What size folding solar panel for 110amp battery (1 Viewer)

[Masman]

I am looking at buying a folding panel .I know I could fit one to roof but don't want to go down that root. I have one 110 amp battery, I don't want to fit another battery. All lights are led. Tv ,and blow heating are about all we use,Tv probably 3 hrs a day maximum. Would I be better off with a 100w panel or going for 120w.Looked at lincoln show nearly bought a 100w bosch but found one on internet cheaper thats120w.Any advice appreciated.

 

[pappajohn]

I would go 120w or if funds allow, even bigger.
You need Sun and it may only appear for short periods so the more charge you can get in in the shortest time the better it will be.

 

[Richard n Ann]

A panel that you can stand up and point at the sun gives loads more power than flat on the roof and in winter there is a massive difference.
People find this hard to believe but my 40w free standing panel delivered virtually the same amps (not amp hours) in February as mid summer as long as it's stood up directly facing the sun. So 100w will be plenty, in fact our 40w panel did us and we had about the same power usage as you.

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[Lenny HB]

Depends where you are using it, 100watt probably OK in southern Europe but if in the UK you can never have enough solar.

 

[Welsh girl]

We use a 60w folding panel and as long as it's sunny we get enough power but forget it if it's cloudy.

 

[two]

If you are stationary for much of the time I think you're better off with ground-based panel. Not only can you face it perpendicular to the sun, you can also move it out of the shade. More important here in UK than further south, perhaps. The greater capacity will top you up faster but will be a waste if you don't need that amount of power (a battery monitor will tell you how much you use) but you'll need to transport it without damage, so check the dimensions for safe storage.

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[Lenny HB]

The problem with the portable ones is to get the most out of them you need to be around all day to keep moving them to face the sun. If you don't want to spend the day by your van and want to go out for the day a roof mounted panel will give far more output as it will always be in the sun even if its not quite at the right angle for max output.

 

[Richard n Ann]

The problem with the portable ones is to get the most out of them you need to be around all day to keep moving them to face the sun. If you don't want to spend the day by your van and want to go out for the day a roof mounted panel will give far more output as it will always be in the sun even if its not quite at the right angle for max output.

It won't always be in the sun though will it?.. It will of course suffer the same shade as anything else on the ground, and you can't move it. I've had both and believe me if you can be bothered to move your free standing panel about 2 times it will massively produce more power, not only because it's in the sunshine but it's tilted up too!

 

[Lenny HB]

It won't always be in the sun though will it?..

Depends where you park, we don't like shade.

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[Richard n Ann]

Depends where you park, we don't like shade.

We tried to park in the sunniest plot but there's a olive tree shading the panel until 11am and then at 2.30 the shadow of a floodlight tower comes across
I need a chainsaw and some dynamite

 

[two]

The problem with the portable ones is to get the most out of them you need to be around all day to keep moving them to face the sun. If you don't want to spend the day by your van and want to go out for the day a roof mounted panel will give far more output as it will always be in the sun even if its not quite at the right angle for max output.

There's no need to track the sun. Just tilt it at a sensible angle and you'll be better off than just laying it flat on the ground. The panels in solar farms are fixed at the same optimal angle all year long (not horizontal).
The only 'problem' I can see with using a portable panel is that someone-else might 'like' it, plus the of faff setting-up.

 

[hilldweller]

a 100w panel or going for 120w..

In the real world you'll never prove either figures. An ebay 120w could easily be 100w. I'd probably trust 100w with Bosch written on it over an unknown Chinese one with 120w written on it.

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[tony_g]

I apologise for hijacking this thread but as it is current I hope my query will see some responses.
When I bought our current van it already had a solar panel fitted. Unfortunately, there was no paperwork to indicate its size/rating but I am thinking probably 40w/60w. I have been thinking about having more solar fitted,either as well as the current panel or start from scratch with a completely new installation. However cost has been putting me off at the moment.
I notice that some other Funsters seem to have success with plug in portable panels as a stopgap.
Could I ask a few questions?
My current batteries are two 135ah AGM and the solar controller is a very basic unit. The batteries are connected in the 'approved' +ve on one to -ve on the other fashion.
So, if I have a portable panel with its own controller and connect it to a permanently live Hella connector in the garage of the van, will that work or will the existing controller 'see' the fresh charge coming in and cut off the existing panel?
Or, if I connect the portable panel via its own controller to the 'other' pair of battery terminals, will that fool the other controller?
I realise I may be talking b.....ks, so please be kind!

 

[autoswan]

Im thinking of getting a portable 100w or 120w panel to keep engine battery topped up when not used for around 7 months of the year and on leisure battery when wilding. Any good ones you've seen for around £100 ?
These look any good ?

https://www.ebay.co.uk/itm/100W-12V-Folding-Solar-Panel-Mono-Portable-Solar-Module-for-Camping-RV-Boat/182448394580?ssPageName=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

https://www.ebay.co.uk/itm/150W-Mono-Solar-Panel-12V-battery-charging-Camping-Boat-Caravan-for-Home-Power/222758066796?ssPageName=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

And I think I read on here before that some panels are better in low light levels in UK than others ? What are they called ?
Thanks.

 

[PhilandMena]

I apologise for hijacking this thread but as it is current I hope my query will see some responses.
When I bought our current van it already had a solar panel fitted. Unfortunately, there was no paperwork to indicate its size/rating but I am thinking probably 40w/60w. I have been thinking about having more solar fitted,either as well as the current panel or start from scratch with a completely new installation. However cost has been putting me off at the moment.
I notice that some other Funsters seem to have success with plug in portable panels as a stopgap.
Could I ask a few questions?
My current batteries are two 135ah AGM and the solar controller is a very basic unit. The batteries are connected in the 'approved' +ve on one to -ve on the other fashion.
So, if I have a portable panel with its own controller and connect it to a permanently live Hella connector in the garage of the van, will that work or will the existing controller 'see' the fresh charge coming in and cut off the existing panel?
Or, if I connect the portable panel via its own controller to the 'other' pair of battery terminals, will that fool the other controller?
I realise I may be talking b.....ks, so please be kind!

I have a roof mounted 125W S.P. and a suitcase 120W S.P. each with their own controller and when both connected my input to the Leisure batteries doubles. So, in my case, one does not cancel out the other, and if I could start again I would have all my panels fixed on the roof, it just makes so much sense. The more the better too.

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[Pausim]

Some of the folding panels include a solar controller and some do not, makes a difference when comparing their prices. The weight can also vary significantly. A lightweight one gives you the option of laying it flat on the roof more easily if you want to go out and think it might “walk” if left on the ground.

 

[two]

Any alternative source is an added convenience, but still may not be necessary. You need to replace the energy consumed one way or another. I keep my batteries going by moving on or being on EHU, so don’t need solar at all. But, maybe, we don’t use as much 12V power as most.

Granted that 200W of solar would be better than 100W, but it would not be twice the benefit.

I only need a modest 3A EHU supply, occasionally, but can end up being provided with much more to no advantage. The cost of a solar system would buy more nights on EHU than I’m likely to need in this van, and I save some weight, but it would be different if I remained stationary for longer and not on a site.

 

[Urs4_2008]

Read through this thread: https://www.motorhomefun.co.uk/forum/threads/mipv-panel.171316/

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[Stealaway]

Here's a bargain if you have room to fit it.

 

[Urs4_2008]

This seems to be good value, but not sure about the charge controller in the kit. I would spend the extra £ to get a Victron 75/15 and put the Victron charger inside the car, next to the batteries, and connect the panels in series to allow double the length of the cable outside. Just my 2 pounds

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/332439680121

 

[pappajohn]

Two panels in series will give you twice the volts but only the amps of one panel.....
Series multiplies volts
Parallel multiplies amps


Pointless in my opinion.

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[Urs4_2008]

Two panels in series will give you twice the volts but only the amps of one panel.....
Series multiplies volts
Parallel multiplies amps


Pointless in my opinion.

That’s your opinion parallel or series gives the same power production in principle, except lower voltage gives more resistance given everything else being equal. Higher voltage means less loss due to heat being generated in the cable. Thickness and length of cable in question decides the factor of importance of series vs parallel.

Ie 2 x 100w panels in parallel gives: 17.5vmax x (2 x 5.7a max)= 200 watts. 2 x 100w panels in series gives: 2 x 17.5vmax x 5,7a max=200 watts.

Let’s assume just for fun he runs a 10m cable to be able to park in the shade, and having the panels in the sun. If he buys a 4mm2 cable (quite thick), loss in parallel will be: 5.53%. In series it will be 1.38%. 12v systems should not be designed to have more than 3% voltage drop. The lost effect is heat from the cable, which can be dangerous if you go out on a limb and design for too big a voltage drop. The cable will become more and more like a light bulb wire.

So why not connect the panels in series? Only reason I see is the higher voltage resulting in you having to buy a Mppt controller instead of a bit cheaper PWM. Shading... guess you won’t put one panel in the shade anyway, so not a valid argument.

 

[pappajohn]

If series is so good why are 99% of multi panel systems wire in parallel....both by pro installers and DIY.
It can't be installation time, it's only a case of swapping wiring configuration at the panels.
who in their right mind puts free standing panels 33ft away and possibly out of view...and expects them to still be there, unless they have nothing better to do than watch the output display constantly.
They are invariably next to the van, so volt drop is neglegable, and usually secured to it.

 

[Urs4_2008]

If series is so good why are 99% of multi panel systems wire in parallel.
It can't be installation time, it's only a case of swapping wiring configuration at the panels.
who in their right mind puts free standing panels 33ft away and possibly out of view...and expects them to still be there, unless they have nothing better to do than watch the output display constantly.
They are invariably next to the van and usually secured to it.

I can think of several reasons, if we assume your statement is correct:

• Probably one of the biggest reasons can be that many controllers are pulse width modulated and doesn’t support the higher voltage of panels in series. Reason being these are cheaper.
• Some roof installations have quite short cable runs and low wattage resulting in negligible difference.
• Some installations on the roof are difficult to avoid partly shading from antennaes etc.
• Also there’s an ignorance regarding the different effects of installations. I’ve had some strange configurations delivered straight from the factory.
• And as long as the power output of the panel(s) is (are) quite small, the inefficiency doesn’t result in glowing wires, and then you only loose some charging power.

In my experience, 4-600 watts in a normal, 3,5 Tøn MH, with 5-6 meter cables and angeled panels, the cables are running too hot for comfort when the batteries are low and charging is at maximum.

But my best advice for anyone planning a solar investment for their motorhome, do some real research and get help from someone experienced before buying and installing by yourself. Not just read forum messages like this one

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[pappajohn]

Each to their own...I know what's most used.
I'm going to leave this thread at this point as there's no point debating it further.....and I might end up in Coventry.

 

[PhilandMena]

Here's a bargain if you have room to fit it.

Not really a bargain when you look at the specification in picture 3

 

[autoswan]

Very confusing, that's why I want a simple croc clip to battery portable 100 120w solar to sit in front of van or next to it. Mainly to top batteries up when Sat at rear of house for long periods unused.
It would be good to get my head around how the fixed perminant solar panels and all the gizmos that come with them work. Is there a thread that shows the basics in layman beginners terms to start learning about how, what and why's ?

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[Urs4_2008]

Not really a bargain when you look at the specification in picture 3

Could you explain?

 

[PhilandMena]

Could you explain?

No Problem! Maximum output for panel is just over 8 Amps which is poor for 200W and you will never achieve all of that anyway,

 

[Ivory55]

Very confusing, that's why I want a simple croc clip to battery portable 100 120w solar to sit in front of van or next to it. Mainly to top batteries up when Sat at rear of house for long periods unused.
It would be good to get my head around how the fixed perminant solar panels and all the gizmos that come with them work. Is there a thread that shows the basics in layman beginners terms to start learning about how, what and why's ?

It’s a bit like the magic circle, it’s called the 12v circle and they are sworn to secrecy so as to keep us normal people in the dark so we can not do anything. Haha

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