What would be the best way to upgrade my small solar system's battery capacity?

affineO
affineO Registered Users Posts: 4 ✭
in Solar Beginners Corner #1
My very small solar setup has only one 35 AH 12V battery, powered by a 100W solar panel. I would like to upgrade the battery, but would not like to waste the one I already have. Is there any way I can do this?
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #2
    How old is your battery?   If it's fairly new you could buy another of the same battery and put the two of them in parallel. 

    When you do this, the new battery will quickly catch up in age to the old battery.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • affineO
    affineO Registered Users Posts: 4 ✭
    #3
    My battery is three years old. I don't think I could run it in parallel.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    #4
    What are you looking for? Larger battery bank capacity? New battery to replace the old (3 years is not bad for a small lead acid battery).

    There are other battery technologies (like various Lithium types) that can be interesting (high surge current, more efficient charging, light weight, etc.)--but they certainly are not cheap.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Alex
    Alex Registered Users Posts: 12 ✭
    #5
    If you want to use the existing and the new battery together, you should make sure the amp-hour capacity (and the voltage) is the same to avoid overcharging.
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  • affineO
    affineO Registered Users Posts: 4 ✭
    #6
    I'm looking for a way to use a new battery that I would buy and my old battery together. I don't think I can put them in parallel, but I was wondering if there was a way to not waste an old battery. My goal is larger capacity in total.
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  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    #7
    PV systems can be difficult to grow gracefully. If you need, or want, more battery storage capacity, with the present battery already 3 years of age, the best use for that battery will be as a core charge against the purchase of a new larger capacity battery.  
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
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  • affineO
    affineO Registered Users Posts: 4 ✭
    #8
    Mountain Don said:
    ...the best use for that battery will be as a core charge against the purchase of a new larger capacity battery.  
    How would I do that? I am searching for information online, but I can't figure out where to get the core charge.
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  • davemac
    davemac Registered Users Posts: 39 ✭✭
    #9
    Mountain Don said:
    PV systems can be difficult to grow gracefully. 
    Agreed!

    Another way to look at it is to keep the small 12V system that appears to be doing a good job and start all over with a new separate system. 

    A little independent 12 V system can be a very efficient way to run an extraction fan, some small LED's or as a little recharge station for your phone.

    The second system can then be tailored to an increased load demand and more future resistant and you have some redundancy with your neat 12V setup as well?

    (This is how I have my system planned, an independent 12V / 100 Ah for compost toilet extraction fan and LED night lamps and a 24 V for the major loads.)
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #10
    The core charge is added to the quoted price , well it is here anyways, when you put your money on the table , so to speak...  they seldom tell you in advance, you have to ask... some do not add on a core charge, some do....
     
    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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  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    #11
    Right. Not every online vendor will have a core charge. A core charge implies a refund for a returned old battery. That is not cost effective for online. Think local.
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
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