200W of solar panels - 2 big or 5 small? (1 Viewer)

Jul 5, 2013
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The dealer has agreed to fix 200W of solar on our new Hymer. He is suggesting that he will use 5 small square 40W modules to do this. I have never heard of this type before - on my present van I have 2 x 100W panels.

Anybody used these smaller modules rather than larger ones please? Are they OK?

Many thanks
 

Lenny HB

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Sounds a right bodge, 40 watt panels would work out more expensive plus all the extra brackets and fitting time, I smell a rat. Like @hilldweller says probably old stock trying to get rid of.
I'd be inclined to tell him to get lost and go to someone who knows what they are doing.
 
Feb 27, 2011
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Multiple solar panels have a single advantage in that if one is covered by shadow the others still produce providing each panel has blocking diodes.

Other than that I agree with everyone else. Smells fishy to me unless he gives a decent reason.

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Abacist

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I am sure that 4 units are going to take up far more roof space than 2 X 100w panels.

I would reject the four on the grounds that you want room left for future increased facilities such as satellite TV, internet satellite, air conditioning roof unit and maybe a larger bedroom roof light and so you definitely want to see a plan of the roof leaving room for future possible use.
 

Techno

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I am sure that 4 units are going to take up far more roof space than 2 X 100w panels.

I would reject the four on the grounds that you want room left for future increased facilities such as satellite TV, internet satellite, air conditioning roof unit and maybe a larger bedroom roof light and so you definitely want to see a plan of the roof leaving room for future possible use.
FIVE
 

hilldweller

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I would reject the four on the grounds that you want room left for future increased facilities such as satellite TV, internet satellite, air conditioning roof unit.

And the roof garden and jacuzzi.

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Abacist

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Oh well! even worse then - don't like it myself and wouldn't want to accept that offering myself. Mind you I suppose you are lucky that he mentioned it, he could have just gone ahead and done it!
 

Techno

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I'd want a scale drawing of what they propose. It sounds poor to me.
As I said you need a picture, if there are practical reasons for it then it is plausible but very unlikely that 2x100 cannot be fitted.
The cost of fitting 5 panels compared to two in labour is ridiculous.
 

Techno

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This is typical (quality) and provided by @Drexxer This was converted to 300 watts
20150603_173931-jpg.64815

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errpaul

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Could be to do with what is already on the roof amd the space available.
On my roof without removing a roof rack cross bar thing I wouldn't have been able to get anything bigger than maybe 80watt. With it removed I put on a 150w and could fit another if needed.
 
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peterc10
Jul 5, 2013
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Thanks for all the comments so far. Please keep them coming.

As Lenny says this is on a brand new A class Hymer B678 that I have just bought off the dealer. It would be unfair to name them, but they have a good reputation on here and he has been very good so far, so I am not sure that there are any ulterior motives. I have agreed a deal with him so he is paying for all this whichever way it is done. I just got the impression that he always did it this way.

There is plenty of room on the roof to fit these so that should not be a problem. And the only thing I may put on the roof in the future is a small fan vent over the kitchen area. If it was so hot that we needed air conditioning, rather than a fan or two then we would move somewhere else, after all that is the beauty of motorhoming.

I am not sure I understand the comments about taking up a lot more space, given that I always understood that no matter what the size a panel was made of a series of individual cells, and that the amount of power produced per square metre was about the same, only varying with the type and efficiency of the individual cells.

My only concern were the connections, but then you still have that with 2 panels. I wonder whether one 200W one would be better, but then if it happened to be on the part of the van that was in shade that could be a problem too.

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peterc10
Jul 5, 2013
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OK just found a photo of the top of a B678, and there seems plenty of room at the front to put on whatever I want. So would it be better to have 2 x 100W or one 200W please?

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StefAndDi

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OK just found a photo of the top of a B678, and there seems plenty of room at the front to put on whatever I want. So would it be better to have 2 x 100W or one 200W please?

Peter,
I asked the same question on here when I was speccing (is that a word) my van.
The consensus was that two were better than one larger one because of the shade issue already mentioned.
I went for 2 x 150 watt panels.
Although I have an Oyster 85 and a roof rack and ladder I still have loads of space left on the roof and my van is only a foot or two longer than yours.
Stef.
 
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peterc10
Jul 5, 2013
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Thanks for everybody's help - yet again this forum has shown it is worth much more than the subs! I have emailed the dealer and asked him to fit 2 x 100W panels instead. There is plenty of room on the front.
 
R

Robert Clark

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And the only thing I may put on the roof in the future is a small fan vent over the kitchen area. If it was so hot that we needed air conditioning, rather than a fan or two then we would move somewhere else, after all that is the beauty of motorhoming.

We had a 400x400 fan/rooflight taken off our new van so the AC could be fitted in its place
Unused and sitting in a box in our loft, if its of any use?

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peterc10
Jul 5, 2013
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Just a quick post to let everybody who helped me with this issue know what the outcome was. The dealer has readily agreed to install 2 panels rather than 5 without any problems. After measuring the roof they said that they could get 1 x 100W and 1 x 150W panels in, making 250W in all. I have agreed to pay the small amount extra they have quoted for the additional 50W over what was originally agreed.

Can't put much more in because the LRM1218 controller's maximum is 275W. But I knew that before I specified it and I have had no problems with 200W in my existing van so should be even safer with 250W.

Thanks again for all your help.
 

Techno

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The electroblok as far as I understand cannot handle more than 15amps despite the 1218 being 20 amps. So beware.

"The MPP solar regulator LRM1218 is a clocked converter which ensures that connected solar modules are constantly operating at their opti- mum level, irrespective of solar radiation, battery voltage and module temperature, while the bat- tery is in its primary charging phase.

The available charge voltages are perfectly adju- sted to match the leisure battery by means of temperature sensors and the option of configu- ring four battery types. The starter battery is charged simultaneously (max. 2.5 A) as soon as the leisure battery has completed its primary charge phase. The maximum charge current to the leisure battery is 20 A."

I would check what your model of electrobloc can handle

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peterc10
Jul 5, 2013
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According to the manual the EBL is able to handle 18A for its mains charging. But, for some reason, they have a 15A fuse on the solar circuit. But what is the chance of me ever getting the full 18A out of 250W of solar panels anywhere North of the Sahara desert I wonder.
 

Techno

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According to the manual the EBL is able to handle 18A for its mains charging. But, for some reason, they have a 15A fuse on the solar circuit. But what is the chance of me ever getting the full 18A out of 250W of solar panels anywhere North of the Sahara desert I wonder.
I have witnessed 22amps from my 300 watts.
Fair enough the 15 amp fuse should protect the Electrobloc

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peterc10
Jul 5, 2013
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A quick question to
Udo.Lang@schaudt-gmbh.de
will sort you.
Already have emailed Udo a couple of times. He recommends the LRM1218 with the EBL 29 and AGM batteries that I have got.

I have witnessed 22amps from my 300 watts.
Fair enough the 15 amp fuse should protect the Electrobloc
But protect it from what? It is on the same circuit as the output of the mains charger which is 18A and is protected by a 20A fuse!
 

Techno

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Already have emailed Udo a couple of times. He recommends the LRM1218 with the EBL 29 and AGM batteries that I have got.


But protect it from what? It is on the same circuit as the output of the mains charger which is 18A and is protected by a 20A fuse!
Perhaps one to ask Udo.

I suspect the 15 amp fuse dates back to pre mppt when it would be optimistic to blow it LOL
 
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peterc10
Jul 5, 2013
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I suspect the 15 amp fuse dates back to pre mppt when it would be optimistic to blow it LOL
I suspect you are right Andy. I also suspect that the first time it blows I may accidentally replace it with a 20A one because I am colour blind :D

And I won't complain if I do get 18A out of my solars.

Edit. Interestingly the circuit diagram confirms what others have said, i.e. that the output from the controller goes straight through to the batteries without any further regulation by the EBL. Good job the LRM regulates it then.

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