New system needed

[Raul]

Many things and combinations are called hybrid. That’s not the hybrid I’m on about. I’m referring to the CELL construction which the panel is made of. The only manufacturer to make these cells is Panasonic. It is made of a triple layer of 1 amorphous sandwiched by two monocristaline, to capture a wider band of the light spectrum. Mono works as other mono’s and the amorphous works on low light. So you end up with a tuned cell that works like two diferent panels in one. Other panel that works very efficient is LG neon R, at 1002mm by 1650mm panel it produces 370w. And the buss bar is at the back of the cell, made of a lattice of copper. Freeing the space covered at the front over the cell.
Being fitted flat on the roof, albedo light effect works best with the Panasonic panel. I have personally tested both. I have fitted container loads of panels on roofs and warehouses ( not on vans before). When I built my van I already had a vast experience with photovoltaics and all I needed is integration to a mobile installation. My house is entirely off grid. As I type , I use energy from the sun. The battery bank is on float, soon to use some for house chores.

 

[Raul]

To simplify, a panel produces approximately 0,5v per cell at vmp, voltage maximum power;
A 36cell panel will be 18vmp (12v battery panel)
A 72 cell panel will be 36vmp (24v battery panel) and grid tie commercial.
A 60 cell panel will be 30 vmp ( grid tie panel) most common.
A 96 cell panel will be 48 vmp ( grid tie panel)
All of these have a higher voltage on open circuit: voc that need to be taken in consideration when you choose your controler. The controllers have a max voc limitation , and temperature coefficient on the panel will tell you how much to adjust for cold weather. Cold raises voltage, heat lowers it. The new mppt controllers, allows you to use big grid tie panels on battery systems, that are cheaper, more efficient than battery panels. Battery panels are more associated with PWM controllers, but a mppt can be used as well. The max advantage of the mppt is when you have a high voltage panel. Is not much help on a 18v panel, but on a 36-50v panel is.

 

[tonyidle]

Sure but simple question is what panels can I fit if I want 500 or 600w into a 12v system

If you buy the components separately rather than a kit you will get better value for money. No panel is '12v' - the job of the controller is to match the panel output to battery requirements. There is a limit on the highest voltage that the controller will accept but it is quite high and published as part of the controller specification. The best value panels at the moment (Watts / £) are the type used for domestic installations and are 240W - 265W output. If you hunt around you should be able to find them for under £150 each.

https://rover.ebay.com/rover/1/710-...0001&campid=5338547443&icep_item=303510387891

https://rover.ebay.com/rover/1/710-...0001&campid=5338547443&icep_item=283729142711

https://rover.ebay.com/rover/1/710-...0001&campid=5338547443&icep_item=254536997079

 

[hilldweller]

She was just trying to be helpful

Had you taken her advice you would have destroyed everything electrical in the habitation area. Let her destroy her own house not yours.

Regretfully we sometimes get similar bad advice on here too, if any advice seems to stand out as different on a forum, triple check it before taking it.

Briefly: Solar delivers very little in the UK until the clocks go forwards: you can't count on it, the hours are short, the angle of the sun is bad. Never use the 12v batteries for any form of heat, they do not hold enough electricity. 300W and two batteries should be plenty in the brighter months if you are using electricity sensibly with all LED lighting.

For heat/cooking - gas. Choose Gaslow refillable or normal Calor type bottles.

 

[Raul]

To confirm, the second link tonyidle posted, I have used several times. They have huge stock, and good deals can be done with cash on collection. My last purchase from them was 12 JA solar 275w at 65 a piece.

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[pappajohn]

My very technical mate says put the batteries in series to produce 24V.

Your very technical mate probably mean connect the panels in series to produce 24 volts.
If he really meant the batteries I would be doubting his very technical qualifications.

 

[Lenny HB]

Now I’m confused as I can’t see much in the way of 12v panels over 160w...if I want more than 300w do I need more panels?
So 4x150 12v panels for 600w?

I would go with Micky's suggestion start with 300 Watts, fit 2 x 150watt panels get a decent MPPT controller that will handle at least 600 Watts then it will be easy to add more panels if needed.

 

[Sooz52]

All sounds good and it’s really helpful thanks. I’m triple checking things before deciding. I’ll size up because I really want to do this in one go. Also I’m sourcing in Spain - so probably nothing will happen for a couple of weeks with the lock down... At least I’m on a nice beach now, it’s about to rain though!

 

[peterc10]

All sounds good and it’s really helpful thanks. I’m triple checking things before deciding. I’ll size up because I really want to do this in one go. Also I’m sourcing in Spain - so probably nothing will happen for a couple of weeks with the lock down... At least I’m on a nice beach now, it’s about to rain though!

If all of your motorhoming will be in Spain it is likely that you will need less solar panels. Most of the advice on amount seems to be based on our UK weather, which is a lot less sunny than Spain.

 

[Lenny HB]

If all of your motorhoming will be in Spain it is likely that you will need less solar panels. Most of the advice on amount seems to be based on our UK weather, which is a lot less sunny than Spain.

If you look at his usage working in the van I think even 300 Watts he might struggle in Dec & Jan.

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[peterc10]

If you look at his usage working in the van I think even 300 Watts he might struggle in Dec & Jan.

I was talking about the OP who is only using a laptop.

 

[autorouter]

Your very technical mate probably mean connect the panels in series to produce 24 volts.
If he really meant the batteries I would be doubting his very technical qualifications.

The OP said she was researching solar for a house. Series batteries, 24V or 48V, makes sense for a house storage system, where there's a single controller input and a single inverter output, with nothing else running from the batteries. It means you can use pencil-thickness wires instead of water-hose-thickness wires to the battery. Obviously had no experience of motorhomes, but not necessarily an idiot.

 

[Sooz52]

After a lot of looking it seems like I have restrictions due to roof size and large vents... so does anyone know makes that are long and narrow? Are there any types which squeeze more umph into a small space or are they all pretty much the same?
I’ll looking into doing the 2 x 150 to start as suggested, each into a port into a nice big MPPT so I can add more after. Is it best to get an MPPT which can take 4 feeds so nothing’s in series?
Battery wise I’m still thinking AGMs - just go for as much Ah as I can fit and afford?

 

[Sooz52]

We also carry a flexible panel on a cheap controller which we can point directly at the sun in winter (obviously optional

I like the idea and with space bring at a premium I might have to do this. How do you connect this up - crocodile clips directly onto the battery terminals? How does this work along with your main controller?

 

[9526]

I like the idea and with space bring at a premium I might have to do this. How do you connect this up - crocodile clips directly onto the battery terminals? How does this work along with your main controller?

It has its own PWM controller (cheapo) and plugs into the side of the van (to a socket directly connected to battery via fuse)

You could of course croc clip the controller leads straight to battery, but I don’t like too many trailing leads through lockers etc.

It makes a surprising difference in a Spanish winter, and in summer you can leave it in the locker

We’re regularly on float charge by mid day, and if sensible rarely struggle for lecky (we charge 1 bike at a time/day)

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[hilldweller]

- just go for as much Ah as I can fit and afford?

Not really. The more batteries you have the longer it takes to charge them.

Simple case, on a good day your solar charges the batteries in 5 hours, a good day's sun. You fit two more batteries, now it will take 10 hours but you don't get 10 hours sun which means those two extra batteries do nothing for you. You have to balance what you use / what you store and what you can charge.

You can ignore the batteries at the beginning of the calculations, what you need at first is - I need XXX watt hours of electricity - so I need XXX plus a bit watt hours of charging.

Then you fit batteries to make up XXX times two ( you only ever half discharge a battery ).

 

[bigtwin]

After a lot of looking it seems like I have restrictions due to roof size and large vents... so does anyone know makes that are long and narrow? Are there any types which squeeze more umph into a small space or are they all pretty much the same?
I’ll looking into doing the 2 x 150 to start as suggested, each into a port into a nice big MPPT so I can add more after. Is it best to get an MPPT which can take 4 feeds so nothing’s in series?
Battery wise I’m still thinking AGMs - just go for as much Ah as I can fit and afford?

The general consensus on here is to avoid AGMs; Gels are much better (they can be discharged to 20% (Depth of Discharge) compared with 50% for AGM) but check that your charger has a suitable charging regime. If it does it will typically be a little slider switch on your charger.

Ian

 

[bigtwin]

Not really. The more batteries you have the longer it takes to charge them.

Simple case, on a good day your solar charges the batteries in 5 hours, a good day's sun. You fit two more batteries, now it will take 10 hours but you don't get 10 hours sun which means those two extra batteries do nothing for you. You have to balance what you use / what you store and what you can charge.

You can ignore the batteries at the beginning of the calculations, what you need at first is - I need XXX watt hours of electricity - so I need XXX plus a bit watt hours of charging.

Then you fit batteries to make up XXX times two ( you only ever half discharge a battery ).

I wish folks would stop repeating this erroneous advice!

If you use twice as much power (whether from a single battery or a pair) it will take twice as long to charge.

Fitting two batteries doesn't cause a charger to take twice as long to charge them; using twice the power is what results in a longer charge time. The number of batteries fitted is irrelevant, its the power consumed that dictates the charge time.

Ian

 

[hilldweller]

. The number of batteries fitted is irrelevant, its the power consumed that dictates the charge time.

Ian

Which is exactly what I said.

I assumed no-one in their right mind would fit extra batteries if they were not going to use the stored energy.

 

[bigtwin]

.. The number of batteries fitted is irrelevant, its the power consumed that dictates the charge time.

Which is exactly what I said.

I assumed no-one in their right mind would fit extra batteries if they were not going to use the stored energy.

Happy that you agree with my post but you did say:

Not really. The more batteries you have the longer it takes to charge them.

You also said:

..... on a good day your solar charges the batteries in 5 hours, a good day's sun. You fit two more batteries, now it will take 10 hours but you don't get 10 hours sun which means those two extra batteries do nothing for you.

I think that you knew what you meant but it read differently. ?

Ian

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[peterc10]

After a lot of looking it seems like I have restrictions due to roof size and large vents... so does anyone know makes that are long and narrow? Are there any types which squeeze more umph into a small space or are they all pretty much the same?
I’ll looking into doing the 2 x 150 to start as suggested, each into a port into a nice big MPPT so I can add more after. Is it best to get an MPPT which can take 4 feeds so nothing’s in series?
Battery wise I’m still thinking AGMs - just go for as much Ah as I can fit and afford?

Monocrystalline panels produce more power for the same area than Polycrystalline ones, so you need to look for those. Other than that all I can suggest is that you do a search on Ebay to find the largest size(s) that will fit your roof. I am afraid it looks like you have got a relatively small roof.

 

[Raul]

I wish folks would stop repeating this erroneous advice!

If you use twice as much power (whether from a single battery or a pair) it will take twice as long to charge.

Fitting two batteries doesn't cause a charger to take twice as long to charge them; using twice the power is what results in a longer charge time. The number of batteries fitted is irrelevant, its the power consumed that dictates the charge time.

Ian

And the charge time is dictated by charge rate. Ifyou gota window of 5 hrs and need a kWh to put back, at 500w two hrs will be sufficient, the rest goes to float and loads. But if you got 200w, you will take that hole 5hr day just to replace the energy without the efficiency taken in. And no absorb time left. Not fully charged. Lead is 70-75% at best round trip efficiency.
At 100w , you’re stuffed, it will take 2 of 5 hr days to fill them back up. Here sulffation will kick in. How much? Depends on how much in deficit you’ll be keep running in to.
The moral is: start with the quantity needed, adjust for charge discharge efficiency, then chose the storage to be able to cope with peak charge discharge and then the panel necessary to cover the hole consumption and keep batteries happy.
There is no other way.

 

[Raul]

After a lot of looking it seems like I have restrictions due to roof size and large vents... so does anyone know makes that are long and narrow? Are there any types which squeeze more umph into a small space or are they all pretty much the same?
I’ll looking into doing the 2 x 150 to start as suggested, each into a port into a nice big MPPT so I can add more after. Is it best to get an MPPT which can take 4 feeds so nothing’s in series?
Battery wise I’m still thinking AGMs - just go for as much Ah as I can fit and afford?

If you’re looking for narrow panels, Titan Energy do them for yacht and narrow boats. They are semi flexible, you can walk on them, and use sunpower cells, one of the best.

 

[peterc10]

If you’re looking for narrow panels, Titan Energy do them for yacht and narrow boats. They are semi flexible, you can walk on them, and use sunpower cells, one of the best.

But if the OP has a panel van they will have difficulty attaching flexible panels to the corrugated roof most have.

 

[Sooz52]

If you’re looking for narrow panels, Titan Energy do them for yacht and narrow boats. They are semi flexible, you can walk on them, and use sunpower cells, one of the best.

Thank you, I shall look

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[Sooz52]

But if the OP has a panel van they will have difficulty attaching flexible panels to the corrugated roof most have.

I have a Hymer, nice smooth roof

 

[Sooz52]

Monocrystalline panels produce more power for the same area than Polycrystalline ones, so you need to look for those.

Thank you, shall research

 

[Raul]

If there is a will there is a way. Many ways to skin a cat. He can glue them, he can attach them to a frame and use panel roof mounts, he can even have them on a tilting mechanism. These things can be overcome, but panel size not so much.

 

[Sooz52]

I just found these, searching for monocrystalline, width 525mm and I could actually fit 4 on the roof leaving the 2x50s in place... hmmm.
No idea what this “wish” site is though but at least I know they’re out there.

https://www.wish.com/product/5dfc46...ALw_wcB&hide_login_modal=true&share=mobileweb

 

[peterc10]

I just found these, searching for monocrystalline, width 525mm and I could actually fit 4 on the roof leaving the 2x50s in place... hmmm.
No idea what this “wish” site is though but at least I know they’re out there.

https://www.wish.com/product/5dfc46b874a22d04f90371c6?from_ad=goog_shopping&_display_country_code=GB&_force_currency_code=GBP&pid=googleadwords_int&c={campaignId}&ad_cid=5dfc46b874a22d04f90371c6&ad_cc=GB&ad_curr=GBP&ad_price=85.00&campaign_id=8163884845&gclid=Cj0KCQjwx7zzBRCcARIsABPRscOkfNnPePBmTDrS-yzE4j8ZhLO6alEctPCDFVWn9rN3VbPnihphVL4aAgQaEALw_wcB&hide_login_modal=true&share=mobileweb

It's a Chinese site. The cost and time of shipping indicates it will come direct from China. And you will have to pay customs duty on top. Good luck with all that, but I wouldn't touch it with the proverbial barge pole. I suggest you start with Ebay or Amazon as you have got better protection if things go wrong.

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