Battery Monitor - Advice & Recommendations

[DDW]

Magnum actually lets you control the transition to Float (end of shore charging) based directly off the BM-measured bank acceptance rate trailing down to mfg spec'd endAmps.

Much better than having to re-calibrate Absorb Hold Time settings as weather / usage patterns change.

Maybe 4-8 such setups exist on the solar side, but I think now unique to Magnum for mains charging?

Apparently Victron eliminated its gear's ability to do that with recent firmware updates?

Not at all unique - every mains charger I have can do that. Magnum is actually one of the least configurable of the lot.

 

[dhays]

I installed a Smart Gauge to monitor the starter bank, and it is nice to see an accurate SoC. Problem is, when it says the battery is at 100%, one has to ask 100% of what? A diminished lead acid battery that now has 70% capacity will still show 100% with the SG. Yes, one can do a 20 hour test, but that is a pain. A coulomb counter like the Link 20 gives you the other half of the information needed, which is how many Ah were used to get to 60% SoC.

Exactly! The combination provides the information that I would want to know in a simple way that even I can understand.

 

[FF]

"Problem is, when it says the battery is at 100%, one has to ask 100% of what? A diminished lead acid battery that now has 70% capacity will still show 100% with the SG."

It doesn't matter , if you are cruising and spend time at anchor and only run the house down to 50% and recharge to 100% you are operating the house set in the best way to keep it alive. However strong it is.

When that 50% discharged comes too soon its time to examine your loads , your charging ability , and perhaps replace the house set.

 

[john61ct]

Could you explain #1? Are you saying the SOC meter controls the charger?

There are many such combined / coordinated / distributed systems, and exactly where the "decision-making" happens is up to the mfg, and doesn't really matter. There does not need to be a full-fledged BM involved either.

The key point is that the endCharge timing is not the normal ballpark guesstimate, but precisely timed based on the shunt reporting true amps acceptance at the bank, precisely conforming to the mfg spec

> 2. Who is reprogramming their SOC meter as weather or usage patterns change? Why would one need to do that?

Unless usage / input patterns are relatively consistent, the proximity of the Float transition to the endAmps condition can vary enormously.

Regular systems cannot know the actual bank acceptance, so when loads are much higher or inputs lower, the Absorb Hold Time may be set too low, or in fact voltage should be kept at Absorb permanently, as the bank is **never** getting to Full.

Conversely, when inputs are higher and / or usage lower, AHT may need to be reduced to prevent harmful overcharging.

Of course 99% of trawler users do not live for long periods off grid without ICE sources running, or are OK with just replacing their banks more frequently.

_____

Perhaps another member here knows of other mains charging systems that have this feature. I am only aware of Magnum, and Victrons kept at older firmware versions. Maybe Mastervolt?

No, I am not interested in when Victron eliminated that capability, but would like to know why, and would like to see it return.

> Many of your posts display a lack of basic understanding of electricity

I am happy to be corrected, enjoy the fact I am learning new things every day.

 

[john61ct]

"Problem is, when it says the battery is at 100%, one has to ask 100% of what? A diminished lead acid battery that now has 70% capacity will still show 100% with the SG."

It doesn't matter , if you are cruising and spend time at anchor and only run the house down to 50% and recharge to 100% you are operating the house set in the best way to keep it alive. However strong it is.

When that 50% discharged comes too soon its time to examine your loads , your charging ability , and perhaps replace the house set.

Yes, and reduced capacity (SoH) is not just the basis for EoL decisions.

Drawing 250AH may be only 50% DoD when new, but becomes over 70% nearing the end, accelerating the bank's demise, the #AH drawn before recharging needs to be reduced if 50% is the goal.

And when a very expensive bank is reaching that point in 3-5 years rather than 7-10, it is worth considering improving the setup, or perhaps buying cheaper batts.

 

[john61ct]

Not at all unique - every mains charger I have can do that. Magnum is actually one of the least configurable of the lot.

Sigh, just not at all true.

99.999% of charge sources only know their own amps output.

Loads may be "diverting" most of that, or even depleting the bank while the charge source is running.

There may be multiple sources running concurrently.

The only way to know amps actually being accepted is a shunt installed right at the bank with all inputs routed through it.

I am in no way stating the endAmps capability being discussed should be the only, or even a major reason to choose a charger.

Obviously to user-customise profile settings, as well as use that feature, require the appropriate base model, suitable remote control and BMK add-ons.

 

[FF]

"Drawing 250AH may be only 50% DoD when new, but becomes over 70% nearing the end,"

Just so, the point is 50% discharged would simply be reached sooner, perhaps 200A of use, a draw of 250A would no longer be possible , so the boater could simply charge more often to make up for the diminished capacity.

This is normal for cruisers that run 50%SOC to 85%SOC , as the noisemaker time for the last push is far to long to endure.Even with a big alt on the noisemaker its still a long charge time.

Some get by with solar for the last bit of charge ,(or a dock), most simply understand the problem and oversize the house bank to make up for the slow death caused by age and undercharging.

 

[nwboater]

Battery Monitors...

I've used the Balmar SmartGuage on my last two trawlers, and just installed their newest product, the SG200 to replace a malfunctioning SmartGuage. In addition to showing SoC as a percentage, this new monitor tracks your house bank's State of Health (SoH), thus displaying a more realistic SoC. It will also display charging amps going into your house bank from whatever source, and amps being withdrawn. Pretty much will do it all -- and for under $300. Soon to be available is an app that will link the SG200 to your smart phone.

http://www.balmar.net/services-view/sg200/

Richard

 

[john61ct]

Did you keep the SmartGauge hooked up to see to what degree SoC% matches?

Especially over time so get a variety of scenarios would be great.

 

[Boatcrazy]

While the SG is simple and easy to use, it also has its limitations....in particular, significant error if charging OR discharging. And since the algorithm it uses is not released to understand it....blind faith becomes a factor. But...on the other hand, you install a amphr counter(like the Victron 712) but fail to put the correct parameters into it, or fail to degrade things like total amphrs yr-by-yr....well, garbage in, garbage out. We use a SG, a Victron 712 (derated yr-by-yr), and a digital voltmeter, and "kind of" integrate all 3 to get a GENERAL idea of battery health. Unless you have a lab-type setup, I'm betting that's about as good as it gets....call it a "SWAG"!

 

[DDW]

Much has been said about AH counters being inaccurate, or becoming inaccurate as batteries age. The only thing that may be inaccurate is the SOC, and this is the least useful number in the whole system. Amps in and out, and AH consumed are as accurate as the instrument is, which is excellent if you avoid the cheap ones. AH from full will be accurate if the batteries are recharged fully periodically - a requirement of AGM batteries, and automatic if a boat is kept plugged in or run very much.

The problems only occur on a liveaboard boat, using flooded batteries with a minimum charging system. In that situation you will be running between 50% and 80% or so, never getting to full charge and so never reseting the AH count. This is a pretty rare situation (or ought to be) on a powerboat. Most these days have AGMs, and only a small percentage live on the hook for weeks as a time without moving.

In my mind, the market for these SOC gages are those people, and those in that situation would be FAR better served converting to LFP, both economically and functionally. Anyone else is better served with a real battery monitoring system.

 

[psneeld]

Why do liveaboards never get to full charge?

I usually do at least once a week.... several different ways.

 

[FlyWright]

Did you keep the SmartGauge hooked up to see to what degree SoC% matches?

Especially over time so get a variety of scenarios would be great.

Why would one periodically disconnect the SG once it was installed?

 

[dhays]

Why would one periodically disconnect the SG once it was installed?

I don’t think the question was if the SG was periodically disconnected, but if was removed when the new monitor was installed.

 

[CaptRowlands]

Balmar has come out with a new monitoring system which is getting good press. It uses new technology and appears to solve many of the shortcomings of previous options. Not sure of cost.

I believe it's good to know status of capacity to help decide- "Shall I run the genny now or can it wait until tomorrow?"

 

[FlyWright]

Balmar has come out with a new monitoring system which is getting good press. It uses new technology and appears to solve many of the shortcomings of previous options. Not sure of cost.

I believe it's good to know status of capacity to help decide- "Shall I run the genny now or can it wait until tomorrow?"

That, I believe, is what nwboater describes here.

Trawler Forum - View Single Post - Battery Monitor - Advice & Recommendations

 

[Simi 60]

Why do liveaboards never get to full charge?

I usually do at least once a week.... several different ways.

Says who?
Every day our batteries are at 100% , 0ah used, usually by 10am and the remainder of the day solar amps are still being squeeeezed in somwhere.

 

[john61ct]

Why would one periodically disconnect the SG once it was installed?

not sure why you thought that was implied

 

[john61ct]

Balmar has come out with a new monitoring system which is getting good press

See #68

 

[FlyWright]

Did you keep the SmartGauge hooked up to see to what degree SoC% matches?

Especially over time so get a variety of scenarios would be great.

Why would one periodically disconnect the SG once it was installed?

not sure why you thought that was implied

Not really sure why I'm replying to you since you have NEVER answered a single salient question of mine, but there is the recap above for you.

Once again, I ask for your reply to the following from these previous posts in this thread which you have not yet answered. For clarity, I have only bolded the parts that warrant response.

How, praytell, do you plan to analyze its accuracy performance?

Please leave the electrical advice to those here with vast electrical experience. Your armchair expertise can be misleading at best, dangerous at worst.

I added numbers for reference.

Could you explain #1? Are you saying the SOC meter controls the charger?

2. Who is reprogramming their SOC meter as weather or usage patterns change? Why would one need to do that?

3. What do you mean by this question? I can't make sense of it.

4. Are you asking us to confirm the year Victron updated their software? And, as a matter of conversation, why do we care when or IF Victron updated their firmware software? Is this in any way helpful to the OP?

Please tell us about your experience or expertise to help us to know if the words you type come from someone who KNOWS what he is talking about. We have many folks here looking for valid, trusted information. Many of your posts display a lack of basic understanding of electricity or communication. Our members deserve to know who is providing this electrical advice.

One last request...I wish you'd read your posts before posting.

 

[mdstrum]

I love our magum Battery monitor. Last year upgrade our gen and inventor and add the battery monitor, totally redesigned the batter bank wiring so all the ground go to a super huge bus bar then a shunt and then the house grounds all go on that side. We also have solar. So I can see amps in, amp out, total amps use total amp stored, it is super accurate. I disagree with voltage only, did that and it only give a feel. with a properly designed setup you can see what devices/equipment are pulling what load (ie tun on bait pump and see the draw, turn on the refigerator and see what our inventer draws, put on all the lights, etc.
I also know when on Solar what it is adding gross amps and net. With just a volt meter you will see a high voltage when solar is charging for 5-8 hours a day but have no clue if it is adding 1 amp or 25 amps of something in between.

I guess I am nerd and like the details.
https://www.magnum-dimensions.com/battery-monitor-kit

 

[FlyWright]

Now that I know my batteries' behavior on the hook for days at a time with a SOC meter, I can tell a lot more about voltage than I used to be able to discern. When it takes a left turn, I know it....but then again, I monitor it as I walk by almost each time.

I suppose a lot of it depends on your familiarity and depth of experience.

What I mean to say is that if you see a deviation from the norm, you know to look into it. You only see the deviations if you're paying attention.

No armchair expert would EVER understand that concept.

 

[DDW]

The problems only occur on a liveaboard boat, using flooded batteries with a minimum charging system. In that situation you will be running between 50% and 80% or so, never getting to full charge and so never reseting the AH count.

Why do liveaboards never get to full charge?

I usually do at least once a week.... several different ways.

I suspect you are not in the situation I described. If you are getting a full charge periodically, then the AH counter will be reset periodically, and will be accurate at all times. Including it's SOC calculation, for practical purposes.

 

[john61ct]

Not really sure why I'm replying to you since you have NEVER answered a single salient question of mine, but there is the recap above for you.

I still see no connection between your question and what I wrote.

Not sure how you did not see my answers.

Let's just drop it, waste of time.

 

[FlyWright]

I still see no connection between your question and what I wrote.

Not sure how you did not see my answers.

Let's just drop it, waste of time.

I agree. There is NO CONNECTION between what I asked and what you wrote. That's exactly the point. Please quote your answers which reply to my bolded questions.

Establishing credibility in posting electrical advice is not a waste of time. That goes for ANY technical advice where lives are at stake. Please share with us your training or experience which qualify you as a reliable source of electrical advice. Anything short of that is a risk to the community.

 

[FF]

"Why do liveaboards never get to full charge?"

Folks at a marina have no problems , its cruisers that love the hook that have a hard time.

TIME is the problem , the last 10% or 15% takes a long time to push in to the batt , so few wuill listen to a noisemaker for that long.

A day under way will usually do it , solar can do it , or a night dockside should do it.

Getting to 100% charged is the only way to get maximum life and use from a battset.

That and never discharging to real dead.

 

[psneeld]

I suspect you are not in the situation I described. If you are getting a full charge periodically, then the AH counter will be reset periodically, and will be accurate at all times. Including it's SOC calculation, for practical purposes.

Well, I think I am. Your statement was just too wide ranging to be accurate.

Like many statements a lot of people have made in this thread.

You might have used the words some or many liveaboardsvwith minimal charging.... And I would have skipped over it.

 

[psneeld]

"Why do liveaboards never get to full charge?"

Folks at a marina have no problems , its cruisers that love the hook that have a hard time.

TIME is the problem , the last 10% or 15% takes a long time to push in to the batt , so few wuill listen to a noisemaker for that long.

A day under way will usually do it , solar can do it , or a night dockside should do it.

Getting to 100% charged is the only way to get maximum life and use from a battset.

That and never discharging to real dead.

I know that, not sure everyone else does.

Lots of misconceptions or misuse of the term liveaboard because it describes a broad range of cruising styles and boat setups.

 

[FF]

"Lots of misconceptions or misuse of the term liveaboard because it describes a broad range of cruising styles and boat setups."

To me livaboard is the folks aground in their coffee grounds that no longer untie from the dock, from year to year.

A full time cruiser will surely be living aboard but the frequent movement takes them out of the liveaboard set.

 

[john61ct]

that's insane

Liveaboards simply means those who live on the boat for at least extended periods, certainly months at a time.

Some are a subset of "cruisers", which just means travelling afar, not frequently returning to a home base. But the two factors are orthogonal.

Those on shore power at least a few nights per week need obviously have no problems with PSOC abuse.

Same with those running ICE electric sources for 7+ hours a day.

Same with those running ICE 1-3 hours in the morning before the solar day starts up.

And then you have those with enough solar and conservative enough in their usage to live on the hook for weeks without burning any dino juice at all, who get to 100% Full (as defined by endAmps) a few days per week.

None of these scenarios are that difficult, nor that uncommon, and in fact all are much easier on a trawler than a sailboat.





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