Keeping the battery topped up when not hooked up

[saint-spoon]

Afternoon team. We have up until now been only been to sites that provide us with an electrical hook up which obviously supplies us with all of our electrical need as well as keeping the battery well and truly full. As the whether grows warmer and the days longer we will be going to some of our favourite sites that do not offer hook up so we will be reliant on our battery to supply our water pump, toilet flush and lighting facilities. I have a 110 amp/hour leisure battery which I reckon should be good for a couple of days or three if we are frugal with our electrical usage. I am thinking about getting a charger of one form or another. I am loathed to buy a fossil fuelled generator because lots of site limit the time (and rightly so IMO) that they can be used due to the noise so I am thinking along the lines of a solar charger but I do want one that clips onto the battery not a permanently mounted one requiring the drilling of holes through my roof for cabling. Obviously there is the requirement to have a charge controller so as to not over fill the battery with squigglies (steam trained marine engineering term for the electrical stuff that flows through wires). What sort of capacity would be required? Looking on line there is anything from 1.2 w-200w available and I was thinking probably something between 40 and 100w would probably suffice. Anyone got experience. We don’t have a telly in our van and obviously the fridge and other gas operable services will be running off gas. Sorry, I did have a look at the past posts and couldn't find what I was looking for.

 

[WoodlandsCamper]

Perhaps a Moddy will be kind and move this post to Technical where you are likely to get more responses.

I myself do not have any solar power (other than sunlight through the windows) but a lot of forumites do so they should be able to help you.

 

[Sproket]

A" few ideas here ...( further down the page ) I like the idea of the flexibility but security could be a problem if left out unattended, if I were to fit one it would have to be at least 100w and roof mounted. ....

 

[saint-spoon]

Sorry Mods, I forgot to put it in the correct section... oooops.

 

[Martin24]

We used to use a 55w free standing solar panel. Because it is not flat mounted on the roof we found this to be plenty as it was mounted at the optimum 45 degrees to the sun. We chained it to the leg of the van and used it all year round on cl's and rallies. Have used it up to six weeks at a time, including TV use with no problems. All the necessary gubbins was mounted on the back of the panel. A socket was attached to the battery and we just had to plug into that. Main advise is to make sure that you change all the lights you use to LED as halogen will drain the battery in no time at all.

 

[Reevco]

As martin says the main consumption will be the lights so change to LEDs
We have an 80w panel on the roof the only problem to date was one morning the battery was to low for the motor movers.
Don't forget, "yes" the fridge does work on gas but still needs 12v to work the circuit board and electrical parts like the igniter. as will the heater water boiler and thermostat / control panel.

 

[ProfJohnL]

From memory
We have previously worked out even allowing for cloudy days the sort of size of solar panel needed to keep a caravan battery reasonably topped up and I think we concluded you would need about 48W and I think that included a couple of hours of telly usage. This tallies with Martin's experience.

I would suggest going for a charge regulator for the panel, as this ensure that the panel is properly loaded, and the more recent ones also ensure the charge voltage to the battery is high enough as well as preventing the battery discharging through the panel when it isn';t producing power.

Many people do have fixed panels on their caravans, and have cables put through roofs, but as an option, you could go for a roof mounted one and bring the cables down and along the roof edge extrusions on the non awning side, and then in through a locker door or a water shedding wall cable gland.

It is important to keep the panels reasonably clean to maximise performance.

 

[TD42]

firstly if you have an older caravan with a power supply unit that doubles as a battery charger it will not fully charge the leisure battery as it charges at 13 + volts it will only charge the battery to about 80%.only newer vans fitted with a Smart charger system will properly charge the battery
Bearing this in mind you should make sure you fully charge your battery preferably after each trip using a proper battery charger of the smart type ,this will initially charge at 14.8 volts then when the battery is fully charged drop down to a maintenance charge rate of 13.8 v

 

[JTQ]

Key in your requirement were the words “As the weather grows warmer and the days longer we will be going to some of our favourite sites that do not offer hook up”.
I say this because solar panel performance and the van demands are very different in those warmer months than this time of the year. Therefore we are talking about summer; that being the case and with no TV and the main use lights LEDs then 40 odd Watts is viable.
However, within sensible limits you can't have too much and at today’s internet purchased panel prices, it cost little more to over egg things. Useful if these off EHU sites seduce you to drift into the shoulder seasons. What will become “limiting” is the bulk of the thing, the sheer practicality of handling the thing getting it into the van without its corners scratching the furniture. I have an 85 Watt panel and would not want to lug that into the van; I made a plywood cassette mounted under the rear of my van to stow it away.
So whilst 40 Watts is IMO “okay”, a 60ish would be better and about the limit if it has to go into the van.
A framed panel can be purchased and modified with hinged leg so it can be propped up facing the sun.
As you realise it will need a controller and this ought to be close to the battery so to both correct for cable losses and the temperature of the battery. It is thought naughty to house it in the battery box but is a widespread practice. Money is well spent on buying a decent quality controller. This will have minimal drain so could be left wired directly to the battery via a protection fuse. I suggest pulling the fuse for longer off EHU layups. The panel can be connected via a polarised DC plug and socket. Configured that way round neither the panel or controller will be distressed if the panel is not connected. One last important point, never stand the panel in the grass as shadows massively kill the yield, stand off the ground on a bit of ply ground sheet of something. Once on board with a decent solar set up I doubt you will look back.

 

[emmerson]

Saint-spoon, we simply carry a spare battery in the car, and have found that most CL owners will charge a battery for you if you do get stuck.Keeps life as simple as possible!

 

[saint-spoon]

thanks chaps, some great advice. the spare battery option is actually something that I have considered and may well go for. I have however found 80w folding panels sets complete with voltage regulators, reverse power diodes that you simply clip onto your battery terminals and away you go, and for little over a hundred quid and with five year plus warranties I think that I may consider one of them. And they come with a soft carry case. I am still looking though as our next three outings are EHU. I only have four halogen down lighters which will be replaced after this trip (when I remember to pop one out to get the size code for it, the rest of my lights are LEDs.

 

[swpostie]

I replaced some of my bulbs with LEDs and, with a 110ah battery, can last a week without hookup.

A week is fairly easy to do if you are sparing with the electric - how many lights do you need on in the evening? Do you really need to pump cold water? How about a battery radio or battery lanterns?

If you are prepared to adopt a "camping" mindset and don't take your electric for granted then it's surprising how little you can use.

If you're just going away for a long weekend you should be able to get away with using the battery as much as you like.

 

[ProfJohnL]

I replaced some of my bulbs with LEDs and, with a 110ah battery, can last a week without hookup.

A week is fairly easy to do if you are sparing with the electric - how many lights do you need on in the evening? Do you really need to pump cold water? How about a battery radio or battery lanterns?

If you are prepared to adopt a "camping" mindset and don't take your electric for granted then it's surprising how little you can use.

If you're just going away for a long weekend you should be able to get away with using the battery as much as you like.

Regarding the type of caravanning every one does, "Each to their own". ONe of the reasons most people opt for caravanning is it allows them the opportunity to take some of their creature comforts away with them.

Being frugal with power is a necessity if you don't have the luxury of a mains hook up, but y there should no need to get the "hair shirt" out. As you say using Led lighting makes a big difference to the power usage, and I agree that turning things off when you have finished using them is also good practice, but with a 110Ah battery in good condition, even a modest 50W solar panel should keep replenishing the battery enough to keep you adequately powered for a week or more, and for some almost indefinitely

A bigger panel will do even better and may well allow the use of tv for longer evenings.