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australia:camping_offgrid

camping off-grid

Introduction

  • one of the main issues when camping off-grid for an extended period is power supply to run fridges and other devices
  • for short periods, lithium ion batteries or lead acid battery may suffice but for extended periods these need to be re-charged and one does not want to rely upon running the car to re-charge them.
  • caravans often have gas powered fridges

portable car fridge/freezer

  • these are generally DC and 240V AC powered and should have a 3 stage battery protection system to turn the fridge off in the event the vehicle battery is going flat (if the fridge is being powered by the main vehicle battery)
  • most have a digital interface which allows user to dial in the desired temperature from 10degC down to minus 10degC
  • some have dual compartments - one as a fridge and the other as a freezer
  • the best size for most families is a 60L capacity but 45L may suffice for a couple
  • a 45L model will generally draw 1A to maintain contents at 5degC in 32degC ambient temperatures
  • fruit and veges are generally placed in the warmer upper parts to avoid spoiling by freezing
  • a 45L model will cost $AU399-$AU699 - check to see if it will fit a wine bottle standing up if this is important to you
  • Dometic CF models are budget level fridges which are more likely to have issues including failure of the lid lock mechanism
  • Dometic CFX models tend to be the favored models for their better build quality but are more expensive

Off-grid power supply

  • there are a variety of components required

solar recharge battery system

choice of battery

  • lead acid battery
    • these may be a deep cycle or dual purpose battery which may provide 12V 110Ah on a full charge
    • A deep-cycle battery is a battery designed to be regularly deeply discharged using most of its capacity, unlike a normal starter battery which is designed to only use a small part of its capacity in a short, high current burst to crank the engine.
    • deep cycle batteries cannot be used to crank start your vehicle, but a dual purpose one can.
    • there is a trade off between the battery's depth of discharge and the number of cycles of discharge and recharge it is capable of and there is an inverse relationship between these
    • these deep cycle batteries are generally designed to discharge slowly over 20-100hrs such as with a fridge, and if they are discharged rapidly such as over 1 hour, you will only get to use around half of the usual capacity and the number of cycles will be reduced
    • none of these lead acid batteries should be fully discharged as this will shorten their life span, and should only be discharged to 20% of capacity
    • Absorbent glass mat (AGM) batteries handle higher temperatures better, self-discharge more slowly, will charge more quickly (usually within 3hrs from a standard car alternator), have deeper discharge depths, are totally sealed, more robust, do not need topping up with water, can be safely mounted inside a car as they do not need to be vented externally
    • these can explode if over-charged or their release valve fails (if they have one)
    • these will usually set you back around $AU230
  • lithium iron phosphate batteries
    • these are lighter, safer, but currently are much more expensive for the battery which generally has much less capacity than a lead acid battery
    • Up to 10x the life of an equivalent Lead Acid battery and weigh less than half as much and has far less self-discharge rates, retaining 80% of charge by 12 months compared with only 40% for typical lead acid batteries
    • More resistant to vibration, less likely to be damaged and have a more stable output voltage which tends to be maintained until capacity falls below 30%
    • LiFePO4 batteries are less likely to explode when over-charged and maintain charge longer than other lithium batteries
    • it should have a built-in battery management system to ensure all cells are charged evenly, and to provide short-circuit protection, reverse polarity protection and over-current protection as well as ensuring a consistent output
    • Deep cycle ones are not suitable for not suitable for use as a primary vehicle starting battery
    • eg:
      • Powertech 12.8V 100Ah Lithium Deep Cycle LiFePO4 battery $AU799

power pack case

  • these not only house your battery but provide a range of very useful and convenient functions which may include:
    • ability to re-charge the battery via either:
      • 240V input
      • solar panel input
      • DC input including from your car's main battery and alternator system
    • various DC output interfaces such as:
      • cigarette socket outlet
      • USB port
      • DC out port
    • possibly a built-in AC sine wave inverter with 240V output
      • HOWEVER, as the lead acid batteries are not designed for rapid depletion, only low current draw appliances should be run - higher draw appliances may need a petrol power generator with an AC inverter
    • a good one will cost around $AU499-699
    • eg:
      • ArkPak 730P $AU699 - 300W Pure Sine Wave Inverter; the only battery box on the market that has a built-in AC-DC and DC-DC charger; battery management system and a dual-battery alternative; 50 amp Anderson socket; 2x 12V sockets; 1x 5V USB 2.1amp socket; 7 Stage smart charge; compatible with LiFePO4; 4.6kg;

solar panels

  • these are usually rated at around 120W
  • more modern “soft fold” panels are much lighter, more compact and more convenient but considerably more expensive than the older aluminium framed ones and may cost $AU699

sockets and other miscellaneous issues

  • Anderson 12/24V socket
    • a specialized socket designed to handle a high, continuous load which allows charge from your car battery or solar panel to flow to your accessory battery in dual battery systems and hence can be used to connect car to caravan
    • can also be used powering high-draw 12-volt accessories such as fridges and air compressors
    • they come in different current sizes eg. 50Amp
  • Merit 12/24V plugs
    • similar to cigarette lighter plugs BUT smaller in size and have the advantage of a superior rugged construction and higher current carrying capability
    • can be converted to cigarette lighter plugs

petrol power generators with AC inverters

  • these are important particularly if you need to run higher current draw appliances such as heaters and microwaves
  • they can also be used to re-charge your batteries if the solar is not adequate
  • make sure you get one with pure sine wave inverter to give clean AC outputs that won't damage your electronics
  • also check how noisy it is as they are perhaps the most hated accessories at camp grounds due to their noise (as well as exhaust fumes)
  • some have parallel stacking capability to combine units for greater power output
  • examples:
    • Ryobi RIG2000PCB 2000W Petrol Digital Inverter Generator $AU999 - 24.4kg 2 x 15A sockets and 2 x USB outlets
    • DeWALT DXIG2200 2200W Inverter Generator $AU1299 - 22.5kg
    • Full Boar SD2200I 2200W Inverter Petrol Generator $AU798 - 21kg, 61db
    • Yamaha EF1000iS 1000W 1 KVA Silent Inverter Generator $AU1299 - 12.7kg, 47-57 dBA/7m

more powerful lithium ion off-grid solar kits for homes or sheds

    • Victron 12v 1200w pure sine wave phoenix inverter
    • DCS 12v 200Ah lithium battery storage
    • 31.5A Votronic solar controller
    • Trina solar panels (2 x 310w mono)
    • Victron Battery Protect (low battery voltage protection)
    • 333Ah 48V dual lithium battery system (2 x DCS PV 10W LFP batteries which provide total 15kW continuous load) = 198kg, $AU17,999 for batteries alone (cw 900kg of lead acid cells)
    • Selectronic 7.5kw SP PRO solar controller
    • Fronius 8.2kw Primo inverter
    • 10 ~ 12kw of solar PV panels - should provide around 19kWh even on the most cloudy days in lower latitudes and average winter evening usages for a house runs at around 10kWh.
    • +/- 5kVa diesel backup generator
australia/camping_offgrid.txt · Last modified: 2020/03/23 00:02 by gary1