Quickie Solar Question

[BlueStringPudding]

I've seen a second hand solar panel for sale that the owner claims has an output of 50v - 60v, 5.35A. All the googling in the world is not helping me find a solar panel of similar output in terms of volts, so I am at a loss to know whether something like this would be a good investment for my boat (12v system) or a dead duck because of the need for additional equipment to drop the voltage.

 

Any thoughts?

[Serendipity]

I've seen a second hand solar panel for sale that the owner claims has an output of 50v - 60v, 5.35A. All the googling in the world is not helping me find a solar panel of similar output in terms of volts, so I am at a loss to know whether something like this would be a good investment for my boat (12v system) or a dead duck because of the need for additional equipment to drop the voltage.

 

Any thoughts?

 

Don't know about the voltage spec, but if it's correct you'll need an MPPT controller to drop it down. (And make sure the spec of the MPPT handles that input voltage, as the cheap ones don't). That may be justifiable for a several panel setup, but not one.

[Grace and Favour]

I've seen a second hand solar panel for sale that the owner claims has an output of 50v - 60v, 5.35A. All the googling in the world is not helping me find a solar panel of similar output in terms of volts, so I am at a loss to know whether something like this would be a good investment for my boat (12v system) or a dead duck because of the need for additional equipment to drop the voltage.

 

Any thoughts?

 

You'd certainly need a MPPT for that BSP (though I suspect the seller is embracing hyperbole in his technical spec)

[Nickhlx]

You'd certainly need a MPPT for that BSP (though I suspect the seller is embracing hyperbole in his technical spec)

 

A 50-60 volt panel producing over 5 amps is around 275 watts - pretty big I would say... I also wonder whether it really is that voltage as most are around 20 to 30 volts per panel.

Perhaps it is two panels in a larger outer casing ? That would be more interesting... You will need some sort of controller else risk of damage to the batteries and not making best use of

the available power - MPPT is the better option but more expensive, and you will need to be sure of the panel spec before committing to the controller, lest it won't handle the panel output.

 

Nick

[BlueStringPudding]

Thanks, guys. What's the difference between a MPPT and a Solar Regulator, then?

[Nickhlx]

Thanks, guys. What's the difference between a MPPT and a Solar Regulator, then?

 

A MPPT controller adjusts itself to load the panel to its optimum output and claims to be able to squeeze up to 30% more energy from them...

 

Nick

[BlueStringPudding]

Yhn,s. Can it have panels of different output voltages and different amps attached to it at the same time?

[Grace and Favour]

Yhn,s. Can it have panels of different output voltages and different amps attached to it at the same time?

 

I have an 'Outlook' FX80 MPPT - - this model can certainly handle different panels/outputs

[BlueStringPudding]

"outback" you mean? They're rather fabulous but I may need to sell my boat to afford one!

[Justme]

Yhn,s. Can it have panels of different output voltages and different amps attached to it at the same time?

 

 

No.

 

Not even the outback. You can have panels that are a different (higher only) voltage to the battery bank.

 

Well you can but it will not work as well as having them on separate controllers or the same wattage panels all with the same voltage/amps.

 

You can wire non matched panels in series if they have the same amps & in parallel if they have the same volts.

[BlueStringPudding]

Okay. Interesting. At the moment I have a 50w bunch of little panels running quite happily through a simple 8a controller. But they are all same. I was assuming I'd need to be able to combine them with the 250w panel through a single controller of some sort. If that's not the case and they can stay connected as they are, then all I need to find is a MPPT or regulator thingy that can cope with a 50v to 60v 5.35a output and wire that in separately. Is that right? Next question... Finding a MPPT or similar that can drop that high voltage to suit the charge needed for my 12v battery bank. Any suggestions? (hint: I am a cheapskate skint person)

Edited May 30, 2012 by BlueStringPudding

[Serendipity]

A MPPT controller adjusts itself to load the panel to its optimum output and claims to be able to squeeze up to 30% more energy from them...

 

Nick

 

Well a bit more than that surely.

 

Additionally the 'proper' ones will take much higher voltage arrays and drop them down to the system voltage, upward adjusting the amp output. ie 17v panels need only an 'ordinary' controller for 12v systems, and will lose the benefit of the spare volts over 14.4v, but if you put an MPPT controller in you get a few more amps out for the extra few volts over 14.4V. And here is the additional bit - if you need to match much higher voltage panels to 12v you need MPPT which again converts the extra volts to more amps at 12v system levels.

Edited May 30, 2012 by Serendipity

[BlueStringPudding]

Would this little blighter do the trick, in that case?

 

My link

[Serendipity]

Would this little blighter do the trick, in that case?

 

My link

 

Well it says it will take 60v input, so it should do.

 

How much can you get the panel for? (for cost comparison with a 17v one)?

[BlueStringPudding]

£45

[Serendipity]

Okay. Interesting. At the moment I have a 50w bunch of little panels running quite happily through a simple 8a controller. But they are all same. I was assuming I'd need to be able to combine them with the 250w panel through a single controller of some sort. If that's not the case and they can stay connected as they are, then all I need to find is a MPPT or regulator thingy that can cope with a 50v to 60v 5.35a output and wire that in separately. Is that right? Next question... Finding a MPPT or similar that can drop that high voltage to suit the charge needed for my 12v battery bank. Any suggestions? (hint: I am a cheapskate skint person)

 

Yes, stick with your existing setup, and parallel a new MPPT controller for the higher voltage panel.

[BlueStringPudding]

Okily dokily. Thanks for the advice.

[Serendipity]

£45

 

Can I have the sellers details please

 

Seriuosly, if you can do better than £1/watt you are doing well. so if that really is 275 watts at £45 + £95 for controller great.

 

What is the seller using it for - perhaps you can get advice on their controller?

Edited May 30, 2012 by Serendipity

[BlueStringPudding]

it was a one off special!

[Serendipity]

it was a one off special!

 

Hmmm - two at that price with one controller would be fantastic.

 

Do you know if it is mono or multi crystalline and the size to help with verification of the stats?

[mickspangle]

Can I have the sellers details please

 

Seriuosly, if you can do better than £1/watt you are doing well. so if that really is 275 watts at £45 + £95 for controller great.

 

What is the seller using it for - perhaps you can get advice on their controller?

 

These look quite good value: http://www.spvconcept.com/panels/et-solar/et-solar-195w-65p-per-watt.html

 

I think they might be 24v though, so would possibly need a fancy controller though

[matty40s]

Hmmm - two at that price with one controller would be fantastic.

 

Do you know if it is mono or multi crystalline and the size to help with verification of the stats?

 

tracer mppt

 

Pedant alert, Polycrystalline.....

 

this is the controller that a few of us have invested in recently also has a panel mt5 panel which you can watch instead of jeremy kyle.they do 10A up to 45A in this range - suitable for a large array.

If you want 6mm cables BSP, I can make them to suit.

 

 

 

edited to add, the controller above can convert 24V and 36V down to a 12V battery bank. You just have to make sure you wire the controller to the batteries and turn on before connecting the panels.

The 5A output of the panel seems very low for that voltage BSP, my new panel gets up to 45V on a good sunny period, and it converts to around 14A.

Edited May 31, 2012 by matty40s

[BlueStringPudding]

tracer mppt

 

Pedant alert, Polycrystalline.....

 

this is the controller that a few of us have invested in recently also has a panel mt5 panel which you can watch instead of jeremy kyle.they do 10A up to 45A in this range - suitable for a large array.

If you want 6mm cables BSP, I can make them to suit.

 

 

 

edited to add, the controller above can convert 24V and 36V down to a 12V battery bank. You just have to make sure you wire the controller to the batteries and turn on before connecting the panels.

The 5A output of the panel seems very low for that voltage BSP, my new panel gets up to 45V on a good sunny period, and it converts to around 14A.

 

Thanks, Matty. I'll take you up on that offer, assuming 6mm cabling is what I need.

 

Everyone:

I've been reading about voltage drop and cable sizing in the threads here and elsewhere, using voltage drop calculators and trying to compare cable sizes on sellers' websites, and I'm just getting more confused not less.

 

First query:

I've got a 50-60v panel churning out 5ish amps (it's. 250w panel). There will be about 3m-4m cable between the MPPT controller and the batteries, that can't be helped because of the layout of the cruiser stern. (Unless the controller lives in the stern area near the batteries, but I'm not mad on that idea as its kinda damp and gets hot). So first question is what size cable do I need for that run? In either diameter or sq mm. And then, where do I find that cable as some websites describe their cable in terms of diameter, some in terms of area, and some in terms of Amps and some in terms of gauges like AWG, (and some don't make it clear whether it's diameter or area) meaning so far I am none the wiser regarding suppliers. Thanks.

 

Second query:

The distance from the MPPT controller to the panel is yet to be decided. Mainly because I am thinking about how best to use my roof space (when I single hand, I walk on the back half of the roof, and in the winter I store coal on the back half. I know from experience the problem with storing coal on the front half, steering goes gaga). So I want to think carefully about the length of the cable run to the solar panel so that I don't make it so long I have to remortgage the boat to pay for the cabling, but so I also find a good compromise regarding how I use my roof practically. What thickness of cable will I need for 2.5m, 5m, or 10m at the panel's 50-60v output? The voltage drop calculators aren't telling me in lay (enough) terms so please don't refer me to one of those. I want to be able to get my head round it and being able to compare multiples like that will help me to understand.

 

Thanks for your help

Edited June 4, 2012 by BlueStringPudding

[Justme]

Keep the controller as close to the bats as possible. You want the long run to be at a higher V (so lower amps) to reduce the losses. Even the full length of the boat would be ok in 6mm, possibly even in 4mm.

[BlueStringPudding]

So you're suggesting putting the MPPT controller in the stern bilge area? Where it gets hot from the the engine and damp from condensation and the rain. Really!? Are they designed for that kind of environment?

Edited June 4, 2012 by BlueStringPudding