Merve said:
Hi Parksy,
.............. Firstly, this was about the cost of caravanning, not a squabble about SPs against hook up. I simply gave an alternative to what most people, me included accept as the norm. ............... The reason I bought a large panel was because of lower light levels in winter. it still has the capacity to charge two professional batteries to max even in winter and I have installed it so that the system can be expanded. It really thumps the charge in in the sunshine whether winter or summer, a fridge can be run on 12v in a caravan but only if you are charging the batteries at the same time as you are when you are travelling! It is, a top quality panel, not some chinese import for a 100 quid. You get what you pay for. ............
Who'se squabbling?
I've
roof mounted and hard wired my own 80 watt monocrystaline solar system which was also done so that it can be added to, so I am fully aware of the alternatives and we agree on most points.
Your earlier point about running the fridge using 12volt created the impression that this could be done when the caravan is pitched which realistically is not the case, lpg bottled gas is used when the caravan is disconnected from the tow vehicle. No matter how good your solar array might be any leisure battery would soon be discharged if a fridge was continually run using the battery.
Fridges use power at night when no solar charge is available
Almost ALL solar panels on sale in the UK are 'cheap Chinese imports', we all like to imagine that ours is superior but the premium price buys exactly the same product, only the retailers profit margin varies significantly.
One of my neighbours is employed in selling and leasing domestic solar systems and he explained to me that most if not all UK suppliers import container loads of cheap solar panels, all from the Far East.
Solar panels are a cheap product.
The only sure way to improve the performance of a solar panel, no matter whether it cost £100 or £400, would be to use high quality automotive cable with a gauge thick enough to minimise voltage drop over the length of the circuit and to use a top quality solar voltage regulator.
As I'm sure that you are aware Merve, there are three types of solar voltage regulators (often called charge controllers).
There are simple shunt controllers which are either ON or OFF, prehistoric by todays standards.
Commonly used by caravanners is the PWM (pulse width modulator) charge controller, fairly inexpensive compromise and reasonably efficient and then there are the much more efficient (97%) MTTP (maximum power point tracking) regulator, significantly more expensive but well worth the cost.
MTTP controllers digitally 'track' the voltage requirements of the battery, the ambient temperature and the available power source (light) and deliver the highest possible amperage to the leisure battery according to the tracked parameters.
Solar panels are significantly more efficient in cooler temperatures but if a photovoltaic cell is obscured by night time darkness, mist, rain, snow or frost it ceases to produce any voltage which is why solar panels are not great during a UK winter.
The PV (solar panel) can be nothing more than a sheet of flexible plastic containing solar cells ( often manufactured in the Far East, these amorphous panels are becoming much less expensive therefore are often fitted to boats, motorhomes and now caravans), it is the charge controller that does the work and the better the controller the more efficient the system.
Swift Caravans have finally begun to embrace solar technology, a small solar panel for battery charging whilst in storage is now fitted to many of their 2013 models.
I think that the third type of panel which you couldn't rememer might be Amorphous, this technology is currently slightly more expensive that mono or poly chrystalline photovoltaic cells (but the price will fall over time) and is used mainly in the production of flexible panels.
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