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Power on a Rally Many of our Rally’s are held
on sites with an Electric Hook-up (EHU).
Some are not, often called ’Off Grid’.
On some Rallies you have a choice. One of the questions we are
asked most is how do you get on without a ‘hook up’. The answer is just
fine, as long as you have
prepared and are careful.
Your Bailey caravan or motor
home is designed to function perfectly without
mains power.
The heating, fridge and lighting will work just fine working on
gas and the leisure battery. Indeed the heating and fridge are sometimes
more efficient on Gas. Items that only work from the
240v Mains are the microwave, the 3 pin sockets and your battery
charger. Everything else, Heating pump/fan,
lights, water pump etc. work off 12v. i.e. your leisure battery. As your
battery is not being charged when you are not on EHU how do I go on?
Your battery is a reservoir of power.
It is continually charged when on EHU. For those vehicles fitted
with a solar panel/s these charge the battery by an amount dependent on
the amount and duration of the sunlight falling on them. Going off grid is dependent on
the reserve in your battery.
How long that lasts is dependent on three things.
How good a battery, how much power you use and how much power you
are harvesting from your solar.
Some people advocate using a generator and this will be
successful. However their
use is subject to time and nuisance restrictions and a good one will set
you back £600 to £1000. A
not insignificant investment and the running costs can be higher than
you might think. So you are going to need a
reservoir full of power I.e. a battery. Lead Acid
batteries have been around for over 100 years.
As a consequence they are known technology and cheap. You can buy
a good quality 100 - 120amp battery for less than £150. Dependent on type, you can pay
more for AGM or GELL lead acid batteries. The AGM
battery (Absorbent Glass Mat) is becoming quite popular as it stands
more charging/discharging than a simple one. It also is truly sealed
i.e. does not need topping up. There are also the latest
technology Lithium Batteries see separate section
below.
Some members double up and
carry two batteries giving them over 200 amps of potential power. All this power is not black
and white. Lead acid
batteries will only deliver about 50 - 60% of their power in a usable
format of power suitable for a Caravan or Motorhome and need charging if
they are not to suffer a shortened life span.
So to return to the question
how long will it last? In
our experience a good, charged lead acid battery will last 3-5 days
provided you do not use higher powered devices such as TVs or Inverters.
To go for longer additional
power input (Solar for example) is necessary.
Solar is dependent on the power of light falling on the panel and
for how long. This can vary
dramatically on a fine summers day a 100w panel will recharge your
battery easily. On a wet
day, you may not harvest anything.
Adding more solar to the roof is a comparatively simple thing to
do, as is changing the solar controller to a more effective type.
Both of these things will enable you to harvest more solar power.
See Members article on Solar Power charger/controllers. On the club web site you will
find links to battery suppliers including Lithium
The great thing about a rally
is that we have been at this for decades and you will have the support
of very experienced members. A List of typical power consumption is as follows, these figures are very approximate 19in T.V.
2-3 amps per hour. Led spot lights
0.3 amps per hour Blown air heating
1 - 6 amps per hour Alde heating
0.5 amps per hour. Water pumps vary
2 - 5 amps per hour Caravan Mover
30 - 40 amps Quad mover
50 - 80 amps.
Lithium Batteries Some of our members are
changing to the new lithium LiPo4 batteries.
These are half the weight of Lead Acid Batteries and provide
almost twice the quantity of power.
i.e a 100amp LiPo4 battery will give you nearly as much power as
2 * 100amp lead acid batteries and weigh in about ¼ of their combined
weight. They can be
recharged many 1000s of times.
So yes they are more expensive but long term costs are
cheaper.
A good Lithium Battery can now be had for approx £500/£600 Not only do
they last many years, they also respond by charging faster, be it by
mains or solar. They are
fare better for the environment, do not contain acid and very, very
safe. Your charger in your van will
handle a lithium battery just fine, so will
a
fitted solar panel and controller.
Going lithium used to be far more expensive and complicated.
Perhaps the most important thing is you must not charge them if
they are below 0 deg centigrade, you can use them to power your van way
below this but can damage them if they are too cold when charging.
Remember if you are on EHU it is easy to cut off the charging in
very cold weather. But if
your van is in storage for example and fitted with Solar Panels then the
protection is a must. Part of a Lithium battery is a
mini computer hidden in the case to control charging etc.
Called a B.M.S. this makes them a straight drop in replacement
for a conventional lead acid battery. Many now have a BMS that automatic
ally cut out charging below 0 deg to protect the battery, some have
built in heaters as well so they can be charged in Arctic conditions. So
make sure your purchase has this protection.
Those of you with Motor homes
can buy a box of electronics called a ‘Battery to Battery’ charger.
This will enable the alternator on the engine to charge a lithium
battery very quickly when the engine is running.
Nice to have but not essential.
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