Need some advIse, trying to wade through the multitudes of options for which portable solar panel and size is right for us. As this is the first time we are making a serious effort to free camp more, we are unsure what size of the panel system we need. Have made the first step decision that it will be a portable system and not mounted on the caravan. it is just the two of us and the van has led lights, tv and pump for the sink and shower, everything else is run on a gas. Firstly with careful (frugal) use of power, how long would a caravan battery last? Secondly, as there is such a wide choice of solar panel sizes and power and particularly brand. Have seen systems that are rated the same output with a price tag that can vary by $300 or more dollars. Will take advise from those who have gone there before us
BarneyBDB said
10:48 PM Mar 9, 2021
Lots of variables involved with this, firstly what is your battery capacity and type, do you just want to use it in summer or all year round? You are right about the variation in price, the cheap ones do not give advertised power and the dearest ones are not guaranteed to be the best.
There is a lot of information already available here in the tech / solar thread.
Whenarewethere said
11:04 PM Mar 9, 2021
There is a lot of information in the Solar Power thread.
Calculate the area of proposed panels. If the stated output is more than 170 watts per square metre it is built from Unobtainium!
Install the controller close to the batteries. Don't use the controller installed on the back of the panels.
I couldn't find an off the shelf product so I made my own. My controller & wire cost more than the panels.
Let's assume a 100Ah battery in your van. If it's in good condition and fully charged it will last for about three days with three hours of TV per day and normal use of other items.
How much solar you need depends upon many things. I suggest 300W and long leads from the panels in order to give you flexibility in their placement. The biggest problem with solar panels is shade - cover (say) 10% of the panel and you lose 60% of it's output. When camped in forests I find solar is barely worth having. This situation is compounded in winter especially in the lower latitudes of Oz with short days and a low sun.
It may be a small generator would be better for you but you cannot (legally) use a gen in a National Park and some other campsites - much depends upon where you plan to camp.
Be careful when buying panels, it seems some companies are selling panels at a claimed higher rating than is true. I have heard good things about these people:
Also consider whether you want a "blanket" or fixed panels - the blanket is lighter and easier to transport but harder to set up correctly.
Magnarc said
08:24 AM Mar 10, 2021
G'day Kurt and welcome to the forum. Call Low Energy Developments in Preston on 03 9470 5851 and talk to Milo, I have bought all our solar gear from them and they are always happy to advise new customers and, they only sell quality products.
Disclaimer. I have no ties to this company other than that of a happy customer.
aastek said
09:37 AM Mar 10, 2021
Thanks everyone for the help. Muchly appreciated. Will be sure to be on the lookout for the panels that contain Unobtainium !!
bgt said
09:56 AM Mar 10, 2021
We have 200 watts of solar 200 amp battery. 12/240 fridge. Only use gas for cooking and hot water. Never connected the tv. Led lights. We move every 3-5 days. We never run out of battery power.
Jaahn said
10:38 AM Mar 10, 2021
Hi Kurt Firstly go to the Solar Power sub forum in the Techies Corner section for ideas. I do not know what battery size you have in your caravan so cannot say how long it will last. Look at the battery for what is written on the side. But the point of having panels is to charge it fully most good days. In previous times we have done what you want to do with 2x70W panels used as portables with a long heavy duty lead and a cable with padlock(security). I still have them and used them on my minibus roof for a while.
If you are in open country there is no problem with keeping the panels in the sun. Move them a few times a day to keep the power going from sun-up to sundown if you need to. If there are trees then you will need to park with that in mind. Use your common sense to know where the sun will be. A long heavy cable makes it much easier than a short one only a couple of meters long. I found that single panels of 70-80W size were easy handled and easy packed away. Bigger panels are not so easy so each no bigger than 100W IMHO. Make up a heavy cable with a connection box on the end so you can plug in the panels. Get a security cable at a boating shop, have some loops put on the end and make some slots in the panel sides to lock them. No good never putting them out while you enjoy a walk, because you think they might get nicked !
In later times we had more battery capacity and 4x 80W panels as portables. Lived like kings Same arrangement with a heavy long cable etc with a plug in box for the panels. On a good day only used two of them. Of course you need a good regulator at the battery and an external socket to plug the cable into. Do not use clamps etc but set it up to be easy. Do not forget to set up a proper charging system from the car also.
Jaahn
PS Currently we have a 140AHr battery and a 190W panel on the roof AND direct charging from the alternator in our small MH. Always free camp. But a couple of portable panels would be nice on hot days and we could park in the shade. , I am under orders !
-- Edited by Jaahn on Wednesday 10th of March 2021 10:46:48 AM
Eaglemax said
11:40 AM Mar 10, 2021
Going portable panels means no charging of the batteries while travelling, thats a big negative. I know you think you wont draw much power but you'll be surprised.
Having said that if you are convinced to mount panels on the roof the more the merrier, with weight a consideration.
Tony
Jaahn said
02:35 PM Mar 10, 2021
Eaglemax wrote:
Going portable panels means no charging of the batteries while travelling, thats a big negative. I know you think you wont draw much power but you'll be surprised.
Having said that if you are convinced to mount panels on the roof the more the merrier, with weight a consideration. Tony
Hi Tony
The simple answer to that is you should be connected to the cars alternator and get lots of free power travelling while ever the engine is running. Not to do so is foolish IMHO as the alternator will be equal to 10 or 20 or even more panels and is the best charger you have. And if the sun does not shine for a while a great backup charger.
Jaahn
PS My alternator puts out about 1500 Watts. How many panels is that equal to ??
Whenarewethere said
02:59 PM Mar 10, 2021
Use the car's alternator to charge the batteries while driving. Also if you have a few days of inclement weather, run the engine for 20 minutes to top up the batteries. Easy.
Put a DC-DC converter near the caravan's batteries so you have maximum voltage for charging from the car, & use the right gauge wire, calculating wire resistance is the total distance of + & - !
Building a quality & flexible system with the cost amortised over 5 years really doesn't cost that much & buys a lot of peace of mind.
It will detail how to start with a energy audit etc so you can dimension your system as a start.
Or going to some of the places mentioned above and thay should be able to do it for you...
Jaahn said
08:02 AM Mar 12, 2021
PeterX wrote:
If you want to get more of a understanding Google the phrase Collyn Rivers books www.google.com/search Look at book "Solar that really works". It will detail how to start with a energy audit etc so you can dimension your system as a start.
Or going to some of the places mentioned above and they should be able to do it for you...
Hi
Good advice about Collyn Rivers' books. I have two of them. Find them here or any good book shop or RV seller. https://rvbooks.com.au/collyn-rivers
OR if you think buying a book is too expensive then just go to the SOLAR sub Forum on this very forum. How easy is that! All topics have been discussed for years in detail.
Need some advIse, trying to wade through the multitudes of options for which portable solar panel and size is right for us. As this is the first time we are making a serious effort to free camp more, we are unsure what size of the panel system we need. Have made the first step decision that it will be a portable system and not mounted on the caravan. it is just the two of us and the van has led lights, tv and pump for the sink and shower, everything else is run on a gas. Firstly with careful (frugal) use of power, how long would a caravan battery last? Secondly, as there is such a wide choice of solar panel sizes and power and particularly brand. Have seen systems that are rated the same output with a price tag that can vary by $300 or more dollars. Will take advise from those who have gone there before us
There is a lot of information already available here in the tech / solar thread.
There is a lot of information in the Solar Power thread.
Calculate the area of proposed panels. If the stated output is more than 170 watts per square metre it is built from Unobtainium!
Install the controller close to the batteries. Don't use the controller installed on the back of the panels.
I couldn't find an off the shelf product so I made my own. My controller & wire cost more than the panels.
https://thegreynomads.activeboard.com/t65231112/custom-6x20-watts-solar-setup-with-mppt/
Let's assume a 100Ah battery in your van. If it's in good condition and fully charged it will last for about three days with three hours of TV per day and normal use of other items.
How much solar you need depends upon many things. I suggest 300W and long leads from the panels in order to give you flexibility in their placement. The biggest problem with solar panels is shade - cover (say) 10% of the panel and you lose 60% of it's output. When camped in forests I find solar is barely worth having. This situation is compounded in winter especially in the lower latitudes of Oz with short days and a low sun.
It may be a small generator would be better for you but you cannot (legally) use a gen in a National Park and some other campsites - much depends upon where you plan to camp.
Be careful when buying panels, it seems some companies are selling panels at a claimed higher rating than is true. I have heard good things about these people:
Kings
Also consider whether you want a "blanket" or fixed panels - the blanket is lighter and easier to transport but harder to set up correctly.
G'day Kurt and welcome to the forum. Call Low Energy Developments in Preston on 03 9470 5851 and talk to Milo, I have bought all our solar gear from them and they are always happy to advise new customers and, they only sell quality products.
Disclaimer. I have no ties to this company other than that of a happy customer.
Hi Kurt
Firstly go to the Solar Power sub forum in the Techies Corner section for ideas.
I do not know what battery size you have in your caravan so cannot say how long it will last. Look at the battery for what is written on the side. But the point of having panels is to charge it fully most good days. In previous times we have done what you want to do with 2x70W panels used as portables with a long heavy duty lead and a cable with padlock(security). I still have them and used them on my minibus roof for a while.
If you are in open country there is no problem with keeping the panels in the sun. Move them a few times a day to keep the power going from sun-up to sundown if you need to. If there are trees then you will need to park with that in mind. Use your common sense to know where the sun will be. A long heavy cable makes it much easier than a short one only a couple of meters long. I found that single panels of 70-80W size were easy handled and easy packed away. Bigger panels are not so easy so each no bigger than 100W IMHO. Make up a heavy cable with a connection box on the end so you can plug in the panels. Get a security cable at a boating shop, have some loops put on the end and make some slots in the panel sides to lock them. No good never putting them out while you enjoy a walk, because you think they might get nicked !
In later times we had more battery capacity and 4x 80W panels as portables. Lived like kings
Same arrangement with a heavy long cable etc with a plug in box for the panels. On a good day only used two of them. Of course you need a good regulator at the battery and an external socket to plug the cable into. Do not use clamps etc but set it up to be easy.
Do not forget to set up a proper charging system from the car also.
Jaahn
PS Currently we have a 140AHr battery and a 190W panel on the roof AND direct charging from the alternator in our small MH. Always free camp. But a couple of portable panels would be nice on hot days and we could park in the shade.
, I am under orders !
-- Edited by Jaahn on Wednesday 10th of March 2021 10:46:48 AM
Having said that if you are convinced to mount panels on the roof the more the merrier, with weight a consideration.
Tony
Hi Tony
The simple answer to that is you should be connected to the cars alternator and get lots of free power travelling while ever the engine is running. Not to do so is foolish IMHO as the alternator will be equal to 10 or 20 or even more
panels and is the best charger you have. And if the sun does not shine for a while a great backup charger. 
Jaahn
PS My alternator puts out about 1500 Watts. How many panels is that equal to ??
Use the car's alternator to charge the batteries while driving. Also if you have a few days of inclement weather, run the engine for 20 minutes to top up the batteries. Easy.
Put a DC-DC converter near the caravan's batteries so you have maximum voltage for charging from the car, & use the right gauge wire, calculating wire resistance is the total distance of + & - !
Building a quality & flexible system with the cost amortised over 5 years really doesn't cost that much & buys a lot of peace of mind.
Google the phrase Collyn Rivers books
www.google.com/search
Look at book "Solar that really works".
It will detail how to start with a energy audit etc so you can dimension your system as a start.
Or going to some of the places mentioned above and thay should be able to do it for you...
Hi
Good advice about Collyn Rivers' books. I have two of them. Find them here or any good book shop or RV seller. https://rvbooks.com.au/collyn-rivers
OR if you think buying a book is too expensive then just go to the SOLAR sub Forum on this very forum. How easy is that! All topics have been discussed for years in detail.
jaahn
-- Edited by Jaahn on Friday 12th of March 2021 08:07:44 AM