Adding on question from new guy

solarfatcat
solarfatcat Registered Users Posts: 12 ✭
in Solar Beginners Corner #1
Hello. I have two 60 watt panels ( 12 v 3.42 a ) , a 10 amp 150w charge controller, and a Excide ng 24 deep cycle battery ( 80 amp hrs ) . I have the panels hooked up in parallel. My question is, could I add another battery ( should it be the exact same, amp hrs, volts ect. ? ) and hook it up in parallel also ? Or do I need a stronger charge controller ? Also, any info on adding a fuse or breaker to this system....and how to install ? Thank you.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Adding on question from new guy

    Don't add another battery without adding more panel. The 120 Watts you've got now should be good for the 80 Amp hour battery. If you add more battery your charge rate will drop. Your controller is just about the right size for the set-up too. Expansion is not advisable.

    For one thing, if you add a battery it has to be the same type. If the first battery is old or has been heavily used even that won't work because the effective Amp hour rate will now be different from the specifications. If it isn't out of spec essentially you'd have to double everything; batteries, panels, and controllers.

    As for fuses, there should be a 10 or 15 Amp fuse on the positive output of the charge controller. You can probably use a 10 because it's doubtful those two panels would exceed 8 Amps at best. You do not need fuses on two parallel panels. Any loads attached to the battery should be fused accordingly: size the wire right to handle the load and the fuse to protect the wire.
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  • solarfatcat
    solarfatcat Registered Users Posts: 12 ✭
    #3
    Re: Adding on question from new guy

    Ok, now I know I need a 10 amp fuse on the + output of the charge controller. What are my options ( would it cause any problems using a 15amp fuse ? ) . Where can I buy one of these ? I've searched the internet, but there are so many. A specific part# or name brand would be helpful. Can I use a 10 amp breaker instead of a fuse ? Any additional info on fuses would be great. Thank you.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #4
    Re: Adding on question from new guy

    Typically, the battery bank is the source of high current in an off grid system. So, all fuses should be located near the battery and their value should represent the size of the wire leaving the + battery bus connection (i.e., 14 awg wiring typically uses 15-20 amp fuses).

    For these smaller systems, you can go to an autoparts or auto stereo supply store... They should have a good selection to fit your needs.

    For nicer setups, you can also go to a boat parts store and look at their DC distribution systems.

    Our host has a fair assortment of fuses and breakers.

    Bluesea and other marine suppliers have a large selection of fuses and breakers too.

    And some others:

    Various automotive holders
    Prime Products

    Your fuses and breakers should always be no larger than the attached wire can support--And branch wiring/fuses/breakers should be at least 1.25x larger than your maximum expected continuous load (otherwise the fuse/breaker may trip).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • solarfatcat
    solarfatcat Registered Users Posts: 12 ✭
    #5
    Re: Adding on question from new guy

    Ok, I purchased a 10 gauge inline fuse holder. It holds a glass AGC fuse. I purchased a 10 gauge holder because all my wiring is 10 gauge. Is this type of fuse ok, or is there a better choice ? I also purchased 10 and 15 amp fuses. Thank you.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: Adding on question from new guy

    It should be fine.
    The other type - MDL - is slower to pop, but it shouldn't matter in this application.
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