DO I HAVE ENOUGH PORTABLE SOLAR?

didi · Senior Member

DO I HAVE ENOUGH PORTABLE SOLAR?

Stratman77 · Senior Member

Without knowing what your actual load is, it's hard to say. My portable 120 watt solar will charge at around 8 amps, but if you use most of that during the day to run your fridge, etc, your battery may not be recharged by sundown. You may need to consider more solar in that case or a small genny.

moblet · Senior Member

The short answer is that it might be. I ran what would have been a slightly lighter load fairly comfortably on 120W and wouldn't attempt your load with anything less than that for your travel plans.

It's not difficult to scale up a portable setup provided your controller can handle the load, so if I were you I'd set out with 120W of panels and a controller rated to at least 15A (for scalability; I doubt you'd need more than 200W if you had to scale up) and see how it went. I don't see the sense in paying for and carting around more panels unless they're needed.

Unless you're only camping in places where trees are sparse I suggest having sufficient extension cabling to be able to position your panels at least 25 metres from your rig.

SnowT · Guru

Di why not have a solar Panel on the roof of the Van..?

For Peace of mind if your driving along it will put a charge into the battery while driving...

-- I would not go longer than 10m unless you plan to have a heavier cable.. [Should be about 6mm2 cable for piece of mind..]

without the true figure of your loads it is far better to have MORE solar than you need...
- Especially if you look at the current conditions.. even thou it summer the sky's are grey and there is not a lot of solar gain....

- To get around the usage of a generator, Maybe think of 12v to 12v off the vans battery.... $200 Plus wire's..

Juergen

oldtrack123 · Guru

didi wrote:
Hi guys I have decided on a portable solar system as opposed to a rooftop one, as I need to park in shade where I can, and hope to be in one spot for a week at a time (free camping). I have a small Camec bar fridge, LED lighting, and need to use my laptop daily for couple of hours and recharge my phone. I also have a small 12v 19" tv that I will use for 2hrs a day. So I thought 120w portable solar should be enough? Will this keep me going without having to top up in a park or would I need more to free camp?
Cheers Di

HI Di

You can suck it & see or you can try to work out your expected daily use

All the gear should have a WATT rating marked on it

List each one with Watts x by expected hrs of dauly use

Add up all the results

Divide that by 12V =Daily Amphrs used x 1.5

That is near enough to what you have to replace each day.

Then you need to consider that there may be days of little or no sunshine

How long you could go without some additional recharging will depend on battery Amphr rating

How do you make up for that?

options:

[a]running the car engine with battery connected

More solar panels

PeterQ

-- Edited by oldtrack123 on Sunday 7th of December 2014 03:17:44 PM

exa41 · Guru

hi Did I ,as Juergen said more is better , if you get a lousy day with little solar as I did at greens you will be in trouble, remember that in less than perfect conditions your panel will only produce maybe 100 watts in to 100ah battery with the load you have and the battery probably won't get much .

didi · Senior Member

Thanks Jeurgen but we wont be doing a lot of mileage in one day. Our plan is try and stay in one place for four days before we move to the next. This means I will be looking for shade while I am parked or use shade awning over van. Also portable means i will be able to get more solar than I would on a roof panel as I can move it around to get the sun.

didi · Senior Member

Sorry peterQ. you are looking at a non techie here. which is why I post so many questions biggrin

Really all I am looking for is a simple answer. It looks like Id be better getter more solar but I might just wait and see first as you suggested

didi · Senior Member

Hi exa. thats true for both rooftop and portable panels though isnt it? In which case a trip to a caravan park will be in order. I do have a good house battery installed already which charges as I run my van, but really just trying to see what will be the best solar wattage for me at present. Really do not want to go to the expense of a solar on top of my van if I hardly get anything from it.

didi · Senior Member

Actually the more I hear about solar the more confused I become. I just want to do free camping as much as possible, but from what Ive gathered about solar panels these may not produce enough energy. Really not going to expense at present.

didi · Senior Member

BTW already have a great grey nomad Brioche who will help me to get solar on but just feel awful asking him for advice all the time. He and his wife have been great already,

moblet · Senior Member

Confusion is optional. I think your original plan is sound enough to run with, just make sure you get a controller that can handle at least 15A so that you can scale up without having to replace it. Scaling up merely involves acquiring more panel(s) with compatible connectors and the associated double adapters but you don't need to think about scaling up unless and until you find you need to do it.

Another way to look at it is that 120W should comfortably cover the lot if you get a bit of sun. If you encounter a spell of gloomy weather then the fridge, lights and phone charging should still be covered but you may have to limit your use of the laptop and/or TV or run the van motor to put some charge into the battery. In two continuous years on the road I only experienced two days that were so gloomy that my panels produced virtually nothing. Your laptop probably carries enough battery charge for 4+ hours' use too so if your panels are falling a bit short you can run it off its battery if you get a couple of gloomy days and recharge it when the sun comes out. Recharging the laptop from the van while driving can also ease pressure on the house battery.

Some people want a solar system that will allow them to do anything anytime, others are happy to adapt their habits according to the amount of power available. If you want to sit inside and watch TV all day when it's raining then 120W may not cut it. If you're happy to adapt then 120W will be enough to keep your food fresh and your phone charged - in other words it's enough to cover the absolute essentials.

Also, if you're travelling with others there is scope for sharing TV watching and charging your laptop from whomever has the most power to spare.

Radar · Guru

Moblet hi,

I liked your reply and that is how we work our system 120 amp battery recharged by 120 watt panel it is basic but simple and I have a cable that I can attach to the car's second battery to help things along if needed. Ralph

oldtrack123 · Guru

HI Di
Using some typical figures for you based on yourexpected usuage

Fridge. Min 20Ahrs

Tv Min 8.5Ahrs
lap top 10Ahrs
total 38.5Ahrs

Your 120W panel on bright sunny days will supply around 42Ahrs Max

A 120W panel will under normal conditions will keep up with your estimated daily use ,with little to spare
Your battery reserve willlast about 2days before it need to be fully recharged
From the above you should be close to being OK unless you get several days with out solar input or without a reasonable run of the engine

Factor that can encrease power usuage include:
high ambient temps around the fridge
Warm loading of fridge & frequent door opening
Very cold settings
Compressor fridge are heavy consumers, as you will note from above

It's power used could easily go as far as <50Ahrs
PeterQ

-- Edited by oldtrack123 on Sunday 7th of December 2014 05:11:19 PM

Treecrest14 · Senior Member

Gday Didi

Re Solar on the roof and parking in the shade...

Are you aware that the solar panels do also generate power even in the shade - just not as much/efficient.

I was assisting my neighbour to attachhis panels to the roofof hhis van and even though we were working in a open carport, once connected they were actually charging his batteries.

Just thought I would mention it..

Glen

Quanger · Veteran Member

Don't forget if your fridge is a 3 way you can run that on gas & save a heap of power, they are fairly economical & perform well on gas, at least mine goes better on gas than 12volts.

Sharke · Senior Member

Di
I find a better way to think of solar is water & a tank . If we dont get enough rain tank will not fill if we do get a lot of rain but dont have a big enough tank means wastage.what is your battery capacity.
Solar gives its best performance between 11 AM & @ 2 PM daily. So this will be the ideal time to be charging phones and using computers. Also i would use a MPT regulator capable of 15 amp.
cheers
Jeff

didi · Senior Member

Thanks Moblet. The fridge is the smallest bar fridge 12v waeco (not camec sorry) but if I haveto sacrifice something its this. I only need it for butter and milk . Cold water and cokes would be nice but not essential. But do intend to have a 20A controller, with 10 metres of 6mm double cable. However may go up to a 160 or 180w panels having listened to you all. They are not much bigger. Cheers

didi · Senior Member

Thanks Glen, but I wanted the panels which would give me the best chance of more solar. My worry is I have a merc Sprinter which can get pretty hot (air con only when motor running) if i park it in sun so rooftop solar not so great especially as it can heat up the roof Ive been told. So looking for something which I can get the most power out of.

didi · Senior Member

Thanks again PeterQ. Its more important to charge up my phone and laptop (will get inverter to charge up by 12v) and have a bit of TV. The fridge is mainly for butter milk and cold water coke, so keeping on low temp. However I am thinking maybe a 160/ 180w panel might be better now. Cheers Di

oldtrack123 · Guru

didi wrote:
Thanks Glen, but I wanted the panels which would give me the best chance of more solar. My worry is I have a merc Sprinter which can get pretty hot (air con only when motor running) if i park it in sun so rooftop solar not so great especially as it can heat up the roof Ive been told. So looking for something which I can get the most power out of.

HI Didi

Solar panels, if mounted with a small air space under them for air circulation, actualy act as a tropical roof smile

Of course the area not covered by the panels will still get very hot , I can understand your wish for shade, that will also reduce the work load on the fridge

One thing to remember ,solar panels can attract light fingered folk

Remember, repositioning portable solar panels so they face directly into the sun can encrease the output quite a bit, especially in the early morning & from mid afternoon

PeterQ

-- Edited by oldtrack123 on Sunday 7th of December 2014 10:27:56 PM

-- Edited by oldtrack123 on Sunday 7th of December 2014 10:28:15 PM

didi · Senior Member

Id like to have rooftop panels PeterQ, but been told they arent as efficient as portable panels as they only lay flat so dont get full sun, whereas portable can be repositioned to follow the sun during they day?

Stratman77 · Senior Member

I certainly agree with PeterQ. I always secure my panels to the van bumper or fence, tree etc. with a chain and padlock. It will deter the opportunist thief, but not the prepared one. Make sure your insurance is paid and you advise your insurance company that you want the panels covered.

oldtrack123 · Guru

didi wrote:
Id like to have rooftop panels PeterQ, but been told they arent as efficient as portable panels as they only lay flat so dont get full sun

,[1] whereas portable can be repositioned to follow the sun during they day?

Yes.as I posted that is an advantage, especially if you are working on the limit smile

With My roof top ones [200W was all i could comfortably fit], I mounted them with a tilt & turntable so I could turn them to face the east at night, around 10am face them north then around 3PM face them to the west[, or to where the sun rose & set .

PeterQ

-- Edited by oldtrack123 on Monday 8th of December 2014 12:22:53 AM

wasn_me · Guru

If you think you need to go portable, that's ok. I would still have at least 80 watts on the roof. It's there all day every day, it's there at 6am while you're still snoozing, it's there while you're parked shopping, sight seeing, (where as the portable is packed up in the boot)

I have 180 watts on the roof,(which works fine) but I'm thinking of building a portable panel to supplement that if needed.

Cheers Pete

wasn_me · Guru

oldtrack123 wrote:
Yes.as I posted that is an advantage, especially if you are working on the limit
With My roof top ones [200W was all i could comfortably fit], I mounted them with a tilt & turntable so I could turn them to face the east at night, around 10am face them north then around 3PM face them to the west[, or to where the sun rose & set .
PeterQ

-- Edited by oldtrack123 on Monday 8th of December 2014 12:22:53 AM

I have been thinking about mounting an 80 watt panel on an aluminium post, with a tilt mechanism for the panel. Then mount the post to a jockey wheel mount on the drawbar ( that would allow the panel to be swiveled)

This would be to supplement the 180watts on the roof

Cheers Pete

Jaahn · Guru

didi wrote:
Id like to have rooftop panels PeterQ, but been told they arent as efficient as portable panels as they only lay flat so dont get full sun, whereas portable can be repositioned to follow the sun during they day?

Hi didi,

My two cents worth. Most of the other replys have been very sensible suggestions. biggrin

But if you want to have portable panels, like I have, you may wish to look at the size and weight before buying. I have some larger ones but they are too heavy and arkward to use regularly on the road. I use two old seperate 70w panels for easy setting up. I put long wires on them and plugs into the regulator which makes it easier to put away etc. I also have had made up, at a boat shop, a 4mm stainless cable with a small loop crimped at each end, as long as the panel wires, so I can lock them to the vehicle for peace of mind. I drilled holes in the panel frames to enable the cable to pass through easily or a lock. blankstare

Works well for me. More panels would be good but we get by with them if the weather is OK. I would buy some more the same smaller size to use as more portable ones. I have a couple of boards which I use as props to hold the panels up to the sun depending on the angle needed. Or just put them against the fence or barrier. Move them several times a day is enough usually to follow the sun. wink Note a folding panel is smaller folded but still as heavy as a large one. I had mine hinged as a folding pair but found them too heavy so unjoined them and put seperate wires.

Cheers jaahn

-- Edited by Jaahn on Monday 8th of December 2014 08:31:36 AM

moblet · Senior Member

didi wrote:
Thanks Moblet. The fridge is the smallest bar fridge 12v waeco (not camec sorry) but if I haveto sacrifice something its this. I only need it for butter and milk . Cold water and cokes would be nice but not essential. But do intend to have a 20A controller, with 10 metres of 6mm double cable. However may go up to a 160 or 180w panels having listened to you all. They are not much bigger. Cheers

If TV and laptop are more critical to you than the fridge then a little more capacity sounds like a good idea. As you can see from PeterQ's indicative numbers, once you've spent four or more hours staring at screens you've consumed an amount of energy equivalent to what your fridge uses in 24 hours. As Jaahn says you need to consider the size and weight of individual panels, and with a modular approach you have the option of only needing to set up as many panels as the conditions (production vs consumption) demand, e.g. if you had 3x60W panels you might only need to put two of them out if the sky is clear.

The bar fridge is inefficient given your limited use of it, but for the cost of a smaller, more efficient fridge (which would also take up living space) you could buy enough solar capacity to run multiple bar fridges, and for all that it would only save enough energy each day for 60-90 minutes of laptop or TV.

Your phone uses an insignificant amount of energy in this context, which is why PeterQ didn't bother giving you a number for it. A good energy conservation habit is to use the phone instead of the laptop where practicable.

Regarding theft, I've not heard of anyone losing panels while they were "home", but have heard of people losing pretty much all their gear having driven off somewhere and left it unattended. Portables can be a pain/risk if you want to keep tripping off from base camp but are fine if you're staying put for days at a time.

didi · Senior Member

On a very limited budget here Moblet so wont be buying another fridge. Just trying to get the best solar for the least money. i will only use the laptop for 2hours a day, but may use the 12v TV for 2hrs also. hope to buy an alarm for solar also.

oldtrack123 · Guru

HI Moblet
That sums t all up nicely

PeterQ