To dumb to make it work to stubborn to not

bettscrewbettscrew Posts: 2Registered Users
So there I was camping along with not a care in the world. Fast forward 2 months. Two batteries replaced, controller replaced wiring replaced new charge controller and my batts aren’t staying charged. I bought 2 6vs rewired my Pv direct to the controller. Getting 20v out of the pv if it’s not connected 12.2 when it is and my new 6v keep loosing power ( I think I have a voltage drain but haven’t found it yet). My pv has no card ( consensus is it’s either a 60 or 80 watt). Should I hook up the pv to the batts direct? My controller gets hot as hell If I plug in the converter. Where did I go wrong?

Comments

  • littleharbor2littleharbor2 Posts: 979Solar Expert ✭✭✭✭
      Two 6 volt batteries, if Golf Cart style 220 ah. will give you 220 ah. @ 12 volts. You need around 22 amps to charge this battery on a daily basis x how many sun hours  3, 4, maybe?  A 60-80 watt panel will only output 3.5 - 5 amps.  Also the solar panel's voltage will get pulled down to just above your battery voltage when charging.
     
       You haven't mentioned your loads but regardless you are way underpaneled.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • PhotowhitPhotowhit Posts: 4,660Solar Expert ✭✭✭✭
    Not sure what our system consists of... 

    ...but if you only have a single panel that is 60 or 80 watts, it's not enough to run much. If it's flat mounted on a camper, even less.

    A 70 watt panel, assuming that it's perpendicular to the sun and in full sun and not parked in the shade, with a PWM charge controller (inexpensive). May produce 70 watts ÷ 17.5 volts (normal for a 12 volt nominal panel) = 4 amps charging current. Most areas in average about 5 hours of sun light per day this time of year, So you have 20 amps charging. You will lose some of this going through the charging system but lets start there.

    Are you using an inverter to power things? I would guess this is what you are calling a converter. The inverter will use some power by it's self. In expensive inverters will not have a stand by mode and might use 20+ watts just turned on. 20 watts at 12 volts will be more than 1 1/2 amps per hour.

    Now back to your measurements. The 20 volts you are measuring is with out a load. The 12.2 voltage you are measuring when connected to the battery bank, is the current system voltage. With other loads (like the inverter being on) a 12.2 volt reading would indicate your battery is about 50% charged.

    Battery companies want you to charge batteries at 10-13% of their capacity. If you have 2 - 6 volt golfcart batteries, you likely have about 220 amphours of capacity. so you would want 22 - 29 amps of charging. Your single 70 watt panel can only give them 4. If this is a weekend use camper, you might get by with a 5% charging or about 11 amps but that would still mean tripling your solar array.


    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • bettscrewbettscrew Posts: 2Registered Users
    I haven’t hooked up my 12dc to 120vac inverter yet. Just been checking the volts over the last week. My 120 to 12 converter is making my controller very hot when plugged in to the house. Either way sounds like I need another panel to get this system working.
    Wife will love that
  • littleharbor2littleharbor2 Posts: 979Solar Expert ✭✭✭✭
    edited May 22 #5
    The converter shouldn't have any effect on the charge controller. you don't have the converter and controller connected together do you? They obviously are both connected to the battery bank but that's where any common connections should end. You don't have the converter connected to the controller, or vice versa do you??

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • PhotowhitPhotowhit Posts: 4,660Solar Expert ✭✭✭✭
    bettscrew said:
    I haven’t hooked up my 12dc to 120vac inverter yet. Just been checking the volts over the last week. My 120 to 12 converter is making my controller very hot when plugged in to the house. 

    WHAT?

    Are you trying to run a 120 volt ac to 12 volt dc converter through your charge controller?

    Sorry, I have no clue what you are trying to do.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • BB.BB. Posts: 27,682Super Moderators admin
    I think we need more details on your hardware and wiring.

    120 to 12 vdc power supplies may or may not make good battery chargers. Details matter here.

    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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