Solar Panel

[johnandrew70]

Hi All
Been thinking of installing a Solar panel on the roof of the van and have found a company who will supply me with 2x80w panels but they are Poly panels and not Mono.
I know Mono are suppose to be better but after looking online i found that there is not much between them performance wise, has anyone any experiance with Polycrystalline panels and is 160w a bit OTT?.

John

 

[JTQ]

An 80-Watt panel is an
80-Watt panel whether it uses Mono or poly crystalline or even amorphous
technology. The difference is in the "effectiveness" of the technologies. So the poly will be a little
bigger area so potentially heavier, an amorphous quite a bit bigger. The latter
though will perform better in dull conditions. The only real benefit of
seeking the mono crystalline is to achieve a smaller lighter installation for
the given Wattage, and between mono and poly that is marginal
!60 Watts is by most of our
standards a heck of a lot and I would suggest is only worth considering if you
are keen winter off EHU caravanners. Even then flat on the roof it will
struggle with typical needs because these in winter are high, the yielding hours and
light intensity are low and the panel is at far from the right orientation.
Also there are strong arguments to compliment it with increased battery storage
capacity to buffer the very inconsistent yield day to day, week to week in winter.
In summer it is a gross over
kill, in itself that is not a problem just and over investment in money, space
and possibly most of all weight. In summer it being flat on the roof is no handicap.
We have used an 85 Watt,
freestanding panel for years and this copes well in all but the winter months,
even then in bright conditions it can sometimes just about cope but such conditions are rare and it
does require a lot of panel reorientation to glean every bit of light going. We carry a second battery configured for specifically our TV use, so in all have 90 plus 60 Ah capacity.

So it depends what you are
looking for, and what usage you need to cover.

 

[Surfer]

From help I have received on here and elsewhere, it seems that the advice is that fitting the panels flat on the roof is not a good option as they should be raised slightly to allow an airflow under therefore mounting brackets should be fitted to allow the heat underneath to dissipate on hot days.

 

[BernardinTring]

Aimed at JQT please, or other contributors if you wish.
In your experience would an 80watt flat roof fitted panel keep a Phantom alarm functioning, current model of alarm, using a new Banner 100 rated battery. Nothing else, on or used, during the winter months.
If not, what are your guestimates regarding recharging periods that would be required.
No experience of this, previous van and Phantom, changed the battery every four to six weeks. Did think this chore had been avoided, Not so sure now though.
Many thanks.
Bernard

 

[johnandrew70]

From help I have received on here and elsewhere, it seems that the advice is that fitting the panels flat on the roof is not a good option as they should be raised slightly to allow an airflow under therefore mounting brackets should be fitted to allow the heat underneath to dissipate on hot days.

hi surfer. I didn't mean install the panel flat I meant it would be flat on the roof. Still trying to weigh up the options. 2 panels would mean 2 lots of brackets and a lot more cable but one panel would not need so much as the panel would would be able to go at the front just behind the heki rooflight.
I dont do a lot of off grid caravanning always been on ehu but it would be nice to think I could if I wanted to. Also I wanted something that would keep the battery topped up in storage with the alarm activated.

John

 

[TonyG]

Aimed at JQT please, or other contributors if you wish.
In your experience would an 80watt flat roof fitted panel keep a Phantom alarm functioning, current model of alarm, using a new Banner 100 rated battery. Nothing else, on or used, during the winter months.
If not, what are your guestimates regarding recharging periods that would be required.
No experience of this, previous van and Phantom, changed the battery every four to six weeks. Did think this chore had been avoided, Not so sure now though.
Many thanks.
Bernard

we kept our alarm and phantom tracker going from Oct to April with one of these stuck in the front window, and not once had that telephone call from phantom saying the battery was flat

 

[JTQ]

Bernard of Tring,
I don’t know the drain of your or other Phantom trackers but
we can take a pretty pessimistic look at what the solar panel would probably
yield and see if things look reasonable.
Throwing some numbers around.
Say the panel fitted horizontal in winter yields only 5% of
its rating for 6 hours a day then:
5% of 80 Watts multiplied by 6 hours divided by 12 volts =2
Ahs/ day
That should support a “drain” of :
2Ah divided by 24 hours = 0,083 Amps [ 83 milli amps]
If the quiescent drain of trackers is approaching this level
then they would be taking 2 Ah/day multiplied by 31 days giving 62 Ah drain a
month. At that level they would be upsetting a lot of people, so I suspect
Phantom have to design for a good bit lower drain, but as said I don’t know.

Note carefully that the low sun angle of winter makes
shadows from trees a real potential issue, so look at the site carefully. If
that is not an issue for you I would expect the panel to do the required task.

 

[MichaelE]

I fitted a 95 watt on my roof this year this year and i couldnt use all the power it generated,to be honest most was wasted as the battery (125 amp) was fully charged by 10 am in the morning on a sunny day.
Now winters here as already pointed out the sun is low and the days are dull whilst away it struggles to keep the battery topped up, so i run just my tv off a seperate battery i fitted.
In storage np it will keep the battery topped up and its doesnt have the drain like water pump , lights etc, so just the alarm is not a problem.
If you do fit 2 , the only extra wiring you will have is the wire linking the 2 up so they are in parallel, you will then have 1 cable still to the charge controller.

 

[johnandrew70]

What happens with the energy that is not used??
I mean the controller stops charging the battery when the battery is fully charged so what happens then.
i have the idea of installing a fan in the fridge vent and running it off the LOAD side of the controller, My controller has a switch to either manually enable the LOAD or allow the Load to be enabled for the daylight hours. this i thought would be ideal for the fridge vent fan Obviously whilst in storage the fan will be switched off.
Back in the summer the fridge was having trouble to cool as it was so hot, even with the vents removed it took some time to cool.
John

 

[JTQ]

If there is no where to put energy it effectively does not
exist. Your controller will simply decouple the panel from the battery.
On my controller the” Load” simply manages the battery discharge
rate and stops the drain on the battery taking the voltage too low. It is not a
feature I bother to use.

You only need your refrigerator cooling fans in extreme
temperatures, so there is likely to be enough sunshine simply to run them from
your battery. You could do this via the “load” ports if you wish.

 

[BernardinTring]

Thanks to all for the information, especially the calculations; phew!
One last request and I know it will have been asked numerous times before, so an apology for that, but if you charge a battery at home, I've a c-teck charger, what should the initial reading be when transferred to the van, and when it has 'settled down' particularly in the current conditions outside, what 'normal' reading would you expect to achieve from a battery, say in 'good condition'.
Mant thanks.
Bernard

 

[JTQ]

Thanks to all for the information, especially the calculations; phew!
One last request and I know it will have been asked numerous times before, so an apology for that, but if you charge a battery at home, I've a c-teck charger, what should the initial reading be when transferred to the van, and when it has 'settled down' particularly in the current conditions outside, what 'normal' reading would you expect to achieve from a battery, say in 'good condition'.
Mant thanks.
Bernard

After the battery has stabilised as you realise and say then its fully charged, off load voltage still depends on the trace alloying in the lead used in its construction. However it should be between 2.7 and 2.9 volts. Having been charged by the excellent CTEK charger that really should have got it as full as it could be.
Without access to data charts for a particular battery build measuring voltage is a bit unreliable for indicating the state of charge.

 

[WoodlandsCamper]

However it should be between 2.7 and 2.9 volts. Having been charged by the excellent CTEK charger that really should have got it as full as it could be.

Typo JTQ ??

Perhaps 12.7 to 12.9 volts

 

[JTQ]

However it should be between 2.7 and 2.9 volts. Having been charged by the excellent CTEK charger that really should have got it as full as it could be.

Typo JTQ ??

Perhaps 12.7 to 12.9 volts

Thanks you are so very right; underpressure trying to do last few Christmas cards!!

 

[johnandrew70]

Well i have ordered the panels, Y connectors, 8 corner mountings, roof gland and cable, i already have a controller all set up that i have been using with a 30w panel in the heki rooflight so dont need a controller.

Has anyone had any problems with drilling a hole in the roof for the cable to pass through?? do i need to worry about wiring that may be in the roof? i am going to fit the panels to the roof at the rear of the van either side of the mini heki in the bedroom then trail the wires over the roof to the front where the tv earial and chimney are then install the roof gland to drop the cable through into the cupboard beneeth then connct the the controller.
the only thing thing i am slightly worried about is drilling the hole, Do i drill from inside out or outside in and do i fill the hole with Sikaflex or just sikaflex the gland to the roof??? also do i drill a hole just big enough to push the cable in tight or big enough for the cable to easily move about really sloppy

John

 

[Surfer]

Well i have ordered the panels, Y connectors, 8 corner mountings, roof gland and cable, i already have a controller all set up that i have been using with a 30w panel in the heki rooflight so dont need a controller.

Has anyone had any problems with drilling a hole in the roof for the cable to pass through?? do i need to worry about wiring that may be in the roof? i am going to fit the panels to the roof at the rear of the van either side of the mini heki in the bedroom then trail the wires over the roof to the front where the tv earial and chimney are then install the roof gland to drop the cable through into the cupboard beneeth then connct the the controller.
the only thing thing i am slightly worried about is drilling the hole, Do i drill from inside out or outside in and do i fill the hole with Sikaflex or just sikaflex the gland to the roof??? also do i drill a hole just big enough to push the cable in tight or big enough for the cable to easily move about really sloppy

John

Where did you buy all the gear as we are still looking at buying however we need to wait until the dealer returns the caravan? I would think it may be better to drill from the inside out for a more precise location inside. The big concern here would be if you drilled through one of the structure cross members in the roof so not sure how you would get around that problem.

 

[Gagakev]

Hi John, as Surfer says I would drill from the inside out to make sure it is where you want it to be,as your roof is proberbly Ali I would source a grommit to feed the cable through, my roof is polyester but still used a grommit to protect the cable when I did the camera this is what I used
The screw in the photo is for illistration only and where i made the grommit from

When fitting the gland I filled it complety with sikaflex making sure there was plenty around the hole and stuck it to the roof

As you can see I also used some ducting to protect the cable. Good Luck

 

[johnandrew70]

Well i have ordered the panels, Y connectors, 8 corner mountings, roof gland and cable, i already have a controller all set up that i have been using with a 30w panel in the heki rooflight so dont need a controller.

Has anyone had any problems with drilling a hole in the roof for the cable to pass through?? do i need to worry about wiring that may be in the roof? i am going to fit the panels to the roof at the rear of the van either side of the mini heki in the bedroom then trail the wires over the roof to the front where the tv earial and chimney are then install the roof gland to drop the cable through into the cupboard beneeth then connct the the controller.
the only thing thing i am slightly worried about is drilling the hole, Do i drill from inside out or outside in and do i fill the hole with Sikaflex or just sikaflex the gland to the roof??? also do i drill a hole just big enough to push the cable in tight or big enough for the cable to easily move about really sloppy

John

Where did you buy all the gear as we are still looking at buying however we need to wait until the dealer returns the caravan? I would think it may be better to drill from the inside out for a more precise location inside. The big concern here would be if you drilled through one of the structure cross members in the roof so not sure how you would get around that problem.

The 80w Solar panels were £62 each including express next day delivery from http://www.friendlygreengiant.co.uk.
Email Patrick there and he will be able to give you a good price on the panels he also has an Ebay Shop http://stores.ebay.co.uk/The-Friendly-Green-Store.
The 20m of 4mm solar cable was £12 from a seller on ebay i didnt need the MC4 connectors as i already had those. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=291037520459&ssPageName=ADME:X:RTQ:GB:1123
Send the seller a message asking for the size you want and he will sort it for you, he is called Jamie.

The Solar Corner mountings are the cheapest i found on Ebay at £16.99 with free postage
http://www.ebay.co.uk/itm/151185271936?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

The Cable entry gland also Ebay.Also the cheapest at less that £9 delivered
http://www.ebay.co.uk/itm/310790513493?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

The Y Connectors for connecting the 2 panels were a bargain as a lot of people wanted a fortune for these, £6.79 delivered for the pair.
http://www.ebay.co.uk/itm/281084744267?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I bought the Controller previously to use with my 30W panel, its a PWM controller and some say they are not as good as MPPT controllers.
http://www.ebay.co.uk/itm/221320901663?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
I am hoping most of this stuff turns up on Tuesday but wont be installing it all until after Christmas Hopefully when the weather is slightly better.
I still dont know abouth the drilling yet and i havent bought the Sikaflex yet to be honest there are so many different ones i dont know whats best.
John

 

[johnandrew70]

Hi John, as Surfer says I would drill from the inside out to make sure it is where you want it to be,as your roof is proberbly Ali I would source a grommit to feed the cable through, my roof is polyester but still used a grommit to protect the cable when I did the camera this is what I used
The screw in the photo is for illistration only and where i made the grommit from

When fitting the gland I filled it complety with sikaflex making sure there was plenty around the hole and stuck it to the roof

As you can see I also used some ducting to protect the cable. Good Luck

Hi Kev thanks for idea with the gromet will see what i can find at work, will have to find one big enough for the 2 cable also i like the idea with the ducting where did you get that? not sure about screwing the clips into the roof though will probably try to sikaflex them lol.
When are you down this way on Holiday might need anouther pair of hands haha.
John

 

[Parksy]

You would make a neater job by using a small hole cutter for the cable entry hole. The cutter uses a drill to center the hole and you can choose a cutter to fit your grommit. Start the hole inside the cupboard after checking that there are no cables in that part of the roof and when you are through the wood and the insulation inside the caravan you can cut from the roof outside using the drilled pilot hole.
Clean up the edges of the hole with emery cloth to remove any burrs.
Pass the cables through the entry gland and the grommit and into the caravan via the hole in the roof, use a grommit without a hole so that you can make a smaller aperture for the cable using a bradawl or similar unless you can source a similar one to that shown in the photos.
Fit the grommit and seal it (and the aperture if you made one for the cable) with Sikaflex and as mentioned earlier, fill the inside of the entry gland with sikaflex and bond it to the roof. You can easily clean off any excess Sikaflex with white spirit when the gland has been fitted.

 

[johnandrew70]

You would make a neater job by using a small hole cutter for the cable entry hole. The cutter uses a drill to center the hole and you can choose a cutter to fit your grommit. Start the hole inside the cupboard after checking that there are no cables in that part of the roof and when you are through the wood and the insulation inside the caravan you can cut from the roof outside using the drilled pilot hole.
Clean up the edges of the hole with emery cloth to remove any burrs.
Pass the cables through the entry gland and the grommit and into the caravan via the hole in the roof, use a grommit without a hole so that you can make a smaller aperture for the cable using a bradawl or similar unless you can source a similar one to that shown in the photos.
Fit the grommit and seal it (and the aperture if you made one for the cable) with Sikaflex and as mentioned earlier, fill the inside of the entry gland with sikaflex and bond it to the roof. You can easily clean off any excess Sikaflex with white spirit when the gland has been fitted.

Thanks for the Advice Parksy out of curiosity how thick is the sandwich construction of the roof (2007 Swift)
i did wonder weather to fill the entry gland with sikaflex to make double sure no water will get in.
John

 

[Gagakev]

Hi Kev thanks for idea with the gromet will see what i can find at work, will have to find one big enough for the 2 cable also i like the idea with the ducting where did you get that? not sure about screwing the clips into the roof though will probably try to sikaflex them lol.
When are you down this way on Holiday might need anouther pair of hands haha.
John

conduit in white here
comes with the saddle clips which are NOT screwed to the roof

they are fixed with the sikaflex.
I was advised and did replace the screws in the saddle clips with stainless steel ones to stop future rust.
Perhaps my type of grommit may not work as I didnt realise you had two cables.....two holes perhaps?????

 

[JTQ]

I bought the Controller previously to use with my 30W panel, its a PWM controller and some say they are not as good as MPPT controllers.
http://www.ebay.co.uk/itm/221320901663?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

John

If that really is your controller it is not suitable for your 160 Watts of solar cells, at 10 Amp rating it is way undersized for the 13.4 Amps the panels will quite frequently yield.
I have not checked for you if it has overload protection or not but even if it is safe in that way it will simply be wasting the panels output.

Edit: it does claim "over current" protection so ought to be "safe" but it does not detail what it does on over loading.
Personnally I would buy a unit suitable for the job.

 

[johnandrew70]

I bought the Controller previously to use with my 30W panel, its a PWM controller and some say they are not as good as MPPT controllers.
http://www.ebay.co.uk/itm/221320901663?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

John

If that really is your controller it is not suitable for your 160 Watts of solar cells, at 10 Amp rating it is way undersized for the 13.4 Amps the panels will quite frequently yield.
I have not checked for you if it has overload protection or not but even if it is safe in that way it will simply be wasting the panels output.

Edit: it does claim "over current" protection so ought to be "safe" but it does not detail what it does on over loading.
Personnally I would buy a unit suitable for the job.

These are the specs for each panel
do you still think i need a new controller??Open-circuit voltage (Voc)Av 21.6V, sd 0.3Voltage at maximum power (Vmp)Av 17.5V, sd 0.2Short-circuit current (Isc)Av 5.02A, sd 0.01Current at maximum power (Imp)Av 4.57A @ 12vMaximum power at STC (Wp)80W ±5%Operating temperature-40oC to +85oCMaximum system voltage1000VdcPower tolerance±5%

 

[Surfer]

Aren't Morningstar supposed to be one of the best controllers on the market? They make a number of different models so I am not sure which one is best to use. I guess you need to go by amperage.