What battery for my setup ?

Fry999Fry999 Registered Users Posts: 12 ✭✭
Hello guys ! 

My battery is a 12V 60aH and it's dying because of overusing it...

I have a 100watt (I'm not sure) solar panel charging the battery and a 600w inverter (1200w peak) giving me AC output.

My DC V meter show me a very low 10.6V during the night and 11.5 during the day coming from the battery. 

I want to change it to a new, more powerful one. 

My electricity needs are :
Charging small devices (phone, toothbrush, shaver)
Charging laptops (80watt one and a 120watt one)
Powering for few hours a small 120w fridge. 
And maybe powering a small evaporative air cooler over night. 

I'll be traveling for a while in Australia (summertime) so I can expect 5-6h of sun charge per day.   

Do you have any advice for a battery model/type suiting my needs ? 

Thank you ! 

Comments

  • PhotowhitPhotowhit Solar Expert Posts: 4,802 ✭✭✭✭
    You should reevaluate your energy needs, I suspect your battery is dying from chronic under charging. running the fridge for 'a few hours' is likely quite a bit more than a single solar panel can produce, and very ugly if you are using stored power alone.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • BB.BB. Super Moderators, Administrators Posts: 28,633 admin
    Are you flying? Is weight (of battery) an issue? Will you be a (more or less) fixed vehicle installation (will you have vehicle alternator to supply some energy)? Size of solar panels (physical size), etc..

    Various Li Ion batteries are certainly lightweight, have high energy density, and pretty close to the "ideal battery" (assuming you stay within their limits (do not over/under charge/over discharge--Picking the right chemistry will affect energy density vs excitement--Smoke and Fire if mishandled). Li Ion type are going to be best for (relatively) quick recharging (i.e., you can get a smaller battery and recharge quickly).

    AGM are heavy, "spill proof", and a bit more stable vs Li Ions. (AGM can take quick charging, but you have to have the solar array and/or AC battery charger to supply the high current for quick charging).

    Flooded Cell Lead Acid batteries are the cheapest solution.. Pretty rugged and forgiving. However, more or less, you can only recharge about 25% of capacity in an "average" solar day (10% rate of charge + 2-6 hours of "absorb" charging from ~80% to near ~100% state of charge).

    In general, a small portable system is not going to be very useful for running a refrigerator (they take "a lot" of energy and run for many hours to cool back down--Generally more than a "small & portable" system can reasonably supply... Even evaporative coolers take a fair amount of energy.

    Of course, anything can be done, but looking for more information to point you more accurately to something that will better for your needs.

    And we need to know your energy needs (in Amp*Hours or Watt*Hours). For example a cell phone may take 10 Watts to recharge in 1.5 hours = 15 Watt*Hours (below assuming "per day" usage or 24 hour usage).

    Cell phone 15 WH (1 day of average use)
    Toothbrush and shaver--Ignore for now (generally those will go for days between charging)
    80 Watt Laptop (that is a pretty large/high power one)... 80 Watts * 4 hours per day = 320 WH per day
    120 Watt Laptop (lots of processing power, large/bright screen)... 120 WAtts * 4 hours per day = 480 WH per day
    Refrigerator 120 Watt * 4 hours = 480 WH
    Evaporative cooler (pure guess) 8 amps * 12 volts * 8 hours per night = 768 Watt*Hours per night
    =======================================
    1,631 WH per day

    Assuming a flooded cell lead acid battery with 2 days of storage and 50% maximum discharge (for longer life)--Optimum for full time off grid use:
    • 1,631 WH per day * 1/0.85 AC inverter eff * 1/12 volt battery bank * 2 days storage * 1/0.50 max discharge = 640 AH @ 12 volt battery bank
    Or (roughly) 2x 6 volt @ 200 AH golf cart batteries in series (12 volts) * 3 parallel strings (600 AH) (6x Golf Cart size batteries--Not a small bank).

    To charge such a battery bank, typically 5% to 10% rate of charge (10%+ better for full time off grid):
    • 640 AH * 14.5 volts * 1/0.77 panel+controller deratings * 0.05rate of charge = 603 Watt array minimum 
    • 640 AH * 14.5 volts * 1/0.77 panel+controller deratings * 0.10 rate of charge = 1,205 Watt array nominal 
    And then there is sizing the array for energy usage and hours of sun per day:
    • 1,631 WH per day * 1/0.52 end to end AC solar power system eff * 1/6.0 hours of sun per day = 523 Watt array minimum
    Anyway, lots of questions (solar charge the battery bank during the day, and charge computers/etc. at night), or can you charge/run the appliances during the day (get away with a smaller battery bank).

    Or bring ~2-4 liters of petrol per day and a Honda eu20i genset and forget the battery bank to run/recharge your equipment.

    Lots of guesses, but it kind of gives you the thinking for sizing the system... Laptop wise, get a 30 or 8 watt laptop (save lots of power), forget the refrigerator and swamp cooler--And now you are down to 315 WH per day (or similar)--And a much smaller/more portable system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Fry999Fry999 Registered Users Posts: 12 ✭✭
    edited November 2018 #4
    Thank you Bill, I'm not flying I'm just super new to this and I want to know more :) you're all very helpful.

    So to be clear, this setup is mounted on a van I bought recently... The guy before was able to power the fridge and some devices (laptop, TV screen) without struggling that's why I'm curious... 
    From what I've understood is that the my battery (usual cheap gel car battery 12v 60ah) is dying or already dead since the regulator from the solar panel tell me it's fully charged, and it's obviously not... 

    My panel is 100cm X 35cm or so (quite small I guess, and I don't have any more information about it sorry) 

    For the watthour thing I'm not sure... I know that the fridge is 100watt. 
    For my laptop they are connected to 120v european AC output and not the Australian 240v output so I don't know if there is any difference in energy consuption in the end... 

    To be more precise  I would charge the laptops for 2h a day (I can already charge the 80w without trouble but my DC V are to low to power the inverter with bigger load) and use the fridge for 4h (but not everyday) when I really need it... 


    I was wondering if an deepcycdee battery 12v 120ah (which is in my budget) would help me to do the job or if I'm really flying tho... 

    Thanks again ! 
  • oil pan 4oil pan 4 Solar Expert Posts: 759 ✭✭✭✭
    A bigger battery won't fix that.
    You need a lot more solar panels.
    Think about it. If you can't keep a small battery charged what do you think is going to happen to a battery twice the size? 
    To run a fridge, just by its self you probably need at least 400 watts worth of panels.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • mike95490mike95490 Solar Expert Posts: 8,172 ✭✭✭✭✭
    >  The guy before was able to power the fridge and some devices (laptop, TV screen) without struggling that's why I'm curious... 

    as Dr House says "People Lie".    He either ran the engine a lot to keep the battery charged, or plugged in.   no possible way 100w of panel can accomplish that.  100w panel on roof will be hard pressed to keep a laptop going for more than 6 hours a day.

    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 ,

  • Fry999Fry999 Registered Users Posts: 12 ✭✭
    edited November 2018 #7
    I can charge the battery in fact, the problem is that it is dead so it don't keep any energy (that's why I'm willing to change it). I'm pretty sure the guy didn't lie, it got the job done by an electrician friend of his and was using it for 3 years. He encountered lack of power only the last few months (because of the dying battery, it looks pretty old). My solar panel could be more powerful than I think but I have no idea. 

    He told me that he disconnected the second battery of the van's battery because he didn't need it to charge it, solar panel is supposed to do the job alone. 

    I am agree whit you that it is not a proper set up but I pretty sure I can figure something out of it (without asking too much, I can get rid of the fridge if needed for exemple ;)).

    PS : I can power the 80w laptop at 9am directly with the solar panel (clear sky) - it must be at least a 150-200w or so ? 
  • mcgivormcgivor Solar Expert Posts: 2,658 ✭✭✭✭✭
    Fry999 said:
    I can charge the battery in fact, the problem is that it is dead so it don't keep any energy (that's why I'm willing to change it). I'm pretty sure the guy didn't lie, it got the job done by an electrician friend of his and was using it for 3 years. He encountered lack of power only the last few months (because of the dying battery, it looks pretty old). My solar panel could be more powerful than I think but I have no idea. 

    He told me that he disconnected the second battery of the van's battery because he didn't need it to charge it, solar panel is supposed to do the job alone. 

    I am agree whit you that it is not a proper set up but I pretty sure I can figure something out of it (without asking too much, I can get rid of the fridge if needed for exemple ;)).

    PS : I can power the 80w laptop at 9am directly with the solar panel (clear sky) - it must be at least a 150-200w or so ? 

    Lots of unknowns, speculation and second hand information from the previous owner
    Tones of excellent information contributed to help guide you towards a ballanced system
    Guesswork will definitely lead to dissapointment, if not tomorrow, shortly thereafter 

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
  • Fry999Fry999 Registered Users Posts: 12 ✭✭
    Well thank you all for your informations :) I'll try and do tests until I find something that will suit my needs. I'll change the battery in the first place, then I'll keep you up 
  • PhotowhitPhotowhit Solar Expert Posts: 4,802 ✭✭✭✭
    Fry999 said:
    PS : I can power the 80w laptop at 9am directly with the solar panel (clear sky) - it must be at least a 150-200w or so ? 
    The wattage listed on an item are usually the maximum energy draw. I have a 90 watt charger for my laptop, and I likely draw 20 watts most of the time in energy saver mode with the battery charging set for plug in use (maintains battery between 55 and 60% so mostly not charging)

    If you just back out your USB ports not in use, figure a USB 2 is 1 amp at 5 volts or 5 watts and a USB 3 is 2 amps at 5 volts of 10 watts, Have 1 of each not in use that's 15 watts that the computer must be able to run off the wallwart but isn't.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
Sign In or Register to comment.