What Solar System is Best for Us?

[nmit5903]

Depends on usage - cruising or overnighters, what you are running off the battery bank, size and type of bank. Power management is a constant battle.

I have run 2 BP Solar 80W on a 690AH AGM battery bank and have found so long as I am running the motor at least twice a day for an hour or so, the batteries stay in the right zone (60-65%+) - thats running one chest fridge, full Raymarine nav set, TV, radio etc. Having said that I am very careful to turn off everything that is not in use at the board.

My view is cant have enough power and I agree with some of the earlier comments - 3-4 panels - the bigger the better if you have the room in davits or something, wind and a genset running off the main diesel tank (dont like petrol on the water).

Most of the solar regulators are 20-30A. Steca are good/reliable and now do a 40A. Make sure it has a readout so that you can see whats going on.

A Xantrax meter for monitoring state of batteries is essential in my book.

Finally the biggest AGM battery bank you can afford and fit.

[D&D]

Originally Posted by nmit5903

My view is cant have enough power ... the bigger the better ...

A Xantrax meter for monitoring state of batteries is essential in my book.

Finally the biggest AGM battery bank you can afford and fit.

What nmit5903 said!

[D&D]

Here is a pic of the SunPower panels (2 x E20's, officially rated 327W@) on our CatNirvana, a Lagoon 440. Our panels run effortlessly with a Flexmax 60 MPPT and we can confirm from our own experience that setup is absolutely 'blue water' suited.

We also proudly note that we now assist Aussie mariners (and land users as well!) to discover SunPower for themselves. So PM us if you want further information. Mention this thread and we'll ensure you receive CF Member special pricing.

[D&D]

...and, after some problems uploading, a couple more...

[noelex 77]

Originally Posted by D&D

The world leader in efficient panels is the American company, SunPower. When we started looking we assumed the officially rated output was an apples-to-apples measure, but it's not. Rated output is lab conditions...and, in reality, lab conditions rarely exist on a vessel! Happily we found SunPower panels with their high rating AND amazing output under cloudy skies and low sun angles; that's the perfect combination for a vessel.
.

Many boats have space limitations and have not got the room to fit all the solar power they would like.
The high efficiency panels are a big help in this regard and Sunpower are one of the very best 20.1% panel efficiency is a big help fitting the watts required.

However, I can find find no evidence there watt for watt performance is any better in real world conditions.
The voltage temperature coefficients are worse than average and the small number of blocking diodes would suggest the performance under hot partially shaded conditions is going to a bit worse (watt for watt) than most of the alternatives.

Sunpower are claiming "exceptional low-light performance" so they obviously feel they have an advantage here. It is always difficult to compare I/v curves, but the performance to me looks pretty average for 800 W/m2, 500w/m2 is a non standard measurement so very difficult to compare, the performance at 200 W/m2 does appear to be slightly better than most.

Area for area the Sunpower panels are excellent, significantly better than the older generation of panels, but I cannot see anything in the specifications that indicate that with the same number of watts these panels will do better, in real world conditions.

[D&D]

Originally Posted by noelex 77

Many boats have space limitations and have not got the room to fit all the solar power they would like.
The high efficiency panels are a big help in this regard and Sunpower are one of the very best 20.1% panel efficiency is a big help fitting the watts required.

However, I can find find no evidence there watt for watt performance is any better in real world conditions...Sunpower are claiming "exceptional low-light performance" so they obviously feel they have an advantage here. It is always difficult to compare I/v curves, but the performance to me looks pretty average for 800 W/m2, 500w/m2 is a non standard measurement so very difficult to compare, the performance at 200 W/m2 does appear to be slightly better than most.

Area for area the Sunpower panels are excellent, significantly better than the older generation of panels, but I cannot see anything in the specifications that indicate that with the same number of watts these panels will do better, in real world conditions.

Our evidence is our own observations. We will explore your specifications remarks further with SunPower tech support and post again with their response. In the meantime, our observations see significant output from our panels starting early in the day. We can also see reasonable output under cloudy conditions, altho not so when we are under heavy overcast. So that's anecdotal, rather than precisely measured evidence.

That said, we can comfortably run a fair array of electrics (2 frigs, freezer, several low watt appliances, computers, stereo) when on anchor with no use of our genset...and similarly when underway (adding 2 chartplotters, some radar, autopilot) altho that can be restricted if the sails are blocking the panels. In any event, we now run the genset only occasionally where, before SunPower arrived, the genset was called on regularly and often.

[Frigoboat Info]

For those not familiar with SunPower cells, these are special cells that have all the electrical contacts on the rear of the cell. these are officially designated Inter-Digitated Back Contact (IGBC) cells, where the visibile surface is completely free of the metal grid collectors seen on regular silicon cells, and thus have all of the surface area available for solar collection. This results in efficiencies of over 22%, and as a result we have panels with smaller physical dimensions compared to those with regular cells. As an example, we are working on a project now to install 6 Solara Ultra 140 watt panels, with SunPower cells, on a catamaran, where the available space allowed only 5 regular panels could be installed. We also offer Solbian panels which use SunPower cells and are thin and flexible enough to sew zippers or Velcro to them and then install them on existing bimini's, dodgers, etc. Of course, system performance is wholly dependent on the configuration of the panels and the number and type of controllers. Many potentially powerful systems seen on boats are compromised by using land-based components and configured as if it were the roof of a house. Using true marine components and configuring the system with shading being inevitable rather than possible, will reap the best results from the investment.

[Frigoboat Info]

Oops! That should be IDBC cells. Inter-Digitated Back Contact.

[skipmac]

Originally Posted by nmit5903

I have run 2 BP Solar 80W on a 690AH AGM battery bank and have found so long as I am running the motor at least twice a day for an hour or so, the batteries stay in the right zone (60-65%+) -

Finally the biggest AGM battery bank you can afford and fit.

From all data from AGM battery makers (at least in the US), research and problems reported by AGM users my conclusion is AGM batteries are not the best choice for cruisers.

The problem is AGM batteries need to be fully charged on a regular basis or suffer an early death. Yes they can accept a faster charge than FLA batteries but for most cruisers off the grid, it's almost impossible to full charge a large battery bank on a regular basis. You claim running yours in the 60-65% range which is contrary to recommendations by the battery makers.

I guess if you have a large budget and don't mind replacing a very expensive battery bank every few years AGMs do offer some convenience in taking a high charge rate.

[noelex 77]

Originally Posted by D&D

Our evidence is our own observations. We will explore your specifications remarks further with SunPower tech support and post again with their response. .

Thanks, I would be very interested in their response.
Difficult conditions for solar panels such as hot temperatures, partial shade and low light are common on boats, so performance under these conditions is important for those that like cold beer

[dlentz]

Originally Posted by Frigoboat Info

For those not familiar with SunPower cells, these are special cells that have all the electrical contacts on the rear of the cell. these are officially designated Inter-Digitated Back Contact (IGBC) cells, where the visibile surface is completely free of the metal grid collectors seen on regular silicon cells, and thus have all of the surface area available for solar collection. This results in efficiencies of over 22%, and as a result we have panels with smaller physical dimensions compared to those with regular cells. As an example, we are working on a project now to install 6 Solara Ultra 140 watt panels, with SunPower cells, on a catamaran, where the available space allowed only 5 regular panels could be installed. We also offer Solbian panels which use SunPower cells and are thin and flexible enough to sew zippers or Velcro to them and then install them on existing bimini's, dodgers, etc. Of course, system performance is wholly dependent on the configuration of the panels and the number and type of controllers. Many potentially powerful systems seen on boats are compromised by using land-based components and configured as if it were the roof of a house. Using true marine components and configuring the system with shading being inevitable rather than possible, will reap the best results from the investment.

That's great only two problems I see;
Warranty is void if used "near" salt water environments (I think a boat qualifies?)
And an exclusive dealer network (at least in my area) that won't sell individual panels.

I'm not bashing them by any means and would consider purchase even without the warranty, but I'm not going to go way out of my way just to purchase someone's product when there are others nearly as good, and easier to obtain.

[Frigoboat Info]

Originally Posted by skipmac

The problem is AGM batteries need to be fully charged on a regular basis or suffer an early death. Yes they can accept a faster charge than FLA batteries but for most cruisers off the grid, it's almost impossible to full charge a large battery bank on a regular basis. You claim running yours in the 60-65% range which is contrary to recommendations by the battery makers.

We sell Energy 1 advanced AGM batteries, and we see far too many being replaced way too early, typically after 2 or 3 years. Most of these batteries were simply sulphated; a result of not being charged correctly. Analysis of this trend shows that it is not the fault of the batteries, but the charging systems. An AGM battery is essentially a flooded lead-acid battery, but with the acid held in a glass fibre mat, and not sloshing around freely. These batteries will take a higher bulk-charge voltage (14.8) than a flooded or gel battery, and will accept a much higher bulk-charge current (1C for Energy 1 AGM's vs 0.25C for flooded) due to their lower, almost non-existent internal resistance, which is reflected in a shelf life of two years plus. However, many charging systems are either not capable, or are not set correctly, to allow the acceptance phase to last long enough to fully charge the batteries. Some chargers have a default time-out setting of 1 hour, where on a large, high-capacity bank this should be four or five hours or more to ensure a complete recharge. One of the most important parameters of a battery charger is the criteria that decides when to switch from the acceptance phase to the float phase. Cue solar panels, which can silently administer the final slow, low current charge, hour after hour, that is required to fully charge the battery. As is the case with flooded batteries, if AGM's are not fully charged regularly, they will begin to sulphate, but that can be addressed by an equalization charge. Energy 1 batteries are Valve Regulated Lead-Acid (VRLA) batteries, and that means simply that the case can be subjected to a pressure of up to 5 psi before the valves open as a safety measure. A normal equalization voltage of 15v will not be enough to open the valves. Nigel Calder took some of my "toasted" Energy 1 batteries, subjected them to an 18v charge, and reported back that he then had some batteries that were back to 100% capacity. The valves did open, as was expected, but the amount of vapour lost was minimal and did not effect the new-found capacity. Nigel is an expert. Don't try this at home ........

[Frigoboat Info]

Originally Posted by dlentz

That's great only two problems I see;
Warranty is void if used "near" salt water environments (I think a boat qualifies?)
And an exclusive dealer network (at least in my area) that won't sell individual panels

Solara and Solbian manufacture dedicated marine products that incorporate SunPower cells, and with full marine warranties. It is the residential type panels like Kyocera, Sanyo/Panasonic, Sharp, etc. that specifically exclude moble and/or marine use in their warranties.

SunPower panels are not available as individual panels in the USA. They are sold through their dealer network exclusively for use in land-based applications. Solara and Solbian use SunPower cells in their marine-specific products.

[dlentz]

Originally Posted by Frigoboat Info

Solara and Solbian manufacture dedicated marine products that incorporate SunPower cells, and with full marine warranties. It is the residential type panels like Kyocera, Sanyo/Panasonic, Sharp, etc. that specifically exclude moble and/or marine use in their warranties.

SunPower panels are not available as individual panels in the USA. They are sold through their dealer network exclusively for use in land-based applications. Solara and Solbian use SunPower cells in their marine-specific products.

Really? I'm not sure, but I believe Krocera's warranty covers "mobile use" which includes marine. Haven't looked at the others, maybe some one else could chime in? And the Solbian panel can hardly be described as "high" efficiency by today's standards (although for a flexible panel that is true, but having been in the solar biz in the past, I don't want any plastic glazing on my panels). Why is Solara so proud of completely manufactured in Germany if the most important part is from a US company? and where is it documented that they are using SunPower's most efficient and latest cells? Because if they're not, there are better values to be had out there.
I know this sounds argumentative, however, I don't mean it that way I mean it more from a skeptical point of view. I'm looking to narrow my choices in the near future also. I'm not just baiting anyone.

[Frigoboat Info]

Quote: Really? I'm not sure, but I believe Krocera's warranty covers "mobile use" which includes marine. No. These warranties specifically exclude mobile and marine use and salt damage. Haven't looked at the others, maybe some one else could chime in? And the Solbian panel can hardly be described as "high" efficiency by today's standards(although for a flexible panel that is true, but having been in the solar biz in the past, I don't want any plastic glazing on my panels).Solbian panels are available with SunPower cells or regular cells. The Solbian panels with SunPower cells are indeed "High efficiency", as they incorporate cells of 22% plus efficiencies. Check out the specs. Why is Solara so proud of completely manufactured in Germany if the most important part is from a US company? Although SunPower is an American company, their cells are made in Taiwan, The Philapines, and Indonesia. and where is it documented that they are using SunPower's most efficient and latest cells? Because if they're not, there are better values to be had out there. SunPower cells are very expensive and are only available to major manufacturers in high volume. What value do you put on a high efficiency solar panel that is lightweight, very flexible and durable, and can be installed on existing canvas bimini's or dodgers using zippers or velcro, snaps, grommets, etc? No expensive, heavy, or ugly tubular framework involved, and can be removed easily and stored below.
I know this sounds argumentative, however, I don't mean it that way I mean it more from a skeptical point of view. I'm looking to narrow my choices in the near future also. I'm not just baiting anyone.