Charging without a Charge controller

westbranchwestbranch Not So New UserPosts: 4,022Solar Expert ✭✭✭
I have a need to connect, short term, a PV or 2 to my camper battery. We are demolishing our old cabin and using the camper for sleeping in, a bit of cooking and showers etc... both my CC's are still in use and I don't want to buy another one for this temporary setup.

Is there a rule of thumb to use for this hookup?

~ 660 amp battery, 25 W and 70 watt panels available. not direct sun as in the shade.

thanks
Eric
 
CL 647 asleep  24V 900Ah C&D AGM
CL 4592  175A E-Panel WBjr, 2 x 4s 140W to 24V 900Ah C&D AGM + 4s 140W 
Linksys Wet54g WiFi Bridge ,  ASUS RTN10 router, Hughes Sat Modem
Omnicharge 3024, Cotek ST1500W 24V Inverter,
1680W & E-Panel/WBjr to come, Eu3000i & 1000i Gens,
West Chilcotin, BC, Canada




Comments

  • mike95490mike95490 Title:User Posts: 6,203Solar Expert ✭✭✭
    Re: Charging without a Charge controller

    panels in the shade will never charge a battery:cry: You have more chance, without a charge controller, of the panels discharging the batteries at night (backfeed)



    660A of battery, 100W of panel, even in full sun, you won't keep up with self discharge.
    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 ,

  • CariboocootCariboocoot Gone Fishing... Posts: 17,615Banned
    Re: Charging without a Charge controller

    Eric;

    The only thing you can do is put a Voltmeter on it and watch. Together those two panels might produce 5 Amps? Not much for a 660 Amp hour battery (assuming the extra 'm' was superfluous), but even a small charge on a not-so-drained battery can push the Voltage too high. That's really all a PWM does; you'll have to stand in for connect/disconnect. But you don't have to do it dozens of times per second, okay? :p
  • SevenSeven Noob with a plan Posts: 292Solar Expert ✭✭✭✭✭
    Re: Charging without a Charge controller

    I have to ask a simple question. Is that battery a 660 amp hour battery or 660 cranking amps? At 660 Ah, that is a massive battery for a camper. Is it is 660cca, running a panel directly to it should keep it charged depending on the amp produced by the panel. I have a couple 100w panels hooked directly to a couple of marine batteries and the most I have ever seen them produce was 17a, and it was short duration.

    ***edit***
    Be sure to run a diode if the panels stay hooked up an night.
  • westbranchwestbranch Not So New User Posts: 4,022Solar Expert ✭✭✭
    Re: Charging without a Charge controller

    sorry, that is 660CCA as Leper pointed out. Probably in the ~100 A range of most car type batteries.

    Ya, caught in the PV panel trap of hi Voltage/low amperage output.

    It is a 'marine battery' used for the camper and the fishing trolling motor.

    Just ordered a cheapo 10a PWM CC off Ebay. Now I can put the panels in the full sun without too much worry.

    thanks for the quick comments.

    Eric
     
    CL 647 asleep  24V 900Ah C&D AGM
    CL 4592  175A E-Panel WBjr, 2 x 4s 140W to 24V 900Ah C&D AGM + 4s 140W 
    Linksys Wet54g WiFi Bridge ,  ASUS RTN10 router, Hughes Sat Modem
    Omnicharge 3024, Cotek ST1500W 24V Inverter,
    1680W & E-Panel/WBjr to come, Eu3000i & 1000i Gens,
    West Chilcotin, BC, Canada




  • mike95490mike95490 Title:User Posts: 6,203Solar Expert ✭✭✭
    Re: Charging without a Charge controller

    Since that battery is a "hybrid" and contains the worst of both starting and deep cycle, avoid discharging below 70%, or you may not get started some morning !
    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 ,

  • westbranchwestbranch Not So New User Posts: 4,022Solar Expert ✭✭✭
    Re: Charging without a Charge controller

    Mike I think you are confusing a camper with a "Winnebagel". ;):roll:;)

    The camper slides on and off the pickup and has its own on board, independent battery, hence the 'marine type' as it is a bit better for long slow use... the main drawback is there isn't enough room for a couple of real deep cycle 6 volt batteries.
    We only get about 2 days before needing to charge up. Water pump gets left on all day, Fridge and water heater are pilot-less units, the furnace fan is the big one and then lights and radio... oh and there is a magic fan that is temperature activated and the seldom used bathroom fan
     
    CL 647 asleep  24V 900Ah C&D AGM
    CL 4592  175A E-Panel WBjr, 2 x 4s 140W to 24V 900Ah C&D AGM + 4s 140W 
    Linksys Wet54g WiFi Bridge ,  ASUS RTN10 router, Hughes Sat Modem
    Omnicharge 3024, Cotek ST1500W 24V Inverter,
    1680W & E-Panel/WBjr to come, Eu3000i & 1000i Gens,
    West Chilcotin, BC, Canada




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