UPS / Solar charging the same battery?

ILFE
ILFE Solar Expert Posts: 364 ✭✭
Living here in Cambodia, as well as in most other SE Asian countries, we get to experience fairly regular power cuts. Unlike in the west, where we are on the phone to the local power company at the moment the lights blink, here, they simply carry on until the power returns from the mains, no matter how long that may be. Major cultural differences.

Anyway, I finally found a place to live that experiences fewer power cuts than other areas of the city. Usually, about once per week, we have an hour, maybe two or three, and usually during the day, of no power. Most of the time, it is just long enough to discharge the UPS enough to cause the computer to shut down.

I figure if I had a bit longer run time, maybe three times the amp hours, I could carry on working online like no body's business. Not to mention, I could still run a fan, a MUCH needed appliance in the heat of the day, along with my monitors, external hard drives, sound system, computer, and other hardware.

To get to my point, I am considering adding an external battery to my UPS, to provide it with that longer run time. But, I would like to add a single panel and PWM controller to this battery, in order to provide additional charging. (The internal battery is still working properly, but I would probably remove it from the UPS.) My question is, does - or should a UPS behave electrically, in a way that I can add a single panel to it, to assist the UPS charging circuit? Would they work together to charge the battery?

Or, as soon as the earth rotates into the sun's rays in the morning, would I see nothing but smoke pouring out of my UPS? We all know how difficult it is to put that smoke back in the box. I really don't want to do that.
Paul

Comments

  • drraptor
    drraptor Solar Expert Posts: 218 ✭✭
    Re: UPS / Solar charging the same battery?
    ILFE wrote: »
    Living here in Cambodia, as well as in most other SE Asian countries, we get to experience fairly regular power cuts. Unlike in the west, where we are on the phone to the local power company at the moment the lights blink, here, they simply carry on until the power returns from the mains, no matter how long that may be. Major cultural differences.

    Anyway, I finally found a place to live that experiences fewer power cuts than other areas of the city. Usually, about once per week, we have an hour, maybe two or three, and usually during the day, of no power. Most of the time, it is just long enough to discharge the UPS enough to cause the computer to shut down.

    I figure if I had a bit longer run time, maybe three times the amp hours, I could carry on working online like no body's business. Not to mention, I could still run a fan, a MUCH needed appliance in the heat of the day, along with my monitors, external hard drives, sound system, computer, and other hardware.

    To get to my point, I am considering adding an external battery to my UPS, to provide it with that longer run time. But, I would like to add a single panel and PWM controller to this battery, in order to provide additional charging. (The internal battery is still working properly, but I would probably remove it from the UPS.) My question is, does - or should a UPS behave electrically, in a way that I can add a single panel to it, to assist the UPS charging circuit? Would they work together to charge the battery?

    Or, as soon as the earth rotates into the sun's rays in the morning, would I see nothing but smoke pouring out of my UPS? We all know how difficult it is to put that smoke back in the box. I really don't want to do that.

    What you have described is know as "Poor Man's Solar System" in Pakistan. Many People have done that successfully. System range from a single 150W panels to as large as 1500W of Solar Panels. Just make sure, the PWM charger current rating > charging current of your UPS.
    Internal Battery is usually removed and UPS is modified for charging the larger external battery.

    During the day when electricity is available both Solar Panels and UPS charges the same battery.
    During a Power failure, Solar Panels provide maximum output ,depending on the Insolation.
    Auxiliary Generators: Engine generators and other sources of power may be connected directly to the battery for charging. It is not necessary to disconnect the
    ProStar from the battery. However, do not use the ProStar to regulate these other
    sources of powe
    http://www.morningstarcorp.com/wp-content/uploads/2014/02/PS2.IOM_.English.EN_.021.pdf

    In this case Charge controller will see the UPS as Auxiliary source.

    if my memory serves me right, Kirchhoff's current law is applicable here ?

    Which brand of UPS you are using ?
  • ILFE
    ILFE Solar Expert Posts: 364 ✭✭
    Re: UPS / Solar charging the same battery?
    drraptor wrote: »
    Which brand of UPS you are using ?

    For the record, the charger controller would be a MorningStar Sunlight 10L-12v
    The UPS is one bought here in Cambodia. It is a Power Tree S650BX (UK model according to the box?)
    I have had it for over a year. So far, it has always performed fine. Something that isn't a common thing to occur here.


    According to the specs on the site and the box it came in, the charger is rated at 2.5 amperes and has a 9AH sealed battery inside. (I have never opened it.) So, my 130 watts panel, my 120AH solar battery and the 10 ampere rated Sunlight controller should do the trick?
    Paul
  • drraptor
    drraptor Solar Expert Posts: 218 ✭✭
    Re: UPS / Solar charging the same battery?

    What are spec for the 130W panel ?

    To charge a 120AH battery you will need ~12Amp of charging current. UPS is only capable of charging at 2.5amps.
  • ILFE
    ILFE Solar Expert Posts: 364 ✭✭
    Re: UPS / Solar charging the same battery?
    drraptor wrote: »
    What are spec for the 130W panel ?

    To charge a 120AH battery you will need ~12Amp of charging current. UPS is only capable of charging at 2.5amps.

    Attachment not found.

    It won't be quite there, I reckon. But, I am in the process of buying the metal to build a pole mount here. It will be built to carry two of these panels. I bought the only panel the shop had. As soon as another one comes in, I will be buying it to add to the pole. If I can go that route, I will change the controller as well, to a 20ampere unit.
    Paul
  • drraptor
    drraptor Solar Expert Posts: 218 ✭✭
    Re: UPS / Solar charging the same battery?

    the maximum current this panel will be able to supply will be 7.71amp with a PWM controller. You can buy a small Mppt charger e.g Ep-Solar Tracer-2210RN or Tracer-2215RN to increase the output.
  • ILFE
    ILFE Solar Expert Posts: 364 ✭✭
    Re: UPS / Solar charging the same battery?
    drraptor wrote: »
    the maximum current this panel will be able to supply will be 7.71amp with a PWM controller. You can buy a small Mppt charger e.g Ep-Solar Tracer-2210RN or Tracer-2215RN to increase the output.

    Well, unfortunately, here in Cambodia, it is a job trying to find a decent MPPT controller. I had to wait (not because of the company or shipping) ... heck, almost six months. for my Midnite Kid. I assure you, NO ONE in Cambodia has one but me. Trying to find a Tracer will be like pulling hen's teeth.

    Besides, with the PWM controller, that panel, along with the 2.5 amperes (maybe?) the UPS provides, it should be enough until I get get my other panel purchased. (God only knows when it will arrive at the shop.)

    Ahhhhhh, the fun times living in Asia.
    Paul
  • LandKurt
    LandKurt Solar Expert Posts: 41
    Re: UPS / Solar charging the same battery?

    I believe the 2.5A figure is the UPS inverter output at 220 V AC, about 550 VA. The specs quote a "restore energy time" of 8 hours for a 8.2 AH battery. That implies the UPS charges the battery at about 1 A, which is a good rate for that size battery.

    Would dumping 7.7 A from the panel to charge the battery once the power is back on fry the internal battery if it isn't upgraded to something larger? What's the highest charge rate you can safely use on a sealed battery?

    If it was close to fully charged the voltage would go up and the charge controller would cut back on the amperage to keep the voltage at 14.4 or so. But if the battery was deeply discharged would it accept more amperage that would be healthy without the voltage climbing about 14.4 volts?

    This forum frequently stresses the importance of matching the charge rate to the battery capacity and recommends a charge rate of 5 to 13% to keep lead acid batteries healthy. What are the upper limits on charge rate if it isn't a daily occurrence? I've recently been wondering about a system meant to run while the sun is shining with minimal batteries to buffer between the panels and inverter. But if the inverter was off and the panels dumped a lot of current straight into a small set of batteries I'm guessing things could go badly.
  • ILFE
    ILFE Solar Expert Posts: 364 ✭✭
    Re: UPS / Solar charging the same battery?
    LandKurt wrote: »
    Would dumping 7.7 A from the panel to charge the battery once the power is back on fry the internal battery if it isn't upgraded to something larger? What's the highest charge rate you can safely use on a sealed battery?

    If I go through with this, and it is looking like I will, I will remove the internal battery completely. So, the only thing the UPS will have to dump its charge rate into, will be the external battery attached it.

    I imagine the highest charge rate for a sealed battery would be about 10% to 15%? One of the experts here may come by and correct this if it is wrong, though.
    Paul
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: UPS / Solar charging the same battery?
    ILFE wrote: »
    If I go through with this, and it is looking like I will, I will remove the internal battery completely. So, the only thing the UPS will have to dump its charge rate into, will be the external battery attached it.

    I imagine the highest charge rate for a sealed battery would be about 10% to 15%? One of the experts here may come by and correct this if it is wrong, though.

    The highest rate for a GEL sealed battery will be C/20 or 5%.
    An FLA battery can take C/6 or higher as long as you monitor temperature and watch for gassing voltage.
    An AGM battery (with very low internal resistance) can typically take Bulk current at C/4 with no problem and can often accept C or even higher IF you monitor temperature and voltage to make sure that the battery will not go into thermal runaway or vent.
    SMA SB 3000, old BP panels.
  • drraptor
    drraptor Solar Expert Posts: 218 ✭✭
    Re: UPS / Solar charging the same battery?
    inetdog wrote: »
    The highest rate for a GEL sealed battery will be C/20 or 5%.
    An FLA battery can take C/6 or higher as long as you monitor temperature and watch for gassing voltage.
    An AGM battery (with very low internal resistance) can typically take Bulk current at C/4 with no problem and can often accept C or even higher IF you monitor temperature and voltage to make sure that the battery will not go into thermal runaway or vent.
    For FLA it will ~5-16% ?
    For AGM (with very low internal resistance) 25% ?
  • ILFE
    ILFE Solar Expert Posts: 364 ✭✭
    Re: UPS / Solar charging the same battery?

    At the moment, due to the time of the year here - rainy season, I am noticing about 75 watts into the battery. I don't sit in front of the controller. But, when I can I look to see how it is performing. I definitely need my other panel to come in, so I can wire them together. Rain is expected all week. So, at the moment, I imagine 75 to 80 watts will be about the best I will get, until the Sun shines through a break in the clouds.
    Paul
  • LandKurt
    LandKurt Solar Expert Posts: 41
    Re: UPS / Solar charging the same battery?

    Are you saying you are getting 75 watts of power out of a single 135 W panel with a PWM controller while it is cloudy? That doesn’t sound right.

    If you are getting 75 watt hours of energy for the entire day, then that would make sense.
  • ILFE
    ILFE Solar Expert Posts: 364 ✭✭
    Re: UPS / Solar charging the same battery?
    LandKurt wrote: »
    Are you saying you are getting 75 watts of power out of a single 135 W panel with a PWM controller while it is cloudy? That doesn’t sound right.

    If you are getting 75 watt hours of energy for the entire day, then that would make sense.

    No. I am saying the display for watts on the Kid controller went as high as 75 watts, during that day.

    Sorry about not clarifying that a bit more.
    Paul
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: UPS / Solar charging the same battery?

    several cautions here:

    1) UPS often have GEL batteries and not designed for many deep cycles, plan on upgrading the battery when existing fails

    2) Heat Often the internal heat sink can only handle the heat the factory battery will last for. Longer run time - you may need a fan to keep the inverter cool

    3) Added solar charge will likely stress the factory battery when the power restores.
    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 ,

  • ILFE
    ILFE Solar Expert Posts: 364 ✭✭
    Re: UPS / Solar charging the same battery?
    mike95490 wrote: »
    several cautions here:

    1) UPS often have GEL batteries and not designed for many deep cycles, plan on upgrading the battery when existing fails

    2) Heat Often the internal heat sink can only handle the heat the factory battery will last for. Longer run time - you may need a fan to keep the inverter cool

    3) Added solar charge will likely stress the factory battery when the power restores.

    Hi Mike,

    1. That's why I had planned, from day one, to remove the internal battery. I have another idea for it - to power a single axis tracker, maybe.

    2. Didn't think of that, thanks. But, I have a couple of extra computer case fans around here that would work fine - maybe overkill in fact.

    3. The only battery connected to the UPS is the external battery.
    Paul