Solar Battery maintainer during storage

I have no experience of Solar Panels but I notice the Solar Charger you mention is fitted with a male cigar-lighter type plug, would simply plugging this directly into one of the fixed female socket inside the van carry the charge to the battery or would there be other problems I would need to overcome?

JCB, this is how they connect, but only low powered ones.

larger, roof or floor mounted panels of (say) 60w - 150w will need a regulator and be connected directly to the battery.

alarms, immobilisers, other 'systems' monitoring, all take a draw from the batteries, albeit a small one, but over time this will drag the battery down.

happened to us on our first MH (didnt realise this would happen) and got a flat battery....since then, always a roof mounted solar panel.

the bonus spin off is that, with a sufficiently large panel, off grid camping  is easily doable, allowing pitching at places where EHU is not available, like some CLs, or temp hol sites....

good luck.

Thanks BB, 

I thought this was the case, As I am only considering one to keep the battery topped-up while the Van is in storage. what would be about the highest Solar Panel Output not needing a regulator? 

Looks to like the one HillClimb is using might be ideal for my purpose

JCB4x4 - yes the solar panel came with both a cigarette lighter and a pair of crocodile clips. I am using the crocodile clips directly on the battery terminals because the cable is long enough and the sunroof / battery close enough together. 

I have trickled charged at least two cars in the past via the cigarette socket so it will probably work in your caravan too - I switch the main isolation switch on the fuse panel off (the alarm etc bypasses the panel - probably all the 12V circuits do) - so I guess the cigarette sockets are still active when the main switch is off

In terms of charging amperage and regulators - a battery charger normally provides 8-12amps when you start charging a flat battery, it will drop to 1-3 amps when topping up. Trickle charging is normally less than 1amp and that low an amperage doesn't do damage.

The Halfords solar maintainer that I use is 6W, so it provides a maximum of 0.5amp so unregulated should be fine.  

Buying a 40, 80 or 120w solar panel mounted on the outside top of the roof would be a good solution if you wanted to regularly stay at non-EHU sites - even a 40W panel is capable of 3amps so would need a regulator

Hello HillClimb,

Really just begun to put my thinking cap on with this one.

So it’s the usual Watts/Volts/Amps calculations with Solar Panels then.

As I’m used to Battery Chargers & Batteries being Amp rated I have just realised that I was confusing the Watt rating for Amps in this case and as you point out to many Amps input would fry the battery, so hence the need for a regulator at higher Wattage's.

Taking this a little further, remembering I really have no previous knowledge of Solar Panel out-put.  

Why are they rated in Wattage?

Why would you use one with a High Wattage/Amp out-put when this would damage the Battery.

Does the Voltage out-put vary for instance ?

When Off-Grid, are all 12v circuits/appliances run from the Solar Panel via the Battery or are some run directly?

I'm beginning to find this topic more than a little interesting and feel I may be asking a few more questions here.

have a look at this thread

https://www.caravanclub.co.uk/club-together/discussions/welcome-hobby-talk/tips-for-making-caravanning-touring-cheaper/how-to-survive-a-non-240v-ehu-site/

plenty of advice on solar panels etc.

rated in wattage as this is a unit of power...

voltage putput will vary depending on the amount of sun. a small panel requires full sun to acheive a meaningful output...a large panel can still generate a healthy putput in cloudy conditions.

however, when a large panel is in full sun, it needs a refulator to restrict the amount of puut to avoid damage.

when off grid, all 12v appliances run from the battery, with the panel replenishing any used power.

good luck.

Thanks BB,

I think I am now beginning to get the picture certainly looks like I will be able to keep myself busy reading through the thread you quote.(a few pages there)

Could end up with a few more pounds on the caravan roof and a few less in OHs Bank Account (well she says it hers) It's joint really, as in I put it in and she takes it out).Usually to waste on food electric/gas etc. 

without trying to get you to run before you can walk, once you get into the off grid thing and perhaps have a largish panel that will keep you going 'indefinitely' in decent sunshine, you might start to think about what devices can be powered by that battery.

obviously, the std 12v systems in your van like water pump, lights, heater pump/fan etc, but then there are the other gadgets that are taken for granted when on EHU.....mains type chargers for phones etc can be run from USB sockets on 12v, heating or hot water runs great on gas, as does the fridge.

the  'snags in the ointment' (as my old boss used to say) are the heating devices like hairdryers, microwaves etc....

in the thread i linked to, Merve uses a large inverter to convert 12v to 230v to run this type of device. however, they will use a fair slug of battery power in a short space of time.

small inverters are, perhaps, more common....we have a 500w one which runs our mains-only Sky+HD box when off ehu.

spunds like you're getting into this a bit....happy reading.... 

It is possible to over complicate the question of non ehu use.  

To simplify it.  

Anything that requires heat isn't really suitable for 12v use. 

Before rushing out and buy a solar panel make sure the your battery is good, you can generate all the power in the world but it is largely pointless if you have no where to put it.   Also money spent on replacing standard lights with Leds is money well spent.  

We have been on site since Thursday charging 3 smart phones and 3 tablets without any problems.  

Finally you will use more gas than you can possibly imagine particularly in the colder months. 

Finally with Solar panels they are more efficient freestanding than roof mounted because of the angle they deployed.  We have a roof mounted panel simply because we use storage and it keeps the batteries charged. 

I have a solar roof panel that I have yet to fit due to a caravan change. 

Originally I simply wanted a small panel to keep the battery topped up as the OP outlines. After thinking about it a bit and looking at prices I came to the conclusion that I might just as well fit a 100 watt regulated unit so that I will also have the facility of going off grid if I want as well as ensuring that the battery is charged correctly.

There is also the problem of Euro6 engines failing to recharge the battery whilst on the move due to the design of the latest alternater circuits to be considered and countered.