Solar panel question

KD3PC · Aug 23, 2011

If you buy a cig lighter panel....it will likely be of no real help on a boat your size...save your $$..

Maine Sail · Aug 23, 2011

kd3pc said:
If you buy a cig lighter panel....it will likely be of no real help on a boat your size...save your $$..

Ditto. Any panel that will actually put a charge back in will not have a 12V receptacle.

Ed Schenck · Aug 23, 2011

But to answer the question the Link 1000 should show positive amps. This assumes that everything is off, i.e. no negative amps, and that the panel is working. As pointed out it is going to be a very small number, less than one for sure.

Stu Jackson · Aug 23, 2011

agaliha said:
1. If I buy a solar panel that has a cigarette lighter connection on it, what will it do to my Xantrex Link 1000?

2. Will it calculate the current flowing backwards through the system and adjust its readings accordingly?

3. Any other things I should think about before doing this?
Agaliha

1. Don't use a cg lighter, the wiring in it is usually too small. If wired properly, the Link will figure + amps IN.

2. Yup, see 1.

3. Wire it to your house bank. Period. Don't use a cig lighter. Second Period.

Really, there are TONS of solar websites, as well as this one, that'll explain how to connect the panel.

rardiH36 · Aug 23, 2011

I presume that your goal is a solar panel to keep your batteries charged up when you aren't at the boat, not connected to shore power, and with nothing on to drain them? Or maybe so you can turn on a low drain item like the VHF or GPS or stereo and expect the solar panel will reduce the battery depletion rate?

If so, I think something like that shown in the attached url is a better bet than a cigarette lighter plug panel which probably is way too small to do much of anything than maybe maintain a charge on a motor scooter's battery when not in use.

http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=160636398510&refid=store

The charge controller in the URL may not be "marine grade", but if you mount it in an always dry location, this shouldn't be a real issue. Marine grade components are best ... but for extra $'s of course.

On my boat, for the purpose of maintaining and even restoring a light usage drain over a day or two, I have one 20W mono-crystalline solar panel feeding into two charge controllers, one for each of my Group 27 dual purpose deep cycle batteries. When I am away from the boat, the main battery switch is off so each battery is maintained independently from the other. This set-up works great. At my berth, I only need shore power if staying overnight for the TV, coffee, maker etc. Otherwise, my boat is never plugged in. The charge controllers kick in when the battery voltage drops to about 12.8 and then cut off when the solar panel charges to just over 14V. Up and down goes the voltage, all day long for the past 2.5 years.

If I had to do it again, and now that solar pricing has fallen quite a bit, I would have gone with two 10w panels. Then each battery really will be independent from the other when the main A/B/All switch is off.

As Stu Jackson commented ... lots of solar advice sites for info.

Maine Sail · Aug 24, 2011

rardiH36 said:
The charge controllers kick in when the battery voltage drops to about 12.8 and then cut off when the solar panel charges to just over 14V. Up and down goes the voltage, all day long for the past 2.5 years.

Rardi,

Your charge controller is killing your panels performance. Measure the time it takes your disconnected batteries, with no loads on them, to fall from 14v+ to 12.8v and then figure on 5 hours of good sun per day and you see how much that charge controller is killing you in time spent being OFF. Getting that last 20% of charge is important but a shunting controller with a wide span between on/off can take forever and this is not always because of the panel size.

A shunting controller with a narrower range between on & off will be in ON more of the time. Unloaded batteries fall quickly from 14+ to about 13.5v but then plateau and can hoover above 13v for a while before continuing to fall down towards 12.8v. This is even more exacerbated the thicker the plates get on the deep cycle batteries or if gel or agm.. Cheap controllers have a wide span in their on/off range and the time spent in OFF can really hurt performance and the time it takes to get back to full..

Bill Roosa · Aug 24, 2011

MorningStar has a modle for RV/boats that has two battery outputs. The amount of atention each gets is programable so you can dump a lot into the house and just a little into the start batts.
If you are trying to "go solar" I'd recommend you get a decent charge controler and size it for your final configruation of solar panels. Getting a 5 amp controler and then upgrading to 10 amp panels is a waste of money.

FourPoints · Aug 24, 2011

There was another real good solar topic thread a week or two, i am using the mobile app for the forum otherwise i would try to find the link for you, but read through that as it goes into lots of detail about what Maine sail said above.

Maine Sail · Aug 24, 2011

Bill Roosa said:
MorningStar has a modle for RV/boats that has two battery outputs. The amount of atention each gets is programable so you can dump a lot into the house and just a little into the start batts.
If you are trying to "go solar" I'd recommend you get a decent charge controler and size it for your final configruation of solar panels. Getting a 5 amp controler and then upgrading to 10 amp panels is a waste of money.

It's called the Sunsaver Duo: http://www.morningstarcorp.com/en/sun-saver-duo

Alternatively you can use a simple Echo Charger or ACR to get charge from one panel to two banks. The benefit is that it would also work with your shore charger and alternator.

Ed Schenck · Aug 24, 2011

This is the thread that Brian references I think. And it is an excellent solar discussion:
http://forums.hunter.sailboatowners.com/showthread.php?p=834807&highlight=solar .

So are there manufacturers of panels and/or controllers to avoid? Or do I just shop price? I have an ACR-like device called a combiner. So I hope a single controller will do the job. Thinking one 50w or 80w panel just so I can leave shorepower off and not worry about the cycling bilge pump. Nothing else is turned on.

FourPoints · Aug 24, 2011

back at my desk now, here's the link:
http://forums.hunter.sailboatowners.com/showthread.php?t=132513

Maine Sail · Aug 24, 2011

Ed Schenck said:
This is the thread that Brian references I think. And it is an excellent solar discussion:
http://forums.hunter.sailboatowners.com/showthread.php?p=834807&highlight=solar .

So are there manufacturers of panels and/or controllers to avoid? Or do I just shop price? I have an ACR-like device called a combiner. So I hope a single controller will do the job. Thinking one 50w or 80w panel just so I can leave shorepower off and not worry about the cycling bilge pump. Nothing else is turned on.

If you're going to spend the money I'd opt for something that can take the marine environment. Kyocera panels are actually warranted in the marine environment and many are not.

The Solar World panels are the old Siemens/Shell Solar panels and are also excellent, durable tough panels. Our Siemens panel is now 11 years old and you'd never know it. Sharp also has a good reputation but I do not know if they are warranted in the marine market. Genasun makes about the best MPPT controller for small panels and will yield excellent ouput from a 50W -80W panel. The the small Morningstar PWM controllers are also good. You basically want a mono or polycrystalline panel. There are plenty of good quality panels out there but also a lot of "cheap" Chinese panels are flooding the market with "price" as the main driver, not necessarily quality. Was just on a boat lest week where the 2 year old panel was covered in 4200 around the edges because water got between the glass and cells. Sadly the 4200 was shading the panel and basically reduced the output by about 85% compared to what it should have been. We removed the 4200 and it began leaking and delaminating again. A "good" eBay deal gone bad....

You really can't go wrong with Sharp, Kyocera or Solar World panels but there are other good ones too. The shunting charge controllers WM sells are quite poor performing in a marine application....

FourPoints · Aug 24, 2011

I'd add the Ganz panels to the list (Defender carries them). They are new, so it's hard to say how many years they will last, but they are marketed and warrentied for marine use, and watt for pound the best panel I have seen on the market, and so far in the ~4 months I have had mine it is doing great. I just about finished the mast to install it above the bimini last night, watch for a post something in the next week or so with the full installation details.

edit for clairification: when I say watt for pound, I do actually mean weight. The Ganz panels do not have any glass anywhere. They use a light weight aluminum back plate, a layer of rubbery plastic , the solar cells, and another layer of rubbery plastic, so they do actually weight next to nothing (a 30 watt panel weighs in at only 4.4lbs)

Ed Schenck · Aug 24, 2011

Thanks guys, excellent! Now to save up a few social security checks.

rardiH36 · Aug 24, 2011

Maine Sail said:
Rardi,

Your charge controller is killing your panels performance.

I hope that its only the performance and not the panel that's suffering!

Seriously, thanks for the useful comments which got me thinking and prompted me to take a look at the specs/description of the ASC charge controller that was on my boat when I bought it 5 years ago. No solar panel with the boat -- just the controller mounted on a bulkhead. The manual states "this rugged unit holds the record for reliability since 1981"! So it ain't the latest in technology. It should resume pulse charging at 13.5v until about 14.3V. Then it shuts off the charging by shorting the solar array. (Why this way instead of just switching off the solar input?)

My other controller is a bottom-of-the-line 7 amp Sunforce which by the owner's sheet, should cut back in when battery voltage is below 13v.

Probably the two controllers are interacting with each other. Certainly, when the ASC cuts out by shorting the panel, then the Sunforce controller also stops charging.

Undoubtedly a dual output charger with new technology would be much better. But with only 20W (about 1.x amp) solar panel that seems enough to keep my two batteries topped up (although probably not optimally) and no plan to upgrade to a high powered array, I will be contemplating this for a while. Certainly I would go best and latest if upgrading to a solar system to support cruising.

FourPoints · Aug 24, 2011

rardiH36 said:
...with only 20W (about 1.x amp) solar panel that seems enough to keep my two batteries topped up (although probably not optimally) and no plan to upgrade to a high powered array...

my suggestion, get rid of both controllers (yes they probably are interfering with each other, so the sunforce probably gets no power when the other controller detects full charge and shorts), replace with a Genasun GV-4, and add a blue sea ACR, total cost is a bit under $200, you will get FAR better performance out of your panel than you get now. I bet it would probably even outperform your current setup swapped with a 30w panel instead of your 20w, after you factor in the limited charging you actually get from the old / mis-matched controllers...