g'day and welcome to part three of our complete off-grid 12-volt dual battery
master class now in this video I'm taking it up another notch and showing you that
you don't need to spend a fortune for the ultimate 12 volt off-grid system with a
setup like this you'll never have to turn your fridge off again you can run all your luxuries
from home with you any time at camp and you can camp for as long as you want even permanently
the first step to a permanent and next-level 12-volt setup is a dual battery system which
we went over in parts 1 & 2 then if you want to run your fridge permanently you're going to
need to charge your battery from more than just the alternator while you're driving you're going
to need permanent solar as well and then some sort of controller or regulator if you're sure
that your vehicle and your setup is suited to a smart battery isolator that's great but you'll
still need to add a separate solar controller or regulator to otherwise if you want the best
of both worlds and a DC DC charger with a built-in solar regulator and it's your isolator and battery
charger as well running a smart battery isolator with a separate regulator means that while you're
driving your alternator is still going to be providing most of the charge to your second
battery but even while you're driving all packed up your permanent solar will be charging your
battery as well using a DC DC charger with a built-in solar regulator is essentially the
same but if your DC charger has solar priority charging like this Adventure Kings 25-year model
that means it'll draw as much power as it can from the solar panel first right up to 25 amps
before drawing any from the alternator that will be less load on the engine and save you fuel with
a setup like this so long as you're driving a good couple of hours every other day or you're parked
in the sun you'll be topping up your batteries in part one I explained just how many empowers you'd
expect to use throughout the day around 24 amp hours for your fridge and say around 6 mph amp
lights add a couple extra amp hours for charging any devices and you can see that you need at least
30 amp hours a day that means with a 25 amp DC to DC charge you need to drive for a bit over an hour
to fully recharge those 30 amp hours or it needs to be parked in ideal Sun for a bit over an hour
to get full 25 amps of solar charge and be aware not all DC DC Chargers are capable of putting out
their stated output as they heat up The Adventure Kings 20 and 25 amp models have been tested right
up to 60 degrees Indian and will continue to put out their state of the output to go back to solar
input charging for a second I explained it need a bit over an hour in perfect sunny conditions to
get you 25 amps however you need 25 amps worth of solar and that equals about three hundred
and sixty watts worth of solar panels if you had say a 160 watt panel with about a nine amp output
you'd need over three hours of ideal Sun to get me to thirty half hours of charge and here's a
quick tip there's PWM and MPPT regulators and without getting too technical there's a fairly
easy way to estimate how much current or amps you can get out of each the first step is to
look at the specs of your solar panel to roughly estimate your PWM output look for the current at P
max specification on the back of your panel this panel here can provide nine point nine amps and
that means that's as much as your pwm can put out if it was charging at fourteen point four
volts times nine point nine amps you're looking at around 140 - what's whereas with an MPPT it'll
generally be able to put out closer to the full power in watts so divided the solar panel watts
by your charging voltage say fourteen point four volts and for the same example above you'd get
11.1 amps that's a significant increase so over a full day let's say ten hours of ideal sunlight
you might get around ninety nine point nine amp hours out of your pwm and about a hundred eleven
amp-hours out of the MPPT coming from exactly the same panel that's when it makes a difference of
course those figures are in an ideal world with no losses in reality you'd have to think about your
wiring and 12-volt setup exactly what regulator and panel you're using and how many clouds are
in the sky or what the ambient temperature is now there are two easy and relatively affordable ways
to ensure that you never run out of power either increase your battery capacity or your solar power
capacity with this single 160 watt solar panel you can expect to get about nine point nine amps
of current double it and you've got double the power that means that if a storm comes through
in the afternoon and you've only managed to get a couple of hours of Sun in the morning your
batteries of still charge twice as fast another option of course is to keep your permanent solar
panel running full-time and then set up your portable solar panel every time you turn out
to camp ideally you'd run them both through the same regulator or your DC DC charger but you
could run your portable solar panel directly onto your battery with its own regulator to top-up the
system doubling your battery capacity is the other option having extra power in reserve is definitely
not a bad thing as we learn in part one deep cycle batteries don't like to be discharged so
if you're running the same amount of gear but have twice as many batteries each battery is only doing
half the work that'll prolong their life overall plus you've got the advantage if you're at camp
for a couple of days it's cloudy and you're not planning to drive anywhere you've got double the
capacity to play with if you're adding extra 12-volt batteries to your setup make sure you
wire them in parallel that's red to red and black to black that'll double the amp hours and not the
voltage and then connect all your circuits off the positive of one battery and the earth or negative
of the other that'll connect both batteries as if they're one large battery and all your charging
and discharging will happen evenly through both it's also a good idea to run batteries of the
same chemistry type the same capacity and around the same age it's even a good idea to get the
same brand so that the batteries are identical and will charge and discharge in the same way I
another benefit to running two batteries is that it makes it so much easier to run your
high-power accessories like inverters now one battery would run new vertic white easily but
if you've got a bunch more 12-volt gear and more accessories having to makes everything work better
running an inverter at full capacity draws a lot of power this 1500 watt unit for example
at 12 and a half volts is drawing about a hundred and twenty amps another important
consideration is to work out how many amp hours your inverter will use and the first thing you
need to do for that is to find the Watts of the appliances you're running usually that'll be on
the back of the appliance it might say the total Watts all you'd have two times the volts by the
amps to find it then take that Watts figure and divide it by your battery voltage let's
say we had a coffee machine that was 1500 watts and our battery voltage was twelve and a half
volts 1500 divided by 12 and a half equals a hundred and twenty amps if I ran this coffee
machine for a full hour it would draw a hundred and twenty amp hours but let's say you're just
making one or two coffees and it's only on for five minutes here's a quick example so I'll take
120 amps and divide it by 60 to get each minute then we'll times that number by five for five
minutes that means if I ran this coffee machine for only five minutes it would still take ten
amp hours out of my battery 10 amp hours is a significant chunk but if you're spreading it
over two batteries it makes much less of a dent another good reason to have some extra capacity
if you're planning to run a big 12 volt set up and remember your inverter will run perfectly
fine off one battery but whether you're using one or two a great idea is to run your vehicle while
using it that way the alternator is charging the batteries and offsetting some of the power that's
being used adding an inverter requires some heavy duty wiring and some heavy duty fuses
but installing one of these lets you run basically all of your luxuries from home when you're at camp
building your dual battery system with a DC DC charger some extra battery capacity and larger
solar panels means you'll never have to turn your fridge off again it's the basis for a
serious off-grid 12-volt setup and it means you can essentially stay at camp for as long as you
want but there are two other bits of gear that I'd recommend packing if you're doing a really
extended trip the first is a generator if you're camping really remote the sun's not out but you
have no plans to move then a generator is a great backup it means you can run all your
gear and keep your batteries charged up and the second thing is a quality 240 volt wall charger
not only does it mean you can plug it into your generator so you know your batteries are properly
charged but if you're going through a town you can stop at the local caravan park top-up all
your batteries would be on your way the one last thing I'd suggest is to get yourself
one of these a multimeter you can always check that everything's working properly and on the
rare occasion that something does happen you can pretty quickly find out what it is whether
it's just a blown fuse or circuit breaker and absolute essential there are some more expensive
setups out there complete power distribution systems lithium batteries and fancy monitoring
screens and they do have their place but if you're after an easy affordable and reliable setup this
is perfect as always if there's any questions throw them in the comments below hit like and
subscribe and check out the rest of the channel for more camping 4WD driving and camp cooking
tips tricks and techniques plus keep an eye out for more of my 12-volt and off-grid videos