Solar advice please.

ontheroadagain

ontheroadagain

Joined
Apr 20, 2020
Posts
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Location
Northern Ireland.
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70,057
MH
Adria Compact SC.
Exp
Since 2017
We were away in the motorhome last week and spent three days off grid.
This has confirmed what I already suspected - due to having a compressor fridge we need more solar.
It was fine during the summer, but with the reduced daylight/sunshine it probably wouldn't have made it to day four.

Our current set up is as follows -
110W flexible solar panel (Factory fitted)
2No 100Ah batteries under the passenger seat.
NDS Sun Control SC300M Mppt controller. (charges leisure and starter batteries)
Note - The controller can take up to a max of 300W of solar.

Do I?
a)Remove the flexible panel and fit 2No rigid 150W panels?
b)Keep the flexible and add 2No 100W panels (this might be difficult due to the location of flexible panel)
c)Keep or replace the controller. (The NDS controller requires a cable from each panel and the motorhome currently only has one cable fitted)

I am no expert so wont be doing this work myself - I just want to know the best way forward.
 
imo remove the flex panel, fit as much as you can mono crystalline rigid panels, a Victron MPPT smart solar controller

Edit: don’t be afraid to fit 24v panels either, my 2 Victron panels were £40 cheaper each than the 12v ones and def seem more effective than the 12v panels I had on my last moho 😉
 
Last edited:
a quick fix might be to buy some portable solar panels ?
 
Not sure how the flexy panels are secured but may be easier to disconnect it rather than remove it if it's stuck down.
Once the wires are removed from the panel it will just sit there doing nothing.
 
pappajohn said:
Not sure how the flexy panels are secured but may be easier to disconnect it rather than remove it if it's stuck down.
Once the wires are removed from the panel it will just sit there doing nothing.
Click to expand...
Yes, the guy that I use has stated that he would not be happy to attempt to remove the flexi panel.
If I keep the flexi panel (currently working well) and NDS controller, is there any issue with adding an additional
150W or 175W panel and a new Victron Mppt controller?
i.e. - two controllers connected to the same batteries.
I assume if the flexi panel failed at a later date, I would still have solar from the second panel/controller.
 
I would ditch the flexible as it will fail in the not too distant future and fit a couple of 150 or 175 watt panels depending on the space available. You could keep the existing controller and fit another one they will work together but that means more cables and hole in the roof.
If you were to fit a Votronic controller they have a 1 amp output for starter battery charging. The MPP 350 can handle 350 watts or an MPP430 is 430 watts.
 
Are there any problems fitting a solar panel across the roof rather than front to back? Wind noise? Increased risk of it being ripped off by the wind when driving?
 
As Wallis Simpson almost said "you can't be too thin, too rich or have too much solar. I've got 3 x 100W flexi panels . They are OK on a bonded roof but not a 'floating' one. Even better if laid on a sheet of correx to aid cooling although without I haven't had problems so far. Flexi is quite a bit lighter than framed panels if payload is tight.
 
If you are looking to use over winter, regardless of how much solar you have you will probably not produce enough, we have a perfectly angled south facing 3.6kw on our house, and at this time of year some days will barely produce 2-3kw, so 500w of flat panels may be enough to power the lights/pump a bit of TV but won't power a fridge for long.
 
No expert, but have you got the charge split to leisure and vehicle batteries right?

When I picked up our van they’d set it at 50 / 50. However, having read loads about it on here I’ve adjusted it to 30% vehicle and 70% leisure. I know some even recommend 20% / 80%.

(y)
 
Sapper520 said:
No expert, but have you got the charge split to leisure and vehicle batteries right?

When I picked up our van they’d set it at 50 / 50. However, having read loads about it on here I’ve adjusted it to 30% vehicle and 70% leisure. I know some even recommend 20% / 80%.

(y)
Click to expand...
10% to the starter battery is plenty.
My solar controller only charges the starter battery at a max of 1 amp keeps the battery topped up all year without a problem.
 
ontheroadagain said:
We were away in the motorhome last week and spent three days off grid.
This has confirmed what I already suspected - due to having a compressor fridge we need more solar.
It was fine during the summer, but with the reduced daylight/sunshine it probably wouldn't have made it to day four.

Our current set up is as follows -
110W flexible solar panel (Factory fitted)
2No 100Ah batteries under the passenger seat.
NDS Sun Control SC300M Mppt controller. (charges leisure and starter batteries)
Note - The controller can take up to a max of 300W of solar.

Do I?
a)Remove the flexible panel and fit 2No rigid 150W panels?
b)Keep the flexible and add 2No 100W panels (this might be difficult due to the location of flexible panel)
c)Keep or replace the controller. (The NDS controller requires a cable from each panel and the motorhome currently only has one cable fitted)

I am no expert so wont be doing this work myself - I just want to know the best way forward.
Click to expand...
Would an option be to change your batteries? You don't say whether they are lithium or not perhaps a lithium battery set up (if you don't already have them of course). It won't be cheap but its something you might be able to do yourself and it might work out a similar price as paying for more solar to be fitted, inc larger MPPT etc?

Fogstar are offering 15% discount today 'Fogstar Friday' apparently ... you will have to make your own mind up if theyre suutable for you of course!

Subscribers  do not see these advertisements

 
Lenny HB said:
10% to the starter battery is plenty.
My solar controller only charges the starter battery at a max of 1 amp keeps the battery topped up all year without a problem.
Click to expand...

Maybe I’m being over cautious with mine then? :unsure:

I’ve got the alarm taking a little, and I never turn my solar controller or MiFi off. As I use the van all year, it doesn’t sit for long periods.
 
I'm with Lenny HB with 1A charging of starter battery, I use votronic duo charger, but also use a £20 Bluetooth battery monitor.(not that I'm paranoid, but I know someone who is )
If room why not add a "domestic" 48v panel many more W for your £.
You can always connect 2 panels on the roof with Y spliters (if same voltage , or in series and dont exceed controler limits) and only one hole in roof.
Can you leave the flexi in place and just mount a larger panel over it
 
Thanks for all the advice.
I have decided just to add one additional solar panel for now. The flexi is still working so it seems a waste to remove it. I may do a full upgrade to lithium in the future and upgrade the solar at that stage.
 

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