Winter Solar Performance

[Ex- Member]

I've been doing some calculations with regard to future solar performance through the winter. I do appreciate this is early winter.

 

It's a nice sunny day now from quite early on 9am we've been getting between 30 and 40 amps all day. At 12.30 we have gleaned 129 amps there's at least 3 hours of sunshine left so we'll probably end up with over 200 amps for the day.

 

I've been looking at a solar sun chart and the sun is almost at it's lowest point which it will hit around the 10th December, however that's only a few degrees more than now, our solar panels are steeply tilted in that direction so on sunny winter days through December & January. I don't see why we can't reasonably expect to glean around 200 amps a day on sunny days.

 

Unfortunately we had to run the engine yesterday following 3 days of overcast & wet weather, even on those days though we were getting 3 to 4 amps an hour. Our batteries eventually dropped to a quarter so we ran the engine for 2 hours yesterday. With the sun out today though the batteries are topping up nicely, the gauge reading well over full and 13.3 volts, but still in bulk charging phase, if it's like this tomorrow we'll be fully charged once again by lunchtime.

 

Our engine running time for charging is now up to 17 hours since coming on the water 3 months ago which is a lot better than we expected. Hopefully our build in genny will be ready soon so any more charging will be quicker and cheaper. I do reckon though that our solar panels are going to provide the majority of our leccy needs through the winter.

 

Many members back along were of the opinion that tilting panels wasn't worth the hassle, I wonder how many amps panels laid flat are currently gaining? We laid our 740 amps flat on a sunny day a few weeks ago and they dropped 9 amps, through a good 6 hour winter sunny day that's 54 amps lost, with the sun even lower now I suspect there would be more loss as well.

 

 

The peak amps so far today are 41.3

 

And as I post we're gleaning 33.2

 

I have also noted that when the sun shine in winter, the light seems very crisp and sharp, not hazy like much of the summer sun often is. I'm sure this is assisting in us getting over well 50% of our rated capacity on sunny days at this time of year.

 

I'll post today's full stats later.

Edited November 10, 2013 by Julynian

[Paul's Nulife4-2]

Hi ya,

I've got 4x30 watt Amorphous panels. Flatish On roof, so only ever going to get approx 7 or 8 amp out of them , At best in ideal conditions.

Today beautiful sunny day),batteries 75% charged,I've ave 3 / 3.5 amp since I noticed the gauge at10:00 (so approx 13amp so far,I would expect a further 6 amp to day,so approx a 19 amp total since 10:00 . (Probably 25 amp for the day at a guess).

Happy with that for such a small installation,mounted flat,in early winter with batteries @ 75% charged.

Wind generator approx .3 / .5 amp ave since 10:00 so probably only get approx 10 amp for the day out of that in total for today (24 hr period,normally A LOT more).

So Approx a 35 amp Free power harvest in total for today.

Edited November 10, 2013 by Paul's Nulife4-2

[dmr]

Paul and Julynian

 

There is lots of info on this forum that explains the difference between amps and amp-hours, and also a few posts pointing out that amps per hour is meaningless.

 

You are posting stuff that would be potentially very interesting if only I could understand what you are saying.

 

........Dave

 

,

 

ian

[nb Innisfree]

Needs to be remembered that it's the angle of the Sun's rays hitting us that accounts for our winter, not the distance of the Sun from us, in fact the Earth is closer to the Sun in the northern hemisphere's winter.

 

It's the increased amount of atmosphere the Sun's rays have to pass through that reduces their effectiveness so angling panels won't have as much effect as may be expected.

[Paul's Nulife4-2]

Paul and Julynian

 

There is lots of info on this forum that explains the difference between amps and amp-hours, and also a few posts pointing out that amps per hour is meaningless.

 

You are posting stuff that would be potentially very interesting if only I could understand what you are saying.

 

........Dave

 

,

 

ian

Thanks for that,

I live in my own simple world I guess,just see my signature statement.

All I know is I get some power from both wind & solar what my little Mastervolt gizmo thingy tells me that this is measured in 'amps'.

Please can you tell me Where am I going wrong in my previous post,so I don't make the same mistake again.

Edited November 10, 2013 by Paul's Nulife4-2

[pelicanafloat]

Needs to be remembered that it's the angle of the Sun's rays hitting us that accounts for our winter, not the distance of the Sun from us, in fact the Earth is closer to the Sun in the northern hemisphere's winter.

 

It's the increased amount of atmosphere the Sun's rays have to pass through that reduces their effectiveness so angling panels won't have as much effect as may be expected.

You are so annoying ..... always clouding the issue!

Thanks for that,

I live in my own simple world I guess,just see my signature statement.

All I know is I get some power from both wind & solar what my little Mastervolt gizmo thingy tells me that this is measured in 'amps'.

Where am I going wrong,so I don't make the same mistake again.

You aren't going wrong .... you know that those who dont have wind power get right peeved when it windy

 

My solar panels on strike .... well, they might as well be. We cruising along so the alternator takes precedence. All I know is that at the end of a 4 hour cruise our amp intake was less than 5 amps, and our supposed percentage was 88% .... difficult to accept til I stuck two fingers upon the battery monitor - literally! Have now reset system to 100% (keeps wifey happy lol)

[Paul's Nulife4-2]

Ime all for any Tricks of the trade to keep Wifey happy.

We all know who the real boss is,

[pelicanafloat]

Ime all for any Tricks of the trade to keep Wifey happy.

We all know who the real boss is,

Rumour has it that it's Julynian ...... or to be more precise Julynian's other half. She always on at him to come up with the stats - that enough to give anyone a headache

Edited November 10, 2013 by pelicanafloat

[bottle]

0.5 amps flat, 4.5 amps vertical facing the sun, 29.2 v, batteries at 71%.

 

400 watts, wired series parallel, into 24v bank

[Ex- Member]

Well todays readout goes like this.

 

187 amph

0.24 KWH

106VP

36.9AP

0.47 KWP

14.2v Max

10.9v min

 

Seems we didn't get over the 200 amps today but close enough. I'm sure I saw 41 amps earlier too, but the max recorded was 36.9. A day like today will give us a couple of days energy, if it's a similar sunny day tomorrow we'll probably be near fully charged by mid afternoon.

 

Our B/B is 700 amps we rely on a simple analogue dial and a digital voltage readout. I find the best time to assess the battery SOC in the morning before the Outback kicks in and other things like lap tops and radio fired up. So hopefully we'll be around 70% SOC in the morning.

 

Another thing we've realised is if we continued charging the batteries when we thought the SOC was at 50% we would have run the engine a hell of a lot more than we actually have burning loads of expensive diesel un-necessarily.

 

We've never run out of power yet and will quite happily let the batteries drop to a quarter on the analogue gage. The reason for this is in the early days we hit a 1/4 full we switched all consumption off and the batteries would recover to over 1/2 full within a couple of hours with a volt usually reading between 12.2 to 12.5 We've done this on 3 occasions now so are quite content that a 1/4 reading isn't draining the batteries too much.

[Justme]

Well todays readout goes like this.

 

187 amph

0.24 KWH

106VP

36.9AP

0.47 KWP

14.2v Max

10.9v min

 

 

 

 

Your numbers do not add up.

 

187ah @ 12v(nom) = 2244wh or 2.244kWh not 0.24kWh

 

One of those number has to be wrong.

 

My 1.2kWp system for example gave these results today

 

52 ah

0.6kWh

107Vp

47.3Ap

0.68kWp

max 15v (yes I know thats high but its a forklift bank so can take it during an EQ charge)

min 12.1

 

52ah x 12v (nom) = 624Wh or 0.624kWh (the difference between n0.6 & 0.624 will be due to the V not being exactly 12v)

Hi ya,

I've got 4x30 watt Amorphous panels. Flatish On roof, so only ever going to get approx 7 or 8 amp out of them , At best in ideal conditions.

Today beautiful sunny day),batteries 75% charged,I've ave 3 / 3.5 amp since I noticed the gauge at10:00 (so approx 13amph so far,I would expect a further 6 amph to day,so approx a 19 amph total since 10:00 . (Probably 25 amph for the day at a guess).

Happy with that for such a small installation,mounted flat,in early winter with batteries @ 75% charged.

Wind generator approx .3 / .5 amp ave since 10:00 so probably only get approx 10 amph for the day out of that in total for today (24 hr period,normally A LOT more).

So Approx a 35 amph Free power harvest in total for today.

[junior]

Electricity blows my brain, but my solar panels are not doing much at the moment.

 

I hope that answers your question.

[Ex- Member]

 

 

Your numbers do not add up.

 

187ah @ 12v(nom) = 2244wh or 2.244kWh not 0.24kWh

 

One of those number has to be wrong.

 

My 1.2kWp system for example gave these results today

 

52 ah

0.6kWh

107Vp

47.3Ap

0.68kWp

max 15v (yes I know thats high but its a forklift bank so can take it during an EQ charge)

min 12.1

 

52ah x 12v (nom) = 624Wh or 0.624kWh (the difference between n0.6 & 0.624 will be due to the V not being exactly 12v)

 

Apologies you're correct it's

 

187 amph

0.24 KWH Not 02.4

106VP

36.9AP

0.47 KWP

14.2v Max

10.9v min

Must take note of where decimal points are

Edited November 10, 2013 by Julynian

[Paul's Nulife4-2]

Thanks Justme,

I have just reprimanded my Mastervolt thingy for leading me astray,(telling me it was amp instead of amph as you suggest. its still doing it by the way,wind gen 0.3amp.Solar 0.0amp)

You just can't get the equipment nowadays !.

Edited November 10, 2013 by Paul's Nulife4-2

[Tony Brooks]

Thanks for that,

I live in my own simple world I guess,just see my signature statement.

All I know is I get some power from both wind & solar what my little Mastervolt gizmo thingy tells me that this is measured in 'amps'.

Please can you tell me Where am I going wrong in my previous post,so I don't make the same mistake again.

 

 

Amps are an instantaneous measurement of the number of electrons flowing. In this case into your batteries. You have to stuff a certain number of electrons into a battery for it to reach a certain state of charge. so if you (say) 3.5 amps was f;lowing for 30 seconds and for the rest of the day a large cloud obscured the sun then few electrons would have been stuffed into the batteries. However if that 3.5 amps kept flowing for several hours you would have stuffed far more electrons in to the battery.

 

The trick is to multiply the current (amps) flowing by the time in hours it flows for so if your 3.5 amps flowed for just one hour you would have put 3.5 Amp hours (Ah) of charge into the batteries. If it did it for 10 hours it would have put 35 Ah into the batteries.

 

Houses usually measure the electricity ( I am being deliberate vague here) in Watts or Kilowatts (KW) so the KWh is a sensible unit to use. However on boats we usually measure electricity in Amps so we tend to use the Ah.

 

You can convert Wh into amp hours by dividing by the voltage but as the voltage varies according to the battery's state of charge and the charging system output you are unlikely to get an accurate figure but if you used (say) 13 volts it will probably be near enough..

 

There is no way a boater can calculate the Ah delivered by the solar panel unless you watched the amp meter all day with a stop watch and noted the time each period of steady amp reading flowed for so a good solar controller or monitor should do it all for you and give an Ah readout.

 

I will stick me neck out and say that apart from calculating cable size an amp reading on its own (without a time component) is a totally useless reading. It is useful when deciding if battery charging has been enough, but even then its down to experience and the bank size needs taking into consideration.

 

Paul, you may do well to read the electrical notes on my website.

[Paul's Nulife4-2]

Thanks Tony,I appreciate that.& will do.

 

Pls note though,I made no reference to amp hrs or amph in my post, number 2,pls have a read ,just ave amps where mentioned (charging) . So didn't understand where the following corrections where coming, or why it should be correct to amph,,it dosnt take a lot to confuse me.

[LEO]

Hi,

 

I got 11.27Kw from my 4Kw installation at home - not bad, lovely day.

 

L

[matty40s]

I was getting a good 9A into my batts at 9.00am from flat panels from a clear blue sky.

I am happy with my solar.

[pelicanafloat]

Thanks Tony,I appreciate that.& will do.

 

Pls note though,I made no reference to amp hrs or amph in my post, number 2,pls have a read ,just ave amps where mentioned (charging) . So didn't understand where the following corrections where coming, or why it should be correct to amph,,it dosnt take a lot to confuse me.

Actually, I thought your 35ampday perfectly reasonable

[dmr]

 

Apologies you're correct it's

 

187 amph

0.24 KWH Not 02.4

106VP

36.9AP

0.47 KWP

14.2v Max

10.9v min

Must take note of where decimal points are

 

Watts is amps times volts, and volts is maybe 13 or thereabouts

So if you got 187Ah (amp-hours) then thats 2431 Watt-Hours or 2.4kWatt-Hours

 

How may Watts of Solar Panel have you got??? (I know you told us before but I don't want to search the forum).

 

I assume the 36.9Ap is peak Amps so this means that at some time today there were 36amps flowing into the batteries.

If this went on for 6 hours then that would have given 221 amp-hours, in reality you "only" got 187 because the sun was not at full blast all day.

187 Amp-hours in November is very good indeed, though it was a lovely day.

The 10.9 volts is a slight worry, do you run something big off the inverter from time to time????

 

.............Dave

 

edited to correct stupid confusion between 2.4 and 0.24kWh its contagious!

Edited November 10, 2013 by dmr

[Paul's Nulife4-2]

Actually, I thought your 35ampday perfectly reasonable

Yes,so did I. But no biggi,

I think the confusion was I apparently missed an ' h ' out in my description somewhere.

 

Cheers.

Edited November 10, 2013 by Paul's Nulife4-2

[smileypete]

Just think 'amps for hours' are Amp hours (Ah) and NOT AMPS!

 

So, what is one amp for 24 hours? Yes it's 24 Amp hours (Ah)

 

Now what is two amps for 24 hours? Bit more tricky, it's 48 Amp hours (Ah)

 

A 110 Amp leisure battery wouldn't make a lot of sense, wouldn't it?

 

cheers, Pete.

~smpt~

[peterboat]

Yes its been a good day for me too batteries healthy watching tv and on puter all those people out there that say that solar dont work yet it keeps on doing its stuff

 

Peter

[MtB]

 

A 110 Amp leisure battery wouldn't make a lot of sense, wouldn't it?

 

cheers, Pete.

~smpt~

 

It probably does to the OP!

 

MtB

[Dottyshirl]

Baffled

Lol