Choosing Batteries for eventual off grid living

freesoulJAH
freesoulJAH Registered Users Posts: 5 ✭
in Solar Beginners Corner #1
Hi there,

We are beginning our journey into the depths of off grid living. I am researching our options, and in the process found a great deal on some batteries, which were lightly used in a data center. I would appreciate it if somebody with more knowledge of battery banks and solar power systems would chime in and give their opinions on these two types of batteries:

C&D Technologies UPS12-490MR

Enersys 12HX505

All ideas, opinions, and suggestions are welcome!

Thank you much!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Choosing Batteries for eventual off grid living

    Welcome to the forum.

    Okay, opinions. I've got lots of them. :D

    Used batteries = pig in a poke. And even though you may still hear it squealing that doesn't mean the pig won't drop dead tomorrow.

    Don't buy equipment first and then figure out what you need later. That's a sure-fire formula for disappointment and wasting money.

    Especially do not buy batteries first; they start to die the day they are made.

    Batteries from a data center are probably not suited to RE use: a difference of being in constant standby vs. being discharged and recharged daily.

    Why are you going off grid? Many people make the mistake of thinking solar is cheaper. It ain't.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #3
    Re: Choosing Batteries for eventual off grid living
    freesoulJAH wrote: »
    We are beginning our journey into the depths of off grid living. I am researching our options, and in the process found a great deal on some batteries

    Welcome to the forum,

    Batteries are the LAST thing you should buy... everything else should be wired up and ready to charge the batteries before you buy them.

    When designing a solar power system you must know what your electrical loads will be.

    It's like buying a pickup truck if you don't know the weight of your load, or the weight of the trailer you will tow, you are likely to buy the wrong truck. You can't turn a 1/2 ton truck into a 1 ton truck by adding heavier springs, and you can't easily expand (or shrink) a solar power system.

    First step is figure out your loads... kilowatthours per day, maximum wattage at any one time, and time of day of the loads.

    Second step is to choose the correct system voltage and battery.

    Then you choose the solar panels, generator, charge controller and balance of system.

    After everything is wired up, you buy the batteries.

    If you do it any other way, you can still ask for advice on this forum, but you will hear a lot of "I told you so".

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • freesoulJAH
    freesoulJAH Registered Users Posts: 5 ✭
    #4
    Re: Choosing Batteries for eventual off grid living
    Cariboocoot wrote: »
    Don't buy equipment first and then figure out what you need later. That's a sure-fire formula for disappointment and wasting money.
    vtmaps wrote: »
    Batteries are the LAST thing you should buy... everything else should be wired up and ready to charge the batteries before you buy them.

    Thank you both for the advice. While pricing components I stumbled on those batteries and wondered if I should jump on a deal before they are sold to somebody else. But because I do not currently know what my load will be, I will continue researching/figuring out a solar power system works -- BEFORE I make any purchases. :-)
    Cariboocoot wrote: »
    Why are you going off grid? Many people make the mistake of thinking solar is cheaper. It ain't.

    We are closing on a property in August. It currently has a 600 ft2 unfinished passive solar home, which we plan to finish and build onto. It is connected to the grid at the moment, but we would like to have energy independence for the home in the near future. There is a well, which runs on electricity...and personally I don't like the idea of our water being shut off if the power goes out. Also, I would feel some satisfaction in building and setting up and running a solar power system.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #5
    Re: Choosing Batteries for eventual off grid living
    freesoulJAH wrote: »
    Thank you both for the advice. While pricing components I stumbled on those batteries and wondered if I should jump on a deal before they are sold to somebody else. But because I do not currently know what my load will be, I will continue researching/figuring out a solar power system works -- BEFORE I make any purchases. :-)



    We are closing on a property in August. It currently has a 600 ft2 unfinished passive solar home, which we plan to finish and build onto. It is connected to the grid at the moment, but we would like to have energy independence for the home in the near future. There is a well, which runs on electricity...and personally I don't like the idea of our water being shut off if the power goes out. Also, I would feel some satisfaction in building and setting up and running a solar power system.

    Do you want energy independence as a higher goal at the price of paying two to ten times more per kWh than you would pay to the power company? If so, then off-grid solar is the choice for you.
    If you want to reduce your carbon footprint, then arguably a grid-tied system is a better way to go.
    If you want the battery system to cover sporadic power outages, then you will need to supplement your solar system with a generator anyway, so your design process should take that into account when sizing your battery bank.

    Also, the Enersys web data on that battery model makes it clear that it is designed for constant float service with discharge maybe once or twice a year (except for testing).
    They will not last very long in cycle (discharge/charge every day) service. In general UPS batteries are not a good choice for off-grid power.
    Some prefer golf cart batteries for their first venture, others argue for used forklift batteries. True deep-cycle batteries for RE use are very expensive and since most people (who do not read enough in advance) ruin their first set of batteries by abuse, they are probably not the best initial purchase when starting your first system.
    SMA SB 3000, old BP panels.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #6
    Re: Choosing Batteries for eventual off grid living
    freesoulJAH wrote: »
    Also, I would feel some satisfaction in building and setting up and running a solar power system.

    Just make sure you feel satisfaction in paying 10 times the cost of grid power. Do some research into the net metering laws in your state... a grid-tie system can have a reasonable return on investment.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • freesoulJAH
    freesoulJAH Registered Users Posts: 5 ✭
    #7
    Re: Choosing Batteries for eventual off grid living
    inetdog wrote: »
    If you want to reduce your carbon footprint, then arguably a grid-tied system is a better way to go.

    why is that so?

    inetdog wrote: »
    Also, the Enersys web data on that battery model makes it clear that it is designed for constant float service with discharge maybe once or twice a year (except for testing).
    They will not last very long in cycle (discharge/charge every day) service. In general UPS batteries are not a good choice for off-grid power.
    Some prefer golf cart batteries for their first venture, others argue for used forklift batteries. True deep-cycle batteries for RE use are very expensive and since most people (who do not read enough in advance) ruin their first set of batteries by abuse, they are probably not the best initial purchase when starting your first system.

    Thank YOU! I was trying to decipher all that info on the batteries with my limited (but growing) knowledge. I couldn't find anything definitive that told me what you concluded. Can you tell me, or point me to a resource that explains how you were able to come to that conclusion from the battery's specs? - thanks!
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  • freesoulJAH
    freesoulJAH Registered Users Posts: 5 ✭
    #8
    Re: Choosing Batteries for eventual off grid living
    vtmaps wrote: »
    Just make sure you feel satisfaction in paying 10 times the cost of grid power. Do some research into the net metering laws in your state... a grid-tie system can have a reasonable return on investment.

    --vtMaps

    I am in New Mexico...so from here it looks like a really good option for us! Thanks for the heads up! :D
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #9
    Re: Choosing Batteries for eventual off grid living
    freesoulJAH wrote: »
    why is that so?




    Thank YOU! I was trying to decipher all that info on the batteries with my limited (but growing) knowledge. I couldn't find anything definitive that told me what you concluded. Can you tell me, or point me to a resource that explains how you were able to come to that conclusion from the battery's specs? - thanks!

    Sure. Google is your friend if you can sort out the authoritative references from the chaff. Experience helps with that and you do not have that yet. :)

    I looked at http://www.batteryuniverse.com/sealed-lead-acid/enersys-datasafe/12hx505/hx500-enersys-datasafe-12hx505-sealed-lead-acid-battery, where I found:
    Sealed lead acid batteries are used in tens of thousands of devices. I couldn't answer the question for every device. However, I can answer it in general terms. It all comes down to energy output and design life. Most electronic devices use a battery as a backup device. That is, it is only there for when the power goes out. In that circumstance, the batteries are rarely used, so you should expect 3-5 years of life out of it. For example, your home alarm system has a battery in it to keep your alarm working when the power is out. Out of 365 days, your power is probably out maybe two days a year. So the battery is only being used those two days. The rest of the time its being trickle charged. Because charging a battery causes heat, after years of exposure to steady currents of electricity, the battery will have simply "dried up". Its electrolyte will have evaporated off leaving the battery unable to receive a charge or store the energy. In the case of a device that's main supply of power is batteries, the batteries will wear out much faster. If you are using the battery on a daily basis, it will probably only last a year at the most. Sealed lead acid batteries can only be charged and discharged 300 times at the most, unless you have a pure lead battery with a high input/output rating. Enersys makes some Cyclon batteries that will last longer.

    This is actually an over generalization, since there are AGM batteries designed specifically for deep cycle use (other than just Cyclon) as well as AGM designed for float service.
    Since RE batteries need to accept a fast charge in the several hours a day of full solar production, avoid GEL type sealed batteries like the plague. They will be permanently damaged by high charge rates but are used in many UPS systems where the charge rate is limited by design and you can wait a day or two of continuous charging to get the batteries back up to full charge.

    BatteryUniversity is good web source for a lot of basic info.

    In general, you can assume (as a crude first approximation) that the carbon footprint of producing something is proportional to the cost. If the cost of your batteries is high enough to cost you more per kWh than power from POCO, then it probably had a high energy input into the battery production. If you can get the same amount of useful power via grid-tie without using batteries, the balance is bound to be better. A GTI (grid tie inverter) is also generally simpler and less expensive than the combination of a CC (charge controller) and a standalone inverter.
    SMA SB 3000, old BP panels.
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  • freesoulJAH
    freesoulJAH Registered Users Posts: 5 ✭
    #10
    Re: Choosing Batteries for eventual off grid living
    inetdog wrote: »
    BatteryUniversity is good web source for a lot of basic info.

    WOW, that site is thorough! Thanks!

    inetdog wrote: »
    In general, you can assume (as a crude first approximation) that the carbon footprint of producing something is proportional to the cost. If the cost of your batteries is high enough to cost you more per kWh than power from POCO, then it probably had a high energy input into the battery production. If you can get the same amount of useful power via grid-tie without using batteries, the balance is bound to be better. A GTI (grid tie inverter) is also generally simpler and less expensive than the combination of a CC (charge controller) and a standalone inverter.

    From what I have read, New Mexico is getting at least 60% of it's electricity from coal (some sources say 80%)...and I would like to reduce my consumption of that resource.

    If the grid goes down and I am using a GTI, am I SOL (unless I have a generator on standby)?
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #11
    Re: Choosing Batteries for eventual off grid living
    freesoulJAH wrote: »
    If the grid goes down and I am using a GTI, am I SOL (unless I have a generator on standby)?
    Yes. And you will need an automatic transfer switch with load shedding (so as not to stall the generator) or a manual transfer switch so that you can turn off A/C or electric range before transferring.

    There is one brand/model of GTI (SMA x000TL-US) which includes their "secure power supply" circuit which will give you one separate 12A 120V receptacle that you can manually turn on to be supplied directly from the panels (no batteries) when the grid is down. It may run a refrigerator or freezer, as long as the motor starting current is not too high.

    A battery system which you use just for standby (no daily cycling) will let its batteries last longer (and therefore cost less) and allow you to charge the batteries during an outage using the generator which will also let you use a smaller battery bank than you would for full time off grid use.
    Note, however, that neither a GTI nor a low cost off grid inverter will allow you to connect your AC loads (i.e. other than the charger) directly to the generator and the inverter at the same time! That capability requires Generator Support, a feature that some Outback and Xantrex systems offer, at a substantial price. Again, that would be useful for someone who is totally off grid more than for occasional power outages.
    SMA SB 3000, old BP panels.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #12
    Re: Choosing Batteries for eventual off grid living
    freesoulJAH wrote: »
    From what I have read, New Mexico is getting at least 60% of it's electricity from coal (some sources say 80%)...and I would like to reduce my consumption of that resource.
    Grid tie is your most efficient way of doing that. Given current technology.
    SMA SB 3000, old BP panels.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #13
    Re: Choosing Batteries for eventual off grid living
    freesoulJAH wrote: »
    WOW, that site is thorough! Thanks!




    From what I have read, New Mexico is getting at least 60% of it's electricity from coal (some sources say 80%)...and I would like to reduce my consumption of that resource.

    If the grid goes down and I am using a GTI, am I SOL (unless I have a generator on standby)?

    Yes, but if it is a reliable power company then a generator is a more cost effective solution for outages and the Grid tie is more effective for loosing the carbon footprint. Having batteries is an expensive and a maintenance headache.
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #14
    Re: Choosing Batteries for eventual off grid living

    A couple AGM's would work with a charger/inverter, a few panels and a transfer switch. However, like everyone has been telling you it's not cheap nor will it lesson your carbon footprint. A Grid-Tie Array with a generator for back up is cheaper and more environmentally friendly at the end of the day.

    With a GT you are contributing "Green Energy" to the system and paying yourself back in reduced utility bills at the same time.

    If you want to give the "man" a single finger salute, then go off grid and cut the chord. It cost money....... lot's of cabbage, but when all is said and done rasing that balled up fist and that one single digit is a hell of a good time. :-)


    ETA........ I got bored once and went into the engineering dept. of the local power company to see how much it would cost for grid power. I sat there and asked how much to run one pole (1)!! and a meter pole to my place, so they could do me the favor of billing me once a month. Power is literally at two ends of my place. Their costs to me alone were in the $5,000 range and that was before I had to hire a lic electrician, pull permits, run the line from the pole to house, yada, yada.......

    I just looked at the guy and said, $5,000 buys a hell of a lot of batteries and I won't get a monthly yank on my crank at the end of it. They also wanted me to split the costs of the two poles up stream with them, since they were less than 5 years old........... Screw That!!

    Grid power may be cheaper if it is already there, but "New Service" up here is getting to be about tied with an RE system that's off grid.
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