Understanding my Battery Monitor

ksanders said:

That sounds like a good analysis based on your reading in depth the manual.

I never did that, so thanks much for the information.

I didn't realize that the units did that much calculating, and it wonder if my xantrex is as sophisticated.

Again, thanks for the information!

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I wonder too...and based on my experience ...limited as it is....the algorithm needs lots'a work.

psneeld said:

I wonder too...and based on my experience ...limited as it is....the algorithm needs lots'a work.

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While it's all very interesting, I don't really want my battery monitor to be as smart as possibly could be.

If the state of charge percentage is within a few percent or even 10%, I really don't care it just gives me a relative indication.

What is important, is the ammeter portion of the state of charge meter. That tells me if my charging system is working properly, it tells me what kinds of loads I'm applying to the battery bank.

ksanders said:

While it's all very interesting, I don't really want my battery monitor to be as smart as possibly could be.

If the state of charge percentage is within a few percent or even 10%, I really don't care it just gives me a relative indication.

What is important, is the ammeter portion of the state of charge meter. That tells me if my charging system is working properly, it tells me what kinds of loads I'm applying to the battery bank.

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I can see that but what the heck do you know about electrical supply and all...

hey ...a friend just bought a 49 Meridian (former rag bagger)...and I have mentioned your existence and travels.

More than once and have told him there is very good info out there on the web to be had...hope you don't mind if I turn him on to all your posts resulting in you may have a new source of questions if you don't mind....

ksanders said:

While it's all very interesting, I don't really want my battery monitor to be as smart as possibly could be.

If the state of charge percentage is within a few percent or even 10%, I really don't care it just gives me a relative indication.

What is important, is the ammeter portion of the state of charge meter. That tells me if my charging system is working properly, it tells me what kinds of loads I'm applying to the battery bank.

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I too, really just look at the current and what has come out of or into the batteries. the % I pretty much ignore, as well as TTG.

Now, i do record the voltage (see comments above) and the CE which is what I truly watch. Once it a while I have suspected that the CE is off, but it usually corrects itself before it becomes an issue.

I guess the short way of putting it is that a good monitor simply logs all the factors an adept "manual" user would and makes the right calculations. Like anYthing else, if you don' allow it to work correctly (such as bringing the batteries to full charge every now and then), it's the old saw of "garbage in, garbage out".

We lived full time, for months at a time, on moorings, with journeys in between the length of the east coast that mostly involved anchoring or mooring. The Hatteras, as we inherited from POs, was a relatively AC intensive, energy inefficient and hungry boat. So managing the inverter batteries was a critical function for us. Like most things, if something is really important to you, you pay more attention to detail and learn a little more about it. Apparent from the responses here, that is not the case with most posters, so the casual or marina-centric boater can certainly dial things back a bit, focus-wise.

Tim: it is best to re-set your Victron monitor at the dock and after being on shorepower charging for 3-4 days. That way you know your House bank is fully charged and in Float mode. Also...don't program it for 420Ah capacity when your batts are 4 years old. I'm not sure of the annual depletion rate for AGMs (you will find it on the net somewhere) but if just 5%pa at end 4 years IF you have done everything else right (not drawing below 50%, etc etc) you have only 342Ah there. It is best to program in a conservative view of your bank's total capacity to keep you well away from the minimum discharge levels. I have flooded golf cart batts, not AGM's, and I make it a practice to never go below 60% before recharging and I decrease the capacity programmed into my SOC meter (a MasterVolt...v similar) by 5%pa. I get 10-11 years out of my House bank, which I put down to this practice AND use of smart regulators.

I've got some more research to do but the problem may be the unit hasn't figured out the batteries are not new and will not hold the 420 ah I told it. But it should know if voltage is below 11 volts for some time the bank is probably less than 80% SOC!

I'll call Victron and find out.

Tim

Maybe I missed it, - Do you have separate starting and house banks?

sunchaser said:

Tim

Maybe I missed it, - Do you have separate starting and house banks?

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Yes, 4 house batteries, each 105 ah connected to the battery selector switch, switch position 2.
One engine start battery on a separate bank, 105 ah also connected to the battery switch, switch position 1.
One genny start battery isolated and not connect to the battery selector switch, 95 ah.
All AGM.

Aquabelle said:

Tim: it is best to re-set your Victron monitor at the dock and after being on shorepower charging for 3-4 days. That way you know your House bank is fully charged and in Float mode. Also...don't program it for 420Ah capacity when your batts are 4 years old. I'm not sure of the annual depletion rate for AGMs (you will find it on the net somewhere) but if just 5%pa at end 4 years IF you have done everything else right (not drawing below 50%, etc etc) you have only 342Ah there. It is best to program in a conservative view of your bank's total capacity to keep you well away from the minimum discharge levels. I have flooded golf cart batts, not AGM's, and I make it a practice to never go below 60% before recharging and I decrease the capacity programmed into my SOC meter (a MasterVolt...v similar) by 5%pa. I get 10-11 years out of my House bank, which I put down to this practice AND use of smart regulators.

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ditto

Aquabelle is right on.

This is exactly what you must do to initialize your victron. Batteries must be fully, fully charged.
I have 980 rated amp hours, but put only 800 into victron since they are 4 years old.

And now that I think of it, I think I too, this morning will reset my victron since I have been under shore power for a week.

When I installed my Victron 602 I equalized the batteries. When the equalize cycle was over I reset the monitor.

fryedaze said:

When I installed my Victron 602 I equalized the batteries. When the equalize cycle was over I reset the monitor.

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He's got AGMs, don't equalize those. I think we (mostly me?) have probably confused him more than helped at this point. Hopefully Victron tech support will
clear things up. My guess at this point is that the battery bank is bad. If t were me, I'd pull them and have them tested by someplace with right equipment and know how. A monitor will tell you this, but only after it has had time to accurately determine charge efficiency. Even in his current situation, Tim's monitor is kind of telling him this via the amps out vs voltage reading. But there is uncertainty for all the reasons we have pounded to death.

Inputting a lower amp hour figure by "guessing" based on age pretty much renders the monitor useless, you'll just know amp hours out and voltage.
Does the Victron require a manual "reset" ? My Magnum does it automatically after every full charge as noted in a previous post.

>Based on the monitors historical data like Al, I'm using roughly 150 amps per day. That's 5 hrs genny run time and why I ordered a 100 amp charger.<

Down 150A no 30A batt charger will charge the set in 5 hours , 10+ is more likely.

Most 30A chargers can not pump 30A at 14+ volts ,on a noisemaker , few will do it even at the power pole.

Most cruisers can not wait for batts to be FULLY charged , so many cycle between 50% and 85% , unless on the move with long engine alt hours.

This (not full charged) damages the batts , even with the help of a de-sulphation unit ..

You need to evaluate of why it takes 150A a day to operate , and how you will restore the batt set when operating.

The 100A batt charger will help IF its a quality unit that can actually put out 100A on a noisemaker .

caltexflanc said:

I guess the short way of putting it is that a good monitor simply logs all the factors an adept "manual" user would and makes the right calculations. Like anYthing else, if you don' allow it to work correctly (such as bringing the batteries to full charge every now and then), it's the old saw of "garbage in, garbage out".

We lived full time, for months at a time, on moorings, with journeys in between the length of the east coast that mostly involved anchoring or mooring. The Hatteras, as we inherited from POs, was a relatively AC intensive, energy inefficient and hungry boat. So managing the inverter batteries was a critical function for us. Like most things, if something is really important to you, you pay more attention to detail and learn a little more about it. Apparent from the responses here, that is not the case with most posters, so the casual or marina-centric boater can certainly dial things back a bit, focus-wise.

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Also, TImjet, it is still not clear to me if you took your voltage reading on rested batteries?

FF, the battery charger is a Charles 100 amp unit, most consider it a quality unit.
My current 30 amp is also a Charles and was putting out about 23 amps when the batteries were below 11 volts.

Richard; initially the battery monitor was calibrated when the batteries were as fully charged as they were capable of being, ie they had been on the charger at the dock for a week or two. During out cruise last week, after we left the dock, and were at anchor the next several days the batteries never were fully charged.

I have not had a chance to call Victron but will this week. I am going to have the batteries tested, but not sure were to have that done. I need experts in AGM batteries.

I am thinking the house bank will not hold near the 420 ah I calibrated the monitor at, but how am I to know what value to tell the monitor?

Still when voltage is below 11 volts and has been for a couple of hours you would think the monitor would not tell me the SOC was 80% regardless of the battery bank capacity.

Wxx3 said:

Also, TImjet, it is still not clear to me if you took your voltage reading on rested batteries?

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Actually come to think of it, if you mean rested batteries by batteries that have had no charge or discharge for at least 2 hours, then no.

timjet said:

Actually come to think of it, if you mean rested batteries by batteries that have had no charge or discharge for at least 2 hours, then no.

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Loads disconnected too (undo a battery cable) as an inverter, tv, stereo, smoke alarms, microwave clock, gfci, etc still draw unseen amps. Also, have you used a VOM to check that the disconnected battery readings agree with the Victron when reconnection occurs?

Ok, I did a little research and Decca recommends after fully charging the batteries, disconnecting them from any load or charge for 24 hrs before taking a voltage reading.

The following chart is from their web site:

[FONT=&quot]% Charge AGM[/FONT]
[FONT=&quot]100 12.80 or higher[/FONT]
[FONT=&quot]75 12.60[/FONT]
[FONT=&quot]50 12.30[/FONT]
[FONT=&quot]25 12.00[/FONT]
[FONT=&quot]0 11.80[/FONT]

[FONT=&quot][/FONT]
[FONT=&quot]Before doing anything else I'm going to check voltage after 24 hrs no load/no charge.
[/FONT]

timjet said:

I am thinking the house bank will not hold near the 420 ah I calibrated the monitor at, but how am I to know what value to tell the monitor?

.

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Tim: if you call the maker of your batteries, they will tell you what annual % reduction in capacity your batteries will suffer IF well-maintained. Victron itself says, for AGM batteries used in shallow-cycling/float mode (ie not discharged below 50% and promptly re-charged to 80% and occassionally back on shorepower with AGM-appropriate charging profile), that AGM's have the following service life:

at 20C (68F): 8 years

at 25C (77F): 6 years

at 30C (86F): 4 years.

Consistent with the above, Victron says service life halves for every 10C rise in ambient battery temperature. (Good reason to keep batts out of engine room if possible.)

Battery service life is measured in charge discharge cycles to the lowest voltage.

It also expects an instant recharge to 100% , something few if any cruisers do.

De sulphators are used by many folks in an attempt to extend the years before replacement.

timjet said:

Ok, I did a little research and Decca recommends after fully charging the batteries, disconnecting them from any load or charge for 24 hrs before taking a voltage reading.

The following chart is from their web site:

[FONT=&quot]% Charge AGM[/FONT]
[FONT=&quot]100 12.80 or higher[/FONT]
[FONT=&quot]75 12.60[/FONT]
[FONT=&quot]50 12.30[/FONT]
[FONT=&quot]25 12.00[/FONT]
[FONT=&quot]0 11.80[/FONT]

[FONT=&quot][/FONT]
[FONT=&quot]Before doing anything else I'm going to check voltage after 24 hrs no load/no charge.
[/FONT]

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Thanks for calling and posting that.

After a little (half assed) rest, my batteries usually show 12.85 volts.

SO, I feel good now

Here's a great new article on the Balmar Smart Gauge. It discusses the very issue of SOC meter inaccuracies associated with battery capacity degradation over time. The Balmar meter seems to overcome this and 'learns' the battery bank but, without a shunt, does not display AH consumed. IMO, having one of each meter may be the best of both worlds.

The article was interesting but only as advertising hype.

I suggest you send it to the numerous mfg of SOC meters for a learned response..

It is my belief that the charge and discharge cycles that are monitored over time CHANGE and reflect the batterys current SOC as it sits aged.

I believe this has been part of their value for decades .

The boating world needs a "Mr. Fusion" reactor.
All that saltwater and minerals, but we can't draw 13 volts DC out of an ocean of it. We have to get creative here.
Don't worry fellows, I got this..

FF said:

It is my belief that the charge and discharge cycles that are monitored over time CHANGE and reflect the batterys current SOC as it sits aged.

I believe this has been part of their value for decades .

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That's your belief, but this gentleman's testing proved that to be not the case. You can believe his test results or disbelieve...your choice. Have you conducted tests to support your belief that current SOCs remain accurate as batteries age?

His position is that even as good as our current run-of-the-mill SOC meters are (and I love having an SOC meter), this Balmar Smart Gauge meter is much more accurate...to easily within 5% accuracy and often 1%.

Here's a link to his other boat project lessons/articles. All very informative.

Compass Marine "How To" Articles Photo Gallery by Compass Marine at pbase.com

FlyWright said:

His position is that even as good as our current run-of-the-mill SOC meters are (and I love having an SOC meter), this Balmar Smart Gauge meter is much more accurate...to easily within 5% accuracy and often 1%.

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Great!, Thanks Al, something more I have to tell the admiral I need!

>Have you conducted tests to support your belief that current SOCs remain accurate as batteries age?<

Nope , I just read Home Power for over 20 years and figure experts not selling a product will be less biased than sellers.

See any >anchor< test for similar results.

The SOC monitors how many amps , it actually takes to fill the battset , and how many actually come out and give a percentage of the difference between the two.

How it was set 5 years ago on installation is meaningless as it measures current reality.

Pun?

FlyWright said:

That's your belief, but this gentleman's testing proved that to be not the case. You can believe his test results or disbelieve...your choice. Have you conducted tests to support your belief that current SOCs remain accurate as batteries age?

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WOW. Flywright

His test consisted of him TELLING us about the test. No data, no details, no nuthin

It was an infomercial. After all his exensive three month study, he admits:


SO, this is his disclaimer, so when you buy it and it down't work, you can't sue his ass, since he told you he had no idea how it worked. magic maybe??

We have a better chance with the fusion idea

Guys, I look at it this way.

I see a battery as a fuel tank for electricity. The problem is that it has leaks and over time, it shrinks. If I put electricity in, I won't always be able to get the same amount of electricity out. How much can I get out at any given time before hitting empty/50%?? That's the $64,000 question. Much of it depends on my reduced capacity as the battery ages.

When I tell my SOC that the fuel tank is "X" big and that it's now full, it tracks the measured output in AH consumed to display the SOC%. When it receives a charge, it adds those measured AHs back into the 'tank'. Over time what it fails to notice is that the tank has shrunk a little since I told it how big it was and there are continuous, albeit very small, leaks of electricity (seen as voltage drops) as the battery sits in an uncharged state.

The accuracy of the SOC% is only as good as the information provided on battery bank capacity (AH). In my case, I have a 3 year old bank of GC batteries which I was told provided 660 AH of capacity when they were new. That capacity has degraded over the past 3 years, but I have no idea how much. I can, and probably should, reduce the entry for battery capacity on my SOC meter by about 10%, (600 AH) but it's just a wild ass guess on my part. How big is my electricity tank? TBH, I have no idea any longer.

It appears that this Balmar Smart Gauge can detect changes in 'tank' capacity and can observe minute drops in voltage that occur in all batteries left uncharged for a period of time. Both of these factors affect the accuracy of the SOC% that unless accurately computed and manually entered in the run-of-the-mill SOC meter, will go unnoticed and will cause SOC% inaccuracies.

If I just had the Balmar unit, I'd only have a partial picture of my electrical system. I'd know how full my electricity fuel tank is in %, but I wouldn't know my 'fuel consumption" in amps consumed in real time or AH consumed since full. Having all 3 pieces of information, I'd know my current burn rate which is helpful in conserving power. I'd have my AH burned since full and an accurate % of capacity. Using those last 2 pieces, I can compute my actual battery bank capacity in AH.

For example, let's say my SOC says I have consumed 175AH since I dropped anchor with no charging and I'm at 73.5% SOC. My Smart Gauge says I am sitting at 65%. Which do I believe? I'd believe the Smart Gauge and can compute that the battery bank capacity is actually at about 500 AH, indicating a decaying battery bank. Without BOTH meters, I could not compute that and would not as readily see the decay of my battery bank.

I suspect the next generation of these meters will incorporate both features and provide a direct readout of SOC%, current flow, AH consumed and actual battery capacity.

I suspect the next generation of these meters will incorporate both features and provide a direct readout of SOC%, current flow, AH consumed and actual battery capacity.

Click to expand...

.

Already exists.