Solar PWM

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Nodge68 said:
You can get round the lower output of flat panels, simply by doubling them up, so fit 2 instead of 1. ;)

Dash mounted panels are pointless, as the UV needed to generate the power is filtered out by the UV blocking coatings on windscreen glass. ;)
Click to expand...

thks, so is it better to fit 2 x 50 watt panels or say something like 2 x 75 watt panels plse

wondered that ref the glass
 
I went for 2 x50w as easier to store and carry, but also gives me the option of doubling the voltage which should help on cloudy days
Ie. One panel only generating 11 or 12v won't charge a battery, but 2 generating 22-23v will have a much better chance, even tho the amps will be less
 
kermit_rr said:
I went for 2 x50w as easier to store and carry, but also gives me the option of doubling the voltage which should help on cloudy days
Ie. One panel only generating 11 or 12v won't charge a battery, but 2 generating 22-23v will have a much better chance, even tho the amps will be less
Click to expand...

perfect , so will get 2 x 50s then , like those german ones u linked to
 
kermit_rr said:
I have 2 of these, not sure why those others are more expensive, there must be a reason,
https://www.photonicuniverse.com/en...onocrystalline-solar-panel-with-5m-cable.html
Click to expand...

cheers, all noted and been putting all the links in a folder on the iPad

so getting 2 x panels it will now be more interesting ref ur tests , parallel or series

or is it better to get a controller where the panels are wired separately on the controller , so running 4 x wires from the panels

see the other panels are marked german , but as u say must be a difference
 
If you're panels aren't well matched, or oriented in different directions to the sun, then separate controllers can be the way to go, otherwise one controller will be fine.
It doesn't matter where you join 2 panels, is the length and size of cable that's important, ref voltage drop and keeping the water out
 
kermit_rr said:
If you're panels aren't well matched, or oriented in different directions to the sun, then separate controllers can be the way to go, otherwise one controller will be fine.
It doesn't matter where you join 2 panels, is the length and size of cable that's important, ref voltage drop and keeping the water out
Click to expand...

Perfect, so buying two panel of the same will simplify things

hopefully I haven’t driven u insane with all the questions as u know there be plenty more

will hang on till u do some tests as a few more months won’t make any difference seeing I have the ctek and been using that for ages

prefer to take my time and then will know once installed will work and not having to buy twice

thks a million for the help , very grateful
 
gstuart said:
What do u think of these please

https://www.photonicuniverse.com/en/catalog/full/59-100W-50W%2B50W-solar-panels-with-2-x-5m-cable-German-solar-cells.html

with controller

https://www.photonicuniverse.com/en/catalog/full/56-100W-50W%2B50W-solar-charging-kit-with-10A-controller-and-2-x-5m-cables-German-solar-cells.html

manual

http://www.photonicuniverse.com/upl...xx24B_solar_charge_controller_user_manual.pdf
Click to expand...

This statement is BS.

"At Photonic Universe we always ensure that our products are of the highest quality. This is why we have selected premium German solar cells for use in this solar panel. These high-efficiency solar cells perform exceptionally well in low light conditions(particularly when compared to solar cells of other origin) and they produce a good amount of power simply in daylight, even when direct sunlight is not available."

Solar cells need direct sunlight, in order to produce current. Yes without sunlight, a solar cell will generate voltage, but it produces little current unless there's sunlight on the cells.

In truth, the cheapest Chinese poly cells are just as efficient as the most expensive cells available.

Save your money and go with a couple of cheap 100 Watt Chinese panels, and a couple of cheap PWM charge controllers, hooked up to your auxiliary battery. ;)
 
Agree the statements are mostly bs, one pv cell is much the same as another, none work under heavy cloud or low light
My logic for mono vs poly, less electrical connections, less to go wrong. That may or may not be irrelevant but made me feel better
I also stayed away from eBay and used a UK source in the hope there might be some quality checking going on and if i did have a problem, more likely to get it sorted
 
To put things into context, i saw 2 general prices on eBay. Half the price, eg £25 for a50w panel including controller, or similar/more expensive prices eg £50-55.
The panels may be ok, I'm not sure i would trust the electronics in the controller, you hear too many horror stories about the very cheap stuff on ebay
I'm not saying what anyone should or shouldn't do, just voicing my thoughts and concerns
 
Mono vs poly is an open debate. I use poly myself, as they have more collection area per panel, this gives them slightly more current output than a mono panel of the same area at a lower cost. Individual mono-crystalline cells are more efficient by 1-3% at turning sunlight into energy, but as they're rounded at the corners, less surface area can be fitted into the panel frame. Poly-crystalline cells being rectangular in form, can be package tightly together, so have a higher cell density for a given panel frame size, which offsets the slightly lower output of the individual cells used. Poly-crystalline cells are cheaper to produce, so a more powerful panel costs less than a similar spec poly-crystalline panel.

I'd go for a couple of £75 poly-crystalline panels, each connected to your battery by it's own PWM charge controller.
With this setup, you'll be able to supply 10 Amps to the battery in full summer midday sun. ;)
 
I have a spilit charge smart relay, 50W panel (folding not fixed) a PWM controller and 130ah leisure batt (CT100 - so its nearer 65AH usable). On a sunny day its works well but most of the time 50w is not enough so I'm waiting on a 200W flexible off e-bay coming from China, was due today but clearly they have difficulties of their own at the moment so I don't mind waiting. The prices on the panels are coming down so much its cheaper to just add panels if you have the space. The 200w flexible is only 19% efficient but its also only £60 inc delivery so if it works I'll just get another and parrallel them. I want to get to 8-10A on a bright overcast day (ie 90% of English summer). I'm pretty sure the split charge relay senses both batts and tops up the starter batt too. I don't actually want this but its pain to add an isolator relay, I've got one but its more complexity and more connections. My target is to run the Webasto 6 hours on a cold night and get a full recharge the next day. At the moment the Webasto drops to min volts / cut out at around 8 hours which limits us to one night away if its cold. The true Webasto (Thermotop) draw is about double the Webasto spec because it cuts in and out so the ignitor runs a lot and you need a fan to circulate the warm air.
 
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