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Old 08-09-2008, 16:51   #31
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Originally Posted by Pblais View Post
You wouldn't set your fuel gage to read 1/8th of a tank low would you? I can't see you being any smarter setting the gage to read incorrectly so you'll do the right thing at zero instead of 50%. Recharging at 50% is a desired goal but it does not mean you have to do it that way even if it is in your best interest to do so. It would be better to set the reading correctly in case you go below 50% for reasons you don't fully understand at the time it happens. You'll also notice the difference in the bank should problems occur.

There is no "correct" setting when it comes to discharge floor.

Fishspearit and I both prefer to see 50% as zero, as we absolutely never want to be below 50% and also would like more resolution from the bar graph display while above the 50% floor.

The Link 10 is not a set of idiot lights, and you can always see actual AH or KWH used by looking at the digital readout.

Discharge floor (see your manual for the Link 10) is a user configurable option meant to be set as the user desires. Calling that "incorrect" is akin to calling the color of someone's shirt incorrect.
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Old 08-09-2008, 18:15   #32
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I have to agree with Paul on this one. While I understand the reasoning, setting the floor %50 is not intutive.

My opinion of the Link 10 is "ok". When I first installed mine, it worked fine. Then I expanded my battery bank. I followed the instructions to program the Ah capacity for the Link 10. For the life of me I could not do it following the simple steps. After numerous calls to their support, it was finally determined that I had a very old version chip in the device. The thing was supposed to be new when I bought it. And I was following the instructions supplied with the unit.

Thumbs up I guess for their support department, but quality control seems to be lacking. And in my installation it was a PITA to add/remove the unit for diagnosis.
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Old 08-09-2008, 18:56   #33
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Quote:
There is no "correct" setting when it comes to discharge floor.
I will agree only to the extent that the designers inteded you to enter the true readings. There can be no assuption that it works the same if you do not. So why not set the battery bank properties to what they really are? Seems more logical. Setting things to what they are ensures you will understand the readings in the same context. The monitor is more than a full ... empty gage. There are subtle things that effect the display including setting the exponent and the bank size. Discharging the bank below 50% will really throw you for a loop when you see it given it has twice as much power as you told it. Why bother to trick the display into asuming you are too stupid to know when to recharge? It begs the question. It does not care when you choose to recharge so why make it display a value that is incorrect?
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Old 08-09-2008, 21:29   #34
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I have a Link2000, and maybe it works differently, but I also have my house bank set with a 50% discharge floor. As far as I can tell, this has no negative side affects with respect to charging, it simply scales the time-remaining display.

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When this option is activated, you may set a discharge floor for each battery bank. When the discharge floor is set to 50%, the Time Remaining display reports time remaining until the battery reaches the 50% discharged level.
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Old 08-09-2008, 21:31   #35
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I have a Link2000, and maybe it works differently, but I also have my house bank set with a 50% discharge floor. As far as I can tell, this has no negative side affects with respect to charging, it simply scales the time-remaining display.
The link 2000 will monitor two banks, is that right?
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Old 09-09-2008, 05:10   #36
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Paul, you are confusing the AH setting of the meter with the "discharge floor" setting. They are two very different functions. Check the manual. It does indeed work correctly if you set the discharge floor to 50% of capacity. Battery bank capacity is set through a different function and not related to discharge floor settings.



Quote:
Originally Posted by Pblais View Post
I will agree only to the extent that the designers inteded you to enter the true readings. There can be no assuption that it works the same if you do not. So why not set the battery bank properties to what they really are? Seems more logical. Setting things to what they are ensures you will understand the readings in the same context. The monitor is more than a full ... empty gage. There are subtle things that effect the display including setting the exponent and the bank size. Discharging the bank below 50% will really throw you for a loop when you see it given it has twice as much power as you told it. Why bother to trick the display into asuming you are too stupid to know when to recharge? It begs the question. It does not care when you choose to recharge so why make it display a value that is incorrect?
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Old 09-09-2008, 05:20   #37
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Very good device! It gives me exactly what to charge and when to do it! The best buy last year for the yacht! We charge two banks of 800 AMPS through two Xantrex chargers of 40 amps each. Going through the shunt it shows perfectly on how much we charge, sometimes as they are connected in line up to 80 amps.
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Old 14-09-2008, 09:50   #38
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Ok, I set the discharge floor to 50%, it was F9 in the advanced settings. I understand what you are saying Paul, my first thought of changing the amp-hour capacity would have messed up it's calculations. Changing the floor setting has been great, because now the time function is usable, it tells me how long I have at the current discharge rate until I need to charge, rather than how long I have until 10.5V

So, any other usefull adjustments people have made to their link that I should consider?
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Old 14-09-2008, 22:31   #39
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The link 2000 will monitor two banks, is that right?
Yes, it does...
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Old 14-09-2008, 22:55   #40
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Is there a known noise sensitivity in the Link 10, Rick? Mine frequently forgets its settings - the true 640 AH capacity gets reset to 200, as well as other defaults. I've gotten fairly adept at mentally integrating across these events, but it would be nice to fix the problem. I'm in my first 500 miles with a new (to me) boat, and part of the, um, fun, is uncovering glitches and finding all those things that weren't apparent in the glow of nautical dementia.

The reset-to-default events are not predictable, but typically are associated with significant events like generator runs. It is currently working with a Prosine 2.0, but that is on the verge of being replaced by an Outback FX2012 when I return from this shakedown cruise. I do not see any obvious cabling intermittencies.

Thanks and cheers,
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Old 12-08-2009, 13:53   #41
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I have just installed a link 1000 to my house bank. All current is flowing through the the shunt as the manuel indicates. It appears to be working correctly, showing proper battery voltage etc. However, the amps are showing a neg 6.0, I turned on some equipent and the number went to a neg 3. Is that not showing an amps going in not out? My only means of charging is my 5-65 watt solar panels, but does not seem to show that. I know they are charging to capacity, it has been operational for a couple of years. Did I hook somthing up wrong, did I even provide enough information to answer my question. Any help would be apprecitated.
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Old 12-08-2009, 14:13   #42
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Hi... at first glance, it sounds like the shunt sense wires are swapped. Voltage would still show correctly, since that is connected to the + battery post.

Cheers,
Steve
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Old 12-08-2009, 14:38   #43
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"BUT...I am having what appears to be a problem. I think I am getting negative amps hours accumulating..."
Ahhh.... I see you've gone from "really cool device" to reality... I have tried 3 different ones in the last 15 (?) years. They all created more work then they solved. My currunt one is very effective though... I just use the voltmeter reading!
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Old 12-08-2009, 16:11   #44
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Break out the slings and arrows you battery monitor lovers. Here, again, is another view.
  • I don't like 'em.
  • I don't believe they can be REALLY REALLY accurate over time.
  • I believe they spawn false feelings of knowing the real state of charge.
  • I believe that they represent an unnecessary complication and expense.
  • I believe that a calibrated digital voltmeter -- properly used and interpreted -- will pretty accurately guage the state-of-charge (SOC).
  • I believe there are a lot of folks, including techies, who'll disagree with the above.
Battery monitors are supposed to act like an automatic calculator of your bank balance. With money, that's pretty easy. Take out $50, put back $50. Easy to measure and monitor and report.

It's not so easy with energy transfers between your boat's equipment and your batteries, however. It's not a 1:1 equation, not by a long shot.

First, there's Peukert's Equation. I believe all modern battery monitors attempt to incorporate Peukert's factor in their calculations, adjusting the numbers depending on the rate of discharge and charge.

Next, there are sometimes loads which don't go thru the shunt, and are therefore not seen or counted. Among these could be SSBs, pumps, etc. wired directly to the batteries.

Perhaps the greatest problem is that of unseen and uncalculated losses, i.e., those occuring as a function of the battery chemistry itself. Sandia National Labs has done an excellent job of highlighting some of these, noting that charge efficiency varies greatly depending on state of charge. Getting from, e.g., 20% SOC to 60% SOC is pretty efficient...well over 90%. However, as the battery SOC begins to approach higher levels, like 80-85%, efficiency drops dramatically, often to less than 50%.

This means that if your battery system is operating in the 80-90% SOC range, it's going to take about twice the power fed to the batteries as they will actually absorb.

Another complicating factor is the rate of charge. Charging efficiency is actually higher with lower rates of charge than it is at higher rates of charge. However, on a cruising boat due to time and other constraints one wishes to charge the house bank as fast as possible, using a high rate of charge (even though more supplied power is wasted this way).

Got all this in your head?

It's enough to make you crazy! And we haven't even spoken of the other variables which can affect energy transfers and storage.

Now, take the lowly digital voltmeter.

IF you let your batteries sit awhile after charging with little or no load on them; and

IF you measure voltage at the batteries with a calibrated digital voltmeter;

THEN you will have a pretty good idea of the SOC of the batteries.

For flooded lead acid batteries:
12.6-12.7VDC is nearly full charge
12.4VDC is about 25% discharged
12.2VDC is about 50% discharged

What about loads you can't really turn off? Like the frig? Well, you'll get to know your boat over time. If a few hours after charging (with only the frig running @ 4-6A draw) you're now reading 12.55V, that tells you the batteries are pretty well up.

Yeah, it's approximate. But so, too, is the battery monitor. It just makes you THINK it's more precise.

Notice that nothing in the above has been said about battery capacity. The voltmeter won't tell you that. The battery could be fully charged, but having lost half it's capacity thru sulfation, stratification, contamination, etc.

Guess what? The battery monitor won't really tell you that, either! But if you know your boat and you pay attention, you'll be able to guage battery capacity pretty well over time. Hey....I used to be able to go for XXX hours without charging; now I can only go half that time!

Doesn't take a $200-500 device to tell you your batteries have lost a lot of capacity!

OK....let go the SLAMs :-)

Bill
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Old 12-08-2009, 16:22   #45
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Ahh... I knew it would start!

Dont worry Betrayfors, these Link Lovers are the same ones that believe a digital meter is more accurate... because it reads to more digits! Seriously, I can pay $400 to get frustrated other ways.... All in good humor though, if you love your Link and the Admiral will allow it in bed with you, It's OK with me....
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