Battery Charging if no or little load

WNY Dave
WNY Dave Registered Users Posts: 23 ✭✭
in Solar Beginners Corner #1
Hi all. New to the site and solar. just a couple of quick questions...

The summer house was setup with wind power (1500W) turbine (broken now unfortunately it's 85' up in the air!) feeding 12 x 6Volt batteries 230Ahr/ea (3 banks of 4 wired series/parallel) for 24 Volt output. The batteries feed 2 x Trace/Xentrex 2000W inverters to the house. Also have a 5K generator for backup/charging.

To start the switch over to solar, We Plan on adding a FM60 Outback controller and 2 x 230Watt (30.1v appox ea) panels to charge them. Will that be enough power to maintain the batteries if there is no load during the week or very minimal load when we are there on the weekends? I can add more panels if needed.

thanks.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Battery Charging if no or little load

    Welcome to the forum Dave.

    What you have there is a (3 * 230) 690 Amp hour 24 Volt battery bank. To get it to charge well on a good day you'd want 69 Amps of peak current potential, which an FM60 can't really handle. Try an FM80 or MidNite Classic 150.

    In terms of panel, in order to produce that much current you need (69 * 24 / 0.77) 2150 Watt array. Two 230 Watt panels isn't even going to wiggle the needle as we used to say in the days of analog equipment. 460 Watts would produce about (460 * 0.77 / 24) 15 Amps, or a 2% charge rate. Enough to keep ahead of self-discharge, but no usage capacity.

    Remember you're trying to replace a 1500 Watt turbine, and in theory the turbine can produce 24 hours a day whereas the panels only produce in full daylight.

    A good thing to do to start is to re-evaluate your usage and see how it compares to the battery bank's 4kW hour (at 25% DOD) capacity, then go from there.

    BTW, I've been to Cuba, NY. Do they still make the cheese there? Famous for the cheese! :D
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #3
    Re: Battery Charging if no or little load

    first you will need to put those panels in series to get them to fully charge 24 v batteries, and as 'Coot says , you need more panels, quite a few more....

    They (2) 'may' be able to keep them topped up if they are fully charged to start with , depending on age and other factors, but they will only supply ~2750 W max per set, depending on how low you wish to discharge them, the lower you go the greater the risk of ending the batteries life span...

    What are your loads in watts?
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • WNY Dave
    WNY Dave Registered Users Posts: 23 ✭✭
    #4
    Re: Battery Charging if no or little load

    Thanks for the quick response and suggestions!

    Yes, they still make and sell the Cheese here!! :)

    Understand on the turbine part. Like I said, there will be no usage during the week, and would have all that time to maintain the charge on the bank. When there, I run the generator to charge them now, and it only drops maybe .2 volts over a couple weeks when not there. but will look into the FM80 or the Midnite Classic one and maybe more panels.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,011 ✭✭✭✭✭
    #5
    Re: Battery Charging if no or little load

    Since you have a nice tower for your wind genny, you might look into having someone lower it and have it checked out, though it might be a fixed tower, most wind gennies need maintenance from time to time so it's likely hinged some where...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • WNY Dave
    WNY Dave Registered Users Posts: 23 ✭✭
    #6
    Re: Battery Charging if no or little load

    THanks...it's a fixed tower, but had some type of gantry bracket thing, the top I believe tilts down to the gantry, for a block and tackle to lower it down or something. Will have to check.

    Until then, we just want to get some type of charging for the batteries. even it's just to maintain them.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #7
    Re: Battery Charging if no or little load

    For minimum panels I'd recommend 1 kW worth. That way you'd have the 5% recommended minimum charge rate when no loads are on. You'd also need a charge controller capable of at least 40 Amps.
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  • WNY Dave
    WNY Dave Registered Users Posts: 23 ✭✭
    #8
    Re: Battery Charging if no or little load

    Hooking up the 2 panels in series to start with, here is what I'm getting thru the controller. I'll add 2 more panels shortly.

    Panel specs Voc=37, Vpm=30.3, Isc=8.25, Ipm=7.6
    230Watts.
    Thanks for the help and suggestions.

    Attachment not found.
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  • WNY Dave
    WNY Dave Registered Users Posts: 23 ✭✭
    #9
    Re: Battery Charging if no or little load

    Update...the batteries are in float mode most of the time, controller output at 27.2 volts. Looks like the 2 panels are keeping the batteries charged quite well so far.

    Still looking for a good deal on 2 more panels to be added.

    Will be getting the daily data out of the controller to see what it has done over the past few weeks since I put it online. Like I said, the inverters, breakers to the house, etc.. are all turned off when we are not there.
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