Solar

tmcnamara58 · 05-26-2023, 06:02 AM

I am looking to add a small solar panel to the radar arch to keep the house battery charged and the fridge running while on a mooring.
I have a Mainship Pilot 34 softtop.

Suggestions on vendor and panel size are welcome.

Thanks

psneeld · 05-26-2023, 06:29 AM

Not sure what you mean by a small solar panel, and would have to know the running amps of your fridge.

But my guess to get through overcast days, a couple decent sized batteries and probably at least 200W of panels will be about the minimum.

Look up the sizes of different panels and see if they will fit on your radar arch.

mvweebles · 05-26-2023, 06:33 AM

Depending on the size of your fridge and climate, I'd guess you need 75AH/day which translates into 1kw/day. Around 200-watts of solar. If you have a soft-top, you probably want flexible solar panels. Mounting is really the only difficult part of the work. As Psneeld insinuates, you do need to factor-in battery capacity as a function of how many cloudy days you want to account for. Depending on your climate, 200AH of available capacity (LiFePO4 have more 'available' as a percentage of rated capacity than Flood Acid) is probably a comfortable minimum.

Although the marketing and pricing is compelling, I would stay away from Renogy. If you ever need tech support, you're screwed. I received a dead-on-arrival inverter which they steadfastly refused to RMA until I filed all sorts of credit card and BBB complaints. In the process, I received blatently wrong information - telling my my new 12.6v battery bank was dead and needed to be replaced before they would RMA my Inverter. It is not possible to exaggerate how bad their support is.

2-years ago I installed two 165W "Newpowa" RIGID panels on a camper van. They are doing fine and I would buy them again, though I never needed tech support so no idea if they are any good. I see they now offer full solar kits but nothing in FLEXIBLE panels. HERE is a RIGID 200W system for under $400. The only other thing you would need is some sort of circuit protection to the battery. I also like a switch on the panel side of the Controller to shut-down the electricity from the panels if service is needed. A circuit breaker works nicely.

Good luck -

Peter

O C Diver · 05-26-2023, 06:58 AM

My slip neighbor in Florida bought one of these kits and has been very happy with it.

https://www.renogy.com/350-watt-solar-flexible-kit/

Maybe you could mount it on your soft top.

Ted

DavidM · 05-26-2023, 07:07 AM

As noted above a minimum of 200 watts will be required as typically a 200 watt panel will produce 50 Ah each day on average. A typical modest size fridge (6 cu ft) draws that much on average.

Any of the 100 watt panels available on Amazon should work. Wire them in series to minimize voltage drop and then to a Renogy Rover 30A controller, also available on Amazon.

David

Don L · 05-26-2023, 08:14 AM

I had a 290W panel for years to maintain my battery with the frig running while out on a mooring. It needs to be bigger than just the load to average out for the days with low solar.

I also cruised for 2 years with that panel before changing to 2-320W panels.

These panels are rigid, but if I would starting now I would just go on Amazon as there are flexible panel kits with controller cheaper than you can buy 1/2 the wattage or rigid panels alone.

mvweebles · 05-26-2023, 08:30 AM

Quote:

Originally Posted by Don L

These panels are rigid, but if I would starting now I would just go on Amazon as there are flexible panel kits with controller cheaper than you can buy 1/2 the wattage or rigid panels alone.

Read the review comments and look for the rating tag that should be affixed to the back of each panel (many of the cheap brands post nothing of the specified rating). Many of the cheap panels are clearly suspect - wattage specs and size specs are vague and claims of efficiency grand. They also come with a PWM controller vs MPPT.

In short, there's a reason they are so cheap. "Buy cheap, buy twice" as the saying goes.

Peter

Don L · 05-26-2023, 09:34 AM

Quote:

Originally Posted by mvweebles

Read the review comments and look for the rating tag that should be affixed to the back of each panel (many of the cheap brands post nothing of the specified rating). Many of the cheap panels are clearly suspect - wattage specs and size specs are vague and claims of efficiency grand. They also come with a PWM controller vs MPPT.

In short, there's a reason they are so cheap. "Buy cheap, buy twice" as the saying goes.

Peter

Yes, but the question is not if they are the best or even if they are "good". The question is whether they meet the need at that lower price.

When I got my first rigid panel solar setup it cost me over $1500 to install a 290W panel just to charge batteries out on the mooring so I could leave the frig on.

Surely a $500 flexible panel 500W system with a PWM controller now available can do the same service and is easier to install.

Same applies to my current LFP cheap house batteries that were $309/ea for 100ah. Maybe not best, but been fine so far for 6 months so why would I have gotten the $800-1000 ones?

backinblue · 05-26-2023, 09:40 AM

I just added a 200W panel to my hardtop. Plenty to run the fridge and keep batteries topped off. While I was at it, I had a small inverter installed so I can run some smaller AC loads w/o needing the generator (single-cup coffee maker, microwave, TV, AC outlets.)

heysteve · 05-26-2023, 10:08 AM

Quote:

Originally Posted by tmcnamara58

Suggestions on vendor and panel size are welcome.

For a vendor, check out CurrentConnected. No affiliation, just a happy customer. Bought my SOK marine batteries and a fair amount of Victron gear from them. Support is excellent.

mvweebles · 05-26-2023, 10:31 AM

Quote:

Originally Posted by Don L

Surely a $500 flexible panel 500W system with a PWM controller now available can do the same service and is easier to install.

Issue is the 500w panels may not be 500w. There is no labeling except Amazon ad.

Peter

NSM · 05-26-2023, 11:18 AM

You might start here. Lots of good basic info and sizing to make sure your panel fits.

https://www.custommarineproducts.com...ar-panels.html

Don L · 05-26-2023, 01:28 PM

Quote:

Originally Posted by mvweebles

Issue is the 500w panels may not be 500w. There is no labeling except Amazon ad.

Peter

I know. But that is same thing as any "from China" product. But in this case my point is this application if it is "only" 450W that is fine.

My way isn't the only way. OK with me for others to do different on their boat. I still have my 640W of rigid panels and an upper end MPPT controller. I think the most I have ever seen out of them is about 500W.

backinblue · 05-27-2023, 06:14 AM

For what it's worth, the installer of my system recommended against flexible panels unless you need them to flex. He said for the same quality panel, the flexible ones are more expensive. But more importantly, any panel loses efficiency as it heats up. A rigid panel with an air space underneath will not get as hot and therefore will produce more power on a hot summer day.

Don L · 05-27-2023, 06:59 AM

Quote:

Originally Posted by backinblue

For what it's worth, the installer of my system recommended against flexible panels unless you need them to flex. He said for the same quality panel, the flexible ones are more expensive. But more importantly, any panel loses efficiency as it heats up. A rigid panel with an air space underneath will not get as hot and therefore will produce more power on a hot summer day.

all that is true in theory, but in the application being asked about isn't an issue really

psneeld · 05-27-2023, 07:09 AM

Other than "mounting on the radar arch"....the non-return of the OP doesn't give us much insight to "the application".....

backinblue · 05-27-2023, 07:10 AM

Quote:

Originally Posted by Don L

all that is true in theory, but in the application being asked about isn't an issue really

Probably true but there is some discussion in this thread about flexible vs. rigid, so I thought it was worth mentioning because perhaps not everyone knows these things.

backinblue · 05-27-2023, 07:16 AM

Quote:

Originally Posted by Don L

Same applies to my current LFP cheap house batteries that were $309/ea for 100ah. Maybe not best, but been fine so far for 6 months so why would I have gotten the $800-1000 ones?

Because quite often you get what you pay for. Many years ago at a power squadron course, the CG instructor made the statement "When purchasing equipment for a boat, always buy the best you can for whatever function you need." I wouldn't say that everyone should follow that 100% of the time, but the point is well-taken. When you rely on something to perform on a boat in less than ideal conditions, the cheapest option is not likely the best.

Also, cheap and inexpensive are not the same things. You should always avoid "cheap". Inexpensive may be ok depnding on your use case.

Don L · 05-27-2023, 07:35 AM

Quote:

Originally Posted by backinblue

Also, cheap and inexpensive are not the same things. You should always avoid "cheap". Inexpensive may be ok depnding on your use case.

And expensive doesn't mean best or even good.

Using the example of my LFP batteries. Tear downs of the "cheap" $300/100ah batteries doesn't show much difference to the $800-1000 ones.

Lots of times the expensive stuff carries the best warranty. Is that because they need to pay for the returns???

backinblue · 05-27-2023, 09:10 AM

Quote:

Originally Posted by Don L

Lots of times the expensive stuff carries the best warranty. Is that because they need to pay for the returns???

That is twisted logic. If they had to pay for lots of returns, wouldn't they have a lesser warranty? They have a better warranty because they have confidence in the quality of their product and they experience fewer returns so they can offer a better warranty.

I wish you the best with all your cheap gear. I hope it never lets you down.