Natural gas well for off grid electric

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highway-equipment
highway-equipment Registered Users Posts: 11 ✭
in Solar Beginners Corner #1
I am looking for some help for generating power at a camp I am building. I have a natural gas well with free gas. I have a 10 kw Kohler generator and 4 8D batteries. If possible I would like to have a system that would charge the batteries and use that with an inverter and charger so I do not have to have the generator run all the time. I have been reading for several months and need some guidance and direction. Anyone willing?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Natural gas well for off grid electric

    It's quite a reasonable prospect. Generator charges batteries, batteries power inverter. Simple.

    The first question is: what are your loads? In other words, what do you want to run? That will determine your Inverter. From there you can figure out how long it ill run off the 8D's or what battery configuration you need. This will tell you what you have to have for a charger.
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  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    #3
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    Re: Natural gas well for off grid electric

    Do you intend to use PV in your system?

    K
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  • highway-equipment
    highway-equipment Registered Users Posts: 11 ✭
    #4
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    Re: Natural gas well for off grid electric

    Right now I did not plan on PV. Might be good in a few years when I get Kids out of college. I will be running a submersible pump 1/2 hp at a spring 370 feet away. Then just lights and daily odds and ends. Heat is radiant in floor with small pump. old Natural Gas frig . I would like to have the generator turn on when banks are low but not sure how complicated that will get. I have an electrician said he will help if I get some info. ( off grid is not real popular in my area) I wondered if the inverter charger combinations or individual components were better? Thanks for response.
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #5
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    Re: Natural gas well for off grid electric

    Natural gas as it comes out of the ground can be pretty dirty, often with a lot of sulfur. It is also quite commonly at 100% humidity - or more, with water condensing out as it loses pressure. Both of those factors might affect how well an off the shelf generator will run.
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  • highway-equipment
    highway-equipment Registered Users Posts: 11 ✭
    #6
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    Re: Natural gas well for off grid electric

    I have have an alcohol drip that takes care of that. I have a well at my home also and have lived there for 20+ years. You are right about the moisture it will cause problems if not taken care of especially in cold climates in winter. Thanks
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #7
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    Re: Natural gas well for off grid electric

    The 1/2 HP pump is a bit of a snag. Running it probably draws in the neighborhood of 800 Watts. Start-up would be much worse - more than double that. So to handle that you'll need at least a 2000 Watt inverter, and pure sine at that (there's no sense trying to get a cheap modified square wave inverter to run it).

    "Just lights and daily odds and ends" can add up to a lot of power. Here's some idea of roughly how you figure this stuff out:

    Total cumulative load (everything that will be on at once) in Watts = minimum capacity of inverter.
    Average Watt load over 24 hours = Watt/hours per day. Divided by inverter's DC voltage = Amp/hrs capacity needed. Times at least 2 (to keep the discharging of the batteries to a minimum) = battery capacity in Amp/hrs (@ the "20hr rate" as it's called).
    Minimum of 5% of battery capacity (10% is better, 15% usually the 'upper limit') = charge current rate. You've got to have a minimum amount of current to keep the batteries from 'sulphating' and thus dying prematurely.

    With your load potential, you're probably better off with a Xantrex or Outback with a built-in charger rather than separate inverter and charger. Perhaps this Outback: http://store.solar-electric.com/fx2012t.html
    If you habitually run loads closer to 2kW you may want to go up to a 24V version (reduces DC current): http://store.solar-electric.com/fx2524t.html

    Your 8D batteries: that is a size, not a specific capacity. Do you have any make/model number? I think in general they're around 200 Amp/hrs. That gives you roughly 4800 Watt/hours to work with. Think of it as a 200 Watt load running 24 hours.
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  • highway-equipment
    highway-equipment Registered Users Posts: 11 ✭
    #8
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    Re: Natural gas well for off grid electric

    I think they are 255 amp hours. Thanks for the other info i will try toget some more specifics. Will it be hard to get the generator to cycle on and of when needed? Last winter I could not get in for a few weeks.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #9
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    Re: Natural gas well for off grid electric

    h-e,
    made it. it seems producing power isn't your problem, but you want some peace and quiet at night and so this inquiry, is this not so? the guys are right that you need to know your loads and for how long they are to be. this would be watts (w) and watt hours (wh) and if large enough we refer to it in kilowatt hours (kwh). it is possible to do this especially given you have free power available through a natural gas generator with its own supply of gas. what happens is you store the power you need plus a tad extra for losses and this cannot allow the batteries to use up more than 50% of its capacity. to do this i suggest an inverter/charger arrangement for while on the genny the batteries can charge and at the same time feed your loads. these are somewhat limited in their feedthrough power and charge, but depends on the loads again. loads up to 10kw will not allow for the batteries to charge making a possible dedicated generator to charge the batteries needed if this one is bogged down too much. if your loads are less than 5kw then there's room on the generator to do double duty.
    as said the batteries can't be allowed to fall below 50% so will half of the battery capacity you bought in wh run everything you need during the evening? if not more batteries may be needed and large electric motors do tend to bog down a tad with the big start surge and could suck the voltage of the batteries down far enough to kick the inverter, or inverters if one doesn't cover the max power used in watts, out of operation.
    now i may be getting ahead of myself or didn't read something right as i did a quick skim to address things in general. with that said i will stop and read more in detail, but i wanted you to know i am here and will throw in my 2 cents.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #10
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    Re: Natural gas well for off grid electric
    highway-equipment wrote: »
    I think they are 255 amp hours. Thanks for the other info i will try toget some more specifics. Will it be hard to get the generator to cycle on and of when needed? Last winter I could not get in for a few weeks.

    "High-end" inverter/chargers like the Outback I mentioned can auto-start generators with an optional gen start kit. The question would be whether the generator is compatible with this function. That's one for the Kohler people to answer.

    Another potential problem with your batteries is that they are probably not true deep cycle types. That means they aren't going to last very long with repeated discharge/recharge. But if you've got 'em, use 'em. Replace as needed.

    10kW is a lot of generator potential. Recharging shouldn't be a problem. Most of us off-gridders only use little gens - less than 5kW. You'll see that the Honda 2000 is very popular. But since you've already got a viable, working gen set-up that's your best choice. If for some reason it isn't enough, you can always add solar panels later.
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  • mikeo
    mikeo Solar Expert Posts: 386 ✭✭✭
    #11
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    Re: Natural gas well for off grid electric
    Will it be hard to get the generator to cycle on and of when needed? Last winter I could not get in for a few weeks.
    The Xantrex XW series inverter chargers have built in relays that can start a generator based on your battery voltage settings.
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  • PhilS
    PhilS Solar Expert Posts: 370 ✭✭✭
    #12
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    Re: Natural gas well for off grid electric

    We survived for many years without solar panels. We'd run the generator for washer/dryer and it'd charge batteries too. Live the rest of the time off of the inverter. Sure, we'd sometimes have to run the gen some more.

    I've been through a few generators since '77. Currently I have a 10KW Kohler propane generator that can be started automatically by my SW2512 Xantrex. (I also have a 4KW Honda backup and a Honda eu1000i in my RV if needed.)

    The gen will start when on "auto" and the battery voltages get low enough. My inverter is actually an "MC" model, made for motor coaches, and "quiet times" are programmed so it won't start automatically in the middle of the night. I don't leave it on "auto" anyway, tho, because:

    I don't want my generator running if I'm not there. Too much can go wrong that could snowball into a catastrophe without attention.

    You could put just a couple of panels in to maintain batteries when you are unable to get there. Obviously, load management would be the key.

    Phil
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #13
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    Re: Natural gas well for off grid electric

    Also, it isn't absolutely necessary to buy a super-inverter just to get the generator start ability - a good battery monitor such as the Bogart Pentametric or the Xantrex LinkLite/LinkPro will include a low-voltage alarm/genstart connection.


    http://store.solar-electric.com/pe3chbamosy.html
    http://www.bogartengineering.com/pentametric.htm

    "Controls and alarms

    Relay output

    Control external relay to go on and off at specified voltage levels and/or %battery state of charge levels. "On" and "off" levels can be independently set."


    http://store.solar-electric.com/xalidubamo.html

    "It is equipped with an internal programmable alarm relay, to run a generator when needed or to turn off devices when the battery voltage exceeds programmable limits."


    The Bogart Trimetric - which is less expensive - may also have an external relay connection, but I can't find anything (with a quickie search) that says it does.


    And...you'll need a good battery monitor in any case.
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  • highway-equipment
    highway-equipment Registered Users Posts: 11 ✭
    #14
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    Re: Natural gas well for off grid electric

    Thank you to everyone for your help. Didnt expect the response I received but it was great, learned alot. I checked today on a large expansion holding tank (86 gal) and wondered if it would be better to run the generator for the submersible pump when water is needed. As for the generator I traded for it and the batteries are from a couple dozers that were disassembled but were all near new (price was right to start with) Could anyone explain the battery monitor to turn on and of generator.
    Is that done by tying into alarms on unit?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #15
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    Re: Natural gas well for off grid electric

    The Xantrex Link * family has a programmable output. For example, you can program it to "turn on" when the battery charge hits 70% and turn off when the battery hits 85%.

    Generators need to have their own automatic starting system (crank, oil, temp, choke, exercise, etc.)--as you probably know better than I... And depending on the type of remote starter it requires--you may need some sort of adapter between the Battery Monitor and the genset.

    The advantage to a "battery monitor" is you can program the generator cycle based on the state of charge of the battery bank--Most other starting systems start the genset when a voltage level is crossed (I would guess) and is not nearly as accurate with respect to state of charge estimation.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • highway-equipment
    highway-equipment Registered Users Posts: 11 ✭
    #16
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    Re: Natural gas well for off grid electric

    thanks for the info.
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #17
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    Re: Natural gas well for off grid electric
    highway-equipment wrote: »
    Could anyone explain the battery monitor to turn on and of generator.
    Is that done by tying into alarms on unit?

    As Bill noted - first the generator has to support automatic start. Basically that means an automatic choke and an autostart module, like this:

    http://atkinsonelectronics.com/product_pdfs/GSCM-mini.pdf

    The battery monitor or the inverter has a circuit which signals the autostart box to fire up (or shut down) the generator.


    There are lots of generator autostart modules:

    http://www.google.com/search?hl=en&safe=off&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=em7&q=generator+autostart&aq=f&oq=&aqi=

    Magnum makes one that will start/stop the gen based on battery voltage sensing - and can also start/stop based on temperature:

    http://www.magnumenergy.com/Autogenstart.htm
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