use of "plug and play" solar for temporary use

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Re: use of "plug and play" solar for temporary use

Post by Tomfoolery »

That same company makes a couple of 100W setups with PWM controller, too, which may fit better on a Bimini. IF that's where it's going, of course. Incredibly cheap, too. 8)



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Re: use of "plug and play" solar for temporary use

Post by BOAT »

I think I could go 24/7 on one of those 100 watt panels you mentioned Tom with my reefer and lithium, but the cooler he selected will need more power than that. His unit would drain the battery below full charge before nightfall so that's not a high enough charge to last the night. He needs enough solar during the day to make the gel battery fully charged before the sun goes down or the battery will go dead before morning.

Remember - he is on gel - you run a gel dead and it's fried forever.
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Re: use of "plug and play" solar for temporary use

Post by Herschel »

Great feedback, guys! :) So, the coffee pot gets regulated to an alcohol stove if shore power not available. Got it. My present AGM battery bank will support my "new" cooler especially with daily shore power access and frequent motoring. But, if I were to need to drop the hook for a night or two due to engine failure, low fuel, or a very beautiful little cove that just calls to us, having Boat's solar system standing by would give me the opportunity to take away any drama about daily/nightly power needs should that time on the hook continue for multiple days. Having a power station of about 100 watts to supplement my house battery would be adding a redundancy, which might bring a higher level of peace of mind, but would not be necessary. I think that is the "cliff notes" version of what you guys are saying. 8)
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Re: use of "plug and play" solar for temporary use

Post by Tomfoolery »

BOAT wrote: Fri Jul 17, 2020 7:59 amHe needs enough solar during the day to make the gel battery fully charged before the sun goes down or the battery will go dead before morning.
Except that he stated that they will be using marinas at night, which is what I've based my thinking on.

But you're right, and if I were planning a system, with what little I know about solar, I'd allow for at least an extra day without sunshine due to weather, or no shore power. And of course, you can always turn the fridge off and wrap it with insulation to last the night without running, much like any temporary blackout at home (but with insulating blanket in the vein of belt and suspenders). Or set the temperature control higher. Or add another battery. :wink:

From Herschel's earlier post, quoted from a purchaser of the subject fridge/freezer unit:

"I think on initial startup when it is cooling from 80 degrees down to 30 or 35 I see about 4 amps of draw. Maybe slightly higher. In an ambient temperature environment of 75 degrees, it will run about 30% of the time. On the Eco setting that is about 2.4 amps, so divided that in 3rds and you will get your hourly consumption. I would bet on 20 to 25 amp hours / 24 hour period. I just installed mine on my sailboat last week. I am using a 100 watt flexible solar panel and my batteries are topped off after just three hours of sunlight in the morning. My panel can produce about 5 and 1/2 amps"

20-25 amp-hours per 24 hour period means 10-12.5 Ah overnight, with the panels slowly ramping up to substantial output as the morning progresses, and which his batteries should be able to provide with room to spare assuming a full charge at the end of the day. Assuming also no shore power.
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Re: use of "plug and play" solar for temporary use

Post by 1st Sail »

Herschel, Once again we seem to be on parallel paths. I started researching the DC fridge/ LI battery/solar/genset back in '18 as we intended to start our tour of US lakes and reservoirs. Wife's health issues side lined that project for '19. In any event she is recovering well so I am looking at the time and $ assembling a solar, LI bat system just to run a fridge and charge laptops, phone, and cameras I turned my attention toward the all in on solutions.

I just replaced my old batteries (agm) with two Optima agm deep cycles 55Ah which is over kill for day sailing out of the marina. However, we are again looking at solutions. Essentially 500-1000watt hour units run $1whr +/-. For $1wh you have no install, charge controller, discharge monitor, SOC (state of charge monitor),charge via 12v under power, or AC, solar, pure sign wave 110vac for electronics, portable, and half the weight of LA or AGM. Maybe not a bad option for something the size of a small suitcase.

One thing I do struggle with is whether the mfg. specs are accurate with regard to Whr ratings. Found this quick conversion online: https://convert-formula.com/ah-wh.

For fridges seems like Edgestar, Dometic, Engle, and ARB are worth review. Looks like $1k +/- gets you 50qt +/-. Now it time to calc what I need for power and make some decisions.
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Re: use of "plug and play" solar for temporary use

Post by BOAT »

Just a note on reefers.

Dometic, edgstar Engle, arb and on and on - NONE of them make the compressor. There is one manufacturer overseas that makes the compressor for all of them. So, your getting the same compressor no matter what unit you get. So, what is the difference that makes an Engle out perform the Dometic?

It's the insulation, the construction, then ventilation (the compressor gives off a lot of heat and that heat ends up back in the reefer if not vented right). So installation is a big part of it too. I was unable to buy my reefer direct from the mfg because they required special installation so I had to import it through a licenced Mercedes upfitter.

With the proper ventilation the unit uses very little energy - if the unit is NOT installed so the sealed vent goes up and over the top the unit works horribly. Same with the Engle - it has a huge empty section on one side just for eliminating the warm air from the compressor - that one feature makes the Engle almost two times more efficient than the Coleman yet they use the same compressor!!

The big breakthrough for the compressor manufacture was when he figured out how to make a two speed compressor. That one is the best to date.
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Re: use of "plug and play" solar for temporary use

Post by Herschel »

Based on my anonymous benefactor's data:
"I would bet on 20 to 25 amp hours / 24 hour period. I just installed mine on my sailboat last week. I am using a 100 watt flexible solar panel and my batteries are topped off after just three hours of sunlight in the morning. My panel can produce about 5 and 1/2 amps"

and the formula calculator, absent shore power, I would need to 'generate' 300 whr's (25 ampsX12 volts) with my engine alternator each day to be assured of enough power to run this frig from my battery bank before my power needs for the rest of the boat are impacted. If I go the power station route, I need to get 300 whr's from my solar array to the power station to run the frig for 24 hours. Am I getting credit toward my MS in engineering somewhere? :) or do i need to head for the dunce corner? :cry:
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Re: use of "plug and play" solar for temporary use

Post by Tomfoolery »

Herschel wrote: Fri Jul 17, 2020 1:21 pm Based on my anonymous benefactor's data:
"I would bet on 20 to 25 amp hours / 24 hour period. I just installed mine on my sailboat last week. I am using a 100 watt flexible solar panel and my batteries are topped off after just three hours of sunlight in the morning. My panel can produce about 5 and 1/2 amps"

and the formula calculator, absent shore power, I would need to 'generate' 300 whr's (25 ampsX12 volts) with my engine alternator each day to be assured of enough power to run this frig from my battery bank before my power needs for the rest of the boat are impacted. If I go the power station route, I need to get 300 whr's from my solar array to the power station to run the frig for 24 hours. Am I getting credit toward my MS in engineering somewhere? :) or do i need to head for the dunce corner? :cry:
You decide, but it's 25Ah x 12V = 300Wh (watch your units). Or more like 340Wh, since the charging voltage is something like 13.5V, and more still since there are losses every step of the way. Your OB puts out something around 15A (based on the current 50 hp offering), but that's presumably at high engine speed. So call it 7A at trolling speeds, for around 3.5h of engine operation.

Unless you add a solar panel to the mix, which will put out almost as much power on a good day, thereby relieving you of the need to run the OB so much, or at all for that matter.

And that's why BOAT suggested more battery, to give you some breathing space. :wink:
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Re: use of "plug and play" solar for temporary use

Post by BOAT »

And that's why BOAT suggested more battery, to give you some breathing space. :wink:

.
Well, because he is using GEL batteries I am VERY concerned because if he drains that GEL battery down to 50% it's ruined forever. Those GEL batteries are like 400 bucks a pop and you don't want to burn up one every year or you just lose all the money that could have been used for a Lithium battery that will drain to zero over and over and over again without damage.

If your going to cut it so close on your battery capacity I strongly recommend you dump the GEL batteries because they will be nothing but lead sinkers in 5 months if you drain them every night.
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Re: use of "plug and play" solar for temporary use

Post by Herschel »

BOAT wrote: Fri Jul 17, 2020 2:32 pm
And that's why BOAT suggested more battery, to give you some breathing space. :wink:

.
Well, because he is using GEL batteries I am VERY concerned because if he drains that GEL battery down to 50% it's ruined forever. Those GEL batteries are like 400 bucks a pop and you don't want to burn up one every year or you just lose all the money that could have been used for a Lithium battery that will drain to zero over and over and over again without damage.

If your going to cut it so close on your battery capacity I strongly recommend you dump the GEL batteries because they will be nothing but lead sinkers in 5 months if you drain them every night.
Well, then, based on Boat's analysis, since I have a set of four year-old Optima's that are doing fine at this point, I might be better served to just have the separate "plug and play" solar plus power station to run my frig. I think I calculated that cost at about $1,200 for everything including the frig. OR invest in new Li batteries (I'll need new batteries in a year or two most likely) and just get the solar array to attach to them when needed. I did see a YouTube sailing couple who bought a less expensive deep cycle battery bank that appeared to be a something between an AGM and a Li on both in performance and cost. I'll try to research the name and get back to you guys. Ouch, looked at the cost of Li batteries: just under $1K each. So, that would be $2K plus the solar and associated gadgets. :cry: So, for a sailor with a modest sailing budget and two working AGM batteries with a planned trip mostly motoring with marina stops each night, I think I will try experimenting in advance with just the frig at first and see how the system handles the added power needs. Just $250 initially. I think the biggest challenge is knowing pretty well the state of charge of your battery bank. My only measure of that is my digital meter that I plug in to the cigarette lighter style 12-volt receptacle. https://www.ebay.com/i/153449441711?chn ... 2eca6a02f6 It reads the voltage coming from the battery, but you have to estimate the percentage of discharge from the numbers between 12.85 and 12.40-ish,which is not very precise. Anybody got a better way to monitor the state of charge of our deep cycle batteries? Sorry for the rambling thoughts, but my mind is swinging back and forth, well, like a Mac in heavy seas on a beam reach. :?
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Re: use of "plug and play" solar for temporary use

Post by Herschel »

It was Firefly Oasis batteries. They advertise discharge capability to 80% or more without damage. https://oceanplanetenergy.com/advanced- ... -group-31/
and they are about half the coast of Li batteries.
Boat, Tom, others? Any thoughts about these puppies? I know, I am taking my own thread off on somewhat of a tangent, but that seems to be easy to do when you start playing around with our electrical systems. There just seems to be an infinite number of ways to rig up power for the boat. :P
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Re: use of "plug and play" solar for temporary use

Post by Jimmyt »

Herschel wrote: Sat Jul 18, 2020 7:38 pm I know, I am taking my own thread off on somewhat of a tangent, but that seems to be easy to do when you start playing around with our electrical systems. There just seems to be an infinite number of ways to rig up power for the boat. :P
I find this very interesting and informative. It seems to be staying on point better than most, actually. :D
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Re: use of "plug and play" solar for temporary use

Post by Tomfoolery »

Jimmyt wrote: Sun Jul 19, 2020 5:36 am
Herschel wrote: Sat Jul 18, 2020 7:38 pm I know, I am taking my own thread off on somewhat of a tangent, but that seems to be easy to do when you start playing around with our electrical systems. There just seems to be an infinite number of ways to rig up power for the boat. :P
I find this very interesting and informative. It seems to be staying on point better than most, actually. :D
Maybe that’s because I haven’t posted in a couple of days. Oops - just drove it off the rails in one post. See what I mean? :wink:

I do agree that Herschel should get the cooler first, and see what it takes to run. He mentioned in his last post that his travel will involve mainly motoring, which makes a big difference. While only 15A or thereabouts, even half power output should provide all the juice they need to keep the fridge running along with some electronics. Shore power at night brings it back to 100% in case the OB doesn’t keep up. That reduces the need for a large battery bank.

And they can always turn the fridge off for an hour or two at a time, or set the thermostat warmer, if battery capacity becomes a problem. Or add a solar panel. Or add another battery. And so on.
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Re: use of "plug and play" solar for temporary use

Post by Tomfoolery »

Herschel wrote: Sat Jul 18, 2020 7:38 pm It was Firefly Oasis batteries. They advertise discharge capability to 80% or more without damage. https://oceanplanetenergy.com/advanced- ... -group-31/
and they are about half the coast of Li batteries.
Boat, Tom, others? Any thoughts about these puppies?
I’m afraid I don’t know anything about them, but before investing real coin into a new chemistry, be sure your system can charge them properly. I’m not clear even on what setting to use on a charger, which are usually limited to sealed, flooded, gel, and LiFePO4.
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Re: use of "plug and play" solar for temporary use

Post by Be Free »

Estimating SOC from battery voltage on a battery that is in use can be very inaccurate. It is better than doing nothing, but when the battery is discharging it will tend to give you a value that would indicate that the battery is more discharged than it actually is (not necessarily a bad thing) and when it is charging it will overestimate the SOC which can cause you to keep your battery undercharged over a long period of time (which is almost always a bad thing). This is mostly applicable to lead acid batteries but is still mostly true for AGM batteries as well.

I've been using this for about a year to monitor my battery bank. It seems to be pretty accurate on the voltage and amperage measurements. Counting amp hours in and out is a subject all to itself, but if you program it to the rated (or measured) 20 hour value for your bank and you don't go over that rate, it will give you a value that is somewhere between "accurate" and "pessimistic" for the percentage of your bank's capacity that you have used.

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