Where Do You Have Your Battery Bank Located & Why?

solartechtown.comsolartechtown.com Solar Expert Posts: 29
Hi guys/ladies,

I'm just curious to know where most of you solar power system owners have your batteries located and what's the temperature in that area/space?

Currently I have 1 (deep cycle battery) located in my shed which can become a bit hot in the summer time, but I'd think that would be okay considering most car batteries stay in your car during extreme heat temps?
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Comments

  • halfcrazyhalfcrazy Solar Expert Posts: 718 ✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    Mine are in my heated garage right under all my solar gear. They now live inside a nice vented box. This picture was early in the moving stages there is a few more parts and pieces on the wall now. They used to live in my house in the mudroom closet along with the inverters etc.
    196.jpg 240.8K
  • solartechtown.comsolartechtown.com Solar Expert Posts: 29
    Re: Where Do You Have Your Battery Bank Located & Why?
    halfcrazy wrote: »
    Mine are in my heated garage right under all my solar gear. They now live inside a nice vented box. This picture was early in the moving stages there is a few more parts and pieces on the wall now. They used to live in my house in the mudroom closet along with the inverters etc.

    Okay great, so what would you say the average temp is in your garage around the summer time, or right around this time of the year?

    For your ventilation, is it setup where a fan is sucking the hot air out of the box, or is it just a hole in the box with a tube connected to it to outside the garage?
  • halfcrazyhalfcrazy Solar Expert Posts: 718 ✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    My garage runs about 55F in the winter and can get up to 85 this time of year. My battery box gets its fresh air from the garage and is exhausting outdoors with the aid of a zephyr fan.
  • BajaGringoBajaGringo Solar Expert Posts: 40 ✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    When we built our place down here I designed the house with a room dedicated to keep my batteries and control / monitoring gear. I am now enclosing the batteries in their own box with plexiglas doors and zephyr vent fans. The winter time temps in there range from around 60 to 68 degrees and about 70 to 76 in summer.
  • BB.BB. Super Moderators, Administrators Posts: 28,167 admin
    Re: Where Do You Have Your Battery Bank Located & Why?

    ~70-80F is the design temperature for your battery bank...

    Other than cold batteries don't supply the AH that warm ones will... The rule of thumb for battery aging life is for every 10C (18F) increase in temperature, your battery life will be cut by 1/2.

    Can conversely, every 10C/18F drop in temperature, your battery life will double (within reason).

    If your charge controller supports a Remote Battery Temperature Sensor--it would be a nice option have.... Frequently solar charge controller over estimate the temperature of a battery bank and set the charging voltage too low---slowing the rate of charge and giving you less than a full charge.

    In the case with very hot batteries (say they have been heavily used that day)--Battery charging voltage drops has temperature increases--so you could have too high of charging voltage with the charge controller and get "thermal run-a-way" (I am not sure that has ever happened with a solar charge controller--but it could in theory).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • solartechtown.comsolartechtown.com Solar Expert Posts: 29
    Re: Where Do You Have Your Battery Bank Located & Why?
    BB. wrote: »
    ~70-80F is the design temperature for your battery bank...

    Other than cold batteries don't supply the AH that warm ones will... The rule of thumb for battery aging life is for every 10C (18F) increase in temperature, your battery life will be cut by 1/2.

    Can conversely, every 10C/18F drop in temperature, your battery life will double (within reason).

    If your charge controller supports a Remote Battery Temperature Sensor--it would be a nice option have.... Frequently solar charge controller over estimate the temperature of a battery bank and set the charging voltage too low---slowing the rate of charge and giving you less than a full charge.

    In the case with very hot batteries (say they have been heavily used that day)--Battery charging voltage drops has temperature increases--so you could have too high of charging voltage with the charge controller and get "thermal run-a-way" (I am not sure that has ever happened with a solar charge controller--but it could in theory).

    -Bill

    So what would you recommend to individuals who do not have a garage or a area that is always 70-80F that they can store their battery/batteries?

    In other words, what could be an affordable alternative, even though the alternative may result in some loss of battery life?
  • BajaGringoBajaGringo Solar Expert Posts: 40 ✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    I think the investment one makes in their batteries warrants spending a little money on building some kind of insulated / protected enclosure. It doesn't have to be fancy or expensive to be effective...
  • solartechtown.comsolartechtown.com Solar Expert Posts: 29
    Re: Where Do You Have Your Battery Bank Located & Why?
    BajaGringo wrote: »
    I think the investment one makes in their batteries warrants spending a little money on building some kind of insulated / protected enclosure. It doesn't have to be fancy or expensive to be effective...

    Exactly, so that's why I'm hoping someone here can suggest alternatives for those who may not have a garage or a place in their home where they can store the battery bank.

    The problem you face when the batteries are in an outside area such as a shed or container is temperature issues, and trying to maintain a certain temperature in that area. To maintain 70-80F you are going to need a heater/cooler(air conditioner) to keep it at such a temp right? And that would just increase your total investment. Surely I'm missing something here, so feel free to fill me in on what you'd do and how you would go about it. :D
  • BB.BB. Super Moderators, Administrators Posts: 28,167 admin
    Re: Where Do You Have Your Battery Bank Located & Why?

    If the battery is on a cold concrete floor--it probably is not getting that warm unless this is sitting in sunlight/against a hot wall (just a guess--my system is grid tied AC and I don't have a battery bank).

    You can probably find something less expensive--but how about something like a Min/Max thermometer with a remote probe that you can "tape" to your battery and measure its actual temperature.

    You don't want the battery running at 100F 24 hours a day for weeks/months at a time.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 28,167 admin
    Re: Where Do You Have Your Battery Bank Located & Why?

    I guess I should add--it depends on the conditions in your building and how much energy you are pumping through the battery...

    For example, in areas where it goes sub-zero--some sort of insulated container (made out of foam, etc.) will keep the batteries at good operating temperature from daily use (so I have read). If your bank has been sitting in very cold temperatures for a few months (fully charged batteries take extremely cold temperatures to freeze/damage) you may need to use a battery heater and generator to get the bank up to above freezing (for good operation). But once the bank is "warm" and operating in an insulated space--you probably do not need to use the heater again.

    For hot areas, the bank maybe best setup in the ground/basement to keep temperatures cool/more uniform.

    Battery ventilation is typically to keep hydrogen gas down (and remove acid mist during charging of flooded cell batteries) and less out about cooling.

    Specific solutions depend on your needs--from what I can tell... Monitoring the temperature of your existing battery may give you a better idea of how much of a problem you really have (or not).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BajaGringoBajaGringo Solar Expert Posts: 40 ✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?
    Surely I'm missing something here, so feel free to fill me in on what you'd do and how you would go about it. :D

    For starters, give us an idea what part of the planet you call home and what your average min/max temps are for winter and summer. Then we can help you come up with some reasonable options...
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    let's try this another way. where were you planning to put your batteries?

    as to mine i keep it in the house as batteries like temps that people like, but i'm not average as i like it a bit colder. bb gave a good recommendation that you get and use a battery temperature sensor to help track the voltage with temperature changes.
    also of note, you should keep the voltage drop to a minimum between the controller and the batteries (unless the controller has the ability to remotely read the battery's true voltage) as this can drastically affect the charge. for instance say you need 14.4v to go to absorb and you have a .4v voltage drop due to the wires. .4v/12v=3.3% just for your information. this creates a net result of 14v at the batteries when the controller thinks it reached the point to leave bulk for absorb. this creates a problem in that the battery will not reach its full charge. it may be a good idea to keep this under a 1% v drop percentage and the farther under 1% the better. this also means that it is probably best to have the controller near the batteries so that lower v drops will be encountered and so the needed wire gauges won't get out of hand.
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    Battery banks and solar mechanicals (4 inverters and 2 CCs) are located in a stone contruction 12x12 metal roofed building sitting about 40 feet from the house and 100 feet from the array. Genny sits on a pad next to solar mechanical building.

    All building wiring in metal conduit.

    Temperature range remains fairly consistent (summer 80< and winter 45> degrees)
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • KamalaKamala Solar Expert Posts: 452
    Re: Where Do You Have Your Battery Bank Located & Why?
    BB. wrote: »
    ... If your bank has been sitting in very cold temperatures for a few months (fully charged batteries take extremely cold temperatures to freeze/damage) you may need to use a battery heater and generator to get the bank up to above freezing (for good operation). But once the bank is "warm" and operating in an insulated space--you probably do not need to use the heater again.
    -Bill

    Uhh... Tony should weigh in on this, As I understand, any lead acid battery, at full charge can withstand all but polar conditions before being damaged. That is, -40 degrees F. However, the Ah capacity of the battery will be reduced.

    k
  • solartechtown.comsolartechtown.com Solar Expert Posts: 29
    Re: Where Do You Have Your Battery Bank Located & Why?
    BajaGringo wrote: »
    For starters, give us an idea what part of the planet you call home and what your average min/max temps are for winter and summer. Then we can help you come up with some reasonable options...
    niel wrote: »
    let's try this another way. where were you planning to put your batteries?

    My location is in TN, and the average temperatures are the following:
    July
    Average High 89
    Average Low 68

    December
    Average High 49
    Average Low 32

    Source: http://nashville.about.com/od/nashvilleweather/a/nashavgtemp.htm

    I planned on placing them in an outside shed, similar to this:
    Brandon.jpg

    The shed has no AC/Heating System, but the shed is lifted off the ground about 8" or 10". So what possible solutions could I give a try? :roll: :D

    Thanks!
  • BB.BB. Super Moderators, Administrators Posts: 28,167 admin
    Re: Where Do You Have Your Battery Bank Located & Why?

    My wording was in-artful... I was trying to say that fully charged batteries can go way below zero F... But they should be heated above freezing to increase capacity and because discharged batteries will freeze at "warmer" temperatures (a fully discharge lead acid battery will freeze near 32F...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    i would say for you to have an insulated box type arrangement up off of the floor as the cold floor will pull the heat from the batteries. this does not and should not be a tight configuration as you should give room to the battery walls and the insulation (sheet form is better) and give even more room on the top and no foil facing to have an accidental short on. the bottom can be made of wood as wood does insulate to a small degree too. if diy is a problem you can buy battery boxes, but this really isn't that complicated or critical. remember that batteries when charged or used will expend a small amount of heat and a modest amount of insulation will help keep the batteries cozy enough to function fairly well in winter. during summer you can open the top to cool them. i should also mention that there is a good possibility that some hydrogen gas could accumulate in the box seeing as how it is a confined area. you won't have a large battery bank to worry about lots of gas building up that a few holes in the top of the battery box couldn't take care of, but always think there could be a possible concentration and act accordingly.
  • BajaGringoBajaGringo Solar Expert Posts: 40 ✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?
    My location is in TN, and the average temperatures are the following:
    July
    Average High 89
    Average Low 68

    December
    Average High 49
    Average Low 32

    Source: http://nashville.about.com/od/nashvilleweather/a/nashavgtemp.htm

    I planned on placing them in an outside shed, similar to this:
    Brandon.jpg

    The shed has no AC/Heating System, but the shed is lifted off the ground about 8" or 10". So what possible solutions could I give a try? :roll: :D

    Thanks!

    I really like that kind of shed as it is quite easy to insulate the walls and roof / ceiling. I have some friends with a similar problem in Southern Baja where daytime high temps often reach > 105. I know of one who used a shed quite similar to the one you posted and with insulation is now able to keep the interior temps in the low 80's with the help of a solar attic fan he installed on the roof.

    It sounds like your summer temps are milder and such a solution should yield you even better results...
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    I'll be putting mine underground. Main reason was to silence the generator noise, but keeping batteries warm in winter and cool in our hot summer is a benefit too.
  • icarusicarus Solar Expert Posts: 5,108 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    Heat is the enemy of batteries. Keep them cool, don't worry about being too cold, unless you really need 100% of the available capacity when it is very cold. Remember, battery capacity goes down with temperature, but battery life increases with cold, and vise versa.

    Given a choice between keeping batteries @75f or 20f I would keep that at 20f any day of the week. If you actually need the capacity, increase the battery size a bit to account for the drop in capacity.

    I have a set of batteries that sit in an un-heated, un-insulated shed year round, (in light service these days) and they sit at -40 for most of the winter. When I pull the switch and turn them on, they are fully charged, and work fine.

    My "real" set sit in an insulated box under a bench, and they can get very cold when I leave for a bit in the winter, but they never get very warm in the summer, even though the OAT might be in the 80's.

    Keeping them stable is probably the best advice.

    Tony

    PS, a full charged battery won't freeze until way past -40. Even 50% charged will take -10f with out freezing. Also, remember, charging and discharging will produce some heat in the battery which will also prevent freezing. I have found that my batteries (in the un-heated shed) will run ~15F above ambient on average during the winter if I am using them a bit.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    tony,
    OAT? is that your new nickname for outside air temperature?:p

    solartechtown.com,
    what tony says is pretty much true, but i am assuming you don't want the capacity to suffer too much and, like i said, this need not be elaborate or complicated for your system. for tennessee it may be sufficient to put them on top of wood and put a cardboard box or even an old blanket over them with a hole for the wires. it still should be elevated on top a bit so as to let the battery breath some and not to absorb much of the minute amounts of battery acid that may leak into the air there along with the gases. keep in mind those items are flammable and i make those suggestions more for illustrative purposes as an accidental short could spark a fire on cardboard or a blanket being they would be near the wires and posts.
  • icarusicarus Solar Expert Posts: 5,108 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    OAT= Outside Air Temperature.

    http://www.batteryfaq.org gives an idea of capacity drop with temperature. A battery really has to get quite cold (0f) before the capacity drops off too much. Even at 0F a FLA will have ~80% capacity.

    http://www.windsun.com/pictures/Batt_temperature1.gif

    Very few people who live in the lower 48 (and have batteries in some kind of enclosure) will ever have capacity issues due to deep cold, Northern MN or mountain environments excepted).

    It is also important to remember that batteries have considerable thermal mass, and will heat up and cool down very slowly. Even if you have overnight temps at 0F, the batteries will take a long time to get to that temperature, and in point of fact few areas get that cold for long enough sustained to get batteries that cold. (assuming they are in a shed or box).

    T
  • solartechtown.comsolartechtown.com Solar Expert Posts: 29
    Re: Where Do You Have Your Battery Bank Located & Why?
    icarus wrote: »
    Heat is the enemy of batteries. Keep them cool, don't worry about being too cold, unless you really need 100% of the available capacity when it is very cold. Remember, battery capacity goes down with temperature, but battery life increases with cold, and vise versa.

    Okay, so would this idea work then:

    On the side of my shed is a path that is shaded year round. There is plenty of room to place a small up-right container against the side of the shed and still have enough walking room to get to the back of the shed if I ever needed to.

    Is it possible to just place the battery/s in the container and leave them, or even better, buy some insulation from Lowes or something and place it on the inside doors/container walls?

    This way the battery/s will get plenty of ventilation, and since the container will never be in direct sunlight year round, I wouldn't have to worry about high temperature issues..
  • dmillerdmiller Solar Expert Posts: 68 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    Perhaps in some situations the vent fan should run for a couple hours at the coolest part of the night to reduce battery temps in summer. Or some form of passive cooling. Battery spacing must affect average cell temp.
    So many good reason for using 2v cells.
    My 12v mobile design has 1" gaps for airflow and possible warm water heat for extreme cold.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    solartechtown,
    i think you may be misunderstanding me here a bit. that battery box will be in the shed with the batteries and not placed outside and separate. that shed will give some protection from the elements all by itself, but the cold will be unimpeded from them sitting on the floor without something semi-insulative. the rest is not very critical either and you may try it without the box arrangement to cover the batteries as it is not hard to throw something over them temporarily if it gets too cold or you see too much capacity degradation.
  • solartechtown.comsolartechtown.com Solar Expert Posts: 29
    Re: Where Do You Have Your Battery Bank Located & Why?
    niel wrote: »
    solartechtown,
    i think you may be misunderstanding me here a bit. that battery box will be in the shed with the batteries and not placed outside and separate. that shed will give some protection from the elements all by itself, but the cold will be unimpeded from them sitting on the floor without something semi-insulative. the rest is not very critical either and you may try it without the box arrangement to cover the batteries as it is not hard to throw something over them temporarily if it gets too cold or you see too much capacity degradation.

    Well the reason that I suggested placing it outside is because, it's surely hotter in my shed than it is outside. My shed, and maybe many other sheds, are similar to a car in the summer time. If you have limited areas where hot air can escape, the internal area of that object (for ex. my shed or a car) becomes hotter and hotter, thus why you should never leave a dog/child/person in a car with the windows up or even with the windows cracked :D Of course it's not as hot as if you had the batteries laying in the middle of the yard where direct sunlight could hit them, but in a shaded area, it's going to be 10% (may be wrong on that percentage :) ) cooler than in a place with limited ventilation?

    So my point of that is, since my shed usually has a warmer temperature than the outside enviroment, and since icarus stated that "heat is the enemy", I thought it would make sense to place the battery/s in a container in an area that receives little to no direct sunlight year around, and a place right next to the shed so there would not be a huge distance from my charge controller to the battery.

    But yeah, that's kind of what I got from icarus's statement and thought that may be possible solution if his statment is accurate..:roll::p
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    the shed will shade them and it will be equal to the ambient air around it in the shed plus some from operations or charging.
  • solartechtown.comsolartechtown.com Solar Expert Posts: 29
    Re: Where Do You Have Your Battery Bank Located & Why?
    niel wrote: »
    the shed will shade them and it will be equal to the ambient air around it in the shed plus some from operations or charging.

    Alrighty, sounds good, I'll give the advice given in this thread a try :)

    Thanks guys!
  • VicVic Solar Expert Posts: 2,934 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    Am a bit late to this thread ... But,

    My power room is 225 feet from the residence. The power room is a Cargo container, cut down to 10-foot length. There is a roof over the container (with Solar panels), and its walls/roof are insulated at R-13. The batteries are in an insulated (R-13 but lightly ventilated) plywood box, with hinged lid.

    In the summer, this power room gets a bit warm in the day -- in the mid 80's F, and as one would expect, it is slow to cool. It just integrates the the thermal inputs, and outputs, but very slowly. The battery electrolyte temps would rise into the 80's F, which I felt were too high.

    SSOOOo, two years ago, added a small window A/C unit to the power room -- 6000 Btu. Works well during the day, but when I am not around to open the power room in the evening to let the lower night temps cool the room, the battery temps rise into the low to mid 80's after 5 or so summer days, AND setting the A/C to a lower temperature, causes it to run into the night more than I would like (am paranoid).

    The bottom line is: If you can possibly couple the battery structure to the earth, DO IT. As discussed perviously on this Forum, a Root Cellar, or a Bermed room approach would be ideal. This minimizes the temperature variations, and requires the lowest energy input to moderate temperature excursions.

    If one cannot use the cellar or bermed approach, then allowing night ventilation should help, even in desert climates. Day-time cooling would be a plus if power is available.

    Insulated battery rooms and boxes are fine, but, in reality, the thermal mass of the batteries just integrate the temperature inputs over a period of time. Using only insulation simply delays the inevitable. I need to open the cover of the battery box at night, and open the 4X8 foot door on the power room to help cool the batteries (and at times, run a box fan at the open door). The 2-Ton bank will drop 3-4 degrees in one night, with this approach, if the temp differential is 12-15 degrees F, or so.

    Will probably add some night-time forced air ventilation to the day A/C for this site. A swamp cooler might do OK in this climate, as it could supply ventilation at night and cooling in the day, but the humidity increase might not be good for the hardware. One could shut off the water pump at night to return the humidity to (near) outdoor levels ... and so on.

    BTW, have used a Radio Shack Indoor/Outdoor thermometer (about $20.) to monitor the inside temps, and did tape the outdoor sensor to the battery case for an approximate view of temps. It does have Hi/Lo temp memory for both In/Outdoor reeadings. Have gone on too long. Interesting experiments, tho, 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.
  • mike95490mike95490 Solar Expert Posts: 8,025 ✭✭✭✭
    Re: Where Do You Have Your Battery Bank Located & Why?

    My battery bank is in a small shed, on a concrete slab near my pole mount array. Some say I should lift the batteries off the concrete, some say it's ok. Batteries are in a corner, in a box, near the CC and Inverter. No good interior photos yet, but shed has been fairly cool in the summer, eves at both sides vented, and seldom gets above ambient. Summer battery temps are around 75F, I expect them to fall to the 40s in winter.
    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

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