well i measured up today for my Solar installation

Bart

Bart

Joined
Jun 4, 2016
Posts
3,188
Likes collected
1,399
Location
Northern Ireland
Funster No
43,436
MH
Boxer L4H2 van build
Exp
Since 2016
So i got onto the roof of my Autosleeper kingham today to measure up for the maximum amount of solar that i can install and i have space for 2 x 150w panels plus an additional 100W of solar, so total 400W

The panels are ( well have to be due to their unique sizes which work with my Skylight placements on the roof )

2 x https://www.ebay.co.uk/itm/150W-12V...per-caravan-boat-150-watt-module/112493865776

1 x https://www.ebay.co.uk/itm/100W-12V...per-caravan-boat-100-watt-module/142455307673

Will these panels work well together ???

I was going to get the following 20A solar controller.

https://www.ebay.co.uk/itm/Victron-...rge-controller-Inbuilt-Bluetooth/123269432108

But am i correct that the 20amp version will be to small for the above panels ?? and that i should get the 30amp version.

https://www.ebay.co.uk/itm/Victron-...777391?hash=item2144896b6f:g:LFoAAOSwxXRbWfDD
 
This site contains affiliate links for which MHF may be compensated.
Yes you'll need the bigger controller. Have you considered a duel controller to maintain the starter battery? You can then have the radio on and not flatten the battery.
 
@Richard and Ann Our radio has that stupid 20 min cut of anyways , and the victron controllers only seem to have the dual charge on their smaller 15amp chargers for some reason.
@Reallyretired Thanks for confirming that.
 
Bart said:
the victron controllers only seem to have the dual charge on their smaller 15amp chargers for some reason.
Click to expand...

That's not a charger output: it's a "load" output - designed for stand alone solar powered lighting, pumps, etc.

The Victron MPPT controllers require that the short circuit current of the solar array is less than the output current rating of the controller.

Because you're using three panels with two different outputs, the only way of connecting them is in parallel. The max power voltage of both types is the same, so they'll happily work together in this configuration. Unfortunately, the combined short circuit current of the three panels (add the individual short circuit currents together for a parallel connection) is over the rating of the 20 amp controller, so you need a bigger one.

If you could find a way of fitting two *pairs* of panels (all 4 the same, or two sets of two) you could connect the pairs of matching panels in series, increasing the voltage but reducing the current and the 25A controller would be OK, even with the same power input. The controller will limit output current, if necessary (i.e. brightest day of the year with the most discharged battery bank), provided the input current remains within spec.

Subscribers  do not see these advertisements

 
Misterg said:
That's not a charger output: it's a "load" output - designed for stand alone solar powered lighting, pumps, etc.

The Victron MPPT controllers require that the short circuit current of the solar array is less than the output current rating of the controller.

Because you're using three panels with two different outputs, the only way of connecting them is in parallel. The max power voltage of both types is the same, so they'll happily work together in this configuration. Unfortunately, the combined short circuit current of the three panels (add the individual short circuit currents together for a parallel connection) is over the rating of the 20 amp controller, so you need a bigger one.

If you could find a way of fitting two *pairs* of panels (all 4 the same, or two sets of two) you could connect the pairs of matching panels in series, increasing the voltage but reducing the current and the 25A controller would be OK, even with the same power input. The controller will limit output current, if necessary (i.e. brightest day of the year with the most discharged battery bank), provided the input current remains within spec.
Click to expand...
Thanks for the helpful info , would it be of any benefit if i went with 2 x 50W panels https://www.ebay.co.uk/itm/50W-12V-...296998?hash=item212aff53e6:g:8D0AAOSwLs9aYf9O
Into one victron controller ( if so what size of controller )
Then for the other solar bank 2 x 150W panels https://www.ebay.co.uk/itm/112493865776?ul_noapp=true into another victron controller ( would the 20A controller be enough for 300W of solar ) https://www.ebay.co.uk/itm/123269432108?ul_noapp=true
This way would be a more expensive option for me than going the 2 x 150W panels plus the 100W panel + the 30 amp victron controller , BUT if there was a benefit of going this route then so be it .
So stick with plan A ( 1 x 30Amp controller ) or go plan B ( 2 x 20Amp controller Plus a 10 or 15 amp controller )
P.S forgot to say i will be reinstalling my battery master ( the one that trickle charges the cab battery once the leisure batteries reach a certain charge )
 
This site contains affiliate links for which MHF may be compensated.
I would have a controller for the two 150’s and a separate controller for the 100w, then at least if a controller goes down you still have some power... and may help if your panels are in some shade...

My set-up... one controller for each 100w panel. Three chances of power if something goes wrong or if 1 or 2 panels in the shade...

E373C79B-EF3A-4584-B970-CC4C3853EE10.jpeg
 
Just smiffy said:
I would have a controller for the two 150’s and a separate controller for the 100w, then at least if a controller goes down you still have some power... and may help if your panels are in some shade...

My set-up... one controller for each 100w panel. Three chances of power if something goes wrong or if 1 or 2 panels in the shade...

View attachment 304591
Click to expand...


My solar controller backs off if the altinator or mains charger is on. Once other chargers go off it slowly starts charging again after a few minutes. Makes me wonder how 2 parallel controllers would act (n)
 
Bart said:
would it be of any benefit if i went with 2 x 50W panels https://www.ebay.co.uk/itm/50W-12V-...296998?hash=item212aff53e6:g:8D0AAOSwLs9aYf9O
Into one victron controller ( if so what size of controller )
Click to expand...

The 75/10 would be fine for 2 x 50W panels - have a look at the table at the bottom of this:

https://www.victronenergy.com/uploa...-10,-75-15,-100-15,-100-20,-100-20_48V-EN.pdf

It would also be OK for the original 100W panel on its own if that's the way you wanted to go.

Then for the other solar bank 2 x 150W panels https://www.ebay.co.uk/itm/112493865776?ul_noapp=true into another victron controller ( would the 20A controller be enough for 300W of solar )
Click to expand...

One 20A controller would be fine for those two 150W panels (they are within the specified "Max PV short circuit current" in the table, whether connected in series or parallel). So plan 'B' would be 1 x 10A controller & 1 x 20A controller as far as I can tell?

Without looking at the costs, I don't think there's much in it in terms of solar yield (maybe some marginal gain with two controllers). Downside of two controllers is cost (maybe), complexity and space to install. There may be arguments that having two controllers gives you some sort of redundancy, but it's a MH, not an ocean going yacht - if there's ever a problem, you can pull in somewhere and get it fixed! :)
 
This site contains affiliate links for which MHF may be compensated.
Minxy Girl said:
Why not get a Votronic one instead with dual ability to charge your leisure and hab batteries ... they do a 430 one which would capable of handing 400w.

Amazon product ASIN B01FFTUOR4
https://www.votronic.de/index.php/e...trollers/standard-version-mpp/mpp-430-duo-dig
Click to expand...



Richard and Ann said:
I've told them Minxy they won't listen :cry:
Click to expand...

I would go that route but i want to be able to see via bluetooth what the solar panels are doing,, and as far as im aware this cannot be done with the Votronic ?
 
Misterg said:
The 75/10 would be fine for 2 x 50W panels - have a look at the table at the bottom of this:

https://www.victronenergy.com/uploa...-10,-75-15,-100-15,-100-20,-100-20_48V-EN.pdf

It would also be OK for the original 100W panel on its own if that's the way you wanted to go.



One 20A controller would be fine for those two 150W panels (they are within the specified "Max PV short circuit current" in the table, whether connected in series or parallel). So plan 'B' would be 1 x 10A controller & 1 x 20A controller as far as I can tell?

Without looking at the costs, I don't think there's much in it in terms of solar yield (maybe some marginal gain with two controllers). Downside of two controllers is cost (maybe), complexity and space to install. There may be arguments that having two controllers gives you some sort of redundancy, but it's a MH, not an ocean going yacht - if there's ever a problem, you can pull in somewhere and get it fixed! :)
Click to expand...

Plan B it is ,, 2 x 150w panels plus 2 x 50w panels with 2 separate controllers
 
Richard and Ann said:
My solar controller backs off if the altinator or mains charger is on. Once other chargers go off it slowly starts charging again after a few minutes. Makes me wonder how 2 parallel controllers would act (n)
Click to expand...
In the same way. No matter how many charging sources are connected to a battery the one offering the highest voltage at any given time takes precedence.
 
tonyidle said:
In the same way. No matter how many charging sources are connected to a battery the one offering the highest voltage at any given time takes precedence.
Click to expand...
That's what I thought, so how would 2 solar controllers get along on the same battery? One will offer slightly higher voltage than the other.. I would have thought (n)

Subscribers  do not see these advertisements

 
so series or parallel ??
I will be connecting 2 x 50W panels https://www.ebay.co.uk/itm/142455296998?ul_noapp=true
to the 15A controller https://www.ebay.co.uk/itm/Victron-...588723?hash=item1a5931d8f3:g:xpMAAOSw0BdbVuXg
then i will be connecting 2 x 150W panels https://www.ebay.co.uk/itm/112493865776?ul_noapp=true
to the 20A controller https://www.ebay.co.uk/itm/123269432108?ul_noapp=true

Also you see the way the solar panels come with massive long leads , i obviously want to shorten these , do i need to buy complete new mc4 connectors or can i just reuse the mc4 connectors that come with the pannels.?
 
This site contains affiliate links for which MHF may be compensated.
Richard and Ann said:
That's what I thought, so how would 2 solar controllers get along on the same battery? One will offer slightly higher voltage than the other.. I would have thought (n)
Click to expand...
This is interesting ,, have you just thrown a spanner in the works ......
 
Ahh, this explains it then(y)

"Yes, multiple charge controllers can be used on the same battery bank. Multiple charge controllers are used in situations where a single charge controller is not able to handle the entire output of a large solar array. When multiple charge controllers are used, communications cables connect the charge controllers, and help them work in unison. Read more about this on our Charge Controllers page."
 
Sometimes you can over think things. :) Check the Victron link given above and download the specification sheets which give amongst other stuff the power capacity for each type. Use the power figure given for 12 volts.

I'm not sure why you want to use two 50W panels instead of one 100W, perhaps space considerations? But if you do use two 50W then I would wire them in series. This is what Victron recommends. I would do the same with your 150W panels two, series connection to a suitably sized controller. The Victron 100/20 has a nominal maximum PV rating of 290W which is a tad under 300W but unless you plan on visiting the equator during a solar flare it will work. The alternative approach would be to use a single 100/30 and connect all the panels to it. Connecting the 150s in series and then the 50s in series (assuming both have the same number of cells) with both pairs connected in parallel.

Subscribers  do not see these advertisements

 
Last edited:
DBK said:
I'm not sure why you want to use two 50W panels instead of one 100W, perhaps space considerations?
Click to expand...

Thanks @DBK yip it is to do with space considerations in a way, i am "preferring" to use the 2 x 50W as apposed to the 1 x 100W as the area this solar is going to on the roof is right at the very rear of the MH , and if i use the 100W panel it ends like 2cm from the rear end of the roof , where as due to the shape of the 50W's they end about 8cm from the rear end of the roof.

DBK said:
But if you do use two 50W then I would wire them in series. This is what Victron recommends. I would do the same with your 150W panels two, series connection to a suitably sized controller. The Victron 100/20 has a nominal maximum PV rating of 290W which is a tad under 300W but unless you plan on visiting the equator during a solar flare it will work. The alternative approach would be to use a single 100/30 and connect all the panels to it. Connecting the 150s in series and then the 50s in series (assuming both have the same number of cells) with both pairs connected in parallel.
Click to expand...
If i wired it this way ( just using the one 30a controller ) if one solar panel was in the shade would the output from just that one panel be effected , with the output from the other 3 panels unaffected ?
 
Also @DBK i have just done a wiring sketch if i wired it just using one 30A controller , can you tell me if that sketch is correct, thanks
IMG_20190519_195507.jpg
 
Bart said:
Also @DBK i have just done a wiring sketch if i wired it just using one 30A controller , can you tell me if that sketch is correct, thanks View attachment 304703
Click to expand...
Yes, that will work, a hybrid or series parallel connection. The main thing is to check they all have the same number of cells. I can't view your ebay link - I can never view ebay links on this tablet - but if they all have 36 it will be fine. If the 50W panels have less it won't work properly as they want a different voltage. Check the spec in the ebay advert, don't trust the illustration as it might be a generic one for all PV panels.
 
NP @DBK the ebay link is for the photonic universe shop , so i have links for the panels directly from them
150W https://www.photonicuniverse.com/en...r-panel-with-5m-cable-German-solar-cells.html
50W https://www.photonicuniverse.com/en...r-panel-with-5m-cable-German-solar-cells.html
they both claim to use German solar cells , but im unsure if they use the SAME cells. hopefully you can tell from them links.

Edit , they both say this in their descriptions : This panel also features innovative 5 busbar solar cells,
and here is the specs for the 50W panel
  • Peak power: 50W
  • Maximum power voltage: 20.2V
  • Maximum power current: 2.48A
  • Open circuit voltage: 23.9V
  • Short circuit current: 2.63A
  • Power allowance range: +/- 3%
  • Dimensions: 590 x 505 x 25mm
And then the specs for the 150W panel

  • Peak power: 150W
  • Maximum power voltage: 20.2V
  • Maximum power current: 7.43A
  • Open circuit voltage: 23.9V
  • Short circuit current: 7.89A
  • Power allowance range: +/- 3%
  • Dimensions: 124 x 67 x 3.5 cm

Does that help!
 
Last edited:
@Bart ... going from what DBK has said, the 50w panels have 9 cells each, the 150w ones 36 cells each so will have different voltages so therefore is saying you can't use them on the same controller.

Subscribers  do not see these advertisements

 
Bart said:
Also you see the way the solar panels come with massive long leads , i obviously want to shorten these , do i need to buy complete new mc4 connectors or can i just reuse the mc4 connectors that come with the pannels.?
Click to expand...
Yes you can reuse the MC-4 connectors but they aren't easy to remove, you can buy a plastic tool to do it or use a couple of small screwdrivers, that's what I did, just ensure that the cable you attach them all to is able to take the total input power.
 
Minxy Girl said:
@Bart ... going from what DBK has said, the 50w panels have 9 cells each, the 150w ones 36 cells each so will have different voltages so therefore is saying you can't use them on the same controller.
Click to expand...
Going from the specs i posted above both panels "SEEM" to have the same voltages . both open circuit voltage and maximum power voltage , or is that not what he means.
As for the amount of cells the panels have i cant seem to find that info out from their info.
Mel here are them specs again, see what u think,, as for the info on the mc4 connectors , thanks , but ive now decided to just buy new ones.


Specs for the 50W Panel



    • Peak power: 50W
    • Maximum power voltage: 20.2V
    • Maximum power current: 2.48A
    • Open circuit voltage: 23.9V
    • Short circuit current: 2.63A
    • Power allowance range: +/- 3%
    • Dimensions: 590 x 505 x 25mm
And then the specs for the 150W panel




    • Peak power: 150W
    • Maximum power voltage: 20.2V
    • Maximum power current: 7.43A
    • Open circuit voltage: 23.9V
    • Short circuit current: 7.89A
    • Power allowance range: +/- 3%
    • Dimensions: 124 x 67 x 3.5 cm
Thanks (y)
 
They're all the same max power voltage so will work OK as you have drawn it. They have different numbers of cells because they have different power outputs.

If you shade any one of the 4 panels you will lose output. With 2 separate controllers you will lose less output (if that matters to you) - btw a 10A controller is sufficient for the 100W or 2X50W option.
 
Misterg said:
They're all the same max power voltage so will work OK as you have drawn it. They have different numbers of cells because they have different power outputs.
Click to expand...
Thanks Glad to know they will work ok with the one controller when wired as per diagram above.


Misterg said:
If you shade any one of the 4 panels you will lose output. With 2 separate controllers you will lose less output (if that matters to you) - btw a 10A controller is sufficient for the 100W or 2X50W option.
Click to expand...
Yar i was unable to see a victron 10A bluetooth controller , as for the shading that could bother me ,, so say for the sake of argument if i 1 panel got shaded would it effect the other 3 panels as well or would the total solar coming in just be from the other 3 panels minus the one that is shaded?
 
Bart said:
for the sake of argument if i 1 panel got shaded would it effect the other 3 panels as well or would the total solar coming in just be from the other 3 panels minus the one that is shaded?
Click to expand...

It's difficult to say with MPPT controllers - with two panels into 1 controller you would lose 1/2 the output if one were shaded (whether series or parallel connected provided the panels are fitted with bypass diodes - most are). With 4 panels (2 x 2) into one MPPT controller, it'd *probably* keep the voltage where the 2 un-shaded panels are still generating and you'd lose the output from both of the other panels - especially if it's one of the smaller panels that is shaded. If it's one of the bigger panels that is shaded, then the MPPT might drop the voltage to suit the remaining panel in that string, so you'd lose about half of the output from the un-shaded string. Pretty much every option loses more than the nominal 25% that you might hope.

(10A bluetooth MPPT https://www.sunstore.co.uk/product/victron-smartsolar-mppt-75-10/ for example)

Subscribers  do not see these advertisements

 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Join us

Log in

Already a member? Log in here.

Latest journal entries

Back
Top