Solar battery charger help

System
System Posts: 2,511 admin
Hi there,

This is my first post on this website. I have recently put together a small solar project that consists of the following parts;

1. 35 amp deep-cycle solar battery
2. 7 amp solar controller to stop overcharging and discharge.
3. 200 watt inverter
4. 12v .2 amp solar panel

After putting this together, I figured out that a .2 amp panel will take forever to fully charge the battery. I decided to upgrade my panel. I am on a budget, and I want to build my own out of photovoltaic cells wired in series to save money.

I was told that when I wire 36 .2 amp cells I still only receive .2 amps total. Is this correct?

Please let me know if you know of any cheap cells/panels that you think will fit my needs. Thanks 8)

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Solar battery charger help

    Yes, you are correct. Wiring cells in series increases the voltage and not the current.

    For you system, you should be aiming at ~3.5 amps @17 volts or so... (5-13% of battery Amp*Hour rating is recommended charging current).

    You are looking at a ~60 watt panel (10% of battery amp*hour rating -- P=V*I=17V*3.5A=60watts). Roughly $300-$350 list price for a good quality panel.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Solar battery charger help

    Okay, thanks

    I found a guy on ebay that sells 36 3.6 amp cells for $140.00. I think I may buy them, and then build the panel myself :D
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Solar battery charger help
    Okay, thanks

    I found a guy on ebay that sells 36 3.6 amp cells for $140.00. I think I may buy them, and then build the panel myself :D

    While it will be fun, and you may learn a lot, you will find that a home-built panel will not be easy to either build, or handle. If not sealed really well, moisture will get in and attack the individual cells, and they will die slowly. For a 2 or 3 year worth science project, it's fine, but don't expect to get 20+ years out of it.
    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 ,

  • System2
    System2 Posts: 6,290 admin
    Re: Solar battery charger help

    Thanks, I'll keep that in mind.

    Do you know of any ways to waterproof solar cells, or a solar panel. I would like to waterproof my solar panel that I have now so I can keep it outside.