solar panel fitting

[Justme]

As you have already spotted the low ish amps are due to the bat being nearly full. You could try turning every thing on till you get to the point that you are draining the battery & then you will see the full available amps from the FM80/array.

 

The reduction due to temperature is not huge.

 

This is the specs for my panels.

 

 

Temperature coefficients of Isc (%): 0.1/Degree

Temperature coefficients of Voc (%): -0.33/Degree

Temperature coefficients of Pm (%): -0.23/Degree

Temperature coefficients of Im (%): 0.08/Degree

Temperature coefficients of Vm (%): -0.33/Degree

Irradiance: 1,000W/m2

Temperature: 25 Degrees

 

As you can see you would need to have very hot panels before you loose a lot of power.

[lewisericeric]

I dont think it's anything to do with the heat either, and they have a clearance underneath from being sat on the ball which allows me to tilt/rotate them.

 

I understand that when it's full or getting near full that it will reduce but the batts when I was enquiring were only at 80%.

 

Also when switching things on, esp the electric immersion at 1kw, it still struggled to get much more above 38amps out of a possible 57.

 

Im wondering if maybe I should swap my cables for some 6mm ones if that would make a difference?

[Ex- Member]

I dont think it's anything to do with the heat either, and they have a clearance underneath from being sat on the ball which allows me to tilt/rotate them.

 

I understand that when it's full or getting near full that it will reduce but the batts when I was enquiring were only at 80%.

 

Also when switching things on, esp the electric immersion at 1kw, it still struggled to get much more above 38amps out of a possible 57.

 

Im wondering if maybe I should swap my cables for some 6mm ones if that would make a difference?

 

80% is pretty full though it works on a curve not at a certain point I think. A flat battery will take all it can get for a while, as the charge replenishes the batteries take less and less amps, I think that's why it takes so long to get to a state of fully charged.

 

If the weather forecast is good for tomorrow be extravagant with power drain your batteries below 50% and see what happens then. I'm not sure if there's a way of measuring input of panels, I would have thought the Outback would be able to do this some how. Maybe you can get some other readings from it somehow?

 

 

 

[lewisericeric]

Its strange you should say that. We didn't get up til late today, around 10 AM and at that point the batts were at 59% but already we had a Amp Peak of 41.9amps

 

I just wish the outback then would give you what you "could" generate from the panels at any moment in time, against what you are actually putting in the batteries because of x, y z (ie: batts being full etc) as that would be more useful

 

Anyway, Just checked, 830pm and a total of 253amps generated today

 

We've not been plugged into shoreline at all in the last week, apart from when I've needed to cheat and have the tumble dryer to urgently dry things or something and, so far, have always had the batts at 100% at 830/9PM. So I'm quite chuffed with that.

 

Another step closer to being a cc'er as that was one thing that always put me off, having to have the engine running 5/6 hours a day. I know it will still need to be ran more in winter, but then again we do get some really nice days in October/November too, albeit not long days

[Justme]

6mm cable is not going to make a huge difference. It is def not your problem.

 

In fact dont do / change any thing till you have sub 60% bats at solar noon on a good sunny day.

(well you could double check that every thing is set up correctly but that is all)

 

 

What are the input volts & amps?

 

Have you found the 180 day stored history on the FM80 yet?

 

It will give peak amps & volts in & out plus total kWh & Ah out, time spent in absorb & EQ (if set).

[lewisericeric]

Hi 'Justme'

 

Yep, I have checked the data logging and thats how i know I got a whopping 253amps in total today with a peak of 41.5

 

The PV Input voltage has a peak of 109v and is mostly over 90v at all times sometimes dropping to the late 80s, and output voltage (to the batts) is regularly 13.5 or more with peaks of 15+

 

Input amps are around 7 or 8 (not sure what that feature is though? input amps from where?)

 

How does that sound?

 

Will definately make sure that the batts are below 60 next time we have a great day like today. I think it's going to be similar on Wednesday so will prep everything for then

[Justme]

Input amps is from the array into the controller.

 

So you had 7 amps at 80-109v which is 560 to 763 watts. However the peaks would not have been at the same time.

 

Cant remember now how many watts your array is (just checked 750w) or what its maximum power point voltage is.

 

Have you changed all the FM80 settings yet to match the battery type you have & how you want them charged?

 

 

My system did 400ah today with a 61amp max into the bats & peaked at 1kWp for a 1.2kWp array.

 

Comparing yours peak amps & total ah to mine adjusted for array size & you are getting the exactly the same as me.

 

61amps / 1200w x 750w = 38amps

400ah / 1200w x 750w = 250ah

[lewisericeric]

Input amps is from the array into the controller.

 

So you had 7 amps at 80-109v which is 560 to 763 watts. However the peaks would not have been at the same time.

 

So how do the input amps of 7 compare with the output amps ? I thought what was coming from the panels to the controller is the 37amps i was getting not just 7!?

 

Cant remember now how many watts your array is (just checked 750w) or what its maximum power point voltage is.

 

When you say the maximum power point voltage, do you mean the total voltage ? Each panel has a open circuit voltage of 36.9v and 'voltage at Pmax' of 29.3v[. I have 3 panels/color]

 

Have you changed all the FM80 settings yet to match the battery type you have & how you want them charged?

 

I did set the operating voltage etc when powering up and believe that the controller is set to wet batteries as default (i have wet batts) still reading the book and learning how to change things but still not sure on what's what, or what i do/don't need to change - even by their own explanations - the manual's not great for a newbie! Don't really understand about changing float times etc etc or why I would/wouldn't need to.

 

My system did 400ah today with a 61amp max into the bats & peaked at 1kWp for a 1.2kWp array.

 

Comparing yours peak amps & total ah to mine adjusted for array size & you are getting the exactly the same as me.

 

61amps / 1200w x 750w = 38amps

400ah / 1200w x 750w = 250ah

 

That's good news then! Are you poly or mono panels? Tilted or flat??? Did you also have full sunshine today? Also, what size is your battery bank?

Cheers, it's good to get feedback from a variety of members too, so would be grateful to hear back from you again

Forgot to mention my array is actually 705watts not 750, I ended up getting 235w panels, not 250w.

Edited May 21, 2012 by lewisericeric

[Ex- Member]

Up at 5am couldn't sleep

 

Noticed how light it was though, knocking on 5.30am now, are any of you solar people getting any amps this time of the morning?

[Justme]

1, So how do the input amps of 7 compare with the output amps ? I thought what was coming from the panels to the controller is the 37amps i was getting not just 7!?

 

2, When you say the maximum power point voltage, do you mean the total voltage ? Each panel has a open circuit voltage of 36.9v and 'voltage at Pmax' of 29.3v[. I have 3 panels.

 

3, I did set the operating voltage etc when powering up and believe that the controller is set to wet batteries as default (i have wet batts) still reading the book and learning how to change things but still not sure on what's what, or what i do/don't need to change - even by their own explanations - the manual's not great for a newbie! Don't really understand about changing float times etc etc or why I would/wouldn't need to.

 

4, That's good news then! Are you poly or mono panels? Tilted or flat??? Did you also have full sunshine today? Also, what size is your battery bank?

 

5, Forgot to mention my array is actually 705watts not 750, I ended up getting 235w panels, not 250w.

 

 

1, You have to remember that watts are watts regardless of the voltage but amps are voltage dependant. 705watts / array voltage of 87v = 8.1amps which will be about the max you get on the INPUT.

 

Then the controller converts that 8.1amps at 81v to 12-14v at 50amps but it still equals the same power IE 705watts.

 

2, Maximum Power Point Voltage = Pmax or in your case 3 x 29.3v or 87.9v. So when the input V = 87v thats when you are producing the most power possible. Dont worry if its not at exactly that as lost of things affect it.

 

3, Yep the manual is great lol.

 

4, I have 1200watts of monos, currently at about 20 deg & facing ESE ish. We had a scorching day yesterday but the sky was not clear, more sort of hazy. Bat bank is rated at 2800ah @5c but has lost some capacity as its a used forklift bank (converted to 4 x 12v). The input was about 50+ amps all day long. We are just about to move the panels to south facing & to 29deg. The angle is not optimal but you dont loose that much over a year.

 

5, That makes it even better as you are getting it from less wattage.

 

Up at 5am couldn't sleep

 

Noticed how light it was though, knocking on 5.30am now, are any of you solar people getting any amps this time of the morning?

 

 

Not yet as the array is currently facing more to the east. The sun is shining onto where they are moving to. The gain from an east facing array is you get more power / energy in the afternoon but at the expense of morning power.

 

Boat would really benefit from an East / West split array. You would get the sun earlier in the morning & till later in the evening so increasing the length of time the bank is on charge for & we all know that banks need time. It would reduce the peak amps but that is not an issue with a large array.

[lewisericeric]

1, You have to remember that watts are watts regardless of the voltage but amps are voltage dependant. 705watts / array voltage of 87v = 8.1amps which will be about the max you get on the INPUT.

 

Then the controller converts that 8.1amps at 81v to 12-14v at 50amps but it still equals the same power IE 705watts.

 

2, Maximum Power Point Voltage = Pmax or in your case 3 x 29.3v or 87.9v. So when the input V = 87v thats when you are producing the most power possible. Dont worry if its not at exactly that as lost of things affect it.

 

3, Yep the manual is great lol.

 

4, I have 1200watts of monos, currently at about 20 deg & facing ESE ish. We had a scorching day yesterday but the sky was not clear, more sort of hazy. Bat bank is rated at 2800ah @5c but has lost some capacity as its a used forklift bank (converted to 4 x 12v). The input was about 50+ amps all day long. We are just about to move the panels to south facing & to 29deg. The angle is not optimal but you dont loose that much over a year.

 

5, That makes it even better as you are getting it from less wattage.

 

 

 

 

Not yet as the array is currently facing more to the east. The sun is shining onto where they are moving to. The gain from an east facing array is you get more power / energy in the afternoon but at the expense of morning power.

 

Boat would really benefit from an East / West split array. You would get the sun earlier in the morning & till later in the evening so increasing the length of time the bank is on charge for & we all know that banks need time. It would reduce the peak amps but that is not an issue with a large array.

 

Thanks for that then justme - its interesting to compare figures from people and also have a bit of expertise on what things mean from someone who knows! So cheers!

 

Julian - my Outback wakes up around 4.30am or it has the last few days. Ive not woken up that early yet, but one morning i checked at 6am and was getting just over 10 amps .

 

On the controller it gives you a time since the outback woke up ( just in hours and minutes not a time , like a stopwatch) so have figured it out that its around 430am it's waking up give or take a few minutes

 

Have you got your Outback yet?

[Ex- Member]

Thanks for that then justme - its interesting to compare figures from people and also have a bit of expertise on what things mean from someone who knows! So cheers!

 

Julian - my Outback wakes up around 4.30am or it has the last few days. Ive not woken up that early yet, but one morning i checked at 6am and was getting just over 10 amps .

 

On the controller it gives you a time since the outback woke up ( just in hours and minutes not a time , like a stopwatch) so have figured it out that its around 430am it's waking up give or take a few minutes

 

Have you got your Outback yet?

 

Hi Lewis, this Outback sounds like a pet

 

Haven't got mine yet although today I was looking again at prices but nothing's changed. I don't need it yet so will bide my time and possibly pick up a bargain outback going cheap on e-bay. I might just get the FM 60 and not the 80 as I really don't think I'm going to need more than 500 watts of solar, with the FM 60 though I can still add another 200 watts or so if need be.

 

I having the whole of next week on the boat and the following Monday and Tuesday as they're bank holidays, so should have all our electrics finished, I've been posting on another thread (battery cabling) my progress, and been getting some help from a couple of members making sure I get it right. I think you have a similar set up to me, the battery bank is 696 amps, can't remember what yours was.

 

I'm still hoping to get on the water end of June, it's going to be tight though as the exterior has to be painted and blacked and I'm running out of dosh

 

 

 

[lewisericeric]

Have you never been on the water on it yet in the 7 years you've had it? How have you been so patient?!

 

My battery array is 330amps, (3 x 110amp batts) but I am thinkin of getting a 4th battery, sitll not sure yet. The batts have been at 100% though every night by 7/8pm so that's been really good so not sure I really want to mess with the battery bank and all the hassle of adding nother battery, changing/extending wiring etc. I suppose it'd be pretty straight forward actually, but just feel like I need a rest now and maybe do some simpler things, like a bit of tiling, or putting some beading up etc

 

I Was also looking at getting just the 60amp one, but there's only about £70-80 difference i think between the 60amp and 80amp, so if I was you julian, I'd go with the 80amp. Like you keep telling me, you never know, maybe you'll end up getting another 2 panels to frame and put on a ball and at least you'll be able to have them without having to upgrade the controller then. Plus the 80amp has the internal fan and the 60amp doesnt (so importate )

 

Have you decided on a colour scheme for the exterior of your boat then? are you doing it yourself, or having someone do it for you?

[Ex- Member]

Have you never been on the water on it yet in the 7 years you've had it? How have you been so patient?!

 

My battery array is 330amps, (3 x 110amp batts) but I am thinkin of getting a 4th battery, sitll not sure yet. The batts have been at 100% though every night by 7/8pm so that's been really good so not sure I really want to mess with the battery bank and all the hassle of adding nother battery, changing/extending wiring etc. I suppose it'd be pretty straight forward actually, but just feel like I need a rest now and maybe do some simpler things, like a bit of tiling, or putting some beading up etc

 

I Was also looking at getting just the 60amp one, but there's only about £70-80 difference i think between the 60amp and 80amp, so if I was you julian, I'd go with the 80amp. Like you keep telling me, you never know, maybe you'll end up getting another 2 panels to frame and put on a ball and at least you'll be able to have them without having to upgrade the controller then. Plus the 80amp has the internal fan and the 60amp doesnt (so importate )

 

Have you decided on a colour scheme for the exterior of your boat then? are you doing it yourself, or having someone do it for you?

 

We were on the water for 18 months 2005/2006 I think, we came off to finish the fit out as it was getting a bit too much with all the tools and stuff. Should have been on dry land for a year then back on the water, but things happened, we expanded our business so extended it to 2 years, then my business partner decided to quit which meant i had to do a lot more, so couldn't get to the boat, then the recession hit, then Lynn's mum died. I could go on, but basically one thing after another and here we are five years later

 

Yeah the 80 amp does make more sense I suppose, I won't building another array that size though 2 would be a bit much me thinks, 2 single panels either end would look quite good though

 

Colour's going to be simple Cream and dark Green. Cream roof and sides panelled in dark Green, stern gunwale bow gas locker & seat lockers in Black.

 

Might get to start the roof next week with luck.

 

 

[lewisericeric]

We were on the water for 18 months 2005/2006 I think, we came off to finish the fit out as it was getting a bit too much with all the tools and stuff. Should have been on dry land for a year then back on the water, but things happened, we expanded our business so extended it to 2 years, then my business partner decided to quit which meant i had to do a lot more, so couldn't get to the boat, then the recession hit, then Lynn's mum died. I could go on, but basically one thing after another and here we are five years later

 

Yeah the 80 amp does make more sense I suppose, I won't building another array that size though 2 would be a bit much me thinks, 2 single panels either end would look quite good though

 

Colour's going to be simple Cream and dark Green. Cream roof and sides panelled in dark Green, stern gunwale bow gas locker & seat lockers in Black.

 

Might get to start the roof next week with luck.

 

Sorry to hear about all that, but yes it is tough living aboard and fitting out. Never mind if you're not in a marina as well! It'll all be worth it in the end though

You're right, it is One Thing After Another and that's why we changed the boat name to that not so long ago. just need to get a signwriter in to put it on the boat now

Yes, I'd definately stick with the 80amp version of Outback as you never know.

 

Good choice on the colour scheme - a man with taste. I love the cream with just one other colour. It always looks a great combo on boats that have it and it's definately what i'll have when it comes to repainting. Looks really fresh and modern too:cheers:

 

 

OK, so another good day today with the panels. I was in work late morning/afternoon so wasn't back until around 5PM, but see that we had peaks today of 41.5amps, generated 310amps overall, with a watt peak of 510w.

 

'Justme', what were your results today? Did you have another clear,sunny day?

Edited May 22, 2012 by lewisericeric

[Justme]

Yeh was another lovely day.

 

Had peaks of 1kw, 106v & 60amps & a slightly higher 420ah & 5.8kWh totals.

 

Our highest ever day was 19/06/2010 & we collected 6.7kWh or roughly 500ah.

Edited May 22, 2012 by Justme

[lewisericeric]

Justme - do you have a couple of the 80 amp Outback controllers? You have a 1200w array which means that could be pulling a max of 100amps?

[Justme]

No just the one. The FM80 can cap the collected power to keep the output below 80amps.

 

When I did this is was not a standard practice to have an array that was larger than the max of the controller. Now most grid connected systems do have larger arrays than the inverter output or its caped output as some are software set to limit it to 16amps to meet the DNO's rules.

 

The reason I did it this way was down to cost / performance. I need X amount of power for as long as possible through the year. Having extra in summer was of no use or value (unlike a grid connected system). As long as the system produced our needs for the longest period then all was good. As the arrays full output periods would not be that long or that often loosing the top of the curve is not an issue but getting more power earlier & later in the year is.

 

 

If in the future I go 24 or 48v I can add lots more PV & still keep the one FM80.

[Ex- Member]

Hi Justme

 

Any assistance appreciated, I'm ok with the basics but need help with this.

 

This is the figures for the 2 x 250w Hyundai panels.

 

Nominal output (Pmpp) W 250
Voltage at Pmax (Vmpp) V 30.5
Current at Pmax (Impp) A 8.2
Open circuit voltage (Voc) V 37.5
Short circuit current (Isc) A 8.7
Module efficiency % 15.5
Temperature coefficient of Pmpp %/K -0.44
Temperature coefficient of Voc %/K -0.34
Temperature coefficient of Iscv %/K 0.052

 

This the spec on the single ET Solar Polycrystalline panel 240w

 

System Rating: 240 Watts

Watts (PTC): 212.9 Watts

Max Power Voltage (Vmpp): 29.74 Volts

Max Power Current (Impp): 8.07 Amps

Open Circuit Voltage (Voc): 37.44 Volts

Short Circuit Current (Isc): 8.69 Amps

Max System Voltage: 600 Volts

Module Efficiency: 14.75%

 

I would like to add between 160 and 200w of FLEXI solar panels for winter. These type.

 

http://www.titan-energy.co.uk/sale--80w----semi-flexible-mono-solar-panel-107-p.asp

Justme - do you have a couple of the 80 amp Outback controllers? You have a 1200w array which means that could be pulling a max of 100amps?

 

Hi Eric

 

Good to see you!

Edited May 11, 2014 by Julynian

[Justme]

The two panels you already have are close enough to be wired in parallel (Voltage at Pmax (Vmpp) V 30.5 / 29.74 Volts) or series (Current at Pmax (Impp) A 8.2 / 8.07 Amps).

 

The new panels are far too low in amps (Im(A) : 4.44) to be wired in series (in effect all the panel will be capped at 4 amps), they are also too low in voltage (Vm(V) : 18) to be added as a second string in parallel.

 

Also of note is when calcing the peak voltage use the VOC (Open circuit voltage (Voc) V 37.5) then apply the temp coefficient. With your 3 panels you have a VOC of 112.44v before working out how much that will increase due to the cold. Roughly add 0.3 to 0.5% (seems to cover most panels) per deg C below there rated temp which is normally about 20-25c ish. So again roughly about 15% for -10. So you are looking at a peak voltage of about 130v. Well within the 150v limit but not enough spare to add any more in series.

 

Going back to you wanting to add some more panels. Those ones do not match well to you existing ones in Vmpp or Impp. Either look at dif panels or use a second controller.

 

Random thinking below.

If you use 4 of the new panels.

You might be able to use your 2 x 250watts in one string (8 amps at 61v). Then make two strings of two of the new panels in series & then parallel the two strings then add the 240w in series with them both. Giving you 16 amps at 66 volts.

 

It will affect performance as the string voltage would be slightly higher than the 2 x 250 watt string.

[Ex- Member]

Hi Justme

 

Thanks for that, I reckon it'll be simpler then to set the additional panels up as a separate mini system with a small MPPT controller. I could leave the controller connected to BB and just disconnect the panels when not required, some kind of through fitted 2 pin plug through roof might be a useful idea, something that could be capped off and watertight possibly.

 

Hopefully prices will drop some more before October, I reckon an additional 200w will ball park half the genny running time from last year.

 

Cheers again

[Justme]

Another way of upping the capacity of the array whilst using the same controller is to increase the battery banks voltage from 12 to 24v.

 

Not always possible I know but can be an option sometimes.

[smileypete]

I would try the large panels in parallel and the smaller panels in series pairs then in parallel with the large ones, something like on the right of this diagram:

I'd not worry that much about a slight mismatch in rated Vmp, you could always test it out in practice on a sunny day with a heavy load on, try each then together

 

Temperature has a far bigger effect but sounds like you have an excess of solar in summer for current needs, and these are just to boost winter capability.

 

Again you could point an IR thermometer at the panels in different conditions, see how different the temps are, I'd expect them to be closer in wintertime...

 

cheers, Pete.

~smpt~

Edited May 12, 2014 by smileypete

[leeco]

Show me some pics of your outback setup at the controller so I get an idea of what to wire mine up like when I get the stuff from bimble.

 

Thanks