Solar panels

[Retread24800]

I have yet to see a sensible discussion on this subject, 

I see ads for solar panels, different sizes anything from 5W to 250W at what efficiency and under what conditions?

Flat or Flexible? 

Different receptors (poly crystalline, silicon Crystalline) or are they all the same?

Two types of controller (PWM or MTTP?) 

Is there a benchmark that we can judge the various claims against?

But what is the ultimate panel/controller combination to give the most watts for your Pound Stirling. 

[colin]

I think you can only go on others experience, and match that with what you need.

As a example, we have a 85w panel feeding a 95ah battery throu a Stecca charge controller, no idea what panel it is (fitted F.O.C.).

Last year with an older VisionPlus LCD tv and sky box, plus halogen lights it struggled a bit in winter, perfectly ok in summer.

This year with a Avtex DRS186 tv and led lights it has no problems, last weekend we had 4 days out and monitored the conditions and charge levels (I rarely bother checking normaly), I have a chart which I've made, I'll post it up sometime. Basicaly over three of the days we drove only 2 x half hour and 2 x 10mins, for only about 3 hrs we had full direct sun on the panel, the minimum the battery got down to was 12.2v on the panel 12.3v checked with meter,

[spartan3956]

As Stalwart says its all based on experience

I was advised to go has big as you can on solar panels unfortunately the roof area i chose to place the panel was restrictive and a 120 watt panel was fitted (£120)

This is connected to a 10 amp controller very basic and cheap £8 but reliable (8 yrs) all connected to a 110 sealed battery.

I have since fitted a 12v charger which allows the engine battery to be topped up when the leisure battery is fully charged. good kit when laid up for winter.

I use this system throughout the summer wild camping lcd TV led lights etc and by midday the leisure battery has fully charged.

Haven't tested during the depths of winter winter using the heater fan but i expect the solar panel would struggle to keep the system fully charge.

Larger panel / s bigger controller and multiple batteries would probably be the order of the day,

Never looked back best thing i fitted.

In winter i used my generator just to help the charging.

[Retread24800]

I am thinking that I would rather pay out for a larger panel than expect a box of tricks to miraculously give a better output to a smaller/cheaper panel,. Think I will measure the free space on the roof and fit two 100+W panels and a mid range PMW 10/15A controller. As far as I can see the only difference in the panels Watt for Watt is the price! which is why I started the thread!

[Tea Cup]

I have two cheap solar panels totalling 190 watts peak, running through a cheap pcm controller, with 2 batteries totalling 220 amps. Initially had a 90 watt and one battery, and would top up with a mains battery charger when on site, but found this limited the time I could spend on aires without access to leccy.

 

Since adding the 2nd solar panel and 2nd battery it keeps the fridge running 24/7, winter and summer, in the hottest continental temperatures and also so far the darkest days just parked on the drive. I have not needed to top it up from the mains, but will do so in deepest winter.

 

I do use a neat little device that I bought from LIDL for just £3.99 that checks the alternator and battery levels with a simple LED display and have found it very useful. I have changed the device's orignal battery clips to a standard cig lighter plug, and can sometimes leave it permanently connected, though I do not feel the need now. There is a similar device available for £7.99 at Screwfix. I had a fair amount of trouble in the early days getting my split charger working correctly, had I realised that this set up would work so well I would have installed the panels earlier, and now wonder if I need a split charger at all.