Charge controler choises

gunrunnera1
gunrunnera1 Registered Users Posts: 7 ✭
in Solar Beginners Corner #1
Hi,

I have been searching and reading as much as possible.
Building a 100 watt panel and need some help on a charge controller.
plan to add more panels as i can afford it.
I am looking at Prostar PS-30M or Tristar TS-45 both PWM.
Or should I buy a smaller cheaper controler for now then buy a MPPT when I can afford it.

Also if you could give me some brand names for a good Sine wave inverter.

Thanks
· Share on Twitter

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,641 admin
    #2
    Re: Charge controler choises

    Controller and inverter need to be matched to your system size, panel Vmp/Imp, and loads supported (12 volt, 24 volt, etc.--How many watts and starting surge, etc. for loads). MPPT charge controllers are nice--but expensive for a simple system with standard 17.5 volt panels and a 12 volt battery bank with short wiring runs from panels to charge controller.

    If you are building a smaller 12 volt system and will be powering small electronics, the Morning Star 300 watt TSW inverter is a very nice unit. If you are powering an Energy Star rated refrigerator, you will need a 1,200 to 1,500 watt inverter minimum.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • gunrunnera1
    gunrunnera1 Registered Users Posts: 7 ✭
    #3
    Re: Charge controler choises

    I'm wanting to do this in stages.
    I just don't want to make a purchase that I will regret.


    Stage 1.
    Lap top 45 watts
    2ea. 60 watt fluorescent lights 18 watts each
    total 81 watts for 6 hours each evening/night.

    Stage 2 Add
    ceiling fan 90 watts
    LCD T.V. 150 watts
    Total watts 301

    Stag 3 Add
    Whole House fan 350 watts
    Total watts 651

    Stage for still planning
    · Share on Twitter
  • gunrunnera1
    gunrunnera1 Registered Users Posts: 7 ✭
    #4
    Re: Charge controler choises

    I forgot. Wanta go with a 24 volt system.
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,641 admin
    #5
    Re: Charge controler choises
    gunrunnera1 wrote: »
    Stage 1.
    Lap top 45 watts
    2ea. 60 watt fluorescent lights 18 watts each
    total 81 watts for 6 hours each evening/night.
    81 watts * 6 hours = 486 Watt*Hours per day
    Stage 2 Add
    ceiling fan 90 watts
    LCD T.V. 150 watts
    Total watts 301
    301 watts * 6 hours = 1,806 WH per day (guess)
    Stage 3 Add
    Whole House fan 350 watts
    Total watts 651
    350 watts * 3 hours = 1,050 WH per day (guess

    Assuming that you get a solid 4+ hours per day for summer and that your system is around 52% efficient:
    • (486+1,806+1,050)WH per day * 1/0.52 eff * 1/4 hour of sun = 1,607 watts of solar panels
    That is a fairly large system. Perhaps, you would choose two inverters.. One small TSW one for your electronics and a larger MSW for the inexpensive motors (MSW inverters are not great for motors, but they are much less costly).

    You also need to size your battery bank for your loads... A good rule of thumb is 3 days of "no sun" support and 50% maximum battery discharge:
    • (486+1,806+1,050)WH per day * 1/24 volt battery bank * 1/0.85 eff inverter * 3 days * 1/0.50 max discharge = 1,010 AH @ 24 volt bank
    The above will give you a good size battery bank with a minimal size solar array (you could add upwards of 2x solar panels to above battery bank and still be within the general rules of thumb for system design). There is nothing written in stone here--You can adjust bank capacity / panel sizes to better fit your needs. However, if you go outside recommended ratings, the battery bank is generally the loser (undercharging or over charging) which leads to shorter battery bank life.

    I would humbly suggest that you purchase your solar panels instead of making your own... It is very difficult for a DIY panel to last decades and be fire safe.

    For the most part, people underestimate their loads and over estimate how much power a solar PV electric system can provide...

    In the end, conservation first, reduce use of loads second, then design the system to support the loads you need.

    This sounds like a backup system for a grid connected home? So, you will have utility power available when the sun does not shine or if load exceeds system capacity.

    If this was an off-grid system where reliability is paramount--then I would highly recommend not doing the DIY panels at all.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • gunrunnera1
    gunrunnera1 Registered Users Posts: 7 ✭
    #6
    Re: Charge controler choises

    Thanks for the info.

    I don't plan on putting the Hombrew panel on my house. I have read info about fire danger from homebrew panels. I wish I had read more sooner, I probably would have not built one.

    Yes I will still be on the grid.

    Trying to learn as much as I can so I don't damage my equipment, cause a hazard, spend unnecessary funds ect.

    I've read most homebrew panels are made of wood is there any reason I can't build it out of aluminum? My work has a fab shop and I could have a panel made out of plate aluminum.
    · Share on Twitter
  • gunrunnera1
    gunrunnera1 Registered Users Posts: 7 ✭
    #7
    Re: Charge controler choises

    what equipment would you suggest that would work for stage 1 and also work for stage 3? or is that not possible.
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,641 admin
    #8
    Re: Charge controler choises

    Solar does not scale well between small and large systems.

    Usually, your best bet is to buy nice components for your small system--then EBay it or sell/give it to a friend and replace everything with what you need for the larger system.

    You can parallel charge controllers (simply run each back to the battery bank)--so you can continue to mix and match panels/charge controllers... But it does become a pain to work on/upgrade...

    For example, you will probably endup with series/paralleling your solar panels together... The Vmp/Imp voltage/current of the panels need to match (within ~10% of each other) for proper operation. If you get a "large controller" with a few panels--you may have troubles matching Imp/Vmp with new generation/model panels a few years down the road.

    It is not impossible to match panels, and if you pick "standard" Vmp voltages--it is easier to match.

    Sorry, I am doing a bunch of hand waving here--but we get these questions all the time on how to upgrade a system, and we start asking for details of panels/charge controllers/battery banks to see how best to mix and match--It would be just more confusing if I gave a generic example of matching problems--lots of variables to play with.

    If you give the power needs (watt*Hours, not just watts), we could take a stab at it... You can usually "grow" a system 2x larger--but it is very difficult to grow one 10x larger without chucking almost all the old equipment.

    Charge controllers and solar panels are the best to move between old and new systems--but getting a large MPPT charge controller for a small 200-400 watt or less system is usually a waste of money (and power--large MPPT controllers use more power internally than small MPPT/PWM controllers).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • gunrunnera1
    gunrunnera1 Registered Users Posts: 7 ✭
    #9
    Re: Charge controler choises

    Thank you very much.

    you have given me a lot of good info to work with.
    I know you here the same old questions so thanks for the info again!

    I ordered a Kilo watt meter today so I can get a better idea of what I need. and try to reduce the load, more than I already have.
    · Share on Twitter
  • AntronX
    AntronX Solar Expert Posts: 462 ✭✭
    #10
    Re: Charge controler choises
    gunrunnera1 wrote: »
    what equipment would you suggest that would work for stage 1 and also work for stage 3? or is that not possible.

    I would just take the plunge and go with an expensive MMPT unit right away. There are multiple benefits of doing this. You can save money by not buying PWM controller. You can wire your panels for much higher voltage than with PWM CC, and still get the most power out of your panels wile getting by with using thinner PV wire.

    I use 100 feet of 10 AWG stranded copper wire with 520W of solar panels wired for 62 - 68 Vmp and 24V battery. Very little wire power loss of only 2.6%. If my panels were wired for 24V for PWM controller, then 10AWG wire would have 21% power loss. 4 AWG wire would be needed to bring power loss down to 2.6%.

    Do you build your own panels for fun or to save money? You can get thin-film panels today for $1 - $1.2 per watt. You can mix and match other panels, as long as you keep Vmp within +/- 5% or 10% at most.

    I decided to go with $500 Outback FM-60 as my first CC instead of cheap PWM CC and happy I did so. It has lots of neat features like data logging and versatile auxiliary device control. Given that it's an old unit now and there is newer and better controller on the market, I do not recommend buying FM-60.

    But if you are only looking to get your feet wet in solar for now, go ahead and buy something cheap like this. You will only be able to use up to 240 - 280 W of solar panels with 24V battery bank.

    Start with small pure sine wave inverter in 600W range. Samlex 600W 24V looks good, but I never tried it. Search this forum for opinions. I use more expensive Exceltech 600W 24V inverter, but it's double the price of Samlex.
    · Share on Twitter
  • lorelec
    lorelec Solar Expert Posts: 200 ✭✭
    #11
    Re: Charge controler choises
    gunrunnera1 wrote: »
    what equipment would you suggest that would work for stage 1 and also work for stage 3? or is that not possible.

    Might I recommend my Rogue MPT-3024? With a 24v system (battery), you can use up to about 800 watts of PV. It's an MPPT controller with data logging for $295. There is an entire thread about this unit somewhere on this forum, and a handful of people who are members here have purchased it and are using it.

    You can view the product info page here: http://www.roguepowertech.com/products/mpt3024.htm

    Marc
    · Share on Twitter
  • gunrunnera1
    gunrunnera1 Registered Users Posts: 7 ✭
    #12
    Re: Charge controler choises

    hello AntronX

    I was trying to save money where can I get these panels from?
    · Share on Twitter
  • AntronX
    AntronX Solar Expert Posts: 462 ✭✭
    #13
    Re: Charge controler choises
    gunrunnera1 wrote: »
    hello AntronX

    I was trying to save money where can I get these panels from?

    There is DuPont 100W thin-film panel available now, but I never tried it. Note that this panel takes double the space of regular mono/polysilicon panel because of thin film lower efficiency. If you feel like spending $1.82 per watt on polysilicon panels, take a look at these non-UL Evergreen panels. Or for $2.52 per watt this panel from our host Wind-Sun. Factor in shipping cost too.
    · Share on Twitter
  • CaptTurbo
    CaptTurbo Solar Expert Posts: 66 ✭✭✭✭
    #14
    Re: Charge controler choises

    [Or for $2.52 per watt this panel from out host Wind-Sun. Factor in shipping cost too.[/QUOTE]

    I have the Trina 230 Mono panels and they are rockin' along great. I wasn't aware that the polys were so much cheaper or I might have gone with them since either one seems to put out the same juice. They both look good to me too even though the mono panels are supposed to be more uniform in color. Not sure that I could spot the difference.
    · Share on Twitter

Categories