beginner needs help with start-up

jrmadbearjrmadbear Registered Users Posts: 8
I want to put up a system and i have a DR 3624 Trace inverter/charger.
i am looking at batteries and i need some help choosing the best setup.
i am a total dummy when it comes to electrical stuff. which battery setup would be the best for a 24 volt system? All things equal would it be better to set up a series of 4-6v or 2-12v. Is there any difference in efficiency, cost and battery life?thanks

Comments

  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: beginner needs help with start-up

    I don't think functionally there's any real difference. But if the amp-hour capacity you need exceeds what you can get a single battery in, then you are looking at parallel strings. For a given size, a 12V battery is going to be (roughly) half the AH capacity of a 6V. Too many parallel strings can be troublesome to keep balanced, so it's better to limit how many you have. Thus, going with the 6V batteries reduces that by half. Of course, you can also choose larger batteries to start with as well.

    But for beginners just starting out, it is often suggested you try using "golf cart" batteries (Trojan T-105 and the like) because they are good batteries for the application that don't cost a huge amount. It is entirely too easy when starting out to kill your first set of batteries in a variety of ways (overcharging, undercharging, forgetting to add water...) and this limits the financial impact. They are also probably a lot more readily available locally. (This is what I've done, so far I've not killed mine but they haven't been in use for even a year yet...! :p ) These are 6V roughly 200AH batteries. (Trojans are rated 220AH, I've seen some mention discount-store versions being 180-200AH.)

    There are some battery FAQs available if you want to learn more. The one I started out with is http://www.batteryuniversity.com/partone.htm and the hosts of this forum have one as well http://www.windsun.com/Batteries/Battery_FAQ.htm


    There are many more questions you need to ask as well, though. You need to determine the loads you will have before you know what size (in amp-hours) your battery bank needs to be to handle it, and you need to know how large your battery bank is going to be before you know how much solar panel (in watts) you will need to properly charge it. (That's just a start! There are a number of others!)

    You mention having an inverter/charger. Do you want to install a solar system? Or just a UPS type system? If solar, you will also need a charge controller, will need to know what your solar insolation is (how many hours of "usable" sunlight you get per day, not just how many hours it is light out) which factors in to how much solar panel you need, so on...! There's a lot to it, but it can be fun! :cool:
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: beginner needs help with start-up

    Before you do anything, I suggest you get a really good handle on your expected loads. All other choices come from knowing your loads. I suggest getting a Kill-a-watt meter (~$20) to log your current loads, and extrapolate your future loads.

    Tony
  • jrmadbearjrmadbear Registered Users Posts: 8
    Re: beginner needs help with start-up

    Thanks, like i said i am a dummy! Can the kwh data form my elc. Bill be a help with this or do i need the peek load
  • GreenPowerManiacGreenPowerManiac Solar Expert Posts: 453 ✭✭✭
    Re: beginner needs help with start-up

    I think if I had to start over again, I'd choose the highest voltage battery setup possible D/C: 48v or better. Rime or reason for battery voltages is not as important as your loads, like stated. What are you powering ? Higher voltage costs more (inverter) in the beginning and less in the long run (wire sizes & circuits). I'd still suggest some book reading on the subject. There are many out there that are easy to understand without all the science and you don't have to be a "Solar Power for dummies" to understand everything.
    Nature's Design & Green Energy on FaceBook : Stop by and "Like" us anytime.. Many up-to-date articles about Renewables every day.
    WWW.GreenAnything.Net    Ad free website.
    Lots of DIY Renewable Energy Projects on ETSY : Solar Panel builds, Wind Turbine builds, Rain Barrel build,etc.  
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: beginner needs help with start-up

    Also, be aware that the Trace inverter is long past end-of-life and if it breaks, there is hardly anyone out there that can repair them anymore (and no parts either).

    Do not spend any more money until you figure out exactly what it is you want to do.

    As Tony says, understanding your loads is the first thing to look at. A kill-a-watt meter and your electric bill is a good place to start.

    You will probably find that you are using way to much electricity to really go off grid. Generating off-grid power is expensive... It will probably cost you $1-$2+ per kWhr, and your utility power is $0.10-$0.20 per kWhr--1/10th the price of off-grid power.

    So, if you have a 600 kWHr per month power bill--that $60-$120 per month bill will cost you (assuming 20 year system life and buying replacement batteries when needed) will cost you $600-$1,200 per month--much of that is upfront money to install the system in the first place (many tens of thousands of dollars).

    Normally, we recommend that people spend money on conservation first (insulation, double pane windows, energy star rated appliances, turning things off, switching from electric stove/hot water to propane and solar thermal, etc.).

    Going off grid solar when you have utility power available will never really save any money. If you want emergency power (storms, earthquakes, local utility is unreliable, etc.), generators are good for short/rare outages. And setting up a battery bank, charger+inverter to run the home during frequent outages (people in the Caribbean do this quite often) can be nice too.

    Of course, many folks want to experiment with solar RE and build a small system first (a couple hundred watts of solar panels, charge controller, plus a couple of 6 volt golf cart batteries and an Inverter) and play with the system first to understand how to run it and the limitations. Even something like that (enough to run a net book computer, a radio, and a couple small lights off grid) is going to cost around $1,000.

    If you want to get a good idea what the major components are and how much they cost, you might wish to browse our host's web store--NAWS.

    In the end, understand and define your needs before you take the first step. Your wallet will thank you.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jrmadbearjrmadbear Registered Users Posts: 8
    Re: beginner needs help with start-up

    Thanks for the 411, I will get a kill-a-watt meter and some books. I think i can do this as I live in a small trailer that is very inefficient yet only uses about 300-350 KWH a month. I will reduce this by upgrading and ajusting my usage.

    I lived without electricy For about a year when I let someone live on my property and they ran the bill up and skiped out. That's when I got the inverter and started building a system, but took the easy way out when I got the electricy back on
    "for my girlfriend's sake". LOL

    I live in the mountians 35 miles out of Albuquerque NM at 6800 ft (plenty of sun).
    I am a bit of a "outlaw" and a life long DIY'er and would much rather support the environment than the establishment.
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: beginner needs help with start-up

    Look at transferring your heating loads from electricity to propane/etc... Solar thermal might be interesting.

    If you stick with electricity because propane is expensive/going up in price--You might look at your major energy users (heat/cooling). Replacing with a heat pump system like the Sanyo Mini-Split might be a good conservation measure. Solar thermal for hot water/heating is also a good project for a do-it-yourself type person.

    Typically, I would suggest that if you want to go off-grid--that you aim at a maximum of 100 kWhrs per month. Seems to be an achievable level for Off-Grid family home (obviously, lots of work to get energy usage that low).

    Take a look at Home Power Magazine for general off-grid/conservation articles.

    As always, take everything you read (including here) with a grain of salt. Research first before spending the cash. Prove to yourself that the project makes some sort of economic sense and will be reliable over the long term.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: beginner needs help with start-up

    350 kwh/month is still ~12 kwh/day. Still a fairly hefty load for a small scale PV system. If this is a battery based system, it is getting to be a real substantial load.

    My rule of thumb is that you can take the name plate rating of your PV divide by 2 to account for all the cumulative system loses, multiply that number by the number of hours of "good" sun you can expect on average,, seldom more than 4.

    So in your case, if my math is right (never a safe assumption)

    6000 watt Pv/2*4=12,000 wh or 12kwh.

    To add in a reserve of three days you would need a system ~say 10kw. 10 kw battery based system might run ~$6-10/watt, or $60-100,000

    You are also going to need a very large, very expensive battery system, and you have to calculate life span cost of said battery, 5-10 years at best with the kind of loading you are considering.

    Now, if you can do everything to conserve, and transfer as much of your energy loads to other sources (gas/propane/heat pump/ solar hot water/solar space heat) so that you can get you use down to say 4 kwh/day, you can see that your system cost(s) drop by 66% making it much more affordable.

    Remember, conservation first, followed by more conservation, then a bit more conservation. Then in some order, solar hot water (much cheaper per btu than Pv solar) passive and active solar heat, ground sourced heat pump, or if you use ac a lot, hot water recovery heatpump, and then, consider PV solar.

    Tony
  • jrmadbearjrmadbear Registered Users Posts: 8
    Re: beginner needs help with start-up

    Will take that advise!
    While I have been researching things I have seen all kinds of DIY kits to build panels, what are your thoughts on this. Can you get a good system with these and is it worth the $. I can't see where they are that much cheaper.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: beginner needs help with start-up

    as to a diy pv you won't match those that are commercially available in quality, performance, or longevity, especially for the costs involved, so i would not do that unless you do 1 as an experiment or for the fun.:roll:
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: beginner needs help with start-up

    DYI panels are not for any "serious" installation. Not to mention getting code approval for homemade panels in any grid tie permit might be difficult if not impossible.

    Besides, UL listed, 25 year warranted panels are available for ~$3/watt. I don't think that any home built one would make any sense.

    Tony
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: beginner needs help with start-up
    jrmadbear wrote: »
    Will take that advise!
    While I have been researching things I have seen all kinds of DIY kits to build panels, what are your thoughts on this. Can you get a good system with these and is it worth the $. I can't see where they are that much cheaper.

    DIY is a great hobby.

    If you burn down your house with them, your insurance will almost certainly not cover it.

    You won't be able to tie your rig into the grid if you use home made panels - again, they are not approved.

    Great for a hobby. You can use them to recharge your phone or some such, but not much else.
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: beginner needs help with start-up

    Broken record time. Link to Panel Fire Thread (non-UL listed panels made from some sort of plastic instead of tempered glass):

    Panel Fire Question

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jrmadbearjrmadbear Registered Users Posts: 8
    Re: beginner needs help with start-up

    Thanks,
    I didn't think it was a good idea to build a large system with these cells and i know this would not work for a grid tie. Your replies confirm that. I was thinking I might build a small battery charging system for some small mining equipment i am building. This would give me some experience with PV panels.
    Along that line, i will be needing to power a 1/4-1/2 horse motor running a blower.Would it be better to stay with a 12v DC or invert to 120 AC and would a DIY kit work for this. ( it will be used OUTDOORS)
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: beginner needs help with start-up

    You need to define your loads better... Is this a pumping application that only needs to run during the daylight (like a solar powered well pump). Or is this something where the power needs to be available 24 hours per day.

    A 1/2 horse system is not small. If it runs for 2 minutes a day vs 12 hours per day makes a huge difference in power requirements (batteries, solar panels).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • hillbillyhillbilly Solar Expert Posts: 334 ✭✭
    Re: beginner needs help with start-up

    I can absolutely relate to the DIY mentality, I am the same... and I did design (my wife would laugh if she heard me put it that way) and install (more laughing) our very own off grid PV system to power our mountain cabin home. I can say that if connecting to the grid had been a bit cheaper I would definitely go that route. Much cheaper, I'd suspect that even when you figure the costs of hiring out all the design and install work you'd come out way ahead when you also factor in all the incentives and factor out all the batteries. Have you penciled out some rough numbers of what a grid tie system might run you after rebates and such, and how much a battery based off grid system would be. Your loads sound pretty substantial to do a full stand alone system. Our home power consumption is usually more like 50-75KWH/month, and others here who are "off grid" live on even less... it gets pretty expensive as you start going with bigger and bigger battery banks, and even bigger PV arrays.
  • jrmadbearjrmadbear Registered Users Posts: 8
    Re: beginner needs help with start-up

    OK ! forget the grid tie, i have no desire nor the $ for a grid tie, the only way i will go is SA with battery storage,pv,wind and generator backup. i have reduced my monthly use to 250 KV last month and will reduce it more. it will take some work as my heat is wood, hot water and stove are propane.
    As for the mining equipment the 1/2 hp motor is on the bigger size, will probably go 1/4 HP. it will be runing a blower for about 1-2 hrs. then off for 1-2 hrs. twice a day in S. AZ in the winter
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: beginner needs help with start-up
    jrmadbear wrote: »
    OK ! forget the grid tie, i have no desire nor the $ for a grid tie, the only way i will go is SA with battery storage,pv,wind and generator backup. i have reduced my monthly use to 250 KV last month and will reduce it more. it will take some work as my heat is wood, hot water and stove are propane.
    As for the mining equipment the 1/2 hp motor is on the bigger size, will probably go 1/4 HP. it will be runing a blower for about 1-2 hrs. then off for 1-2 hrs. twice a day in S. AZ in the winter

    250KV is a lot. better be sure of everything before you pull the plug.

    Blower could run directly off PV, and skip the losses involved with recharging batteries. Is this your fresh air in the mine ?

    Are you blowing fresh in, or sucking bad out ?
    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 ,

  • jrmadbearjrmadbear Registered Users Posts: 8
    Re: beginner needs help with start-up

    this is a blower to seperate the material using a "drywasher". would it be better to set up a charger and say 2 12vdc deep cell batteries for cloudy conditions and runing after sundown?
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: beginner needs help with start-up

    Just to clarify Mikes terrible joke--He is refering to your typo of 250kV which would be 250,000 volts... We assume you intended to type 250kWHour for your power usage.

    Just as a very rough rule of thumb, the PV electricity will cost you about 4x as much if you need to run it "in the dark" vs just during daylight.

    So, if you can run the fan when the sun is up (perhaps even a solar tracker would be a good choice here)--then solar panels plus a DC motor designed to run on solar would be a good choice.

    Solar Guppy or Windsun can probably direct you to some folks that sell DC Motors designed to run on solar panels (I can't find any right at the moment).

    If you need to run the fan (and other equipment) in the "dark", then you will need a full up off-grid solar system. You can decide to go with:
    1. solar panels + charge controller + batteries + DC loads
    2. solar panels + charge controller + batteries + Inverter + AC loads
    #1 will probably be a bit more efficient... However DC motors are typically more expensive and hard to get (plus you will have to adapt them to your use). Plus you will be limited to the 12/24/48 volts that you choose for your bank voltage. Low voltage circuits need heavy wire and/or short runs to keep voltage drop reasonable.

    #2 will be the easiest to use. You can get generic 120 VAC (or 240 VAC) devices cheaply and look for more efficient models (now that energy efficiency is a big thing). Almost anything you need is available in 120 VAC, and you can send 120 (240) VAC much longer distances over smaller gauge wire than you can with DC.

    Of course, there are mixes of systems (you can use 100 VDC solar array to send that power a reasonable distance to a remote battery shed) and you can always use a DC fan local (say top of mine) and send 120 VAC down for lighting/small tool use.

    And you may end up with two solutions... A dedicated solar panel + DC motor for ventilation and a separate off-grid battery based system with inverter for in-mine / at night / living space use.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: beginner needs help with start-up

    I guess from looking around, I would suggest that you contact www.sunpumps.com directly. It looks like they have some stand-a-lone DC solar motors available (they retrofit pump jacks for one).

    However, they do not list anything on their website as off-the-self at this time.

    If you are going to need the batteries for cloudy weather/off-sun use anyway--I would suggest sticking with off-grid+batteries+inverter system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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