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Solar woes!


macmorph

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Hello all!

 

I'm struggling and in need of some advice from someone with and understanding of soalr setups. I have 2x 250w panels- Voc 37.8v Isc 8.9A each - connected in parallel to a Tracer PTR4210AN 40A controller feeding 2x 6v Trojan batteries in series giving me 12v at 225Ah. Cable runs are 6mm, about 5mt from the PV to contoller and 1mt from the controller to the batteries.

 

Now, I know the sun is weak now so I shouldn't expect much from them but the controller shows (at best) 30 something v and 1.4A coming in from the PV array, most of the time though it's more like 0.9A. This is far below what I'd expected to get from this setup. Am I being unrealistic? Have I messed up on my selection of components?

 

I'm lost at to what could be wrong...

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Just now, macmorph said:

I'm lost at to what could be wrong...

Nothing wrong.

 

October to about March solar produces between 0% (most days) and 5% (on a very good day) of the rated output.

 

If you are getting 0.9 amps, it WILL get lower.

 

You will need to find an alternative of electric production for the Winter

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It's called winter.  You have 500 watts in summer sun perpendicular to the sunrays in perfectly clear air. in England nowhere near perpendicular to the sunrays in murky air in winter you typically are doing well to get 10 % on a sunny day on an overcast day 5 amphours is good . The voltage coming in is controlled by the tracer controller so that is your 30v x 1.4 amps which adjusts the load to maximise the watts in to then convert that to the maximum it can produce for the batteries.

 

Beaten to it

 

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Furthermore, the Tracer is pretty pants at tracking mppt at very low panel outputs. It might be better for the winter to have the panels in series except that any shading on either panel will defeat any series advantage. So series will only help if you’re well away from trees or any other shade. And keep the panels leaf free. 

1 minute ago, jonathanA said:

Really ? 

 

My house roof mounted panels produce a lot more than 5% of their capacity on a good day at this time of year and rarely nothing at all...  they do of course produce it for a lot

less time given the shorter daylight hours.

And they’re no doubt tilted pretty high on a pitched roof?

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Yep and facing south....

 

you do have to give yourself a chance which is obviously much harder on a nb roof 

 

But tomake a sweeping statement that you will get nowt is pants you may get nowt if your not facing the sun , panels not tilted and under trees or shaded by buildings etc...

 

having said that as I don’t have panels on my boat at the moment I could be way off I’m just comparing to house panels which is not entirely fair I accept

Edited by jonathanA
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Can't really say any more than has already been said, but just here to agree.

 

I have 2 x 100 watt flat mounted solar and up until a couple of weeks ago could get maybe 2 or 3 amps out of them. Now that the sun never gets anywhere near high enough to shine directly on to them I'm lucky to get 1 amp even though it's shining brightly on these glorious cool days. 

 

Just a fact of winter you'll have to get used to I'm afraid.

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Also you will find that the controller will throttle back when charging if it thinks the battery is nearly full. 

Best thing to do in winter, to determine the effectiveness of your system, is check the kwh generated for the day. This is easily seen if you have the mt50 panel. Mine shows 0.28kwh for today with 350w. Not to bad for a winters day as quite sunny today. 

 Checking the daily generation is better than spot checking at random times as there are many variables that come into play at any point in the charging cycle, the effect of these variables will of been smoothed out when checking the daily generation. 

To summarise some of the previous posts

Typical narrowboat Solar can produce a lot of 'free' energy in summer but in winter it will only produce a few bonus amps. Bonus amps are better than no amps. 

Edited by reg
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22 minutes ago, David Mack said:

Winter. That's what's wrong.

Thanks David... nice to know I did nothing wrong!

21 minutes ago, Alan de Enfield said:

Nothing wrong.

 

October to about March solar produces between 0% (most days) and 5% (on a very good day) of the rated output.

 

If you are getting 0.9 amps, it WILL get lower.

 

You will need to find an alternative of electric production for the Winter

Thanks Alan. I can run the engine or generator so I have plenty of power... was just hoping for more solar! Praying for a short winter now :)

21 minutes ago, reg said:

You've answered your own question I think. 

:)

 

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20 minutes ago, Detling said:

It's called winter.  You have 500 watts in summer sun perpendicular to the sunrays in perfectly clear air. in England nowhere near perpendicular to the sunrays in murky air in winter you typically are doing well to get 10 % on a sunny day on an overcast day 5 amphours is good . The voltage coming in is controlled by the tracer controller so that is your 30v x 1.4 amps which adjusts the load to maximise the watts in to then convert that to the maximum it can produce for the batteries.

 

Beaten to it

 

Thanks for the reply.... I'll be hoping for a short winter :)

18 minutes ago, WotEver said:

Furthermore, the Tracer is pretty pants at tracking mppt at very low panel outputs. It might be better for the winter to have the panels in series except that any shading on either panel will defeat any series advantage. So series will only help if you’re well away from trees or any other shade. And keep the panels leaf free. 

And they’re no doubt tilted pretty high on a pitched roof?

I'll just have to learn to live with low output it seems....

13 minutes ago, Rumsky said:

Can't really say any more than has already been said, but just here to agree.

 

I have 2 x 100 watt flat mounted solar and up until a couple of weeks ago could get maybe 2 or 3 amps out of them. Now that the sun never gets anywhere near high enough to shine directly on to them I'm lucky to get 1 amp even though it's shining brightly on these glorious cool days. 

 

Just a fact of winter you'll have to get used to I'm afraid.

Yep, seems my expectations were way too high! Good  to know I didn't do anything wrong in the setup though. Roll on summer!

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13 minutes ago, reg said:

Also you will find that the controller will throttle back when charging if it thinks the battery is nearly full. 

Best thing to do in winter, to determine the effectiveness of your system, is check the kwh generated for the day. This is easily seen if you have the mt50 panel. Mine shows 0.28kwh for today with 350w. Not to bad for a winters day as quite sunny today. 

 Checking the daily generation is better than spot checking at random times as there are many variables that come into play at any point in the charging cycle, the effect of these variables will of been smoothed out when checking the daily generation. 

I was thinking to get the wifi unit for the Tracer so I can use the app to monitor and produce reports...

Thanks to all for the replies! Seems my setup isn't at fault then, just a part of winters curse! Ah well, it'll soon be summer and then maybe...

I'm going to get the wifi unit and see what reports I can pull off to see how the setup performs over days and weeks. Now I'll stop looking at the Tracer display every half hour ?

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9 minutes ago, macmorph said:

Praying for a short winter now

 

 

Unfortunately the path of the sun across the sky will be about the same as last year, so in that respect it's going to be almost exactly the same length.

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21 minutes ago, jonathanA said:

Really ? 

 

My house roof mounted panels produce a lot more than 5% of their capacity on a good day at this time of year and rarely nothing at all...  they do of course produce it for a lot

less time given the shorter daylight hours.

 

 

Your house panels will no doubt be mounted at well above ground level (even tree level) and probably on a Southerly(ish) facing roof. They will be mounted on the slope of the roof at an angle of 30 degrees (?) towards the sun.

 

A narrowboat roof will be very, very low down, probably amongst either trees or buildings (or both) will be mounted flat with the panels facing whichever way the boat is facing.

 

19 minutes ago, jonathanA said:

having said that as I don’t have panels on my boat at the moment I could be way off I’m just comparing to house panels which is not entirely fair I accept

I would suggest that without any knowledge of the performance of solar panels on a boat roof your comments are not really much help.

 

The Sun is very low on the horizon and because of the distance it now needs to travel the strength of the light is further reduced. 

It is not uncommon to have clouds, rain, or snow at this time of year - further reducing the amount of available sunlight.

 

Solar panels are 'measured' based on unobstructed 'midday' sun vertically above the panel.

We are at approx. 53 degrees North and will NEVER get anywhere near 100% of the rated wattage.

 

I generally work on Summer output being 50% of rated output (allowing for latitude, cloud cover etc) for 12 hours per day and a winter rating of 5% of that (Summer) figure for 6-7 hours per day. In effect about 2.5%.

 

Of the many threads on the subject it has always appeared that the majority of folks with solar panels on their boat get similar results to mine.

 

It is useless looking at 'momentary' readings - take a monthly readings and divide by the number of days to get a TRUE reading of watts produced.

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