Venting question from rookie - small system in cabin

GXB2000GXB2000 Registered Users Posts: 5 ✭✭
Hi everyone,

We are working on installing a very small system for a summer cabin. It will consist of a single deep cell marine battery and a few small solar panels. We will use it with an inverter to power 3 8watt LED bulbs for a few hours each night + charging cell phones.

The current plan is for the battery to go into a small closet area with no door that is open to the cabin (cabin is about 800 square feet). 

I've been reading a bit about venting and want to see if this is something we need to do.  

Part of the reason we are going to solar is because we don't like the idea of coleman lanterns in the cabin (safety + a pain), but now realizing there might be some issues with solar as well. 

Any information, suggestions, ideas are appreciated. 


 (i don't have full system specs at hand as I'm not leading the project). 
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Comments

  • BB.BB. Super Moderators Posts: 26,837 admin
    OK... Your loads are small, which make the system less expen$ive, and potentially le$$ things to go wrong (shorts, fires, theft, etc.).

    First, the 12 volt Marine battery is not (usually) a very good "deep cycle" battery. But it is relatively cheap and not bad to start to learn about your operating your system. If your battery lasts 1-2 years--you are doing good.

    Using 6 volt @ 200 AH "golf car" batteries is usually a good start (cheap, rugged batteries)--But even this "minimum" system is, probably, about 2x the 12 volt @ 110 AH (?) battery you have. Golf Cart batteries will typically last 3-5 years (lead acid batteries will last longer if in a cold environment).

    I always like to start with loads, then design the battery bank to support those loads. Then design the solar array (plus genset backup, if needed) to keep the battery bank happy.

    Since you typed about safety--Yes, you really need to uses fuses or circuit breakers to protect your wiring. Fuses/breakers are there to protect your wiring from overheating (overloads, short circuits) and not to "protect" the devices (i.e., a fuse/breaker will not keep your radio/lights/computer supply from failing).

    I have to go right now, but if you can tell us a bit more about the installation. Roughly, where it will be located (nearest major city) so we can figure out how much sun you will get. How much and when the cabin will be used (summer weekends, any winter usage, a couple weeks full time a year, or what)?

    Also, do you need just 12 VDC or will you want a small AC inverter to power laptop/cell phone chargers, run power any distance (12 volt systems can only send "usable" energy a few 10's of feet cost effectively. A 120 VAC system can send power 100's of feet very easily---I.e., outdoor lighting, etc.).

    See you in a bit.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GXB2000GXB2000 Registered Users Posts: 5 ✭✭
    Thanks Bill - getting the specs as we speak. 

    We are using a marine battery because we already have it. 

    Yes, we will be using an inverter to power the 3 8 watt LED lights. 

    We use the system only about 8 weeks per year, and it is located in southern Quebec. We will take the battery in for the winter and will charge it every month or two as needed.

    We have used the system before on a temporary basis and everything works, battery charges etc. This will be the first time we are "making it official" and installing things on a more permanent basis.

    Thanks!
  • SolraySolray Registered Users Posts: 246 ✭✭
    edited July 19 #4
    Actually lead acid batteries don't like being too cold. Freezing them damages them. They like being about 70° F
    For cell phone charging just put a couple cigarette lighter sockets hooked to the battery and plug in a USB adapter there, or get a 12v USB and just hook that into the battery. Either will work.
    I wouldn't want to mess with an inverter for your needs.

    For winter, just keep the battery connected to a maintainer, rather than hassle with remembering to charge it up all the time.

    For a lead acid battery you will want it in a box and vent it outdoors with some pvc. You don't want hydrogen gas inside with you.

    Have you considered some small battery powered stick up led lights? They will probably do all you need to do and you can charge the phones in the car.
    There are even small solar ones you can stick outside.
    https://www.amazon.com/gp/aw/d/B016O9EZA6/ref=mp_s_a_1_1?ie=UTF8&qid=1500493225&sr=8-1&pi=AC_SX236_SY340_FMwebp_QL65&keywords=led+stick+up+light&dpPl=1&dpID=41EnkH6WFOL&ref=plSrch
  • GXB2000GXB2000 Registered Users Posts: 5 ✭✭
    edited July 19 #5
    Thanks Solray. 

    We already charge our phones directly to a 12V as you outline above.  

    The  2 mantle Coleman lanterns we use throw a lot of light - nothing in the battery powered LED space that we've tried comes close. The 8 watt AC LED's (65W equivalent) throw a similar amount of light to the Colemans. 

    Re: putting the battery in a box outdoors - I take it you are saying even a very small setup like ours poses a risk of gassing? 
  • littleharbor2littleharbor2 Solar Expert Posts: 681 ✭✭✭✭
    For your small loads you should consider a small AGM battery. You don't have to deal with venting problems. They will vent if charged with too high of voltage. The solution, charge them at the proper voltage, simple. They have charging info on the battery case. Typically 14.4 volts in bulk/absorb.  Now you don't have to worry about having the battery indoors.

    BTW a fully charged battery will withstand some pretty extreme low temps without damage or threat of freezing. a fully charged Flooded lead acid battery can withstand temps down to -80 degrees F.
    http://usbattery.com/winter-storage-maintenance-tips-flooded-lead-acid-batteries/

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • SolraySolray Registered Users Posts: 246 ✭✭
    I never wanted a lot of bright light in a cabin personally, but you might be doing some surgery in there for all I know. I have an LED battery powered pole light for an outdoor umbrella that is extremely bright (24 or so leds, 12000 lux) so there are a lot of options in the battery powered arena that will give the same or similar illumination as your 8 watt lamp.


  • SolraySolray Registered Users Posts: 246 ✭✭
    GXB2000 said:
    Thanks Solray. 

    We already charge our phones directly to a 12V as you outline above.  

    The  2 mantle Coleman lanterns we use throw a lot of light - nothing in the battery powered LED space that we've tried comes close. The 8 watt AC LED's (65W equivalent) throw a similar amount of light to the Colemans. 

    Re: putting the battery in a box outdoors - I take it you are saying even a very small setup like ours poses a risk of gassing? 
    You can have the box indoors and vent it outdoors through a wall, you can use an RV wall vent made for venting an oven or furnace, it will have a screen inside that prevents critters from entering.
  • EstragonEstragon Registered Users Posts: 1,545 ✭✭✭✭
    > @GXB2000 said:
    > Thanks Solray. 
    >
    > We already charge our phones directly to a 12V as you outline above.  
    >
    > The  2 mantle Coleman lanterns we use throw a lot of light - nothing in the battery powered LED space that we've tried comes close. The 8 watt AC LED's (65W equivalent) throw a similar amount of light to the Colemans. 
    >
    > Re: putting the battery in a box outdoors - I take it you are saying even a very small setup like ours poses a risk of gassing? 

    You might find the LED lights are 12vdc fed by 120vac wall wart. I've found some (most?) work fine with the range of voltages involved in running direct off batteries (~11-16v).

    I personally wouldn't get too worked up about the battery in the closet thing. On my boat I have a 12v starting battery and 2x6v golf cart deep deep cycle in a box not much bigger than the batteries, under the transom steps in the main cabin with no outside venting. Ideally I'd use AGMs, to avoid the gassing issue, and also to eliminate the possibility of leakage when heeling or rough weather, but it's worked fine in the 8 years I've had the boat, and it's quite commonly done. I'd be a lot more concerned if I had my 12 L16s from my cabin system sitting 3 feet from the stove in the boat.

    One thing to watch for is when the battery gets older it may need to have distilled water added more frequently.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • VicVic Solar Expert Posts: 2,815 ✭✭✭✭
    Marc,   this has been my thinking exactly ...   had almost asked a moderator ...   Thanks!   Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 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.
  • GXB2000GXB2000 Registered Users Posts: 5 ✭✭
    uh oh, look what I started!

    Anyway...we use the full light for cooking and cleaning. Everything else gets the low light level.

    Our setup is very basic  - I think we have 3 15W panels somebody bought at harbor freight 8 years ago.

    Anyone else have an opinion on the need to vent?

    (great forum btw). 
  • Marc KurthMarc Kurth Solar Expert Posts: 411 ✭✭✭✭
    @GBX2000 Sorry, I did not mean to derail your thread and I apologize.

    Marc
    I always have more questions than answers. That's the nature of life.
  • HorseflyHorsefly Registered Users Posts: 258 ✭✭✭
    edited July 20 #14
    @GXB2000 - I am certainly not an expert, as my system uses AGM batteries without an enclosure.  However, for the last 15 years or so we had a little tiny 12V panel on our deck at the cabin, charging a marine  FLA "deep cycle" battery that we used only for charging cell phones when someone was at the cabin.  The wooden box that the battery has been in all that time is right in the living room / kitchen / great room of the cabin, and has never been vented. Sounds like a fairly similar set up as yours.  As far as I can tell we are all still alive. 

    Steve

    P.S. You're right, this is a great forum. It's where I learned a ton before we installed our system. It has had a great atmosphere, prior to the arrival of a couple of people (maybe one?).
    Off-grid cabin: 6 x Canadian Solar CSK-280M PV panels, Schneider XW-MPPT60-150 Charge Controller, Schneider CSW4024 Inverter/Charger, Schneider SCP, 4 x Vmax XTR12-155 12V, 155AH batteries in a 2x2 24V 310AH bank.
  • mike95490mike95490 Solar Expert Posts: 7,284 ✭✭✭✭
    My suggestions:
    Use either a very efficient inverter (Morningstar suresine 300 comes to mind, but it's pricey) or go with straight DC lighting.
    For DC lighting, look at  www.superbrightleds.com or /www.wiredco.com/LED_Lighting_Low_Voltage_s/1874.htm
    Both sites have GOOD LEDs that are bright and engineered to have a decent lifetime,  Also many strip lights will give great ambient lighting too.   LED's are all about beam pattern, and the largest problem is not brightness, but dispersing that light evenly.  Second is heat.


    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 ,

  • GXB2000GXB2000 Registered Users Posts: 5 ✭✭
    Thanks everyone, this is great!
  • SolraySolray Registered Users Posts: 246 ✭✭
    You are quite welcome, friend. :)
  • mike95490mike95490 Solar Expert Posts: 7,284 ✭✭✭✭
    venting battery fumes.  Two things here, first is H & O gasses from the recharge process, second is the smell from the sulfuric acid that can really stink up a house when charging a battery hard.   for a couple batteries, Hydrogen buildup is not very likely, but you may still have fumes..
    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 ,

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