BiFacial Solar Panels

[van Rix]

While consdering a suitable solar panel for my van, I see that there are 'bifacial' panels available that claim to increase the output of the panel by receiveing reflected light into the back of the panel. This is supposed to be beneficial especially if mounted against a white background : I have a white van. However, I am not convinced that the 'bifacial' feature will be worth the extra cost and the extra gain will not be much, especially if the panels are mounted low on the roof. If they were angled up towards the sun, this might be a different matter.

Does anyone have any thoughts or observations that they could share?

Thx

 

[wildebus]

I've not used them myself but I've seen the specs for these and they do seem to offer what seems a remarkable benefit and I have my own doubts to how likely how much of that extra could be achieved, but I really have no idea!
Depending on the weather, may be able to do a side-by-side comparison of "normal" panels vs bifacial panels in around 6 weeks time to see how much extra they offer.
The benefit is meant to be about reflected light .... If you do get them, it could be worth getting some of those big plastic self-adhesive mirrors and stick them on the van roof to maximise the reflection?

 

[trevskoda]

You could make a frame that allows the mounted panel to be tipped forward or to a side as to get charge from sun early morning or evening.
It would require a set of rams and a pump motor to work,me i would just fit a extra panel to save any probs,i get away with 200w flat on roof,12v tv led lights radio electric flush toilet and electric fridge run of a smart inverter 600w.

 

[van Rix]

Thanks for your comments.

Wildebus: A comparision would be really informative but I think I have to decide in the next couple of weeks. Please post if you manage to do your comparision test.

As I have a Sevel L3 van, roof solar space is somewhat limited. I was hoping to maximise the output of my panel by having a angle bracket and get the output benefit from inclination together with reflected light. But thinking about it. The van roof that would reflect the light would be largely shaded by the panels and high off the ground. I suspect that the claimed increase in output is for white backgrounds like snow.

(The angle bracket that I was thinking about is like the one shown here.

Following trevskoda's comments, perhaps I may get away with the 315w (https://www.bimblesolar.com/solar/large-panels/ja315w-bifacial-solar-panel) rather than the 400w LG version that would require me to up-rate my 30A ep-ever solar controller. Decisions, decisions ! I better look at the panel prices again..... and LG v JA Solar......!

 

[ScoTTyBEEE]

I'm planning on fitting these width ways on a Sevel L3. I haven't done any measurements yet so it might not work, but if it does, then 2 of these would outperform any 315w bifacial.

https://www.bimblesolar.com/solar/large-panels/270w-perlite-54cell-small

You'd be ok with your controller still as it can handle over current, just means you'll get more performance in the winter when you need it. It's perfectly ok to run 40A through your 30A controller as you'll rarely ever get 100% even in a sunny country with flat panels.

I had a 310w panel in the Algarve in summer and the normal amps was 17/18 max, a 30A controller would have only given marginal gains, even though the panel required 30A (I did have a 30A so could see if it went over 20, barely ever)

 

[wildebus]

I'm planning on fitting these width ways on a Sevel L3. I haven't done any measurements yet so it might not work, but if it does, then 2 of these would outperform any 315w bifacial.

https://www.bimblesolar.com/solar/large-panels/270w-perlite-54cell-small

You'd be ok with your controller still as it can handle over current, just means you'll get more performance in the winter when you need it. It's perfectly ok to run 40A through your 30A controller as you'll rarely ever get 100% even in a sunny country with flat panels.

I had a 310w panel in the Algarve in summer and the normal amps was 17/18 max, a 30A controller would have only given marginal gains, even though the panel required 30A (I did have a 30A so could see if it went over 20, barely ever)

As above
The typical "rules" with Solar Controllers is:
a) Never Exceed the quoted input voltage. If you do so, you will likely cause terminal damage to the controller
b) Do not exceed the quoted input current. Because the input current will always be lower - and usually by a fair margin - you would likely never exceed this even with a oversized solar installation.
The quoted currents on Solar Controllers are based on the output currents - and so a "30A" controller will be rated at around 450W. If you do the maths on a) and b) you will find that something like a Victron 100/30 - which is 100V input max, 30A input max could handle a theroretical 3000W Panel array even though it is a 440W Controller - but anything above the 440W just gets dumped as the real limit is 30A OUTPUT.
One last one.... Many controllers DO have a power limit as well as a voltage and current limit, so important to double-check that as well. I am testing one out at the moment which has a quoted power limit of no greater than 150% of the controller rating - so it is a 20A controller, but no more than around 380W of power is permitted to come in. This can be important if oversizing for winter use as you could overload in summer.

 

[ScoTTyBEEE]

Here's a couple of the max input watts for 2 models of the EPEVER for interest sake.

TRIRON

TRACER - Probably the one the OP has

I don't think Victron controllers can handle over current. Anyone else know?
But as Wildebus pointed out, look at the manual as they all differ, as the two different models above highlight!

 

[RAW]

I went to a Solar Installer, Ian Emberton, of Xerogrid, he advised a Panel that is suitable for roofs
This one:


I have that single 285W Panel Attached to a Victron 100/30 (sadly not the bluetooth version) Seems to work fine
Recent Output in a lot of cloud

Output in Sunny week (in UK)


So all in all the Victron 100/30 is coping well with the load and I could potentially add more solar if I wanted to, although as the whole roof is fibreglass this would have to be bonded somehow rather than drilled fixings.

Not sure if that helps at all

Robert

 

[wildebus]

Here's a couple of the max input watts for 2 models of the EPEVER for interest sake.

TRIRON
View attachment 1639
TRACER - Probably the one the OP has

View attachment 1640

I don't think Victron controllers can handle over current. Anyone else know?
But as Wildebus pointed out, look at the manual as they all differ, as the two different models above highlight!

As posted, the victrons can handle "excess" power as long as the input Volts and Currents are not exceeded

 

[ScoTTyBEEE]

OK I understand now, thanks.

 

[Welkyrober]

I've been using bifacial solar panels on my van for about a year now, and I'm very happy with them. I've seen an increase in production of about 20%, even though my panels are mounted low on the roof. I think it's worth the extra cost, especially if you're planning on doing a lot of off-grid camping.

 

[RAW]

I've been using bifacial solar panels on my van for about a year now, and I'm very happy with them. I've seen an increase in production of about 20%, even though my panels are mounted low on the roof. I think it's worth the extra cost, especially if you're planning on doing a lot of off-grid camping.

Which brand or manufacturer have you used ? TIA