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Discussion Starter · #1 ·
I've decided to get rid of my propane fridge and put in an Engel dop-in 12v model:

https://www.engel-usa.com/products/...n-models/engel-mb40-drop-in-remote-compressor

I believe it will use between 24 and 50 amps per day, depending on the ambient temperature and whether I run it as a fridge or freezer. I currently generate all my energy needs with two 45w panels and store it in one big 160a battery (I have a 70a cranking battery as well). I realize I'll have to upgrade my energy system with the new fridge. I can fit one big 240w panel over my bimini (fixed between the hard dodger and the arch) or two 100w panels. The price per watt is much cheaper with the big 240w panel. I would also upgrade my battery bank to one 220a battery. MMy energy use is low (all LED, tiller pilot on windvane, manual everything) so I should have a daily energy requirement of about 50 or 60 amps tops. I like keeping things simple. My questions are:

Will I have enough solar panels (total 330w) to reliably meet my energy needs?

Is there any disadvantage to using one big solar panel instead of two smaller ones?

Will my house battery bank of one 220a deep-cycle battery be enough? Batteries are expensive here and, unfortunately, we can't get the 6v golf cart batteries that are so popular in the US.

If anyone has any suggestions or advice, I'd be grateful. I suppose I will also upgrade to a better solar controller as well. Thanks in advance!
 

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I've seen suggestions to use two panels, each with its own controller, so that you'll get maximum output of any panel that isn't shaded, as opposed to a compromised output if a large panel is even partially shaded from time to time. That made sense to me.

Unless sunshine is guaranteed, a 220AH bank is pretty marginal to be running a fridge or esp. a freezer even though I believe the newer models are much more efficient than our old Adler Barbour which uses over 5 amps running (usually at a 50% duty cycle)

We currently are running a single 100W panel, a 440AH bank and have upgraded our alternator to 90A capability with a 'smart regulator' and unlike past seasons this summer we did not need to plug in anywhere. Very pleased with this setup.. the solar (in sunny conditions) gets about 10-15AH ahead of the fridge during daylight, cutting our daily draw by more than half. We do get 12-14 hours of sun in our summer months so that helps a bit too....
 

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Tartan 37
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Looking at solar myself, will be good to see what is discussed here. Next season we hope to moving to a mooring and I want to keep the fridge going, if possible. Other than the bilge pump that would be the only thing running when moored. Cruising of course is another thing I assume.

I am very interested in the newer flexible panels, but I see one solid panel on the davit, or maybe the dodger, or both? If dodger, we are planning to build a new one maybe this winter, perhaps the flexible type can be built into the dodger?
 

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I am very interested in the newer flexible panels, but I see one solid panel on the davit, or maybe the dodger, or both? If dodger, we are planning to build a new one maybe this winter, perhaps the flexible type can be built into the dodger?
We bought the SolarFlex panel from GoPower/Carmanah. So far so good. Using bungees to hold it atop the dodger at the moment, but someone suggested sewing 'corner pockets' into the dodger that you could slip the panels into. That would leave them free to be optimally positioned at various times when moored or docked. Orientation makes a huge difference to the output of these things.
 

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with 2 you have redundancy and a backup in case of physical damage to one or the other and all you would need to do to stay alive is to reduce consumption.

most budget cruisers use 1, or a big one and a small very small one wherever space may dictate.

2 seems to be the way to go for most.

since im not currently cruising I only have a maintainer panel and single battey bank at 100amps, altough bigger than needed for that around 85watts back on the davits....

a second one would be the way to go if I added a small drop in cooler or other gear

good decision on the engel drop in!

jealous
 
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Looking at solar myself, will be good to see what is discussed here. Next season we hope to moving to a mooring and I want to keep the fridge going, if possible. Other than the bilge pump that would be the only thing running when moored. Cruising of course is another thing I assume.

I am very interested in the newer flexible panels, but I see one solid panel on the davit, or maybe the dodger, or both? If dodger, we are planning to build a new one maybe this winter, perhaps the flexible type can be built into the dodger?
my old boat had the very popular semi hard dodger design that actually is easier to buiild or make than a full canvas dodger

the hard top was curved making a felixible panel the best choice there

back out on the davits a smaller hard panel works great with some aluminum mounts.

I am a huge fan of the new harder flexible panels being made today.

look at webb chiles moore 24(race boat) GANNET and look at the panels he installed on deck on the sides

they are shatter proof and deck proof(trampling on and off them) however he made custom covers for them just in case

honestly today the sheer volume of options for panels and power management makes it harder than before

it used to be gettting an mppt controller a good panel and wires was as complicated as you can get

NOW! watch out:D
 
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islander bahama 24
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The OP is getting a 220 amp hour battery which can supply the night half of the 50 amps per 24 hours.

With 330 watts of solar he has more than enough to run the freezer all day and still charge up the 220 amp hour batt.

Theres no use going crazy about it apart from connections the whloe solar instalation is maintenance free. Stick them in any manner he likes that gets sun for his area.

In the trade wind areas with my configuration I found that the early mornings the big problem. So I got a small 70 watt panel and prop it up on deck against the base of the mast at 45 degrees. It grabs the sun from sun-up because the wind is always east... or NE or SE.
 

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Discussion Starter · #13 ·
I've seen suggestions to use two panels, each with its own controller, so that you'll get maximum output of any panel that isn't shaded, as opposed to a compromised output if a large panel is even partially shaded from time to time. That made sense to me.

Unless sunshine is guaranteed, a 220AH bank is pretty marginal to be running a fridge or esp. a freezer even though I believe the newer models are much more efficient than our old Adler Barbour which uses over 5 amps running (usually at a 50% duty cycle)

We currently are running a single 100W panel, a 440AH bank and have upgraded our alternator to 90A capability with a 'smart regulator' and unlike past seasons this summer we did not need to plug in anywhere. Very pleased with this setup.. the solar (in sunny conditions) gets about 10-15AH ahead of the fridge during daylight, cutting our daily draw by more than half. We do get 12-14 hours of sun in our summer months so that helps a bit too....
Thanks for the advice Ron! I agree that 220a is a bit small for a service battery bank, but the options here are limited. As it is, this battery costs about USD$500 in Brazil!! I'm going to think about using 2 panels over the bimini, each on their own controller, but it will double my cost for sure. Perhaps I'll leave my existing two 45w panels on their own controller and run the new one(s) on a better MPPT controller.
 

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My suggestion would be the renogy 100 watt panel
We installed one last year. Ordered it from Amazon, and got free shipping. Amazon.com : RENOGY 100 Watt 100w Monocrystalline Photovoltaic PV Solar Panel Module 12V Battery Charging : Patio, Lawn & [email protected]@[email protected]@http://ecx.images-amazon.com/images/I/[email protected]@[email protected]@41rOZxjogoL I'm adding another soon.

The combo price for two including the controller would be the least expensive way to go, but I'm using the Blue Sky 3024i MPPT controller.

Ralph
http://www.sailblogs.com/member/brogdon/?xjMsgID=294526
 

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Discussion Starter · #15 ·
The OP is getting a 220 amp hour battery which can supply the night half of the 50 amps per 24 hours.

With 330 watts of solar he has more than enough to run the freezer all day and still charge up the 220 amp hour batt.

Theres no use going crazy about it apart from connections the whloe solar instalation is maintenance free. Stick them in any manner he likes that gets sun for his area.

In the trade wind areas with my configuration I found that the early mornings the big problem. So I got a small 70 watt panel and prop it up on deck against the base of the mast at 45 degrees. It grabs the sun from sun-up because the wind is always east... or NE or SE.
That's what I've been thinking too. I can run the fridge off the solar panels during the day while charging the battery and then lower the temperature setting at night if necessary. I also cruise in an area of very light winds and end up motoring more than I'd like to admit. One of the advantages of the Engel fridge is you can use it as a fridge or freezer. When motoring you can set it to freeze and then turn it off at night. I would like to keep things as simple as possible, hence the idea of one big panel, one controller and one battery.
 

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The low price per watt for that 240w panel will quickly jump once you factor in the costs of shipping, mounting, and the MPPT controller it will most likely require.

My initial thinking was that I'd go with 2 x190 watt rigid panels but the the weight with mounting hardware would have been over 75lbs and the cost of building a support frame above the bimini would have been over $500 by the time I built something sturdy enough and that looked aesthetically pleasing. That framing cost really changes the value proposition of the rigid panel unless you already have an arch, davits, or a hard top.

Also the larger "grid tie" panels (usually those larger than 200 watts fall into this category) typically have a high nominal voltage that pushes you into using more expensive MPPT controllers versus the cheaper PWM with the 12 volt nominal panels. While I don't want to reignite the MPPT vs. PWM debate that has been discussed to death on this and other forums, it is important to consider total system design when making equipment selections.
 

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Discussion Starter · #17 ·
with 2 you have redundancy and a backup in case of physical damage to one or the other and all you would need to do to stay alive is to reduce consumption.

most budget cruisers use 1, or a big one and a small very small one wherever space may dictate.

2 seems to be the way to go for most.

since im not currently cruising I only have a maintainer panel and single battey bank at 100amps, altough bigger than needed for that around 85watts back on the davits....

a second one would be the way to go if I added a small drop in cooler or other gear

good decision on the engel drop in!

jealous
Fala Christian! With the big 240w panel I'd have a total of 3 panels (the two existing 45w panels and the new one). I agree that the big panel is a bit like putting all one's eggs in one basket... The problem here (as you well know!) is that we don't have all the (cheap) options and products available in the US and Europe. We have to work with what's available. As it is, I'm going to pick up the fridge in Canada and fly it back as a piece of luggage! Sadly, I can't bring the panels as well on the plane...
 

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Fala Christian! With the big 240w panel I'd have a total of 3 panels (the two existing 45w panels and the new one). I agree that the big panel is a bit like putting all one's eggs in one basket... The problem here (as you well know!) is that we don't have all the (cheap) options and products available in the US and Europe. We have to work with what's available. As it is, I'm going to pick up the fridge in Canada and fly it back as a piece of luggage! Sadly, I can't bring the panels as well on the plane...
i know you know how it is "down here" jaja

I once brought a motorcycle engine back in suitcases and built up my restored honda xr600 that way peice by peice

here in el salvador they have small 20 or 30watter, 85, and big 120s or so and thats it unless you order from the states and pay import duties etc

surprisingly they have 6volt trojan batteries that are only priced about 30 percent higher than in the states which if you think about it is a steal! they use them for remote cell phone tower maintenance things.

if I ever come back down to the boat, I also have a friend in the battery business that can hook me up with some batteries if I ever start my electric inboard project but that may never happen.

I think the 2 small 45 panels and one big one over the dodger or on davits is a safe bet and would probably work real well

those engel fridges are awesome!

good luck man
 
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I don't think Renogy is in the same class as Kyocera. From the Renogy Warranty download:

http://renogy.com/wp-content/uploads/2014/04/Warranty-off-grid-kits.pdf

"LIMITED WARRATNY: Renogy warrants this product will be free from defects in
...
The warranty does not cover failures result from ...natural elements, ..."

Yes, we all make typos (Warratny ?!) but a real grown-up business sends that stuff past legal and engineering and other people and multiple eyes have to fail to read it. Typos on an important legal document like the warranty mean it isn't a very established business "yet".

The warranty also excludes damage due to natural elements, which would mean rain and salt water spray. So, there's no warranty for exterior or shipboard use. That's even better than the companies that exclude "use on moving vehicles" and boats.

Coming back to the numbers...

"I believe it will use between 24 and 50 amps per day, "
Let's say that's 50, and it would be 50 Amp-hours not amps. It would be important to know if that's at 12.6 volts (battery power) or 14.4 volts (alternator power) since the overall wattage pulled will be different. Split the difference and let's say 50 AH at 12.6 volts for a nearly full battery...

"...one big 160a battery ...I would also upgrade my battery bank to one 220a battery."

" I should have a daily energy requirement of about 50 or 60 amps tops." 10AH for everything else seems conservative, but if you have LED nav and cabin lights, or no night lights, it might be.

"Will I have enough solar panels (total 330w) to reliably meet my energy needs? "
If you are using an MPPT controller, you will get about 15% more power out of the panels than any other kind of controller. That is, an MPPT controller will give you almost the full rated power at battery voltage (330W at 12.8 volts, about 25 Amps) and depending on installation angle, time of the year, how far off the equator you are, you can count on that for the equivalent of about 5 hours per sunny day. So, about 125 Amp-hours per day from the solar panel. Without the MPPT controller, possibly 15-20% less power because other controllers throw out the excess voltage from a solar panel, which might be 17-22 volts for a nominal "12" volt system. Even if you didn't use MPPT you'd probably see 100Ah per day, which would be "enough" but give you less of a safety margin.

If you're making 125 Amp-hours and consuming 60Ah, you'll have plenty of power. I'd even suggest keeping the 160Ah battery as long as it is in good condition, and not replacing it until it weakens or there's some other good reason.

Assuming, of course, I've gotten my math right, which doesn't always happen.
 
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