Solar Panel Questions

[RAW]

I have a couple of Solar panel questions @wildebus and others ?
New van has a small Solar panel on her and a rather rubbish looking charge controller, with a Lamp plugged into the Streetlight port and for what purpose I have no idea. Pictures to follow.

• with little knowledge of the Solar Panel that is on the Van, how can I work out what the output of the Solar panel is ?
• has anyone used any flexible solar panels and are there any that are better than others ?

Thanks in Advance
Robert

 

[Nabsim]

If you can get the panel off easily it will have (rather should have) a special plate on the back of it. Dave May be blue to tell you without doing this though

 

[Squiffy]

If you have a multimeter set it on Amps ( usually the centre lead plug is the common and the plug either side of common is volts/ohms or Amps depending on where you plug into) max amps on most cheap multi meters is 10amps which is plenty for average single solar panel fitted to a vehicle. Disconnect the pos and neg leads coming from the solar panel at the controller connect the multimeter leads to the solar panel leads for a short period ( Enough time for the amps to settle on the display) if this is done on a bright sunny day it will give you the max amp output that your particular panel will supply ( Probablyin the 5-8 amps range), then change the multimeter leads to volts and measure voltage output which again on a sunny day should be in the 21-27 volts DC range this at least will show you that it is supplying a usable output. Phil

 

[wildebus]

I have a couple of Solar panel questions @wildebus and others ?
New van has a small Solar panel on her and a rather rubbish looking charge controller, with a Lamp plugged into the Streetlight port and for what purpose I have no idea. Pictures to follow.

• with little knowledge of the Solar Panel that is on the Van, how can I work out what the output of the Solar panel is ?
• has anyone used any flexible solar panels and are there any that are better than others ?

Thanks in Advance
Robert

Is this panel a flexible one? If so checking specs by lifting panel will probably be tricky but that - if possible - is the way.
Connecting up the Victron controller to it and then leaving it for the day will tell you from the data a good indication of the Voc.
I would just physically measure it and that is a good indication. Panels tend to be the same rating per square metre, so a 100W panel tends to have a working area twice that of a 50W.
Then determine if mono or poly. Mono panels have distinct centre bits between the cells; poly tend to appear more of a single large area with lines down them. A poly panel is usually around 10-15% lower in capacity for a given size.

Flexible solar panels .... They vary tremendously in quality, much more than glass ones. For a reliable flexible panel, budget at least 2x the cost/watt compared to a glass panel. Assuming you are talking about updating the panels on the new Sprinter I would strongly recommend you stick with glass.

 

[RAW]

Flexible solar panels .... They vary tremendously in quality, much more than glass ones

I want to avoid having to drill holes in the roof and there are no roof bars.
So for off-grid I think the best approach would be, as you say above, maybe get someone to weld a simple rack onto the Van, create a double array of glass panels, maybe 2 x 310W which are on a piece of angle and can be tilted.
Costs from the Top of my head:
Rack: £500
Panels: £260
Kit for making tiltable: £100
Cables and ancillary £30
TOTAL IRO £900 and a lot fo work with output at 620W

Alternative, less work but not such great output in power as the above,
3 x Good Flexible Solar panels like www.bimblesolar.com/solar/small-panels/150w-semi-flexible
Panels £600
Glue £20
Cables and ancillary £30
TOTAL IRO £650 and less work but output MAX at 450W

Thoughts ?

 

[Nabsim]

If I had a van I would definitely be looking at a roof rack/rail system. The way you can fix panels and move if necessary is a bonus. Can you not get clamp on racks still like I see on work vans for yours?
Only need one hole for gland box entry that way and may make it easier if you want to go for tilting panels later on.

 

[wildebus]

Well, in your financial comparision, take off the £100 for the tilting kit on option 1 as you are not having that feature in option 2 (comparing oranges and apples otherwise).
Next, £500 for rack? what access do you have to the underside of the roof? if you can access it then you could do similar to the approach I took - Add your own roof rails ...

IMG_20170820_105556 by David, on Flickr
Doing this will cost around £100 on your van
And you can get fixing kits, like shown in this picture ...

Entry Box routing and Panel Mount by David, on Flickr

This approach also encompasses the point made by Neil ...

If I had a van I would definitely be looking at a roof rack/rail system. The way you can fix panels and move if necessary is a bonus. Can you not get clamp on racks still like I see on work vans for yours?
Only need one hole for gland box entry that way and may make it easier if you want to go for tilting panels later on.

The reason I went for what I did was precisely to allow flexibility of fitting. My panels are fitted flat, but I could easily change to a tilting system, or move panels around whenever I want.
These are in place but I can move them in minutes

400W in Place by David, on Flickr
There are no factory rail systems for the Sprinter Mk 1 (T1N) model, and Roof racks would need holes drilled anyway unless gutter-mounted - and using those would stop the use of the awning (gutters are low on these age vans (the transit jumbo is just the same).

I would do some measurements as well. Do you think a pair of 310W panels will fit on top of your MWB Sprinter? I worked out I could just squeeze in 600W (6 x 100W) on my LWB from front to back if I filled the roof with panels and my van is of course longer than yours - by just shy of a metre.
And as the rear end and front end are the same, that means you have around 1.6 square metres less roof space to accomodate panels, plus I am guessing you have at least one roof vent to have to work around?
Some numbers on this thread ... https://motorhomebuilder.com/threads/van-size-comparisons-the-germans.66426/

I would have a look at the sprinter-source forum and get some ideas there as well.

 

[Nabsim]

Your system was exactly what I was thinking of Dave. A raised rack may be better if you have a few skylights as you could fit above them but obviously restrict opening. If only one roof vent or more close together your system is a no braine to me.
Can you get raised stand offs for your slides anyway Dave, something that would allow say six inch mount above roof to clear vents?

edit: I hate auto correct and predictive text at times lol

 

[wildebus]

Your system was exactly what I was thinking of Dave. A raised rack may be better if you have a few skylights as you could fit above them but obviously restrict opening. If only one roof vent or more close together your system is a no braine to me.
Can you get raised stand offs for your slides anyway Dave, something that would allow say six inch mount above roof to clear vents?

edit: I hate auto correct and predictive text at times lol

I could do that very easily with some aluminium C Channel - along the lines of what Phil Admin as done. I was toying with just that in order to add another panel at a jaunty angle over the MaxxAir fan but decided against it and looking at other quirky ways to add capacity

 

[RAW]

All very interesting @wildebus and @Nabsim THANKS
I am toying with ideas at present as Van is still in it's infancy and some issues to tackle first anyway, not in any order:

1. Slide Door not opening from inside, just found out this AM
2. STILL smells of Dog
3. Pre-heat light stays on whilst driving on dash

 

[wildebus]

All very interesting @wildebus and @Nabsim THANKS
I am toying with ideas at present as Van is still in it's infancy and some issues to tackle first anyway, not in any order:

1. Slide Door not opening from inside, just found out this AM
2. STILL smells of Dog
3. Pre-heat light stays on whilst driving on dash

for #1, see if this helps at all .... https://www.wildebus.com/wp-content/uploads/2020/02/Sprinter-Sliding-Door.pdf

 

[Greggbear67]

Another solar panel question, just how bendy are the flexible solar panels?
Wanting to fit solar to my Mellor bus conversion but don't really want to drill the roof except for cable access. Will the panels flex enough to follow the profile of my roof?
Thinking of sticking down with Sikaflex or similar, then sealing the edges with some kind of waterproof mastic. Thoughts please.....

 

[Squiffy]

Hi Gregg maybe this will help

 

[SquirrellCook]

I've been using Lensun panels for a few years with about a 50% failure rate. They have been good and replaced them. Shame they have often been a different mounting pattern. I bonded studs to the GRP roof and retained the panels with aluminium straps. Air moving under them makes them vibrate they tend to fail shortly after. Also they like to be bent with the curve going from short side to short side. Unhappy if you try the other way.
No failures for over a year now, but the roof is a mess from alterations to remount the new panels. Towards the end of last year I've mounted two cheapy panels and they are much more flexible. Time will tell if they are any good. Half the price of lensun though.

The new build Betty is getting four very expensive panels and I do hope they will be trouble free. https://midsummerenergy.co.uk/buy/flexible-solar-panels/miasole-120W-CIGS-flexible-solar-panel

 

[Nabsim]

No idea what sort of radius is on your bus Greg but is it an option to mount rigid panels around the curve a bit like the vikings made a turtle shield wall with shields? Not sure I am describing what I mean very well lol

 

[Greggbear67]

I'm trying to stop the wind getting under them when I'm driving, I hear its preferable if possible. Radius isn't too severe, I think if I mount 2 panels long ways on the roof but side by side & 1 each side of the centreline I can take the wiring down from 1 side near to my batteries. Hopefully when funds allow I can then mount 2 more panels in front of them to give around 400 watts total. I plan to just drill 1 hole in the lid if I can get away with it for all 4 wires to join up together...

 

[RAW]

The new build Betty is getting four very expensive panels and I do hope they will be trouble free. https://midsummerenergy.co.uk/buy/flexible-solar-panels/miasole-120W-CIGS-flexible-solar-panel

I like those panels but as you say VERY expensive - I might look into it more if they come down in price.

 

[Nabsim]

I thought the flexible panels had to be stuck down so there is no movement/air getting under them?

is it an option to get more small panels @RAW (rigid) and fill the space with those? Can’t remember where now but saw some 50W Victron panels cheap a couple of months back. I know it’s more cables to join though.

 

[SquirrellCook]

I might look into it more if they come down in price.

I doubt if the price will drop, since I've been looking at them the price has risen. That said in the US they are much cheaper, it just a case of getting sensible postage.