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Rainwatcher
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Discussion Starter #1
Time to play hypothetical questions.

Let's say I have a boat. What boat isn't important. Let's say it has radar. Let's say there's a race called, say, Swiftsure. Let's say this race usually lasts a long day and two nights. Let's say it can go longer.

Now let's say I want to run radar for the entire race. The reasons I want to do so are my own, and aren't the question here.

First, is that doable? If it is, what will it take? Radar is an enormous drain on batteries, I'm aware of this. So okay, we shut off the reefer, we don't use hair dryers during Swiftsure and we observe some semblance of battery discipline during the race.

So begin. Is there a radar small enough, a battery large enough or a charging system capable of keeping up with a radar running all night?
 

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Master Mariner
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A radar uses very little juice on 'standby'. Once it is powered up and adjusted to the range you want, you can just put it on standby and power it up when you need/want it. This can be on a schedule where if the screen was clear, another vessel or danger could be 1, 5, 15 or 20 miles away, or every so many minutes, or any variation thereof.
Most radars take less than a minute to go from standby to full operation, as there is no warm-up time necessary. You could actually have your cold beer and your radar, too!
That's how we run ours unless we are using it for real-time navigation. It is just too distracting to have running all the time. We prefer the chartplotter page full time.
 

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Barquito
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Presumably you could put in as many batteries and solar panels on board as you need to keep the radar running non-stop... and run the vacuum cleaner while your margarita mixes in the blender.
 

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Does this race not permit you to run your engine in neutral to charge batteries. While you can't charge well at idle, even at ~1500 rpm, it's pretty fuel efficient and the alternator would probably keep up with everything aboard and then some.

At night, I like to run the radar overlay on the chartplotter chart screen. Especially, when viz is down. I've crossed the Gulf of Maine when I could see nav lights departing Europe. This past summer, we had vessels cross within a mile that we never saw. When on the Maine coast, we had one at 1/10th mile that we could hear, like we were standing aboard, and never saw it. Had to be a lobster boat doing 15 kts, we were under sail. We tried to avoid, but it kept turning randomly. Our best best was to standon and hope they saw us too. I'm sure they did. When we got close, their course changed to pass port to port. But close...... my wife and I were both on watch and at the ready.
 

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If its a race then the weight of the extra batteries could become an issue so I would be inclined to go with a larger alternator on the inboard if possible with more frequent runs for charging or a light weight Inverter Generator along with Solar Panels to keep up with the load on the existing batteries.
 

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Not enough information on battery capacity or charging ability.

Radar and its display uses 2-3A in full operating mode. Let's say 3A. This will use 72Ah/day, 108Ah for the 36hrs you note, or 216Ah over 3 days assumed maximum time. Pretty moderate power consumption, actually.

This is running full-time, which doesn't seem necessary, but you asked for that. It is also at full-rated spec, which I find conservative - actual use is generally less.

So with modest battery capacity or recharging ability, it is easily done.

Mark
 

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Measure your power consumption with all electronics active. Do the maths ?A*h=Ah.

You can increase battery capacity by replacing your lead batteries with LiFePo4 batteries, more usable capacity and less weight.
AGM 1.5 Ah/kg
LiFePo4 7 Ah/kg
 

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The Li thing has been beaten into the ground. Noteworthy is many if not most cruisers have not converted to Li. You may want to look at morgancloud for a discussion.
Currently have lifeline agms. 1025 ah. When they go will replace with firefly. Have several of my friends who have done so with good results and much less expense. No need to rework and buy new devices for my electrical system. No fear of over charging and fire or explosion. More than adequate weight to usable ah ratio.
At present on passage turn the radar off and on. Not to standby. Do sweeps every two to four hours depending on situation. If in shipping lane leave on standby but watch AIS and sweep if anything on AIS or every hour. If in fishing grounds (e.g. off PR) will leave on at night or low visibility.
Radar use depends on commonsense. If there’s risk of collision turn it on. If not then not.
Remain surprised how often you see something well before it shows up as a target (if at all) particularly at night.
 

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Since the OP was specifically asking about a race, I assume the radar would be used full-time for tactical reasons. Weight would also be an issue, but it wouldn't make sense to spend on LFP batteries for a single race. Otherwise, installing LFP batteries is probably the best decision we have made, and best piece of gear added, to our cruising boat and lifestyle. Simply a game-changer on so many levels. Lots of bad information and practices out there, and fire/explosion myth is at the top. Overcharging them will likely ruin them, as it will gel and agm lead batteries, but easily avoided with normal charging practices like used with gel and agm. However, undercharging them is of no consequence at all, while it will quickly make slag out of gel, agm, and flooded lead batteries. Undercharging is probably happening on 80% of all boats equipped with lead out there, while overcharging is so rare as to make news when it does happen.

Morganscloud should not be used as a definitive source of information for anything. So much of that is uninformed, misinformed, or outdated opinion. Much is good too, but one should definitely exercise caution and seek corroboration of their opinions. As for choices most cruising boats are making wrt batteries, there is unfortunately a wave of conversion to LFP going on right now. To the extent that there are long wait times for supply. I say unfortunately because there is a lot of fly-by-night and snake oil sales popping up now, and many consumers refuse to educate themselves. Frankly, I'd be happy if everyone else stuck with lead.

Mark
 

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My next house battery upgrade will be LiFePO. This newer technology does not explode, like older Lio batts could. The newer technology is not affected by water, like original Lithium batts. In fact, you can explode any lead acid battery, via rare overcharge or short faults, so I don't see this as a difference.

LiFePO are lighter, contain more Ahr capacity (per equiv size lead acid) and you can run them down to 20% of capacity, as opposed to the 50% floor on lead acid.

They also charge in a fraction of the time, significantly reducing generator time. They are also much less effected by partial charging.

Effectively, you get 2 times the useful capacity in the same footprint. The only downside I see is that they currently cost 3 times as much to buy. I expect that will compress. Of course, you'll need charging sources that have settings for this battery type. Mine does.
 

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Cost is a slippery issue. For example, our equivalent capacity LFP bank only cost 20% more than the last bank of Trojan T105 FLA's we had to buy in Panama. It is the same price as equivalent capacity Lifeline AGM's bought in the US. Over its expected lifetime, it will be the same price or cheaper than FLA's, and many times cheaper than AGM or Gels.

So if one is buying batteries outside the US, or plan to buy top quality AGM or Gel, and/or plan to keep them a long time, LFP is not a cost issue - it is even cheaper in some terms.

But then, they allow operating modes generally not available to LA. For example, we run our water heater and AC-powered watermaker off them. They never need to be fully charged, so our generator usage has plummeted, and we don't carry as much solar as we would need for LA. If we had a smaller air conditioner or larger LFP bank, we could run the AC off of them. Same with an induction cooktop, if that was a desire.

The basic fact that LFP does not ever need to be taken to full charge, and can run their entire lives at partial state of charge, is just a couple of points that Morganscloud misses in their opinions.

We are on our 3rd year with LFP, and they have only reached full charge a few times. In fact, when they do have the potential to reach full charge, we just turn on high draw equipment and make water or heat water, etc. As long as we have some power stored in them, we are good to go. During cloudy, rainy or short days, we often operate them in the 20-50% SOC range for days or weeks. Whatever weak solar can go into them during the day is generally enough to keep them operating.

This type of operation will kill any lead battery within a year.

Mark
 

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Might want to price things out. A 400Ah LFP bank is ~$2300. This is equivalent capacity to 660Ah LA. Down in the EC, Budget Marine is selling 660Ah of T105's for $1200, and 630Ah of Lifeline AGM for $2350.

These prices pretty much scale accordingly to larger/smaller capacity needs. So you wouldn't need to win a large lotto to afford them over Trojan T105's, and they aren't any more expensive than Lifeline AGM's for you.

BTW, that pricing for LFP came from cruising boats who recently installed LFP in the EC.

Mark
 

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Another thing to mention is the weight difference...its huge.
And less space required

If your batts need to get to full charge, you will be burning diesel when on the hook
 

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Our "hi def" 3G Broadband Lowrance radar uses very little power compared to our former (older) Furuno radar. Different technology.

What kind of radar technology does this hypothetical boat have?
 

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The Lowrance 3G broadband radome itself draws 18W (~1.5A), but needs a compatible display. The smallest 7" compatible Lowrance display consumes 1.3A in operation - for a total radar power consumption of 2.8A. Pretty much the same as a dedicated Furuno unit that I was using as an example above.

But the point is that a 3A draw is not as enormous as the OP might be assuming.

Mark
 

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Does this race not permit you to run your engine in neutral to charge batteries. While you can't charge well at idle, even at ~1500 rpm, it's pretty fuel efficient and the alternator would probably keep up with everything aboard and then some.

At night, I like to run the radar overlay on the chartplotter chart screen. Especially, when viz is down. I've crossed the Gulf of Maine when I could see nav lights departing Europe. This past summer, we had vessels cross within a mile that we never saw. When on the Maine coast, we had one at 1/10th mile that we could hear, like we were standing aboard, and never saw it. Had to be a lobster boat doing 15 kts, we were under sail. We tried to avoid, but it kept turning randomly. Our best best was to standon and hope they saw us too. I'm sure they did. When we got close, their course changed to pass port to port. But close...... my wife and I were both on watch and at the ready.
We had friends whose boat was hit in fog by a fisherman who simply wasn't looking. Took out about 10 feet of their rubrail and hull/deck joint, so you could see out of the quarter berth. He tried to turn tail, but our friends had noted the registration numbers on his bow, so he didn't get far.
 

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Here and respect your statements. Agree newer tech is safer. Disagree about current expense and need to be very careful as regards installation. They may be Li based(newer formulations in the pipelines maybe further game changers) or carbon. Hopefully will get a few more years out of current set. They are still at 80% +/- after 4 years but they do get back to 100% fairly frequently. Battery tech is being driven by the cars and improving rapidly. Expect to switch when they get to mid sixties. Still don’t know to what. Would like not to redo everything whereas the fireflies are a simple swap and it is less expensive.

Yup from what you say if you’re in a fog running radar seems wise. Commercial fish boats are scary to be near.
 

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I'm not exactly sure what you are saying, but batteries at 80% of original capacity will not go back to 100% occasionally. 80% of original capacity is considered end of life for batteries. I certainly wouldn't be waiting to mid-60% for a cruising boat unless you have a very large bank and small usage relative to it. Or don't rely on batteries and plan to always be close to a place that sells batteries.

Difficult to disagree on expense seeing how I related actual current experiences and published costs and not hypotheticals or guesses.

LFP is not exactly newer tech - it has been around for many years. There is no "safer" lithium now, because the current prismatic chemistries are the only ones that have ever been used in the marine industry - they were never "unsafe" in the past. There really isn't any "new formulations" in the pipelines - it is a pretty mature chemistry. There are always lots of academic and media hype around the next game-changer, but these are never right around the corner.

Let's assume that Firefly LA are comparable in usable capacity to LFP. The price of 400Ah firefly is $2000 - pretty much the same as LFP. But it will cost you 200lbs and 3x the space. It will also require more strict charging regimes - unlike LFP, they only handle partial states of charge for a short time, then need to be reconditioned at full charge.

Mark
 

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Rainwatcher
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Discussion Starter #20
The hypothetical boat does not yet exist. Or rather, it exists as a hull yet to be selected and purchased, with an electrical system and electronics suite to be designed. (Tear it all out, all of it, start over. Go wild. These systems almost certainly aren't going to be the major expenses.)

What is morganscloud?
 
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