Solar The Solar Panel Thread

[Bellbirdweb]

OK - I am sure this will be covered and maybe more than once but I can not find a clear answer and everyone seems to have different views...


I have a 100ah house battery and a roof mounted 90w solar panel. If I connect a portable 80w panel with it's own regulator what happens???
will...
a) both will produce power and the combine power is fed into the battery
b) the panel which is producing the most power will produce power for the battery and the other will do nothing.

Sparky tells me option a
RV installer tells me option b

I am planning a trip to Bathurst this year, I will be taking a second portable battery (also 100ah) with me and not sure if best is to keep them connected together and run the 2 sets of panels or to separate the batteries during the day for charging with each panel charging one battery, then connect the together at the end of the day.

You can connect 2 different solar arrays, each with their own controllers in parrallel to a single battery.

The charge current will be the combination of both sets, so should do exactly what you are wanting it too.

If you want to connect the 2 batteries in parallel that would work as well.

 

[Dobbie]

My understanding is option A with:

• Both inputting to battery but if one is more in the shade, then it could be inputting less
• Both need regulators....and separate connections to the battery. Roof panel goes via its onboard controller but portable must have its own separate controller and be wired directly to battery, not via Setec or on board controller
• Both must have blocking diodes (usually standard these days) to prevent conflicting charge issues and leakage

It's even possible to hook up two panel with a y connector and one controller to boost the external charge.

If you want to monitor while they're charging, hook up a voltmeter.....it'll reassure you and find any problems, if there.

I'd be inclined to ignore the Rv installer ....most, in my experience, are not tradesmen. Some are, of course, but I haven't found a real one employed by a caravan place recently. I definately go to a qualified auto electrician....your experience may be different but that's what I've found.

 

[Bellbirdweb]

My understanding is option A with:

• Both inputting to battery but if one is more in the shade, then it could be inputting less
• Both need regulators....and separate connections to the battery. Roof panel goes via its onboard controller but portable must have its own separate controller and be wired directly to battery, not via Setec or on board controller
• Both must have blocking diodes (usually standard these days) to prevent conflicting charge issues and leakage

It's even possible to hook up two panel with a y connector and one controller to boost the external charge.

If you want to monitor while they're charging, hook up a voltmeter.....it'll reassure you and find any problems, if there.

I'd be inclined to ignore the Rv installer ....most, in my experience, are not tradesmen. Some are, of course, but I haven't found a real one employed by a caravan place recently. I definately go to a qualified auto electrician....your experience may be different but that's what I've found.

Yep, exactly right

 

[Vere]

Thanks guys, that is what I thougrt - and also hoped for :whoo:

 

[mikerezny]

My understanding is option A with:

• Both inputting to battery but if one is more in the shade, then it could be inputting less
• Both need regulators....and separate connections to the battery. Roof panel goes via its onboard controller but portable must have its own separate controller and be wired directly to battery, not via Setec or on board controller
• Both must have blocking diodes (usually standard these days) to prevent conflicting charge issues and leakage

It's even possible to hook up two panel with a y connector and one controller to boost the external charge.

Hi @Dobbie,
I may be wrong, but my understanding is that if you intend to have multiple solar panels each with its own solar charger, then there is no requirement to have blocking diodes. Blocking diodes are necessary only if one has multiple solar panels connected in parallel as input to a single solar charger. I this case, if one panel is in the shade and the other in the sun. The one in the sun will discharge into the one in the shade.

Also, I think I remember, in a low powered solar setup where the solar panel is connected directly to the battery without a solar regulator, a blocking diode is also necessary otherwise when the panel is out of the sun, the battery will discharge back into the panel.

cheers
Mike

 

[Dobbie]

That could well be correct as well as almost all decent panels these days come with diodes....when I first started mucking around with solar they weren't the norm...hence my banging on about diodes. I don't think the series or parallel set up affects that.

I'm glad you took @Drover to task about that Mike....I'm to blame not him.

The low power panels with no regulator are always different in setup. ....I'm investigating some of them to replace some "rustic" shed lighting I need to do soon. I've got a mower battery...I think it's about 4amps ....and want to put led strips to a 12v socket in a battery box and power that with a small solar panel. I'm thinking as small as necessary....maybe a 20watt or less if I can.

Any advice on that? Reason for doing it is to use what I have here and to save wasting it.

but I've definately noticed the newer panels are far more efficient than my old ones.

 

[Drover]

Am I getting the blame again for something you said @Dobbie San ???????????...........seems Mike did a quick edit...lol,lol.....................easy to tell if a diode is fitted somewhere in the food chain, flat battery in morning if not..............................I have a couple of those 2w panels that keep the shed battery topped up, it just runs some lights and test stuff, old Ute battery that at full juice is about 12.4, good enough for it's retirement job.

 

[mikerezny]

That could well be correct as well as almost all decent panels these days come with diodes....when I first started mucking around with solar they weren't the norm...hence my banging on about diodes. I don't think the series or parallel set up affects that.

I'm glad you took @Drover to task about that Mike....I'm to blame not him.

The low power panels with no regulator are always different in setup. ....I'm investigating some of them to replace some "rustic" shed lighting I need to do soon. I've got a mower battery...I think it's about 4amps ....and want to put led strips to a 12v socket in a battery box and power that with a small solar panel. I'm thinking as small as necessary....maybe a 20watt or less if I can.

Any advice on that? Reason for doing it is to use what I have here and to save wasting it.

but I've definately noticed the newer panels are far more efficient than my old ones.

Hi @Dobbie and @Drover,
OOPs, apologies. It is not the first time I have done this, so I will apologise again in advance because I am sure it will not be the last.

It is probably worth getting a 40W panel, anything less is not that much cheaper. And a 40W panel will charge and float bigger batteries. I wouldn't bother with a 10W panel. 20-30W would also work ok on the small battery in the mower.

I got mine from:
http://www.ebay.com.au/itm/40W-60W-...REGULATOR-/222170104698?var&hash=item0&_uhb=1
I see it has gone up a few dollars. I paid $49.95 and no delivery since I could drive around to pick it up. The main thing is to get a Mono cell. Perhaps you can get something similar and pick it up from an eBay seller in Brisbane.

Adam Welch on YouTube has some great videos testing solar regulators. In particular exposing the many cheapies around that claim to be MPPT but aren't.

But he raved about this little one 6V/12V 10A which I got from China for only $6.69 delivered. It has a three-stage charger, so good for keeping the battery continuously on float.

I have used both of these for the last 7 months on our Penguin and am very happy with them.

cheers
Mike

 

[mikerezny]

easy to tell if a diode is fitted somewhere in the food chain, flat battery in morning if not..............................I have a couple of those 2w panels that keep the shed battery topped up, it just runs some lights and test stuff, old Ute battery that at full juice is about 12.4, good enough for it's retirement job.

Hi @Drover,
if I am not mistaken, a solar charger / regulator already has the functionality to prevent discharging the battery back into the panels when there is no sun. So, if a single panel is wired to a battery via a solar charger / regulator, a blocking diode is not actually needed.

Here is an informative article discussing topic this and making note of the difference between blocking and bypass diodes:

https://www.solar-electric.com/solar-power-technical-tips.html/

But this article does not seem to mention the need for blocking diodes on multiple panels to handle the situation where some of the panels are not in sunlight and some are in sunlight.

cheers
Mike

 

[Drover]

That's why I said you can soon tell.........nowadays it's a given that it isn't going to bleed.

 

[Dobbie]

Probably academic these days Mike, with most solar issues people face being protected by the diodes which are more or less standard. My understanding was the regulator prevents overcharging but doesn't have a back flow as such. I could be wrong.

Our van solar setup works brilliantly....it's the same as we've always had and been able to augment shaded roof panels with the portable input very easily. Only issue we've ever had was a blown fuse when I hooked up the compressor to the Anderson....too light a fuse.

Nobody in their right mind, if they want a good strong solar setup, would set the proposed shed installation like mine....though it's encouraging that @Drover already has. I rest my case.

I think we're all on the same wavelength ......or solar band...and the differences are dependent on the relative age and specs of the panels.

All of the discussion on this thread is related to caravan setups with new panels, so I'll refrain from digressing yet again to avoid confusion.

(With my proposed shed setup, it's more a matter of making existing surplus items work. I'm a stubborn idiot and hate spending money if I've got something that just might work......along the lines of your chippy.

It's replacing a couple of those solar shed lights Jaycar marketed about ten years ago...I paid around the $40 mark for each, thinking they were a good idea but they never really worked. My surplus stuff is: old mower battery, old battery box with 12v socket and Anderson wired in, an old voltmeter just to test in the initial stages, a surplus strip of led lights wired to a 12v plug and a lot of enthusiasm and bloody mindedness!

We've recently put in a huge fire pit with the bbq next to it and the old shed blew down in a storm so it's been rebuilt and deserves some lighting. It's like the Taj Mahal of open sheds now!

I'll give it a go and if my old 10watt panel gives enough to keep the old battery charged, I'll smile every time I use the lights over there.

Anyway, it's fun trying ...I'll lash out and buy a 40watt panel if it doesn't!)

 

[mikerezny]

(With my proposed shed setup, it's more a matter of making existing surplus items work. I'm a stubborn idiot and hate spending money if I've got something that just might work......along the lines of your chippy.

It's replacing a couple of those solar shed lights Jaycar marketed about ten years ago...I paid around the $40 mark for each, thinking they were a good idea but they never really worked. My surplus stuff is: old mower battery, old battery box with 12v socket and Anderson wired in, an old voltmeter just to test in the initial stages, a surplus strip of led lights wired to a 12v plug and a lot of enthusiasm and bloody mindedness!

We've recently put in a huge fire pit with the bbq next to it and the old shed blew down in a storm so it's been rebuilt and deserves some lighting. It's like the Taj Mahal of open sheds now!

I'll give it a go and if my old 10watt panel gives enough to keep the old battery charged, I'll smile every time I use the lights over there.

Anyway, it's fun trying ...I'll lash out and buy a 40watt panel if it doesn't!)

Hi @Dobbie,
ok, now I understand where you are starting from.

Since you already have an old battery and an existing 10W solar panel, would it be stretching the budget to add the simple solar regulator I suggested? It would give the old battery protection from being overcharged and probably extend its life. In the event that the experiment is a success and sometime down the track, the battery decides to move on, you may have a better more precious alternative that would simply slot in.

As you know, I love the idea of more with less.

cheers
Mike

 

[Dobbie]

Following on from my shed setup ponderings, I came across this article...I was looking for max capacity of an unregulated panel.. ...but I thought it provided good, solid, basic information so might be useful to answer some of the frequent solar questions....not all, but some

https://www.whitworths.com.au/pages/adviser/solar_power.asp

I have now confirmed I don't need a regulator for my small battery and low capacity panel.....over 1.5% of rated battery capacity requires a regulator. I hadn't come across that specific figure before.....

 

[mikerezny]

I have now confirmed I don't need a regulator for my small battery and low capacity panel.....over 1.5% of rated battery capacity requires a regulator. I hadn't come across that specific figure before.....

Hi @Dobbie,
this is useful information for me.

I was considering getting and carrying a spare solar regulator in case the one I now have fails.
My 40W panel gets a max current of a little over 2A. My battery is 105Ah, so 1.5% is about 1.5A which is close enough 2A.

So, you saved me $7 and having to carry another item. The way I have it wired, if the regulator fails, I can easily bypass it until I get a replacement.

Thanks
Mike

 

[alexvk2]

I was told by the supplier that they can be either screwed on by the eyelets in each corner or by glueing straight to a surface, no mention to a air gap. I will email him and double check as Ive been asked this before. They would be ok on my vans roof as its not a flat surface. Stay tuned.

My experience with thin flex panels FWIW
I have had to return 2 of them to Jaycar as each failed to either deliver power (half or less the rated) or had intermittent connection fault. The another factor is I was on a friends yacht - looked at his flexible panels that had been in the weather for a couple of years and the plastic had gone very cloudy so I'd guess they no longer put out much of their rated output.
So I chose to use the heavier glass/alloy to increase power on the panda - 2X120W

 

[Dobbie]

I'd definitely agree with that ....I have a portable fold up 120 panel (eight sections which fold up to the size of one...the blanket type) which can be a pain to set up as it just wants to collapse all the time. My temporary solution is a broom handle, small hooks and some rubber rings cut from an old tyre tube, then lightweight bungees to peg the base to the ground. They're used infrequently so I can live with that.

However, having tried this type and the lighter flexible panels I think they have a use only in a non permanent installation. Both would weather far too quickly and are less efficient when placed on a solid surface, such as a car bonnet or a tool box (they absorb the heat from the surface) and the eyelets they come with rust quickly and won't take much pressure from tie downs.

Both of them I've found to give close to maximum rated charge ...over 13.7 from memory....so that was encouraging ....but for a permanent fitting on a yacht or a caravan, not suitable.

I love the portability of the folding type....but they're expensive...and I love the light weight of the semi flexible ...but they're more expensive for what you get...so, as many have done, I'll stick to the heavier but solid aluminium framed versions. I'll just need to get fit to lug them around.

In the meantime, I'll play around with my "absolutely no cost" shed lighting to keep me interested in solar.

 

[Drover]

Have seen folks with the flexy panels and while I was initially interested after seeing theirs with a bit of age and some stuffing around packing, nah.
Having a big hard roof on the Ute a solid panel screwed down works wonders but for getting the max out of the sun my portable wins hands down, just requires 30 secs 3 times a day to move it, it has the van battery charged up by the time the roof panel gets a full hit of sun.

 

[Fabulous]

I've read the thread, however still have a quick question.

How do I connect a portable panel to our battery in the van, do people run a lead through the floor and connect panel and regulator via an Anderson plug, just working out the best way to get the wire to the actual battery ?

Or would it be better to build a mock up 12 pin plug for the solar panel and simply plug in to the main wiring of the van ?

Thoughts ideas ?

 

[Crusty181]

Hardwired from an Anderson plug, small hole through the floor fused into the battery compartment

 

[mikerezny]

I've read the thread, however still have a quick question.

How do I connect a portable panel to our battery in the van, do people run a lead through the floor and connect panel and regulator via an Anderson plug, just working out the best way to get the wire to the actual battery ?

Or would it be better to build a mock up 12 pin plug for the solar panel and simply plug in to the main wiring of the van ?

Thoughts ideas ?

Hi @Fabulous,
maybe I am missing something, but there are no wires on the standard Jayco 12 pin plug that would be suitable for connecting to a solar panel and regulator.
There is a 12V wire that connects from the tug battery to the van battery vis the 'aux' input on the Setec. This is NOT suitable for connecting up a solar panel. The Setec unit adds a diode in series with the Aux input to prevent the van battery feeding current back to the tug.

There is also the 12V connection via two of the heavy duty pins on the 12-pin plug. These go directly to the 12V input for the fridge.

In my Penguin, I ran a lead directly from the battery via an inline fuse to an Anderson plug that is just inside the external hatch. The negative is that I have to leave the hatch open when I connect up the solar panel. The positive is that I don't have to drill through the floor and then worry about mounting an external Anderson plug and making it secure, robust, and waterproof.

cheers
Mike