Sizing a Solar Panel Battery Charger

Quinn
Quinn Registered Users Posts: 7 ✭✭

Hi I’m new to this forum and have question I’m hoping someone much smarter than I can answer.  I’m looking at purchasing a new type of portable stove that uses a small amount of electricity for off the grid use. The manufacturer told me the smallest battery they recommend is a 12VDC 35AH. A fully charged battery I am told will provide for 2-3    1-1/2 hr uses before it will need to be charged.

The question is what size solar panel will I need to buy to re-charge the battery in a decent amount of time?  The electricity it uses is 100w / 20min pre heat and 100w / 30sec for ignition. Then it uses 15W continuously to run a small blower and fuel pump for however long you want to cook or heat which for me I figure 1-1/2 hrs. Per time.

So it’s 100W for 21min then 15w for 1-1/2 hrs two times per day from a 12vdc 35ah battery.  Sorry if it’s confusing but I’m trying and if anyone can help it will be great. Thx


Comments

  • mike74820
    mike74820 Registered Users Posts: 44 ✭✭
    i would say at least 200 watts of solar panels and a minimum 10 amp charge controller 

  • just starting
    just starting Registered Users Posts: 235 ✭✭✭
    What type of stove is this ?
    200ah LiFePO4 24v Electrodacus Sbms40 quad breaker chest freezer to fridge- Samlex PST 1524 - Samlex pst3024  - 1hp shallow well pump-Marey 4.3 GPM on demand waterheater - mama bear Fisher wood burning stove, 30" fridgarair oven ,fridegaire dishwasher  Unique 290l stainless D.C. Fridge-unique 120l portable fridge/freezer 
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Please, tell us more about this magic stove.  I know of one propane stove than uses just a 9V battery for the spark ignition,
    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 ,

  • Quinn
    Quinn Registered Users Posts: 7 ✭✭
    Thanks for the info mike74820 I will look into it ASAP. Hopefully a 200w portable solar panel system is available if not I will make do and thinking of hooking it up to a small Lithium Fe battery. Any idea on how long a 200w panel will take to re-charge the battery? I will also be able to use the battery / solar outfit for some Led lighting and a Ham Radio.  Gatt Energy is the company that makes the stove www.gattenergy.com should get you there. If if works as advertised it's pretty neat no propane or liquid fuel it uses wax. I figure if and when the SHTF a stack of wax will be cheaper and easier to keep around than propane tanks and disgusting kerosene.      
  • mike74820
    mike74820 Registered Users Posts: 44 ✭✭
    edited April 2016 #6
    how long it takes cant really be said until you know how many amp's you are using in a day. but to give you and example if you use 20 amp's in a day that,  The 10 amp controller will give back the 20 amps in about 3 hours in good sun
  • Quinn
    Quinn Registered Users Posts: 7 ✭✭
    Thanks again Mike. One more question and I promise to leave you alone. To help me understand usage:
     If it's lets say (2) x 100w for 30 min = 100w hour    and   (2) x 15w for 1-1/2 hours = 45w hour
    Add them together  100w hr + 45w hr = 145w usage for the day   or   145w / 12vdc = 12amp. Is that how it works or am I way off?

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Watts consumed x Time ( hours )  = watt hours consumed  ( say 250 Wh consumed)
    Harvest, you can expect about 80% of the PV panel nameplate.  100w panel can be expected to produce 80W under ideal conditions. 250Wh  @ 80W would need nearly 4 hours of perfectly aligned sun.
    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 ,