Solar panels fixed or portable

baglimit2002 · Veteran Member

Solar panels fixed or portable

Possum3 · Guru

One 120W Solar Panel may keep one battery topped up if you were careful with power usage and had clear sunny days - certainly not enough power to keep two batteries full or free camp. I have my panels on roof of van as a preference (no packing up, storage problems), I know many others like portable to chase every bit of sunlight -

Jaahn · Guru

baglimit2002 wrote:
Was thinking of buy a genny at one stage but recently when to rawsly park in the flinders ranges and got talking to a nomad that runs only solar panels was impressed as to the volts that where being replace in the batteries he run a engel caravan fridge 90 litres and a 40 litre beer fridge on a slide he does have a genny to run air conditioning when ask about what size panels got told they where 2x150 panels as i only need to recharge 2x 105 amphour batteries so would a 120watt panel be enough your thoughts andy

Hi andy smile

It is hard to say how much solar you need. Depends on how much power you use and the sun light hours you get too. It also depends on whether you want to just use less when the batteries are a bit low or do want to keep using it 24/7.

I suggest you read the threads in this section and also the Solar Power section up the top. There is also a search function in the blue bar further up called search. Try that too. All these questions have been talked about many times, as it is a common thing to ask. smile

Jaahn

PS I would find it easier to read your post if you used some punctuations. Break you thoughts into shorter sentences with a full stop. It is very hard to understand when you put it all into one continuous sentence that is so long. Cheers J.

baglimit2002 · Veteran Member

Sorry about having no full stops and proper spelling left school at 12year had no choice will not ask any more

Possum3 · Guru

Andy,
You are a newish member so we understand that you are not aware of all the intricasies and sections on the GN site.

Most of us give information to try and help others, sometimes it is misunderstood and some people feel affronted, but generally we are an understanding bunch of old farts (apart from the Ladies of course) from differing backgrounds, just enjoying life on the road.

Please keep asking and we will try and assist, or tell a yarn and we'll have a laugh.

baglimit2002 · Veteran Member

Sorry about having no full stops and proper spelling left school at 12year had no choice will not ask any more

rockylizard · Guru

Gday...

Andrew, as others have alluded to, the decision on how much solar/battery you need is dependent on what you have and what you want/need to run on 12V ... including any inverter/s.

This spreadsheet attached below was developed by Richard Graylin ... I found it by happenchance some time ago.

Take the time to determine the usage you anticipate from the appliances etc you have and it will give an idea on a solution.

Cheers - John

PS - Forum 'format' will come in time ... laying out your query all punctuated is good ... but we can struggle through

Aus-Kiwi · Guru

Depends on your situation? Room on roof etc ? To me I prefers fixed as security and keep charging while suns out . The unltermate is to have both solar and generator to top up when you have continuous overcast days .. Wired and set up to charge off your motors alternator or another alternator fitted ? Your only limited to your own ideas, budget etc .

DMaxer · Guru

Hi Andy, welcome to the forum. As you have already found out most posters are friendly. Just ignore the others. I have one 120w pan and one battery and it runs TV, lights and the phone and laptop, the last one through a small inverter. Start small and add if need be. My panel is fixed on roof. I have free camped for weeks on end in winter and not flattened the battery. I also have it hooked up to car gen for charging whilst travelling. Enjoy your travels and keep posting.

Kebbin · Guru

It comes down to moving the panels all day long and if you have enough room for fixed, so maybe one portable that can be plugged in and some fixed. And keep posting, some people me included do not think things through enough before commenting, so ask away baglimit2002, that's how everyone of us learns.

Woody n Sue · Guru

Hi there Baglimit2002 I personally prefer as much battery and solar as I can realistically fit / carry keeping weight in mind.
I also have a genny for the air con but only take it when needed, I'm not full time .

Please don't take jaahn's comment to heart there are lots of us out here that had to leave formal schooling early, I too have been chipped for not putting in commers n full stops , and I don't give a rats arse just because some have had a university education dos me mean they are better people or know more about life or how to fix things that arnt working properly .

Having said that it would be nice if Jaahn came back and said so himself as has been said here often of late there is no tone of voice in comments when using a keyboard and comments can be taken the wrong way.

Keep the sun side up and enjoy what you have worked hard for
Keep smiling it makes people wonder what you have been up to

As the Penguins say " smile and wave boys smile and wave "

Woody

CC Bear · Senior Member

Welcome to the forum and I will add my two bob worth. Nothing worse when you have glasses and bad eyes than a big mob of print with no spacing.

When I see those post I do not read them because of my eyes so the OP will not get the benifit of my post and experience. This will happen in every forum you go too so no use putting your tail between your legs and hiding.

People here are helpful and there is a lot of information in each section and the search button.

A lot of us never finished school or like me they just did not want me back so just gave me a bull sh-t pass and the same with my apprenticeship. You just have to grab hold and pull yourself up each time.

As I said welcome and I hope you enjoy your time here. Cheers

PS when I am in Adelaide next will give you a call.

-- Edited by CC Bear on Wednesday 17th of May 2017 11:51:55 AM

AJC · Veteran Member

Hi there Baglimit2002,

Many of the previous comments are helpful, so let me see if I can summarise.

The amount of solar does not depend on the size of the batteries - it depends on how much we're taking out of them - and that's how much charge we need to put back to keep them happy. If you're wanting to work out how much solar, then maybe this will be useful: http://12voltblog.com.au/how-much-solar-do-i-need/

Hope this helps.

Cheers

AJC

-- Edited by AJC on Wednesday 17th of May 2017 06:05:36 PM

Tony Bev · Guru

baglimit2002 wrote:
Sorry about having no full stops and proper spelling left school at 12year had no choice will not ask any more

Hello baglimit2002

No one is trying to get at you, for any reason
Most of the older (more experienced) people, also have not the best eyesight anymore, that is why someone asked you to put in a few full stops, so that they could read your question better, in order to give you a better answer

I am not an Electrician, but I will try to answer your question, with what little knowledge I have, in a none technical way, as there is not a straight forward, yes or no, answer to your question

Your batteries (2 x 105 Amp Hour) would last longer if they were not discharged less than half way, or 50%
The experts will say that your batteries will allow you to use 105 Amp Hours each day

A 120 watt solar panel will give approximately 6.7 amps each hour, while facing directly into the sun
Experts sometimes say that there is an average of about 6 good sun hours each day
This means (to me, so I could be wrong), a 120 watt solar panel will put (6hours x 6.7 amps) = 40.2 Amp Hours, back into your batteries

If you are using less than 40.2 Amp Hours each day, then when the sun goes down, your batteries will be fairly full

But....
And this is why people are saying that you first have to calculate how much power you will be using, before they can answer your question

If you happen to use more than 40.2 Amp Hours of power, with 2 x 105 AH batteries, and a 120 watt solar panel, then your batteries will eventually go flat

The experts, (I followed their advise before I brought my solar system) say something like this

Calculate how many Amp Hours of power you will be using each day
Buy batteries big enough (or larger) to let you draw this power, without flattening, and possibly destroying the batteries
Buy solar panel/s big enough (or larger), to put into your batteries, more than what you are pulling out

I hope that I have not confused you, as much as I think, that I have confused the experts

DMaxer · Guru

I am sure this poor poster will have a huge opinion of this site. Just unbelievable!

Mike Harding · Guru

DMaxer wrote:
I am sure this poor poster will have a huge opinion of this site. Just unbelievable!

He's being precious. Jaahn's comment was reasonable in content and nicely put in tone.

Aus-Kiwi · Guru

She'll be right like our gramma etc is perfect ! I know mine isn't !! Text .. don't take too seriously ,,

Hylife · Guru

Baglimit2002.
Solar is great, but cooking, heating and cooling appliances just use way too much power to run from batteries
Lets start the solar process correctly.
Step 1 is to determine how much 12V power you will use in amps or watts for all the devices you will want to run per day.
Every 12V product you will want to use will have documented somewhere (perhaps on a label?) how much power it uses.
Everyone's needs are different and we all have different appliances too, but once you know what you will use, we can work up to how much you will need to store (batteries), and how much solar you will need to replenish what you are taking out of those batteries.

Jaahn · Guru

baglimit2002 wrote:
Sorry about having no full stops and proper spelling left school at 12year had no choice will not ask any more

Hi baglimit2002 smile

Sorry if you took offence at my post. I was trying to be helpful by pointing out it would be easier to read if you put in some full stops. Your choice really ! However do not feel that you should stop posting. Keep going here for sure. wink

I do not care if the punctuation is good or bad, just hard to follow if there is no stops. As you can see with this post I type out and idea then put in a stop and a space. Then start another idea as another sentence. I never went to uni either just did tech. When you talk to someone you stop and take a breath after each idea. The full stop is just like that. hmm

Cheers Jaahn

sandsmere · Guru

baglimit2002 wrote:
Sorry about having no full stops and proper spelling left school at 12year had no choice will not ask any more

Don't worry about the fullstops and spelling Andrew.

I had no problem reading or understanding your OP at all.

Cheers mate. And keep on posting and asking questions. That's what these forums are all about.

swamp · Senior Member

hi
Andy

160 watt panel harvests around 38ah in a 24hr period
200 watter panel harvests around 48ah in a 24 hr period

Remember the further south the more solar required ,,, Why because there is less available 100% solar rays per day

Your situation 2x 105 ah batteries
acceptable 2x 160 w
ideal 2x 200 w
Some people even have more watts per 100ah of battery
The quicker u can charge your batteries the less u will be effected by poor weather . 2nd Your recovery time will be quicker . 3rd This will be of benefit in intermittent weather when u have a small window to charge .

U can only use what u can recharge

210ahr of batteries == available amperage 105ah

Fridges biggest consumers both combined hot summer day heavy usage 100ahr down to 40 ahr on a cool day
Lights /pumps / tv / radio

macka17 · Guru

Hey.
Spent my 13th Birthday at sea on a North Sea Trawler off Longscar.
We all dumb to a point.

One picked me here for full stops once.
Reply to.
Full stop every few words. or two\three at a time like such...
They shut up....,,

Panels.
40 yrs of them.
I just lie them flat. but live in tropics and van always in sun.
even at home beside pool deck.

I've found little difference myself. but I don't sit and measure every drop of anything.

I just Started with an 80w and 50w from yachts.
added panels till system floated by lunch time.

Battery's float. me happy.

Had 2 x 40w as mobiles. They ended up on carport roof for boat battery's.
35yrs down track one gone to god.
T'other still ticking over. 2.17a.(first 30+ yrs 2.2a.)

Last van.

2 x 105a AGM Batt's.. 340w panels with another 80w on Patrol

With 3.8kva Genny in rear for air cond.

NEVER ran out of juice. in any weather.

You travel. with or without Air cond. Have a genny.

Seriously.

-- Edited by macka17 on Thursday 18th of May 2017 05:08:51 PM

Moonraker · Senior Member

IMHO and to make it simple you need one 120w solar panel for each 120 ah battery. The panel is best on the roof of the van if possible to max the amount of sun exposure especially while travelling on the road. A portable panel is good if you are camped up and in the shade.

-- Edited by Moonraker on Saturday 20th of May 2017 11:23:00 AM

OutbackMK · Senior Member

G'Day buddy welcome to the forum, I have panels on the roof of my van as supplied by Jayco and everything seemed ok till after two days camping my aux battery in the truck couldn't run the Waceo in the back that I use as a deep freeze. The fridge in the van was on gas but its freezer was too small for much stuff hence the problem.
Solution: I brought a 120W solar blanket on evilbay, it will drape over the bonnet and should keep the Waceo running when the truck not being used, cost us $375 and packs down the size of a laptop bag. This may be an option rather than a panel as it packs small and can be moved around to catch the sun as required.
We also spent a week at Rawnsley Park and Bendleby Ranges last October and had a blast doing Skytrek and Billy Goats Ridge at Bendleby but as we were driving every day truck battery always had plenty of juice..
Brian

Jaahn · Guru

Moonraker wrote:
IMHO and to make it simple you need one 120w solar panel for each 120 ah battery. The panel is best on the roof of the van if possible to max the amount of sun exposure especially while travelling on the road. A portable panel is good if you are camped up and in the shade.
-- Edited by Moonraker on Saturday 20th of May 2017 11:23:00 AM

Hi smile

In my opinion that is the bare minimum requirement for panels. Better to go up 50% or even double for good performance to keep the batteries well charged early in the day.

Like swamp said

"Your situation 2x 105 ah batteries = acceptable 2x 160 w, ideal 2x 200 w. Some people even have more watts per 100ah of battery.
The quicker u can charge your batteries the less u will be effected by poor weather . 2nd Your recovery time will be quicker . 3rd This will be of benefit in intermittent weather when u have a small window to charge."

If you have them on the roof you need more, if you have portable ones you can get away with less watts but more personal work to get the power, by shifting them around during the day. Your choice hmm

Another point is to learn to charge things and use power during the later part of the day when there is plenty of power free and going to waste.

Jaahn

Ron-D · Guru

What kills my battery big time while free camping is the pump when we shower , how too gauge amp hrs on the thing is rocket science, and our showers are splash and dash..

Mike Harding · Guru

Ron-D wrote:
What kills my battery big time while free camping is the pump when we shower , how too gauge amp hrs on the thing is rocket science, and our showers are splash and dash..

It shouldn't.

I don't know what the typical pump used in caravans is but my home-made bush shower uses a low cost bilge pump which readily produces a 3m head of water (probably more) and consumes around 1.25 amps at 12V.

Let's assume your pump is considerably more powerful and uses 7.5A. Showers in a caravan are usually short to conserve water so let's say five minutes.

This means you are using 7A5 for 1/12 of an hour or 0.625Ah which is not much at all. Even if we double it and give your pump a 15A consumption it's still only 1.25Ah.

It sounds as if there is another issue.

Ron-D · Guru

Your right Mike when we used to shower in the shower tent we just had a small battery and alligator clips and it worked well,

with the van now we have an internal pump it's bigger and it supplies sink, toilate ,hand basin and shower, it's a different animal, where we struck trouble was arrived at a site with a fully charged battery From home ,because it was overnight no solar next morning the pump kept running on could only stop it by isolating the power to thepump,the battery meter still showed a 11.9 volt reading ,at home the reading was 12.5 volts so I hooked the car Plug up and started the engine bingo back to normal running,beats me it has to be the pump the lights are Led and the little bit of power from the car alternator solved every thing...

-- Edited by Ron-D on Monday 22nd of May 2017 07:47:10 PM

Tony Bev · Guru

Ron-D wrote:
Your right Mike when we used to shower in the shower tent we just had a small battery and alligator clips and it worked well,
with the van now we have an internal pump it's bigger and it supplies sink, toilate ,hand basin and shower, it's a different animal, where we struck trouble was arrived at a site with a fully charged battery From home ,because it was overnight no solar next morning the pump kept running on could only stop it by isolating the power to thepump,the battery meter still showed a 11.9 volt reading ,at home the reading was 12.5 volts so I hooked the car Plug up and started the engine bingo back to normal running,beats me it has to be the pump the lights are Led and the little bit of power from the car alternator solved every thing...

-- Edited by Ron-D on Monday 22nd of May 2017 07:47:10 PM

My water pump, (not sure of manufacture), like yours, it is used to pump all water in the RV

I have tested with an el-cheapo clamp meter, and it shows 5 amps when working, so they are a bit power hungry

Ron-D · Guru

Yeah Tony that's great information we will have to be carfull how long we run the pump in certain circumstances,at the moment we have an 80 W panel and a single agm battery ,Iam thinking about a 200W portable panel an maybe use the shower when the panel is in the sun....