australia:camping_offgrid
camping off-grid - power, batteries, solar, fridges
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
Basic set up for a 12V car auxiliary battery system
12V battery - usually 100Ah deep cycle to fit a standard battery box (preferably LiFePO4)
battery box with voltmeter and various plugs including at least 2x Anderson plugs (these are bidirectional 50A)
Anderson plug cables to your devices with an inline fuse in the system to avid short circuits damaging your battery or starting a fire
optionally have Anderson plug cable with cig lighter female port on other end (or two of them)
optionally have one plug to two Anderson plug cable
optionally an amp meter with Anderson plugs on either side to measure voltage, current and total power used (or supplied) through the cable
optionally a connection from boot to externally mounted Anderson plug at rear of car to provide power to your tent, etc via an Anderson plug extension cord
battery charging systems such as:
240V AC battery charger for your type of battery (usually 15A or 25A)
DC-DC charger if charging from your car's alternator
need to connect this to the car battery with an inline fuse
need to connect to auxiliary battery via cable with Anderson plug
may need to connect a wire to the car ignition system
solar cells and solar charger (this may be included in your DC-DC charger) with Anderson plug
12V vs 24V vs 48V
general rule:
12V best for small systems with less than 300Ah
easier and safest to use
plenty of accessories available
can be charged from your car alternator using a DC-DC charger
not great for high wattage devices over 500W
24V best for RV's where you need more power
cheaper as has half the amp requirement and thus less copper needed than 12V
more efficient as less voltage drop across long wires
can still use 12V accessories via a 24 to 12V converter and these generally have 90% efficiency
BUT solar panels need to be at more than 24V to charge them hence you may need group parallel panels into pairs of series panels to overcome shading issues etc whilst still giving the needed voltage
cannot be charged via your usual 12V car alternator
still relatively safe as under 30V so 24V is a nice sweet spot for larger more demanding systems
you need to connect two 12V batteries in series to get 24V - not all 12V batteries allow that
48V is best for solar power homes or cabins
wires for DC currents
red is positive
black is negative / earth (connect black wires before red wires to a charged system)
6 BSB / AWG is rated for over 50A and has resistance of 1.3mOhm/meter
8 BSB / AWG is rated for around 40-50A and has resistance of 2.1mOhm/meter
10 BSB / AWG is rated for around 30A and has resistance of 3.3mOhm/meter
12 BSB / AWG is rated for around 20A and has resistance of 5.2mOhm/meter
14 BSB / AWG is rated for around 15A and has resistance of 8.3mOhm/meter
18 BSB / AWG is rated for around 10A and has resistance of 21 mOhm/meter
22 BSB / AWG is rated for around 3A and has resistance of 53mOhm/meter
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
solar recharge battery system
main options
fast charge, high capacity but heavy and expensive
fast charge, medium capacity
HardKorr Heavy Duty Battery Box $AU219 3.2kg
15A battery charger designed for LiFePO4 with Anderson plug connection modification $AU250-300
Drypower 12.8V 55Ah Lithium Iron Phosphate (LiFePO4) 8kg $AU799 or a 100AH battery for same price but 13.5kg
slow charge, medium capacity, light weight and compact power station
choice of battery and battery box / power station
Charging your auxiliary battery from your car alternator
solar panels
sockets and other miscellaneous issues
MC4 connectors
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
tow bar extension wiring:
Merit 12/24V 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
wiring
-
battery packs wired in parallel (reds to reds and blacks to blacks)
distributor box (eg. Victron Lynx Distributor)
inverter charger (eg. Victron Multiplus Inverter Charger 3000 W 12V)
red and black to distributor box DC in
earth wire to distributor box earth
3 wires (active, neutral, ground) from Shore power to AC in
3 wires (active, neutral, ground) from AC out to AC-DC distribution panel with a breaker
thus the inverter charger can:
combine amps from Shore power AC (eg. 30A) with the amps from the batteries if usage exceeds the Shore Power amperage
if power usage is less than the incoming Shore Power AC, then unit can use this to charge the batteries via the same cable to the distributor box
provide AC outlets
MPTT solar controller
red and black “battery wires” to distributor box
earth wire to inverter charger earth
red and black “PV” / solar wires“ to solar circuit breaker
solar panels are wired in series (or 4S2P pending requirements) and wired to a circuit breaker which is used as a disconnect
australia/camping_offgrid.txt · Last modified: 2022/01/03 18:41 by gary1