#97190  by NeilV
 Tue Jul 28, 2015 5:21 pm
So I'm biting the bullet and going for a 250w panel to start with...

Looking at the $269 "install kit" from AASolar cost $4 less than the than the panel! :o

I wonder if I can source the pieces cheaper myself?

Can get the 'feet' for 50-60 on TM https://trademe.co.nz/921123117p so wiring, fuses and screws shouldn't cost $200 really should it?
 #97201  by Neddy
 Tue Jul 28, 2015 9:50 pm
I mounted our solar panels using aluminium extrusions running along their outer edges. The extrusion needs to have its right-angle opened out a bit so as to fit the camber of the roof. The extrusion is fastened to the solar panel frames with pop rivets and the base is glued and pop riveted to the roof. Suitable extrusions cost about $8/meter or so. There is no need for fancy cable entry fittings. Drill a hole through the roof, poke a rod through and force it rearwards until it is flat, leaving a nice clean horizontal entry port for the cable. The generous application of a good quality sealant completes the job. There is no need for expensive connectors - you can solder any required joins. Don't put any junction boxes, fuses or the like on the roof. Rotate the solar panel(s) such that their cable comes through the roof as near as possible to the switchboard.

I have tried (but apparently failed) to get you to spring for the extra few dollars and buy a second 250 watt panel.
The day will come when you will wish that you had! At the very least, run enough aluminium extrusion to mount a second panel. Just hope and pray that that particular model and size of panel will still be available when you want it. Which you inevitably will! Save money somewhere else. Anywhere else.


PS: Those TradeMe mounts look quite good. Make sure to leave a space for that second panel......

 #97207  by NeilV
 Tue Jul 28, 2015 10:20 pm
Thanks Neville

I'm convinced, but the missus needs a lot more convincing it seems, she doesn't even think solar is worthwhile (!)

As a last resort, would you say dropping 240v install entirely is worth the extra 250w panel? To be legal, I'd then have to either run an extension cable out a window when parked at home (like now) or run anything 'mains powered' entirely off the 1200w inverter (pure sine so not a problem, but unlikely to be good for my 'little' 104ah batteries at that sort of load!)

As we rarely (if ever) likely to park up, I'm now seriously considering this alas sparky fees and rcbo box will easily outcost the extra $320 on a panel upgrade [installed cost]

What grade wire do I need to consider (per) 250w panel at 30v/8a to the controller?
And if two go into it, what size wire out to the batteries please?
 #97212  by muzzanic
 Tue Jul 28, 2015 11:23 pm
I'm with Neddy, I know it's a lot more money, But go with the extra Panel.

The only time you will regret it is the day you pay for it, From there on in it will save your butt.

With 500w You should be able to get by without plugging into 240v power.

 #97219  by Derb
 Wed Jul 29, 2015 7:20 am
With regard to cable size - dont be a scrooge with copper! Big fat heavy 20 - 50 amp cable will serve you well and apart from reducing voltage drop, will allow for further panels in the future should you require them. With regard to the junction box (or lack of) . If going up this route I would suggest gluing a small coil of extra cable on roof to give you length for later use. Copper is not expensive in the larger scheme of things. Cheers.
 #97224  by NeilV
 Wed Jul 29, 2015 8:13 am
So JCar 50a dual core would suffice? Not a problem AT ALL (6.99/m is not worth scrimping!)

I think i was expecting jumper cable size wire??? :lol:
 #97225  by Neddy
 Wed Jul 29, 2015 8:16 am
Neil, that extra solar panel will make the crucial difference as to whether you are energy independent or not.
Sit down with your wife and calculate how many nights in a campground you would have to save to recoup that investment. (Not many!)

Your task priorities should be set by how you propose to use the vehicle. If you will be mainly "off grid", concentrate on getting the DC side of things up and running. If you will be spending the majority of your time plugged into the mains, then the AC side of the install is the more important.

Do things once and do them right - or delay doing them at all until you can do them properly.
Installing solar panels is awkward - fit 2 or none. At the very least you need some sort of logical upgrade plan. Without this you will find yourself having to do many jobs twice and buying equipment that does not fit with your ultimate objectives.

Don't worry about the details until you have got the big picture clear in your mind.

 #97235  by muzzanic
 Wed Jul 29, 2015 9:32 am
Having the extra panel will mean that you have a lot more chance of going into night time with the battery fully charged & this in turn will mean that the battery won't discharge as deep & that will make your battery's last longer.

Not having to plug into the grid gives your far more options to enjoy your motor home.
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