Working with Battery Monitors and Combiners

[john61ct]

Originally Posted by ramblinrod

If one wires it that way (which is the correct way), but if one has a split bank or other banks they are attempting to monitor with the same coloumb counter, that is where the problem lies.

What would give anyone the impression that would work?

Originally Posted by ramblinrod

Smart Gauge is not the solution as it gets messed up with combiners.

So you (and your friend) claim. Please don't post such speculation as if it were fact without some detailed testing, or a credible source.

[DotDun]

Originally Posted by ramblinrod

If one wires it that way (which is the correct way), but if one has a split bank or other banks they are attempting to monitor with the same coloumb counter, that is where the problem lies. My point, though perhaps not as clear as I thought it was, is that one cannot monitor multiple banks with a coloumb counter, and a Smart Gauge is not the solution as it gets messed up with combiners. The solution is one monitor per bank to be monitored.

Originally Posted by john61ct

So you (and your friend) claim. Please don't post such speculation as if it were fact without some detailed testing, or a credible source.

It's clear not everyone understands that the SmartGauge does not use a shunt! It's only voltage monitoring and computer models.

In a short read of the Smartgauge website.....

SmartGauge compares the results of the measured state of charge with the results of the calculated state of charge and uses this comparison to automatically adjust both the battery "model" and the "algorithm" so that future calculations will become more accurate. This is why it is so important to keep SmartGauge permanently connected to one battery bank.

SmartGauge Electronics - SmartGauge compared to Amp Hours Counters

I read one battery bank to mean only one battery bank, i.e., no split or combined bank(s). No surprise the SmartGauge gets confused. RTFM

[john61ct]

Gibbo means "as opposed to moving it from one bank to another", which you can do with a shunt-based BM.

It's two leads are directly connected to only one bank. The fact that it is continuously connected means over time it gets more accurate observing the bank's behavior (not just voltage BTW), and will ignore short-term anomalies.

A connection to another bank **only when charge current is present** is no more confusing than any other charge source.

If you think it is, and still want to use a SmartGauge, then use a one-way Echo Charge or B2B charger.

[lateral]

Originally Posted by ramblinrod

If one wires it that way (which is the correct way), but if one has a split bank or other banks they are attempting to monitor with the same coloumb counter, that is where the problem lies. My point, though perhaps not as clear as I thought it was, is that one cannot monitor multiple banks with a coloumb counter, and a Smart Gauge is not the solution as it gets messed up with combiners. The solution is one monitor per bank to be monitored.

I ran this past John at JGTech and he said the SG would work fine.
That is the house and start linked via SI-ACR Bluesky.
But, I do see your point. I don't see how it can work with house an start paralleled off for charging. When the charging is stopped they are isolated and the SG then may be able able to make some sense (via its algorithm) of the voltage, but it would have to be pretty smart esp if there is volt drop due to loads plus a residual surface charge.
Perhaps the algorithm is configured to measure voltage vs time in charge mode (batteries combined) and then at discharge (isolated) and build a profile slowly getting more accurate as the data base builds in this scenario with respect to time in each mode.
Solar would complicate it further as the banks would stay combined for longer giving the SG less time to build a profile on house bank only.

This is with the SG wired direct to house bank posts as manufacturer directs.
I would be curious to mainesails response on this.

[ramblinrod]

Originally Posted by john61ct

Please don't post such speculation as if it were fact without some detailed testing, or a credible source.

Sir, I have every right to post my opinions based on my learnings, and personal and professional experience, without gathering and linking technical papers from industry authorities greater than myself (any more than you seem to do while expressing your opinion.

If you believe you are any more priviliged than I to express opinion, you are completely mistaken.

As we see from the link posted by the manufacturer themselves (supplied by another poster)....

THE BALMAR SMART GAUGE IS NOT ACCURATE (not even designed to work accurately) WHEN INSTALLED IN A CIRCUIT WITH A BATTERY COMBINER.

[Stu Jackson]

Originally Posted by lateral

>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I would be curious to mainesails response on this.

Why? Have you read his very detailed SG testing on his website?

He wrote:

#3 Test Smart Gauge for accuracy during charging & discharging events, including solar, inverter loads and DC loads. Batteries were determined full when charge current fell to less than .5% of Ah capacity at target absorption voltage. (absorption charging voltages varied by battery type).

**********
It means that I did see the Smart Gauge get a bit confused when the bank was being charged. It can’t really track the capacity of a battery charger now can it…? However we are only talking about 10-12% variation from the Ah counters during charging, and not a huge deal when you consider how simple this battery monitoring unit is. Another issue with tracking SOC during charging is charge efficiency variations, so it was much easier to do this testing on the discharge side of the equation.
As soon as the charge source was discontinued, the Smart Gauge fairly quickly identified the accurate SOC of the bank, and was back within approx 2% – 3% of the two painstakingly calibrated Ah counters.

************
The SG MUST be connected to the POLES on the house bank, NOWHERE else. [I personally (me, Stu) consider this CRITICAL to all these questions about combiners, etc. It makes them meaningless questions.)]

***********************************

The entire writeup is here: https://marinehowto.com/smart-gauge-...nitoring-unit/

Point being: he wrote "the book" on the SG testing, what more could he possibly add? Unless I'm missing your point, if so, sorry.

[john61ct]

Originally Posted by ramblinrod

THE BALMAR SMART GAUGE IS NOT ACCURATE (not even designed to work accurately) WHEN INSTALLED IN A CIRCUIT WITH A BATTERY COMBINER.

First of all Balmar is just the distributor.

Next, I could not find the above text anywhere, please provide a link.

Finally, direct from Merlin, the actual manufacturer in the UK:

Q: I appreciate connections must be made direct to battery terminals etc, but my question is: "will Smartgauge work in a 1/2/both battery switch arrangement"?

A: In short the answer is yes the unit will operate fine. What you will find is that when you select the "both" option on the switch the voltages in the batteries will balance due to the paralleling effect so the smartgauge will show both banks as having the same voltage. When the batteries are disconnected again the voltages will change and smartgauge will pick up in this.

Q: When the switch is set to Both, does the smart gauge effectively tell you the state of charge of the two combined batteries, or it it still intelligent enough to be only giving the state of charge of the single battery it would otherwise be sensing?*

A: It would still be reading the two batteries as independent banks however you will get the same reading because as you parallel the banks together there voltage will balance.

Q: In other words, assuming that Smartgauge is wired so that it is sensing the charged state of Batt 2, simple voltage display only for Batt 1 (all direct to battery terminals) -and if the Batt switch is set to Both, Smartgauge % charge display will still be valid only for Batt 2?

A: That is correct the smartgauge % readout will not be effected by the paralleling of the batteries.

[Dockhead]

Originally Posted by john61ct

First of all distinguish between SmartGauge, and all the others that work off a shunt. The latter are counting coulombs, every flow in and out, you have to tell them the capacity (adjusting down over the years) and if wired properly, they keep their normal level of accuracy such as it is.

SmartGauge figures everything out on its own, and if the ACR is only closed while charging, should be no problem.

Rather than just joining the two banks together if the issue concerns you, a one-way device like a B2B may be a solution, the SmartGauge would see that as any other charge source, should also include Echo Charger or a diode isolator (yuck).

I have designed one-big-bank systems where a Starter/Reserve subset gets isolated from House loads when SoC drops low enough, but that presumes that event is a rare exception.

As long as the "normal situation" prevails most of the time, any SG confusion would correct itself pretty quickly.

This.

SmartGauge can't tell anything useful about SOC achieved during charging even without a combiner, so just ignore that.

Once you've been discharging for a while, it will settle down and come up with a very good idea of where you are. And this is the information you actually need.

[Dockhead]

Originally Posted by john61ct

. . . Q: In other words, assuming that Smartgauge is wired so that it is sensing the charged state of Batt 2, simple voltage display only for Batt 1 (all direct to battery terminals) -and if the Batt switch is set to Both, Smartgauge % charge display will still be valid only for Batt 2?

A: That is correct the smartgauge % readout will not be effected by the paralleling of the batteries.

Are you sure about that? SG will be reading the voltage of the whole system, including the interconnected second bank. I guess it would not tell you much about the SOC of Batt 1, if it's different from Batt 2 and they have just been interconnected. Once they've been interconnected for long enough for the charge to equalize between them, then that would be different I suppose.

[Stu Jackson]

Originally Posted by ramblinrod

>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

THE BALMAR SMART GAUGE IS NOT ACCURATE (not even designed to work accurately) WHEN INSTALLED IN A CIRCUIT WITH A BATTERY COMBINER.

Rod, I, too, couldn't find this in the manual. Didn't you say you got it elsewhere from a link? If I missed that link in this topic, I apologize, but could you repost it? Thanks.

[john61ct]

Originally Posted by Dockhead

Are you sure about that?

As I said that was a response from Merlin, the manufacturer.

How I feel about it is irrelevant.

[john61ct]

Originally Posted by ramblinrod

Your statements above do not accurately represent my position in any way, on totally unrelated matters.

http://www.cruisersforum.com/forums/....php?p=2369611

[Stu Jackson]

Originally Posted by Dockhead

Are you sure about that? SG will be reading the voltage of the whole system, including the interconnected second bank. I guess it would not tell you much about the SOC of Batt 1, if it's different from Batt 2 and they have just been interconnected. Once they've been interconnected for long enough for the charge to equalize between them, then that would be different I suppose.

Dockhead, you are quite right. However, I suggest that we examine how we actually USE charging sources and switches (be it a 1-2-B or a combiner which is, after all, just an automatic switch,m right?). And do this in relation to the SG.

All of us have been taught to isolate batteries AFTER charging has been accomplished. At this point, the system voltage drops from, say 13.4V back to 12.7 or 12.8V. A combiner would open. A skipper would switch from B to one bank (if he didn't already have his charging sources sent to the house bank first anyway).

As a result, the SG then gets to work doing it's thing.

If the two separate banks remain combined, you are completely correct.

But that is not how we MANAGE our systems. Of course, there's always the brain fade days.

But since all MY charging sources (alternator, charger, solar) go to my house bank, I don't ever mess with my 1-2-B switch. Ever. Set it to the house bank and I am DONE.

SG or no SG.

But, given how the SG works, charging is simply not part of the equation, so, if managed properly, your well intentioned and thought out point, shouldn't come into play.

[lateral]

Originally Posted by Dockhead

This.

SmartGauge can't tell anything useful about SOC achieved during charging even without a combiner, so just ignore that.

Once you've been discharging for a while, it will settle down and come up with a very good idea of where you are. And this is the information you actually need.

Good stuff DH. But it re-inforces the fact that if you are charging 6-7hrs per day
(and simultaneously discharging), with solar, you are not going to get any relevant SOC during this time.
I guess, when you really need to know , in the wee hrs & black outside, it has settled and it is "accurate".

Stu, I had read MS appraisal of the Balmar Gibbo's SG when he first wrote it but had forgotten his response to this particular issue.
I am not going to abandon my own logic to anyones, even MS's, without corroboration, if it is difficult to follow.
I continue to install products, that on the face of it appear ideal, only to find they have some significant shortcomings. Thats marketing.

[Dockhead]

Originally Posted by lateral

Good stuff DH. But it re-inforces the fact that if you are charging 6-7hrs per day
(and simultaneously discharging), with solar, you are not going to get any relevant SOC during this time.
I guess, when you really need to know , in the wee hrs & black outside, it has settled and it is "accurate".

Stu, I had read MS appraisal of the Balmar Gibbo's SG when he first wrote it but had forgotten his response to this particular issue.
I am not going to abandon my own logic to anyones, even MS's, without corroboration, if it is difficult to follow.
I continue to install products, that on the face of it appear ideal, only to find they have some significant shortcomings. Thats marketing.

I think we all agree.

There are some things SG can't do. You shouldn't expect it to know what SOC you've achieved during charging.

But SG does very well that one thing which you really need for a battery monitor to do -- which is to tell you at o-dark hundred whether you're still OK
for a while or whether you need the crank the gennie.

That's why I like SG much better than amp-counting monitors that are clueless pretty much all the time.

I don't see why it wouldn't work fine, or at least, as well as it normally works, on a bank which is charged with a combiner, but separated during use.