Solar Panels... where do I start?

[clbrof]

Hi all,

 

I have used the search function on the forums and I have come to realise, as well as the solar panels, I will also need a controller module?

 

My battery bank is 310AH and are currently only charged by the engine. Summer is coming up and I would love to not have to run the engine every other day!

 

What sort of wattage of solar panels should I go for? Does any old controller work with any old panels?

 

Also am on a budget, please dont suggest the best panels for thousands of pounds.

 

Many thanks for your help!

[Nickhlx]

I think the most likely reply as to how much you should add is "as much as possible / you have room for / can afford."

 

If funds limit, get a controller that will cater for the max you will ever fit, and if space limits what you fit, get a MPPT controller that will make the best out of what you will fit.

 

If funds don't limit, get a MPPT controller anyway and fit the most you can.

 

Big panels ( house panels) are likely to be the best bang per buck, and most difficult to steal ( carry away).

 

 

Nick

 

 

 

[clbrof]

house panels?

 

So i dont need to buy '12v' ones?

 

I have around 200 to spend on solar bits

[Chris Pink]

Liveaboard I assume.

 

Start with your usage. Laptop/ TV, fridge, led lights. If fairly normal no big inverters then 200-350W is a good target. Allow £1 per watt.

Controller - either £50 or £150

Installation parts, fixing £60

 

A good choice at the moment is 1 or 2 200-250W house panels with the £150 MPPT controller. Measure carefully the panels are big and will fill a roof.

 

Other than that look at 2-4 12V suitable 100W panels then you can have either regulator.

 

Dependent on demand this will do you April to September 90% of your usage. 10-20% over winter.

 

A big inverter would change this picture considerably but if you only used it with the engine on it would be fine

 

If you don't have good metering it would be worth considering a controller with a good meter or a digital ammeter and voltmeter off eBay.

 

house panels?

 

So i dont need to buy '12v' ones?

 

I have around 200 to spend on solar bits

 

Ok, crossed post.

 

Then 2 x 80W 12V panels and a cheap controller.

Edited February 16, 2013 by Chris Pink

[Kiwidad]

house panels?

 

So i dont need to buy '12v' ones?

 

I have around 200 to spend on solar bits

 

Good luck! 1 panel will take most of that!

[clbrof]

Yup living aboard

 

Would something like this

 

http://www.ebay.co.uk/itm/Perlight-240w-Poly-Solar-Panel-High-Efficiency-Silver-Frame-MCS-250w-BARGAIN-/150968034552?pt=UK_Gadgets&hash=item23266564f8

 

coupled with something like this work?

 

http://www.ebay.co.uk/itm/20A-30A-50A-60A-MPPT-Solar-panel-Charger-Regulator-controller-12-24V-AUTO-/390543069459?pt=UK_Gadgets&var=&hash=item5aee2e5113

 

Has anyone tried Chinese solar panels/controllers *ultimately, probably all come from china... but has anyone ordered straight from China?

[Chris Pink]

No. The controllers are crap. To use a house panel you will need to spend more on a controller. It's the input voltage that has to match and exceed the highest panel output voltage.

 

Read my post above - the first bit - it outlines the options.

 

They are unlikely to be true MPPT controllers. That panel is a good deal but measure your space. They are big. And you will need a controller with >40V input.

[clbrof]

No. The controllers are crap. To use a house panel you will need to spend more on a controller. It's the input voltage that has to match and exceed the highest panel output voltage.

 

Read my post above - the first bit - it outlines the options.

 

Okay so for around 300 i can get a house panel and a Mppt? Are there any brands? Suggestions?

[Nickhlx]

Okay so for around 300 i can get a house panel and a Mppt? Are there any brands? Suggestions?

 

Panels vary in their efficiency and cost, with the latest / most efficient ones being a few percent more efficient, i.e. produce a few more watts per sq. mtr., but much more expensive.

 

If you are "practical / DIY orientated have a look at the various E-Bay sites selling Solar cells and see if making your own will work out cheaper.

 

Chris's point about the controller is a good one - getting a proper MPPT controller will also cater for a better / wider range of input voltages and make the best from that...

 

Nick

 

 

[lewisericeric]

house panels?

 

So i dont need to buy '12v' ones?

 

I have around 200 to spend on solar bits

House panels are generally speaking, more efficient than the 12v panels. We have 3 x 230w ones and are really impressed.

 

Whatever wattage of panel you're looking at, divide that by 12(v) to find out the ampage of the MPPT controller that you'll need.

 

Ie: if you buy a 250w panel you will need a controller capable of handling 20 amps

 

250 / 12 = 20.8

 

HOWEVER, it would be best to get a controller that has a little bit more than that capacity incase you decide to get another panel in future to add to your array. This will then save you costs down the line of getting another controller.

 

For example we have 690w of solar but got an Outback 80amp MPPT controller (which we are really happy with and they also do a 60amp version) just Incase we did decide to add another panel - it's unlikely we will as we now have more than enough, but you never know!

 

ETA -'I agree with Chris Pink about the Chinese controllers - if you can't afford a half decent controller, I really wouldn't bother with a solar array as you need to pay for it to perform. Buying a cheap controller will only cause inefficiency and problems and it's likely that you'll have to replace it for another one shortly after !

 

I understand you've got a budget but try and get the best you can and if you can't get something decent, hold off and save for a bit until you can - you've a few months yet before its truly summer which is when youll be getting the most out of them anyway

Edited February 17, 2013 by lewisericeric

[Alanji]

Because my handrails are about 3 inches from the side, full size panels would have meant too small a walkway would be left. I bought these 200w panels http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=321062083720&ssPageName=ADME:L:OC:GB:3160

[MtB]

ETA -'I agree with Chris Pink about the Chinese controllers - if you can't afford a half decent controller, I really wouldn't bother with a solar array as you need to pay for it to perform. Buying a cheap controller will only cause inefficiency and problems and it's likely that you'll have to replace it for another one shortly after !

 

 

I keep hearing people mentioning that cheap controllers are no good, but I'm no-one seems to ever suggest a specific 'good' controller. I know from experience that choosing by price alone can generally guarantee a low quality product, but conversely a higher-price product may be good, or may just be a cheap product being sold at a higher price!

 

So, can anybody give me a link to a sensibly-priced MPPT controller that is known to be good quality, is sold from the UK and will control, say, a pair of 120w panels please? I would be very grateful. Many thanks.

 

 

MtB

[Chris Pink]

Tracer are good. Though their range seems to be changing. There's a reasonable price Steca too, no personal experience but a good brand.

 

Feel free to ignore this.

[MtB]

Tracer are good. Though their range seems to be changing. There's a reasonable price Steca too, no personal experience but a good brand.

 

Feel free to ignore this.

 

Thank you Chris. I don't ignore you whilst you are being civil. A big relief to you I'm sure

 

 

MtB

[MoominPapa]

I keep hearing people mentioning that cheap controllers are no good, but I'm no-one seems to ever suggest a specific 'good' controller. I know from experience that choosing by price alone can generally guarantee a low quality product, but conversely a higher-price product may be good, or may just be a cheap product being sold at a higher price!

 

So, can anybody give me a link to a sensibly-priced MPPT controller that is known to be good quality, is sold from the UK and will control, say, a pair of 120w panels please? I would be very grateful. Many thanks.

 

 

MtB

 

I know everyone poo-poos the cheap Ebay controllers, but this Ebay linky fits your description. It's certainly reasonably priced, and I've had an identical unit controlling a 100W panel for 18 months which has behaved impeccably, and it is definitely a true MPPT controller.

 

Just re-read your post. A pair of panels? In that case you'll need to 20A version: ebay No direct experience of that one, but assuming it's otherwise the same as the 10A, should still be good.

 

MP.

[lewisericeric]

I keep hearing people mentioning that cheap controllers are no good, but I'm no-one seems to ever suggest a specific 'good' controller. I know from experience that choosing by price alone can generally guarantee a low quality product, but conversely a higher-price product may be good, or may just be a cheap product being sold at a higher price!

 

So, can anybody give me a link to a sensibly-priced MPPT controller that is known to be good quality, is sold from the UK and will control, say, a pair of 120w panels please? I would be very grateful. Many thanks.

 

 

MtB

 

If you read the rest of my post Mike, I did somewhat recommend an MPPT controller - The Outback.

 

Whether you consider that sensibly priced may be different to my opinion of it being good value for money with its capabilities, not to mention the extended warranties etc.

[Chris Pink]

A bit of overkill for a couple of low voltage panels.

 

@moominpapa; how do you know this is a true MPPT controller. I see the ad doesn't show maximum input voltage which can be a clue.

[Rebotco]

I bought direct from China (100 watt flexible panel) and the tracer 10 amp Mppt controller.

Loads cheaper than the same things from the UK. Had no problems at all, took a couple of weeks to arrive, but I'm more than satisfied with the goods and the service.

Communication with the seller by email through ebay was excellent too.

[smileypete]

I keep hearing people mentioning that cheap controllers are no good, but I'm no-one seems to ever suggest a specific 'good' controller. I know from experience that choosing by price alone can generally guarantee a low quality product, but conversely a higher-price product may be good, or may just be a cheap product being sold at a higher price!

 

So, can anybody give me a link to a sensibly-priced MPPT controller that is known to be good quality, is sold from the UK and will control, say, a pair of 120w panels please? I would be very grateful. Many thanks.

The Tracer ones are sometimes sold under the name EPSolar, the new ones are called ETracer I think. With any controller, it's worth finding out the absorption charge voltage and absorption charge time, sometimes the cheap ones have a low charge voltage and very short absorption time.

 

A decent MPPT should be able to accept a high panel voltage and convert it to a much lower voltage for batt charging, and a proper MPPT will have chunky toroid inductors inside that allow this conversion to take place. BUT some of the cheap MPPTs like 'WellSee' are fake MPPTs and are in fact a cheap PWM controller, a look inside will tell all.

 

Nevertheless PWM controllers can be OK on a smaller install for charging 12V batts with the lower 18Voc camping solar panels. Might be interesting to work out the cost per watt improvement of the MPPT vs PWM, to the cost per watt of the panels.

 

cheers, Pete.

~smpt~

[steve hayes]

Nevertheless PWM controllers can be OK on a smaller install for charging 12V batts with the lower 18Voc camping solar panels. Might be interesting to work out the cost per watt improvement of the MPPT vs PWM, to the cost per watt of the panels.

 

Agree

 

We have 2 * 80w panels (to allow ease of access down the roof whilst single handing in locks) and a 20A PWM controller. In direct sunshine we get about 11Amps into the batteries and generally see about 5 - 6 Amps if the sun is out.

 

The whole lot including cables & couplers off Ebay today ~ £200

 

Steve

[MoominPapa]

A bit of overkill for a couple of low voltage panels.

 

@moominpapa; how do you know this is a true MPPT controller. I see the ad doesn't show maximum input voltage which can be a clue.

Mine is installed with an ammeter, and you can see when it does an MPPT search: every so often the current drops to zero for less than a second, and then rises in steps as the controller homes in on the maximum power point.

 

MP.

[OldPeculier]

Loads of helpful stuff here

[clbrof]

Thank you everyone for your help!

 

I think I have found a good match

 

http://www.ebay.co.uk/itm/150968034552?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

with

 

http://www.ebay.co.uk/itm/121066130476?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

 

The panel produces 40 volts and 240w max. The controller can cope with 20A (or 260w, according to the advert) and can handle up to 100volts. Is this correct? can someone confirm this?

 

Many thanks

 

Colin

[Kate and James]

Hiya,

Saw this ARTICAL recently, thought it may help... I believe there is another artical coming in the next issue showing them being made etc... Could be worth a look

[Chris Pink]

Thank you everyone for your help!

 

I think I have found a good match

 

http://www.ebay.co.uk/itm/150968034552?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

with

 

http://www.ebay.co.uk/itm/121066130476?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

 

The panel produces 40 volts and 240w max. The controller can cope with 20A (or 260w, according to the advert) and can handle up to 100volts. Is this correct? can someone confirm this?

 

Many thanks

 

Colin

 

Looks good to me. MC4 cables on that panel. Do check the size though I've just installed 4 on a widebeam and they are big.