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UK Caravanning (uk.rec.caravanning) A forum for the discussion of caravanning undertaken by residents of the United Kingdom, whether in the UK or abroad. It encourages the interchange of views on the merits of models of caravan, makes of tow car, accessories, caravan sites, caravan clubs, and other related topics. The term caravan is to include trailer vans, motor caravans and trailer tents.

Solar Panel



 
 
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  #1 (permalink)  
Old February 13th 07, 07:33 PM posted to uk.rec.caravanning
Darren Hebden
external usenet poster
 
Posts: 3
Default Solar Panel

Hi

Does anyone have any experience with solar panel chargers?

Are they any good for charging the battery or are they just a waste of time?

Any input would be welcomed.

Thanks

Darren


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  #2 (permalink)  
Old February 13th 07, 07:56 PM posted to uk.rec.caravanning
Mary Fisher
external usenet poster
 
Posts: 3,847
Default Solar Panel


"Darren Hebden" wrote in message
...
Hi

Does anyone have any experience with solar panel chargers?

Are they any good for charging the battery or are they just a waste of
time?

Any input would be welcomed.

Thanks

Darren


We bought one from Maplin a few years ago, it was about £10 and we use it
for trickle charging the leiusure battery in our big (12') caravan. The
little (10') one has no electricity.

We've been very pleased with it - but if you get one don't leave it out in
the rain. We had corrosion in the connections when we did that (over several
months) and it all had to be replaced.

Mary




  #3 (permalink)  
Old February 13th 07, 08:13 PM posted to uk.rec.caravanning
Dave Fawthrop
external usenet poster
 
Posts: 1,831
Default Solar Panel

On Tue, 13 Feb 2007 20:33:30 GMT, "Darren Hebden"
wrote:

|!Hi
|!
|!Does anyone have any experience with solar panel chargers?
|!
|!Are they any good for charging the battery or are they just a waste of time?
|!
|!Any input would be welcomed.

There are several other alternatives for keeping a leisure battery charged,

You can caravan without that orange cable FAQ
---------------------------------------------
updated 23/07/06

This FAQ is intended to give some pointers on how to caravan without
that orange cable, or at a site where hookups are not available. It
does not try to say what is best, because that will depend on your
individual circumstances, but does try to give basic information about
the methods and the advantages and disadvantages of each alternative.

For general information on batteries see: http://www.batteryfaq.org,
this is a bit US oriented, but lead acid batteries are much the same
worldwide.

Domestic multimeters now cost as little as ?2.50 and are useful for
caravan work.

Charge
------

A new fully charged 110Ah Leisure Battery will last most people for a
weekend, but very few a week. For longer than a few days you will
have to recharge the battery somehow. Remember that as batteries get
older and as they have more use/misuse they will hold less charge, and
eventually need replacing.

Leisure batteries are usually *not* the no maintenance batteries
becoming common in cars. If yours allows topping up, always check
your electrolyte, and top up to marks on the body with
distilled/deionized water regularly. You should always charge your
battery(s) before you leave home, either on the bench, or by leaving
the van powered up, you should give either method several days to
fully charge. Cheap chargers make gas, so you must top up the
electrolyte. Expensive electronic chargers do not fully charge the
battery, and make less gas so need topping up less frequently.
Remember also that the electrolyte will evaporate slowly even while
the battery is unused.

There is very little power in a leisure battery so you should use it as
sparingly as practicable. You should use LPG for as many things as
possible, water heating, heating, cooking, fridge etc. You should also
make sure that the your electric appliances will run off 12 Volts. High
power electrical equipment is bad news. A 1000 watt heater used on its
own, will run for less than 1 1/2 hours, 500 watts less than 3 hours.
250 watts some 5 hours. As a general rule something like a TV taking
50W or 4 amps for a few hours per day is the heaviest load practicable.

The output voltage of a battery falls slowly as a charge is used, and
eventually the 12 V equipment will stop working. TVs etc. need as
many volts as possible. Thin long wires which may be supplied by the
van manufacturer or as a D.I.Y. addition, may have a high voltage
drop. If possible add extra wiring for TV, or other electronic
equipment, of thick wires ?2 sq mm? or preferably more, and as short
runs as practicable.

You should find out how much charge you use on an average day in the
van. The maths is simple 110AH=1320wattHours. watts=12*amps,
amps=watts/12, at 12 V DC. Find how many watts/amps each appliance
uses from labels or instructions. Multiply these by the hours each is
used daily. Add daily charge used in watthours or amperehours used by
each of your appliances together to give daily charge used. You
should replace this charge averaged over 2-3 days. There are many
alternative ways of replacing this charge, the choice is yours, and
will depend on your personal circumstances. Beware especially of red
"standby" LEDs, the circuit behind them uses about 7 watts, which is a
tiny amount of power, but they are on 24 hrs, less the hours they are
used, per day. Allow 12 ampere hours or 144 watthours *each* per day,
which is a significant drain on the battery.

Car
---

You can use two batteries. An extra battery can be charged in the
back of the car via a split charge relay. This battery should be
securely fastened into the car. The batteries contain Sulphuric acid
which is nasty stuff and if the battery tips over it can do a lot of
harm to the car. Also if you have a crash a battery hitting the back
of your head may cause serious injury. The tiny amounts of hydrogen
and oxygen produced, should cause no problems, in a well ventilated
car. If you use marine batteries, many of these will dump the gasses
overboard via a plastic tube. If you go out in the car and "do"
things on most days while using the van, this should give you enough
charge. If you stay on site or just drive to the local town/beach this
method will not work for you. At some sites battery charging
facilities are available. Swap the batteries daily or at slightest
sign of low voltage. Be warned however that batteries are heavy and
cumbersome to change, and this is not a method for the unfit.

You should ensure that when the van is being towed the battery is
actually being charged. There are no less than three ways in which
the van can be wired, and three ways in which the car can be wired
giving ?5? combinations, some of which do not charge the van battery
when towing. see: http://www.volvoclub.org.uk/towbar_electrics.htm.
If you tour continuously this will be important, but if you just tow
to a site and eventually home again you can probably ignore this
method.

Site chargers.
--------------

Some sites particularly CC CLs advertize charging facilities for
batteries, usually in some sort of barn or outhouse. If you carry a
spare battery, this can work very well, a single battery only charging
during the day it is less convenient. Humping a leisure battery around
requires some strength, and is not for the unfit.

Solar
-----

Solar cells are available specifically for vans, but are rated pointing
directly at full sun, which rarely happens in UK, but they do give some
output even on cloudy days, unfortunately the retailers do not tell you
how much. A charge controller is a good idea. If possible point your
cells due south, slightly below the maximum local elevation of the sun.
As a general rule you will need *big* cells 25 watts or preferably more.
The Australians with all their sun fit 80 watt solar panels or larger.
If you calculate charge needed as above, you can get a better estimate
of the size of cells required.

Wind
----

Wind generators are rated at a high wind speed which rarely happens in
an English summer, they give a lower output at lower wind speeds. The
power from a wind generator varies as the *cube* of the windspeed, so
half the wind speed gives a eighth of the power. A charge controller is
a good idea. Many caravan sites in the countryside are surrounded by
trees, which reduce wind speeds. Other sites by the seaside are better
for wind generators. As a general rule you will need a 25Watt generator
or preferably more powerful. If you calculate charge needed as above you
can get a better estimate of the size of generator required.

Generators
----------

Portable petrol driven generators with 240Vac output can be plugged
into your van. They however make a noise which other campers find
objectionable. These generators will also charge your battery, but how
much will depend on the generator and charger in use. Most sites
will forbid their use during the night, so you will need to use 12V
for some of the time.

Invertors
---------

Invertors which change 12Vdc to 230Vac, are commonly available.
Increase the charge calculated above by up to 20% for things run via
invertors. These should be wired directly to the equipment which uses
230VAC. Do not wire the output of the invertor to the van 230VAC
sockets, which run the charger, which runs the invertor, which runs
the charger ....
--
Dave Fawthrop dave hyphenologist co uk
20,000 free e-books at Project Gutenberg! http://www.gutenberg.org
For Yorkshire Dialect go to www.hyphenologist.co.uk/songs/
http://www.gutenberg.org/author/John_Hartley
http://www.gutenberg.org/author/F_W_Moorman
  #4 (permalink)  
Old February 13th 07, 09:24 PM posted to uk.rec.caravanning
Bert W
external usenet poster
 
Posts: 115
Default Solar Panel

Darren Hebden wrote:
Does anyone have any experience with solar panel chargers?

Are they any good for charging the battery or are they just a waste
of time?


What's a solar panel charger? You need a good solar regulator, because
panels tend to give 16V or more. You must not connect solar panels directly
to a battery.

--
Regards, Bert W
www.whattowcar.com

  #5 (permalink)  
Old February 14th 07, 11:16 AM posted to uk.rec.caravanning
Mary Fisher
external usenet poster
 
Posts: 3,847
Default Solar Panel


"Bert W" wrote in message
...
Darren Hebden wrote:
Does anyone have any experience with solar panel chargers?

Are they any good for charging the battery or are they just a waste
of time?


What's a solar panel charger? You need a good solar regulator, because
panels tend to give 16V or more. You must not connect solar panels
directly
to a battery.


Except those which are designed to do just that, like ours.

To date I'm the only one who's answered your question, Darren :-)

Mary


  #6 (permalink)  
Old February 14th 07, 04:40 PM posted to uk.rec.caravanning
Darren Hebden
external usenet poster
 
Posts: 3
Default Solar Panel


"Mary Fisher" wrote in message
t...

"Bert W" wrote in message
...
Darren Hebden wrote:
Does anyone have any experience with solar panel chargers?

Are they any good for charging the battery or are they just a waste
of time?


What's a solar panel charger? You need a good solar regulator, because
panels tend to give 16V or more. You must not connect solar panels
directly
to a battery.


Except those which are designed to do just that, like ours.

To date I'm the only one who's answered your question, Darren :-)

Mary


Thanks everyone,

I think I've made up my mind, I'm planning go caravanning for the first time
this year without a hook-up and was considering my options.

Generators I think are too noise so I'm not going for that, and solar panel
are expansive for the higher wattage ones.

So I think the best option for me would be to by a second battery and charge
it up and keep it as a reserve.

Thanks for all your help.

Darren


  #7 (permalink)  
Old February 14th 07, 09:28 PM posted to uk.rec.caravanning
Dougal
external usenet poster
 
Posts: 524
Default Solar Panel

Darren Hebden wrote:
"Mary Fisher" wrote in message
t...

"Bert W" wrote in message
...

Darren Hebden wrote:

Does anyone have any experience with solar panel chargers?

Are they any good for charging the battery or are they just a waste
of time?

What's a solar panel charger? You need a good solar regulator, because
panels tend to give 16V or more. You must not connect solar panels
directly
to a battery.


Except those which are designed to do just that, like ours.

To date I'm the only one who's answered your question, Darren :-)

Mary



Thanks everyone,

I think I've made up my mind, I'm planning go caravanning for the first time
this year without a hook-up and was considering my options.

Generators I think are too noise so I'm not going for that, and solar panel
are expansive for the higher wattage ones.

So I think the best option for me would be to by a second battery and charge
it up and keep it as a reserve.

Thanks for all your help.

Darren


I'm unsure whether you are a first-time caravanner or just a
first-time caravanner without mains - the latter I suspect.

Either way I think that you've made the right choice and your
experience with batteries will guide you as to whether the move is to
your liking leaving open the possibility of solar charging as a future
'enhancement'.

The solar option suits my lifestyle with no ability to use mains
electricity (*) and usually no access to the mains anyway.
* - not quite true as I run an inverter to charge camera batteries.

I use a 50W panel. My longest period of use will have been about ten
days and ended by the need to move on rather than the need to find an
alternative means of charging. I've never felt even close to being at
risk of running out of charge on a single battery installation.

I suspect that my level of electricity usage will, however, be
described as light by the standards of many not that I have felt any
need to limit battery use.

There are no problems connecting solar panels directly to batteries
but a large panel and small battery is not a good match. The output
characteristic of the panel is such as to drastically cut the charging
current as full charge is reached. (http://tinyurl.com/36jra7). There
is however no other control or monitoring and you will be a little in
the dark as to the charge rate/status etc.. Controllers can give you
this usually combined with over-discharge protection and charge
equalisation charging (essentially a contolled over-charge) - this may
be a good selling point regardless of need.

As to panel purchasing advice I'd recommend that you deal with
manufacturers if possible or known experts in the field (frequently
marine outlets). The prices at normal retail outlets and caravan
dealers are extortionate.

The panels available from these commercial sources are intended for
exterior use and the connections are suitably robust and waterproof.

  #8 (permalink)  
Old February 14th 07, 10:56 PM posted to uk.rec.caravanning
Bert W
external usenet poster
 
Posts: 115
Default Solar Panel

Dougal DougalAThiskennel.free-online.co.uk wrote:
snip

The solar option suits my lifestyle with no ability to use mains
electricity (*) and usually no access to the mains anyway.
* - not quite true as I run an inverter to charge camera batteries.

I use a 50W panel. My longest period of use will have been about ten
days and ended by the need to move on rather than the need to find an
alternative means of charging. I've never felt even close to being at
risk of running out of charge on a single battery installation.

I suspect that my level of electricity usage will, however, be
described as light by the standards of many not that I have felt any
need to limit battery use.


I agree on that. In summer I never use mains hook up as I'm a moderate user
(battery 95 Ah + 2 roof mounted solar panels Pmax about 60W). But an
inverter (for my laptop and camera batt.) has entered the standard outfit...
so ;-(

In general. In northern Norway the sun angle is small, but light is
available 24/24! So you do not have to go to the equator... In winter or off
season I use mains of course. The comfort of floor heating (via mains 42V)
is more of interest to me than spent a few bucks. But in summer? It makes me
independent of certain pitches or sites or better in 'the rough' (wild?)

There are no problems connecting solar panels directly to batteries
but a large panel and small battery is not a good match. The output
characteristic of the panel is such as to drastically cut the charging
current as full charge is reached. (http://tinyurl.com/36jra7). There
is however no other control or monitoring and you will be a little in
the dark as to the charge rate/status etc.. Controllers can give you
this usually combined with over-discharge protection and charge
equalisation charging (essentially a contolled over-charge)

snip

I disagree on that (the direct connect matter). As said a solar panel give
about 17,5V and xxA current. There's no way a battery will accept this when
it's not fully discharged and damage will be done to the battery (cooking,
overloading). A regulator is absolutely necessarily. I've good results with
a Solsum regulator (about 50 Euro a few year ago), There are newer ones
nowadays of course. See:
http://www.stecasolar.de/en/art/uid_.../beetools.html
(sorry for the long link...)

--
Regards, Bert W
www.whattowcar.com

  #9 (permalink)  
Old February 15th 07, 06:10 AM posted to uk.rec.caravanning
Dave Fawthrop
external usenet poster
 
Posts: 1,831
Default Solar Panel

On Wed, 14 Feb 2007 22:28:07 +0000, Dougal
DougalAThiskennel.free-online.co.uk wrote:


|!The solar option suits my lifestyle with no ability to use mains
|!electricity (*) and usually no access to the mains anyway.
|!* - not quite true as I run an inverter to charge camera batteries.
|!
|!I use a 50W panel. My longest period of use will have been about ten
|!days and ended by the need to move on rather than the need to find an
|!alternative means of charging. I've never felt even close to being at
|!risk of running out of charge on a single battery installation.

Was that in summer or winter? In winter we are back in the van much
earlier than in summer, so use much more electricity from the battery.
There is less sunshine during the winter even on sunny days.

|!I suspect that my level of electricity usage will, however, be
|!described as light by the standards of many not that I have felt any
|!need to limit battery use.

TV? Radio? lights from 1600Hrs in winter?
--
Dave Fawthrop dave hyphenologist co uk
20,000 free e-books at Project Gutenberg! http://www.gutenberg.org
For Yorkshire Dialect go to www.hyphenologist.co.uk/songs/
http://www.gutenberg.org/author/John_Hartley
http://www.gutenberg.org/author/F_W_Moorman
  #10 (permalink)  
Old February 15th 07, 07:59 AM posted to uk.rec.caravanning
Mary Fisher
external usenet poster
 
Posts: 3,847
Default Solar Panel


"Dougal" DougalAThiskennel.free-online.co.uk wrote in message

....

The solar option suits my lifestyle with no ability to use mains
electricity


.... ours too because we don't pitch on places with hook up anyway :-)

Mary


 



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