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How many do I need ?……. How many Batteries?

 How many Solar Panels?……. How much will it cost?  

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Article by Val Rigoli ©, free advice freely given, my personal thoughts and advice gathered from in-excess of 40 years of practical hands-on experience, learned skills, and industry knowledge.
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For other RV related articles you may find interesting please check my Tech page

This article is mostly a guide to hopefully help you understand what you need to consider BEFORE you start spending too much time and money setting up your RV , however it is not, and can not be a full step by step guide to the full set-up and fit up process, as it is just too involved for just one article, however  if you read some of my >>articles here<< it will help a lot smile

**UPDATE**  Hey just how crazy super cheap are solar panels at the moment compared to a few years ago, it may be well worth while covering your whole roof with solar, it is a fact that you can never ever have too much solar!

When it comes to sizing up the things that you need for a system that will work well for you, sadly there is no standard set-up, no one size fits all' type of thing, almost everyone is going to have different needs, and will operate their camping in different ways.

Things like the way most people operate their fridges, lights, TV's and appliances etc, and how long for on a powered site, or not, etc etc.

How often folks will move from place to place (this usualy helps to charge the batteries), or how long they want to say in one spot, some want to stay for weeks (lucky ducks)

So then when sizing up solar panels and/or batteries required for a good working system there are many considerations that need to be taken into account.
Note: Solar is great, but for just a few it is not required, or even practical for them, I do cover this Briefly below .

Sorry if as you read on this starts to look a bit complex, but it can be very complex, and it can cost you a fair amount of money, so it is in your best interests to get it right the first time.

If you want to skip to a very very rough guide, have a look at  lower down in this article (starting in BOLD red).

So here are some of the main things you need to consider when sizing up your system, the sort of things you need to know so that you can correctly size up your requirements.

Of course you need to know what you want to operate from your system, and it's best to draw up a list, start with the likes of...

Lights, TV’s (LCD LED is best), Laptop/s, Fridges etc etc, include everything that will be drawing power from the batteries.

You need to find out how much the items will draw, and workout how long each day you will need to run each item, then can get an idea of how much power you will be consuming each day.
Then you need to think about how long you may be staying away from mains power without running your vehicle, i.e. like only over night, or a full day and 2 nights, maybe 3 to 4 days, or a week or more, this will make a huge and dramatic difference to the system you need.

My advice to anyone that only parks up for 3 days or less is to 'battery up' and not bother with solar at all, solar is not practical for shorter stops, and as long as you have a good well put together >>car charging system - click here<< in the vehicle, it's much more cost efficient to carry enough battery capacity on board, I believe that everyone should have 3 days in their battery bank (though not always practical), and still without draining them down too far.
If your going to stay 3-5 days then you can add enough solar to cover half your daily draw, so with the 3 days already in your batteries, plus the solar you can go now for 5 days, but any longer than this, then you need to have enough solar to completely cover your daily draw for each day , plus some.

Now how would you like to recharge your batteries when your away from mains power, maybe a >>generator with a smart battery charger- click here<< connected to it, or is running your vehicles engine your back up system, or is solar an option, or part of your plan?

You need to think about the time of year and where you intend to travel, this also plays a very important part of sizing up a system for a few reasons. The available solar irradiation varies dramatically between Summer and Winter, and also between the North and the South of Australia, so you need to take this into account too.

Talking about the climate, your fridge for one thing will not be working as hard in Winter as it will in Summer, and you won’t be in and out of it for drinks so often either, but also there is less solar charging available too.

Low draw appliances , these include the newer LCD LED TV's,  LED lights,  water pumps don't use much over a days use,  mobile phone and camera/camcorders use very little too.
lights are now the very best way to go for your lighting needs, they use very little power, and as they become more popular they are getting cheaper, and coming out in a better range of fittings, and this will only get better.

But come to any sort of heating device, now these consume huge amounts of power (current), things like jugs, toasters, microwaves, hair dryers, it’s not really practical to run these sorts of devices from your batteries (at all really) for anything but a very short length of time, and even then it will cost a heap extra for the much larger inverter needed to drive these things.
Running the likes of the things mentioned above for longer periods can be done, but in most cases the cost of the extra equipment to allow you to do it would give most bank managers heart failure. And don’t even think about running Air conditioners from your batteries, it just can not be done without a road train full of batteries and solar panels. 

Val's best tip: Bigger is mostly always better, be it batteries, solar panels and most definitely wiring/cable size!
I will always suggest that people fit as bigger battery/batteries as they can fit and afford, it makes for good sound economical reasoning, you see the larger the battery capacity the less percentage wise you will be draining them, and so the longer they will last both in power usage, and battery life, with the extra advantage of more capacity if and when needed.  
The bottom line here is that it might cost a bit more $$ initialy, but it will save you more in the long run, and give you added flexibility, so win win smile

Extra solar note, Because solar panels are so so cheap now days, so now when folks ask me to size up their solar requirements, I always tell them that they are best off putting as much solar as they can fit on their Motorhome or Caravan roofs, as you can never ever have too much solar.

I then send them to look on eBay to buy the solar panels, because most solar retail stores just charge too much compared to Australia sellers on eBay!
However I always warn folks to compare the physical size of the panels (mm²), against the better known brands like Kyocera and BP etc,
because some shonky ebay sellers are claiming some of the cheap Chinese solar panels, are a larger wattage than they really are, also check that the panels are 36 or 72 cell panels.

Battery note: all >>AGM batteries- article- click here<< are deep cycle batteries by the very nature of their build, now the standard AGM battery range has a design life of 5-8 years, and Ritar (the batteries that I mostly sell) make a dedicated DC (8-12 years) battery life, I recommend these batteries, especialy for batteries in constant daily use, these dedicated DC (deep cycle) AGM batteries have been built with extra thick lead plates (good thing), so that they have even better performance and a longer service life.

Things you might like to learn a bit more about --- >>Smart Battery chargers<< ---- >>Battery Monitors<< --- >>Wiring, traps and pitfalls<<

If your asking anyone for advice on a battery or solar/battery system to suit your needs, you need to give them as much information as you can, so they can more accurately size up a system for you that will do all that you expect it to do.
Warning note: If they don't ask the you kinds of questions that I've been talking about above, you need to seriously think about 'do they know their stuff (sadly many don't)' and do they really have your best interests at heart, or do they just want to sell you stuff!!

Rough guide, and I mean rough, imprecise! vague! ballpark!
These costings are just for the solar and their battery systems.

For Caravan, Campervan, Motorhome, Camping trailer, Boat, four wheel drive & tent etc,
if you want to park up for a week or more.

Small set-up, 4x4, Camper Trailer, etc
Portable 12v compressor fridge of about 50 to 80 litres,
Maybe a
small LCD TV, LED lighting and some small low draw appliances, all used conservatively .
Needs about...
100 to 150 watts of solar panels with solar controller
1 x 100Ah to 120 Ah AGM battery + smart charger 5 to 10A (for charging at home, or in van parks)

Cost, around $900 to $1,200

Small Caravan, Campervan, Motorhome, Boat etc.
Upright Gas/electric fridge running on gas
small LCD TV, LED lighting,
some small low draw appliances, all used conservatively .
Needs about...

1 x 100 to 150 watt solar panel with solar controller.
1 x 100Ah to 120 Ah AGM battery + small smart charger
5 to 10A (for charging at home, or in van parks) 

Cost, around $900 to $1,200

Small Caravan, Campervan, Motorhome, Boat etc.
12v compressor fridge 80 to 140 litressmall LCD TV,
some small low draw appliances, all used conservatively .
Needs about...

2 x 150 to 200 watt solar panel with solar controller.
2 x 120 Ah AGM batteries + smart charger
15 to 25A (for charging at home, or in van parks) and a Battery Monitor

Cost, around $2,000 to $2.500.

Larger set up now, Caravan, Campervan, Motorhome, Boat etc.
Larger 12v compressor fridge 150 to 220 litres, medium size LCD TV, laptop, fans, inverter etc. 
Needs about...

4 x 150 to 200 watt solar panels with solar controller
2 x 260 Ah AGM batteries + Smart charger
40 to 70A (for charging at home, or in van parks) and a Battery Monitor

Cost, about $4,000 to $5,000

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