Solar panel source wanted, Pacific Northwest

Larry H · Oct 27, 2016

I have decided to install solar power on my 37ft Puget Trawler. Does anyone have a recommendation for a company the sells the panels and controllers? Preferred area is Seattle north to Bellingham.

Any recommendation for panel or controller brands would also be appreciated. I think I want panels in the 260-280 watt range and a MPPT controller.

Thanks in advance for any help.

TDunn · Oct 27, 2016

Amazon. You only want an MPPT controller if you have multiple panels in series.

DavidM · Oct 27, 2016

You do want a MPPT controller. All solar panels over about 150 watts are 34 volt Vmp panels. If you hook one of these up to a cheaper PWM controller, you will lose 60% of their power output.

Also Amazon does not sell 150+ watt panels because they can't be shipped UPS.

Wholesalesolar.com is a good source of panels and controllers. They sell Morningstar, Blue Sky, Outback, Magnum- all good controllers. But check shipping costs which can add a lot if you are just buying one panel.

Do you know how to spec your controller? Post your total installed watts and I can help you with that.

David

Ex Sailor · Oct 27, 2016

Larry H said:
I have decided to install solar power on my 37ft Puget Trawler. Does anyone have a recommendation for a company the sells the panels and controllers? Preferred area is Seattle north to Bellingham.

Any recommendation for panel or controller brands would also be appreciated. I think I want panels in the 260-280 watt range and a MPPT controller.

Thanks in advance for any help.

As TDunn said ......
I would definitely look at Kyocera panels. I know it's not the N.W. but www.emarinesystems.com

I would re think using the MPPT controller, it will give out tons of RFI which will make your VHF useless !!. If you go with panels in parallel, I would use a PWM controller instead. They are waaaay cheaper eg. flexcharge
Just say'n and any efficiency aside, the RFI out of a MPPT controller would be a deal breaker for me. Good luck with this .... FB

TDunn · Oct 27, 2016

You can also buy them at Home Depot. The stores may not stock them, but you can buy them on line and have then shipped to your local store free. I was wrong about the MPPT controller for large wattage panels. You do want an MPPT controller for the high wattage 30+ volt large panels.

Note, that you can buy large panels via Amazon, but the order won't always be fulfilled by Amazon. At any rate Amazon is a good way to find out what is available.

JDCAVE · Oct 27, 2016

Ex Sailor said:
I would re think using the MPPT controller, it will give out tons of RFI which will make your VHF useless !!. If you go with panels in parallel, I would use a PWM controller instead. They are waaaay cheaper eg. flexcharge [/FONT][/COLOR]
Just say'n and any efficiency aside, the RFI out of a MPPT controller would be a deal breaker for me. Good luck with this .... FB

Ex Sailor said:
I don't think this is good advice. We don't have this problem with our system, although it has been reported on some of the earlier controllers. Definitely use a MPPT controller!

BTW, we find that solar panels will sometimes confuse an alternator shutting it off and on, shutting the tachometer off and on. This occurs when the battery bank is near fully charged and a number of people have reported this problem. So we normally turn our panels off when travelling.

hypersloth · Oct 27, 2016

Check With Itek on Hammer dr. I believe they support the residential installers locally.

kev_rm · Oct 27, 2016

TDunn said:
Amazon. You only want an MPPT controller if you have multiple panels in series.

Slight nuance - You want MPPT if your input voltage is much higher than battery voltage.

Now, you also do want your input voltage to be much higher than your battery voltage because copper is expensive and higher voltage = smaller wires. ergo, generally recommend MPPT.

I second the recommendation on Amazon.com. Renogy is cheap right now.

kev_rm · Oct 27, 2016

JDCAVE said:
Ex Sailor said:

So we normally turn our panels off when travelling.

Click to expand...

+1 (or any other source of charging present)

dhays · Oct 27, 2016

kev_rm said:
Slight nuance - You want MPPT if your input voltage is much higher than battery voltage.

Now, you also do want your input voltage to be much higher than your battery voltage because copper is expensive and higher voltage = smaller wires. ergo, generally recommend MPPT.

I second the recommendation on Amazon.com. Renogy is cheap right now.

I don't know anything about solar systems but doesn't it matter a lot as to how big a solar system you will have compared to the battery bank and its SOC? My understanding is that the main advantage of the MPPT controller is, as Kev points out, that you can then use the excess voltage of the panel output. The advantage increases as the temperature drops which may be important here in the PNW.

So if someone was going to use a smallish panel layout which was used primarily to keep the batteries topped off and handle small continuous loads such as a smaller fridge, wouldn't a PNW controller work almost as well with much less cost, less risk of RF interference etc...?

kev_rm · Oct 27, 2016

dhays said:
I don't know anything about solar systems but doesn't it matter a lot as to how big a solar system you will have compared to the battery bank and its SOC? My understanding is that the main advantage of the MPPT controller is, as Kev points out, that you can then use the excess voltage of the panel output. The advantage increases as the temperature drops which may be important here in the PNW.

So if someone was going to use a smallish panel layout which was used primarily to keep the batteries topped off and handle small continuous loads such as a smaller fridge, wouldn't a PNW controller work almost as well with much less cost, less risk of RF interference etc...?

I think if you're trying to avoid all risk and don't care about costs so much (like wasted panel capacity)... maybe running the generator would be better :socool:

twistedtree · Oct 27, 2016

Ex Sailor said:
I would re think using the MPPT controller, it will give out tons of RFI which will make your VHF useless !!. If you go with panels in parallel, I would use a PWM controller instead. They are waaaay cheaper eg. flexcharge
Just say'n and any efficiency aside, the RFI out of a MPPT controller would be a deal breaker for me. Good luck with this .... FB

I have to disagree with this on both points. If you are getting RF noise from your MPPT controller, then you have some combination of a crappy controller and/or an installation issue. I have an MPPT controller on my boat and get no interference at all, and all the equipment is within maybe 5' of each other. Lots of other people have the same controller (outback) without problem, and similar results from Morningstar and other good vendors.

As for not using MPPT, I think that's crazy, especially on a boat where you want to suck every last drop of power out of the limited sq feet of solar space that you have available. MPPT will yield more power extraction for parallel installations too. This is even true if you are running with smaller so-called 12V panels (or 24V if you have a 24V system). The MPPT power point for those panels is still above the battery charge voltage (typically around 16V), and a PWM controller will not be able to extract that extra power.

Oh, and keep in mind that PWM (conventional) charge controllers are high frequency switching devices just like an MPPT controller, so are just as subject to interference with a crappy design. Spend the $$ on a quality controller and you will save yourself a lot of headaches.

twistedtree · Oct 27, 2016

The Alternative Energy Store (AltEStore.com) probably has everything you need, so worth considering.

Full disclosure - I'm an advisor to them, but I have no financial interest or incentive from them.

DavidM · Oct 27, 2016

Let me explain PWM- pulse width modulating and MPPT- maximum power point tracking controllers as well as some theory of solar panels:

Solar panels were first made to produce a nominal 12 V so they could be hooked directly to a 12 V battery. These panels have an open circuit voltage- Voc of about 21 V and a voltage where the maximum power is produced- Vmp of about 17 V. But they will work fine if simply hooked to a 12V battery with no controller. The voltage will start at 12 or so until the battery gets charged, then rise to 13, 14 and at full charge it will be 14.5 or so. But the solar panel keeps putting out voltage and current and the voltage will slowly rise to 15+ where it will start boiling (disassociating) the electrolyte.

So, a solar panel is more or less a constant current device. It puts out its maximum current when connected to a short circuit and drops slightly to its maximum power producing point of 17 V (remember power is V * A) and drops to zero at its maximum open circuit voltage of about 21.

So this is where the PWM controller comes in. It starts pulsing the output to keep the voltage from rising to boiling and switches to float of about 13.5 when they are fully charged. But since the solar panel puts out its maximum power at 17, keeping the voltage at 13-14 wastes some of the power because the voltage is lower than 17, so you lose 20% approximately.

Then along came MPPT controllers. These essentially are voltage reducers that let the panels operate at 17 V but "transform" the voltage down to 12-14 V as required. They pick up the 20% or so of power loss, less internal losses.

These nominal 12 V panels are made from a few watts up to about 135 watts. Any more and they are 24 V or greater panels. A 24 V nominal panel which is what the OP is going to buy to get 260-280 watts per panel is going to have a Vmp of 34 volts. When you hook that up to a PWM controller (and many PWM can't take that high of an input voltage) and a battery, it drags the voltage down to the 12-14 that the battery needs. So the usable output of the panels drops to about 1/3 of rated output. That 270 watt panel is no better than a 90 watt panel when hooked up to a PWM controller and a 12 V battery.

So it is absolutely essential to use a MPPT controller with any 24 V panel which is roughly 150 watts or more each.

One other thing about these higher wattage panels- due to size limitations they can't be shipped by UPS. Truck shipping of a single panel is expensive and can be as much as $100 to ship one panel. So check the delivered cost when shopping.

David

twistedtree · Oct 27, 2016

djmarchand said:
Let me explain PWM- pulse width modulating and MPPT- maximum power point tracking controllers as well as some theory of solar panels:

Solar panels were first made to produce a nominal 12 V so they could be hooked directly to a 12 V battery. These panels have an open circuit voltage- Voc of about 21 V and a voltage where the maximum power is produced- Vmp of about 17 V. But they will work fine if simply hooked to a 12V battery with no controller. The voltage will start at 12 or so until the battery gets charged, then rise to 13, 14 and at full charge it will be 14.5 or so. But the solar panel keeps putting out voltage and current and the voltage will slowly rise to 15+ where it will start boiling (disassociating) the electrolyte.

So, a solar panel is more or less a constant current device. It puts out its maximum current when connected to a short circuit and drops slightly to its maximum power producing point of 17 V (remember power is V * A) and drops to zero at its maximum open circuit voltage of about 21.

So this is where the PWM controller comes in. It starts pulsing the output to keep the voltage from rising to boiling and switches to float of about 13.5 when they are fully charged. But since the solar panel puts out its maximum power at 17, keeping the voltage at 13-14 wastes some of the power because the voltage is lower than 17, so you lose 20% approximately.

Then along came MPPT controllers. These essentially are voltage reducers that let the panels operate at 17 V but "transform" the voltage down to 12-14 V as required. They pick up the 20% or so of power loss, less internal losses.

These nominal 12 V panels are made from a few watts up to about 135 watts. Any more and they are 24 V or greater panels. A 24 V nominal panel which is what the OP is going to buy to get 260-280 watts per panel is going to have a Vmp of 34 volts. When you hook that up to a PWM controller (and many PWM can't take that high of an input voltage) and a battery, it drags the voltage down to the 12-14 that the battery needs. So the usable output of the panels drops to about 1/3 of rated output. That 270 watt panel is no better than a 90 watt panel when hooked up to a PWM controller and a 12 V battery.

So it is absolutely essential to use a MPPT controller with any 24 V panel which is roughly 150 watts or more each.

One other thing about these higher wattage panels- due to size limitations they can't be shipped by UPS. Truck shipping of a single panel is expensive and can be as much as $100 to ship one panel. So check the delivered cost when shopping.

David

SteveD · Oct 27, 2016

Platt Electric

I bought mine from Platt Electric. You call up and order the panels and then you can pick them up from one of the many stores that are scattered all over the PNW. Before you pick them up, fill out this form (http://dor.wa.gov/docs/forms/excstx/exmptfrm/buyersretailtxexmptcert_e.pdf) with box 6a checked, and you will save the sales tax on the transaction.

Platt is probably not the least expensive source for this stuff, but you will save shipping and it certainly is convenient.

dhays · Oct 27, 2016

Dave and Twisted, thanks for the information. Those posts helped me understand it a lot better.

foggysail · Nov 2, 2016

I remember a similar discussion here in the forums earlier where there was solid recommendations to use an MPPT controller. IF YOU HAVE SPACE for an additional panel, you will be far better off to use a good controller and add the additional panel. That additional panel will by far provide greater output than you will achieve with an expensive MTTP controler. NO way will I spend upwards of $300+ for MTTP!

Now there is an exception as someone earlier pointed out. IF you have high voltage panels, you then will benefit performance wise to go with MTTP. A solid benefit to going to higher voltage panels is that you can avoid using heavy wire to get from the panels to your controller and battery.

I do recommend that one study the voltage/current curves supplied by the panel's manufacturer. For low voltage panels, one can tolerate some voltage loss in the distribution wiring because when the batteries (my experience with wet cells) can accept higher charges, their terminal voltages are lower than a fully charged battery. Now as the terminal voltage increases, the demand/acceptance of battery charge current diminishes so the wiring drop will also diminish. To be sure, one needs to do the math (voltage losses and expected cost vs benefits) for his individual case.

JDCAVE · Nov 3, 2016

foggysail said:
That additional panel will by far provide greater output than you will achieve with an expensive MTTP controler. NO way will I spend upwards of $300+ for MTTP!

No. you put the extra panel on as well as the MPPT controller. All of the effort and hassle of putting panels on an expensive boat and you are worrying about saving $300?

You put on both because as Peter points out you never have too much solar on your system. And you want to keep your batteries topped up to the extent possible. In the PNW, you rarely have a situation where you are fully charged after a day of charging, and you want to get all the way to 100% SOC if you can to maximize the longevity of your battery bank.

Larry H · Nov 3, 2016

Thanks to everyone who posted on this thread. I have gotten a lot of good info, and found a very local source, Platt Electric. While chasing links, I have found several solar companies in my local area. Thanks to Steve D, I now know about the WA state
solar sales tax exemption. I hope to install two 260 to 300 watt panels and a MPPT controller this year.

twistedtree · Nov 3, 2016

Good luck with the project, and let us know how it turns out.

foggysail · Nov 3, 2016

JDCAVE said:
No. you put the extra panel on as well as the MPPT controller. All of the effort and hassle of putting panels on an expensive boat and you are worrying about saving $300?

You put on both because as Peter points out you never have too much solar on your system. And you want to keep your batteries topped up to the extent possible. In the PNW, you rarely have a situation where you are fully charged after a day of charging, and you want to get all the way to 100% SOC if you can to maximize the longevity of your battery bank.

Sure and you can add tower for additional panels and don't forget the dinghy panel. From my four years experience with solar, I do not need more solar power. There are those who find it challenging to also heat hot water. Like in all real things there is a point of diminishing returns. As to worrying about $300? No, I just seek to maximize the bang for my bucks, for me the MTTP is out. But to each his own--

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