Solar panel

[bnb080]

Hi this is my first post, I am looking at having solar panel fitted I have 2 x 110a leisure batteries would 120 watt panel and a victron mppt controller be adequate I would be off grid for no more than 4 days. Normal usage ie lights tv etc gas for heat fridge and water. Thanks in advance

 

[Guigsy]

In the summer, probably, probably yes.

In the autumn and spring when it's cloudy... you'll probably deplete the batteries. But you might have enough capacity to last 4 days.

In the winter in the UK, solar does almost nothing.

 

[Jimbohorlicks]

You will be ok with that for most of the year but I would look towards a second panel once you have a summer season under your belt.

 

[Stealaway]

You will be ok with that for most of the year but I would look towards a second panel once you have a summer season under your belt.

Yep as above -- Better with two

 

[Richard n Ann]

Hi this is my first post, I am looking at having solar panel fitted I have 2 x 110a leisure batteries would 120 watt panel and a victron mppt controller be adequate I would be off grid for no more than 4 days. Normal usage ie lights tv etc gas for heat fridge and water. Thanks in advance

Depends on usage, there are so many variables the question is very difficult to answer.

We managed with a 40w free standing panel for a couple of years for spring/summer/autumn use. That's probably equivalent to an 80w flat panel though. We just charged phones, bit of LED lighting and a couple of hours of TV in the evenings.

We've now got a 150w roof panel and for our use it's way OTT but better for when the evenings draw in in the autumn.

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[two]

Welcome!

I don't think you need any Solar but, if you decide to go that route, I'd get two panels and connect them in series. I say that because I think they'd generate enough voltage to charge your batteries in adverse conditions when a parallel set would not be able to do anything. If you always travel South, or don't go out in Winter, you could ignore that suggestion.

 

[gus-lopez]

 

[Lenny HB]

Our first van we got away with an 80 watt panel, last van we had 200 Watts, current van 300 Watts & that is only just enough as we rarely ever use EHU.
If fitti g more than one panel it's far better to wire them in parallel, series might be more efficient but shade on one panel and you loose all output.

 

[bnb080]

Thanks for the replies I think I will go with 2 panels as suggested. Cheers Colin

 

[two]

series might be more efficient but shade on one panel and you loose all output.

By-pass diodes?

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[Raul]

By-pass diodes?

In series will crush the hole string. Diodes or not. If you meet the voltage with one, no need to series to up the voltage. Just parallel.

 

[two]

And I believe all the panels on my house are joined in series(?)

 

[f6c]

Welcome aboard

 

[two]

In series will crush the hole string. Diodes or not. If you meet the voltage with one, no need to series to up the voltage. Just parallel.

Yes, you need a controller that can cope with the higher voltage.

 

[Al n Val]

I just picked up our new Rapido on Thursday and drove it straight to SAP Doncaster for all “the extras” fitting on, this includes 450W of Victron 24v panels going into a Victron 100-30 Smart Solar controller. These will provide power to a pair of 100ah Lithium batteries, as a back up I’m refitting a Victron 12-12-30 DC to DC controller so hoping we have enough juice to be going on with

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[Raul]

And I believe all the panels on my house are joined in series(?)

It’s not comparable. Your grid tie inverter needs a minimum voltage to start and feed in. That’s accomplished with a string of panels in series. However, a shade in any point on that string, it will lower the entire string output. The only think will help in there, is Tigo optimisers with normal grid inverter, or, solar edge inverter with optimisers.
You don’t need series on a van, unless the panel is lower than 18v. That’s not the case, all 12v panels have 36cells, producing 18-20v, more than enough to charge a 12v bank. You will series connect two 12v panels, if you charge a 24v system. Again, or go for 72cell panel for that and still no need for series. Series works well in fixed, like your house, where the shade is predictable and temporary transits. On mobile the shade can be from anywhere.

 

[autorouter]

I'd get two panels and connect them in series.

If you meet the voltage with one, no need to series to up the voltage. Just parallel.

With two panels, you could wire them through a switch to change between series and parallel, depending on conditions. Assuming it's an MPPT controller that will take the voltage.

 

[Raul]

With two panels, you could wire them through a switch to change between series and parallel, depending on conditions. Assuming it's an MPPT controller that will take the voltage.

Been there, done that. Nothing to gain. Anyone can wire as they wish, I’m only trying to help folk and wiling to share from my experience. Anyone can take what they want from it.

 

[donkey]

With two panels, you could wire them through a switch to change between series and parallel, depending on conditions. Assuming it's an MPPT controller that will take the voltage.

I agree that would be an alternative but can't imagine having to look at the output every: hour, 10 minutes, minute............ I think that would be a step too far for me.

Only joking Autorouter, I appreciate your posts on here.

Geoff

 

[Raul]

The conclusive test is to have both versions side by side with same number of panels and same controller. I have done it in the past. Many variables to take in. With the switch over is not for efficiency.

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[Outdoors Dad]

What issues could arise if two solar panels of different wattage are connected in parallel?

 

[Raul]

Depends on voltage and amps. If voltage is equal or close up to 10%, then parallel no problem.
If amps are close or equal, then series no problem.

 

[Outdoors Dad]

I have a 150w solar panel currently on the roof but I don't have enough space to put the same size panel next to it, but could probs fit 100w panel

 

[autorouter]

To narrow down your search, it might help to know that the voltage depends largely on the number of cells. The smaller panels are usually 36 cells (9 x 4), and higher power types are often 60 or72 (6 x 10 or 6 x 12).

 

[two]

An alternative solution is to add a second controller for the extra panel.
That would remove any problem with panels being incompatible (or shaded) and provide resilience.

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