having the exact same capacity). When you draw a battery down deeply (below 10.5 volts or so for a 12 volt battery), you can actually have a weak cell that is drawn to 0% state of charge, and actually begin to be "reversed" charged by the other good cells. Becomes more of a possibility on higher voltage banks (like 48 volt banks). You have so many cells in series--that it is not as obvious when 1 out of 24 cells is "dead" (48 volt nominal becomes 46 volts nominal--everything still works---6 volt battery becomes 4 volt battery--and nothing works).

    And, as you discharge a battery, its electrolyte gets weaker--and its freezing temperature rises to near 32F (dead battery). Keeping batteries near fully charged in cold climates greatly drops the freezing temperature of the electrolyte. For example, a 40% state of charge battery will freeze around -16F.

    Some vendors say that their AGM stye batteries can operate to lower states of charge (20% SOC) without excessive damage (although, the cycling life is still dramatically reduced). And AGM's, because there is air in the glass mat + electrolyte are much less suseptable to freezing damage (discharged battery in very cold climate--however, never charge or discharge a frozen battery--warm it up first).

    In the end, how deep you draw your batteries is your choice... To a degree, if you have 2x as many batteries, the bank will last 2x (or a little bit) longer (but at 2x the price of batteries--so there is not a lot of savings in having a hugely oversized bank).

    Also, while your flooded cell batteries will function if drawn below 50% state of charge (and if quickly recharged back to >75% SOC)--Remember that a battery loses capacity as they age. So, somebody that cycles a battery 100% to 40% SOC -- will have to replace the battery when its capacity falls to 60% of new.

    Somebody who cycles a battery 100%-80% SOC -- they will still have a good working battery bank if the capacity is down to below 50% of new capacity (from aging).

    In the end, what kills most batteries is; undercharging (also called deficit charging)--simply more loads than available charging current to bring the battery reliably back above 90% state of charge. Overcharging (more of an issue with AGM's which lose their electrolyte if venting from over pressure/temperature). And not keeping the plates covered with pure distilled water. And leaving batteries sit for months (and longer) without recharging--batteries sulfate and will not properly recharge.

    Other things that keep batteries happy. Keep them at "room temperature" (ideal is around 70-80F). Hot batteries age quicker, cold batteries have lower effective capacity. And keep the tops clean and don't let debris fall into the cells.

    Lastly, if you have an expensive bank, AGMs, or just like to instrument your system--look at installing a Battery Monitor--It will probably "save your battery bank" one day. The meter gives you a simple XX% state of charge reading (plus a whole bunch of other data) at all times. So that others (who did not pay for the bank) can understand your rules (i.e., turn off the loads and/or start the genset if battery is at 50% capacity or less on the meter) without having to pull out a hydrometer (not possible with sealed/AGM batteries) or having to wait 3-4 hours of battery no charge / no load to get an accurate resting voltage.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: HI all, IM NEW TO SOLAR AND THIS IS WHAT I HAVE SO FAR

    Here's an interesting article about batteries. Worth a read:

    http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/evs_17paper.pdf
Sign In or Register to comment.