Solar panels for self installation

[Boxerman]

Hi does anyone have first hand solar panel knowledge /experience , that they can share? firstly questions
1.what wattage would I need to support a caravan not connected to mains ?
2.would I need a second leisure battery?
3. Do they connect direct to the battery through dedicated regulator?
What make should I avoid?
The Caravan is 16 months old and has electric/gas heating and hot water
Electric and gas fridge ,
LED lighting
Tv Avtex 12 volt and 240
If that helps understand the power requirements
Thanks in anticipation and happy new year to all
David

 

[Mr Plodd]

There are too any variables to give a definitive answer.

As far as Wattage is concerned that is totally dependent on all of the below parameters.........

Time of year (more daylight in summer)
Whether it's sunny or cloudy. Bright sunlight produces far more power than cloudy. My domestic set up can produce 25+Kwh per day in the summer, but this time of year when its cloudy less than 1 Kwh per day (tgats not a lot!)
A caravan solar panel would have the same vast differences
Shade or partially shaded pitch?
How long you intend being "off grid"
Your fridge will require gas or 230v, it cannot be run just off 12v
Electric heating will require 230v.
Water heating will require gas or 230v
12v TV doesn't consume a vast amount of power.

All the batteries in the world are of little use if you don't have the means to recharge them. A solar panel can only do so much, don't expect it to replace EHU

A dedicated controller is required in order to connect solar to leisure battery. There are various makes, I believe "Victron" are a good make.

 

[Boxerman]

In your opinion is solar worth bothering with? I understood that gas would have to be used in conjunction with solar and 12 volt, but it’s not really sounding like it’s worth the expense for little gain ?

 

[Beardy]

In your opinion is solar worth bothering with? I understood that gas would have to be used in conjunction with solar and 12 volt, but it’s not really sounding like it’s worth the expense for little gain ?

The only real gain (IMO) is that it opens up a wider choice of available sites / pitches. If you account for the cost of the solar system and a lithium battery to take full advantage of it, you'd have to spend an awful lot of time off grid to recoup your outlay.

There is a convenience advantage. The solar keeps the battery topped up in situ so saves you the hassle of hooking up the EHU or removing the battery to charge it occasionally, but you don't need a particularly big solar panel to do this - I use a £30 25W charging system which copes OK.

 

[Mr Plodd]

I have a 100w solar panel on my caravan. It keeps the 110ah leisure battery fully charged, even at this time of year (no alarm or similar drawing any power) and the caravan is alongside my house and is shaded from direct sunlight.
In the summer it provides me with plenty of power for 3 or 4 days off grid. But that's when it's light until late in the day and we are not watching TV, running the space heating etc.

If you intend doing a lot of camping off grid then solar is worth seriously considering, but if most of your camping is on EHU then you need to weigh up the cost against the benefit. If the site charges extra for EHU, and you can manage without it then you could save the cost of EHU which can add up over 14 nights, but there is then the cost of gas for cooking, water heating etc! If its cold then the heating will chew into your gas supply pretty quickly.

If not on EHU you are then reliant on enough day/sun light to keep your LB charged up.
So sadly there is no definitive answer, sorry.

 

[Oscarmax]

Hi does anyone have first hand solar panel knowledge /experience , that they can share? firstly questions
1.what wattage would I need to support a caravan not connected to mains ?
2.would I need a second leisure battery?
3. Do they connect direct to the battery through dedicated regulator?
What make should I avoid?
The Caravan is 16 months old and has electric/gas heating and hot water
Electric and gas fridge ,
LED lighting
Tv Avtex 12 volt and 240
If that helps understand the power requirements
Thanks in anticipation and happy new year to all
David

Over the last couple of years solar panels have dropped in price, suggest fit 2 x 120w a 100/20 Victron MPPT controller wired up in series, connect directly to the battery via a fused connection. Over the last few years we have not used the Sargent onboard charger.

The system we fitted in 2017 is only a 2 x 80w with a Victron 75/15 MPPT controller, we have added a Fogstar lithium battery.

 

[Guzzilazz]

I don't have experience of caravan installations, but do in the marine environment having installed and upgraded on my past boat. The main issue is that you can only have what ever sized battery in a van compared with a boat. Additionally, absorption fridges are dreadfully inefficient compared with compressor fridges, as they are basically a heater.

As said above MPPT controllers are superb providing that you connect the panels in series. The MPPT box is basically a smart charger which will keep you batteries in excellent condition. The rule of thumb is that you need the same wattage panels as battery AH - so 100 AH battery needs 100W of panel - for an MPPT installation 2x50 W in series would be best.

My boat had 300 AH of AGM domestic batteries (separate from the engine start battery), and would run the compressor fridge, LED lights, instruments, VHF radio etc for at least 3 weeks without mains.

 

[Buckman]

As said above MPPT controllers are superb providing that you connect the panels in series. The MPPT box is basically a smart charger which will keep you batteries in excellent condition. The rule of thumb is that you need the same wattage panels as battery AH - so 100 AH battery needs 100W of panel - for an MPPT installation 2x50 W in series would be best.

My boat had 300 AH of AGM domestic batteries (separate from the engine start battery), and would run the compressor fridge, LED lights, instruments, VHF radio etc for at least 3 weeks without mains.

Fitting the MPPT Invicta controller has made a difference to the charging in our caravan during the winter months. We only have a single 100w panel.

 

[IanB1485]

I have fitted several caravans and motorhomes with various sizes of solar panels including my own which has 260W of panels on the roof, the main advantage is it will keep your battery charged whilst in storage(outside) and when off grid may keep your 12V systems( pump, lights) running, with careful use. We use ours at festivals so definitely off grid, even manage to run (part time) a 60W cool box to keep the beer cool, during those long hot summer days we get in england

 

[trevormonty]

TV is biggest power consumer in your setup. Without it a 100AH leisure battery should run your caravan for a few days on single charge.

I'd differently recommend Victron charger as it is compact, has BT for monitoring by ph and supports both LiFeP04 battery if you decide to upgrade in future. If you sell van just swap it out for cheap PWM. Could start with single 100W and see how you go but given work involved in fitting panel may as well fit larger 200-250W and be done with it.
Victron model Nos eg75/15
75 is max input voltage from solar panel. Typical panel is about 24V so in theory it could support 3 in series but I think Victron recommend 2. If using single 200-250w panel input voltage is only 24v.
15 is max current (15Amp) it can deliver to battery.
If you fit a 250w panel in theory it could deliver 20A but only on for 1-2 hrs on fine summers day, most time would be putting out <15A. 250w panel won't damage 15A charger.

NB solar panels aren't light, their weight and associated HW, cabling, controller reduce caravans user payload.

 

[GUMPY]

When I got my van I fitted 120w panel, a Victron controller and later a 105A LifePo4 battery. I can manage 5 days off grid even with the TV, selected for it's low current <2amps @12v as well as it's picture.
Would I change anything? The answer is Yes I would add a second panel in series to prolong the time off grid.

 

[IanB1485]

Never put solar panels in series unless a. you can guarantee equal sunlight /m2 hits each panel or b. you fit an optimiser on each panel ,the output of panels in series is the least of the string panel .i.e if one of the panels is in shade then it will limit the current being delivered by the string. the 200W flexible ones from Renogy ( a reputable company) weigh only 4.5kg- never used one but am severely tempted