Amp-Hour counting

[witzgall]

All,

One of the most requested features for a future update of the SG200 is amp-hour counting. We are getting ready to work on this for the next release. I would like to solicit some feedback and help in understanding what people want, how they use what the have now (If another vendor's product) and what they would like to have.


Here are our initial thoughts on what we could do:
1. Show AH remaining - based on the aged capacity of the battery bank.
2. Show a counter of AH used, that resets when 100%.
3. A 24h rolling ah usage. Note there is no built-in real-time clock but we can count time passed. This could be resettable so the period started when then user wants it to start.
4. a resettable "trip odometer" type meter, resettable by the user.
5.??

Please use this opportunity to provide feedback to what is useful to you, the cruising sailor. As much as possible, state what you want, and why. Please also include some info about your battery and vessel usage.

Chris

[Wood]

Chris -

Would this be replacing any other functionality or in addition to? That will effect my preference.

My preference would be #4. If I understand this correctly it would measure -AH and +AH and pretty much zero at 100% anyway but be able to monitor any duration needed.

This would give me the most flexibility.

My current use is FLA 500AH on a mooring with no solar. I am building a 560AH lifepo4 system and having a frame fabricated for ~ 700w solar. I will be full time cruising in less than a year.

[Frankly]

I have an older Xantrex Link (round face) that I have been using for years. Have found the simple display very workable. The 4 lights indicating 1/4,1/2,3/4, full provide a quick and dirty Indication of house bank situation, if I need more accurate info can look at the negative AH number, or voltage. Looking at Ampere draw is also handy. Don't know of anything else I would use.


600 AH 12V FLA bank with 200 watts of solar and 100 amp Balmar.


Frankly

[Pete7]

Chris, certainly 1 and 2. The ability to switch to see what is happening on a single separate circuit like the fridge would be nice, if it can handle a second shunt.

We currently have the Sterling Remote power panel. Worth noting it doesn't know or care how big the bank is, just measures and reports what is used and replaced.

https://sterling-power.com/collectio...nagement-panel

[Sternwake]

My BM is the BlueSky IPN pro remote in conjunction with my Bluesky2512i charge controller.

It irritates me that once it believes the battery to be full, by whatever 'float current' trigger or time I have programmed, it will say 0 Ah from full, but any additional charging over that seems to have it count above that.

So when this occurs, when I discharge, I can be ~10Ah from full and it still says 0Ah from full, and I know it is untrustworthy and needs to be reset, but it is likely to again occur the next day and there is no way to stop this from 'counting above zero'.

This only gets worse as the batteries age and need more current to be held at absorption or float, and it gets to the point the Ah from full screen is a total joke and I judge state of charge by voltage held under X amount of amps and lots of experience with the same general overnight loads..

It is quite good with my new AGM battery as amps will taper to zero and on recharge, 0ah from full does happen right around the time amps taper to 0.5% at Vabs, but it was horrible on my previous AGm at the end of its life when amps would not taper below 4% @ Vabs, no matter what.

I get to full often, and resetting the battery monitor is not difficult, but doing so when the sun is still shining, means disconnecting the charge controller from batteries, and almost all solar controllers say to not do this, disconnect while the panels are making juice. So I am basically forced to reset at night when a grid powered charging source has had amps taper to 0.5% or less at Vabs.

I'd love to have a single button to reset AH from full to zero, and never have it count 'AH above zero', or if it did count it, have it as an 'over and above zero Ah from full' screen, just to see how much went into heating the battery holding it at float or absorption. When more and more is wasted as heat its another datapoint indicating battery replacement is in the perhaps not so distant future.

Battery temperature would be a nice feature to have displayed easily. Mine would display battery temp If I bought the BS2512ix instead of the BS2512i solar charge controller, but I'd have to press a series of clunky buttons to find that screen. I'd much rather have a dial to switch between screens. The only button I want is a 'reset now to 0Ah from full, and 100% SOC'

[dougweibel]

I like to be able to see (in order of priority)

1. AH used
2. % remaining
3. Time remaining

An auto reset of AH used based on battery voltage above threshold when current draw above threshold is nice, but also having the ability to manually reset is important.

% remaining should be based on a max amp hour value I determine. Recommendation based on the battery monitor's observed data would be nice too, but I want the final say.

I like the time remaining feature but on all the battery monitors I have used it is based on the current load current and therefore fluctuates too much. It would be nice, and more useful, if it could be based on a past hour average current load or similar.

560 AH AGM, 6KW generator, 360 W solar, 40A Volvo alternator x 2, Victron BMS

[steve77]

In addition to the SG 200, I use the Blue Seas System VSM. I compare it to the SG 200 to arrive at what i consider to be my battery SOC.

Yes, I would like some type of Ah counting on the SG200. Given a choice, I would vote for Ah consumed from 100%.

Thanks!

Steve

[smac999]

Originally Posted by Sternwake

My BM is the BlueSky IPN pro remote in conjunction with my Bluesky2512i charge controller.

It irritates me that once it believes the battery to be full, by whatever 'float current' trigger or time I have programmed, it will say 0 Ah from full, but any additional charging over that seems to have it count above that.

So when this occurs, when I discharge, I can be ~10Ah from full and it still says 0Ah from full, and I know it is untrustworthy and needs to be reset, but it is likely to again occur the next day and there is no way to stop this from 'counting above zero'.

every BM I have seen does this. but as soon as you start draining it will reset back to 0. IE +50 to 0 after a min of draining. then neg.

[SVHarmonie]

Originally Posted by witzgall

All,

One of the most requested features for a future update of the SG200 is amp-hour counting. We are getting ready to work on this for the next release. I would like to solicit some feedback and help in understanding what people want, how they use what the have now (If another vendor's product) and what they would like to have.


Here are our initial thoughts on what we could do:
1. Show AH remaining - based on the aged capacity of the battery bank.
2. Show a counter of AH used, that resets when 100%.
3. A 24h rolling ah usage. Note there is no built-in real-time clock but we can count time passed. This could be resettable so the period started when then user wants it to start.
4. a resettable "trip odometer" type meter, resettable by the user.
5.??

Please use this opportunity to provide feedback to what is useful to you, the cruising sailor. As much as possible, state what you want, and why. Please also include some info about your battery and vessel usage.

Chris

Hi Chris,

We have been using a SG200 for over 2 years in full time cruising with a 24V battery bank of 8 Firefly G-31 batteries for a C20 rating of 464 A-hrs. Charging is from 630W of solar and genset powered chargers. Typically we run the genset every other day. Solar supplies about half our total A-hr usage. It has been a great tool.

I really don't see a need for Amp-hour counting. It wouldn't add any useful information to the way we use and control our batteries above and beyond the SOC values. One issue I see with adding an A-hr integration function is if the A-hr total wasn't exactly consistent with the SOC percentage and SOH value it would cause less sophisticated users a lot of angst.

There are a couple of things I like to see if they were possible. The ability to display a SOH of greater than 100%. Two reasons for this. My Firefly batteries have run at 100% for months at a time. Seeing trends, even if they are small, from 110% down to 100% would be useful. Also, if the reported SOH is a number like 200%, then I know something is way out of whack...

A cycle counter since the last reset. This might be best buried in the menu system, but knowing how many cycles the system has "under its belt" to do its calculations would be useful. In the same vein if it was possible to show an estimate of the accuracy of the SOC or SOH number would be nice to have, but this might not be possible.

Finally, a display option to cycle through Voltage, amp draw, and SOC. Or maybe a way of displaying all those values in a smaller font.

[letsail]

We just upgraded from a 2006 Bavaria 39 to 2017 Bavaria 46. I installed a Victron BMV-712 in both. I would list priorities as you have them for #2 and #3. Personally I lean on Ah consumed more than Ah remaining. I log the state of the batteries daily based on how many NET amp hours were consumed during the day before. The low point of consumption is usually dawn. Then the solar kicks in. With our new(er) boat, which has a SilentWind, we are borderline self-sufficient, even with a freezer and two fridges. Background info: We have 4 100ah AGM batteries, three years old for the house circuit. We have separate batteries for the engine/Genset and a separate for the bow thruster. My battery monitor only monitors two systems.. so the bow thruster battery is not monitored. The older boat had 6-six volt 110Ah lead acid golf cart batteries, wired to create 3 big 12 volt batteries. Replaced every 4 or 5 years.

[sailinglegend]

Originally Posted by witzgall

...One of the most requested features for a future update of the SG200 is amp-hour counting.... I would like to solicit some feedback and help in understanding what people want....

Chris

I’m a little confused as to why your are attempting to add Amp hour readings to your SG-200 when you already know that all shunt based Battery Monitors are inaccurate when Ah counting - which is why the original SmartGauge was invented in the first place.

I refer to your own post on the bloated Balmar SG-200 Battery Monitor thread.

Originally Posted by witzgall

...When choosing the data to show on the SG200, we purposely omitted AH remaining, or Ah consumed, and similar counters. This was not a blind decision, there is some reasoning behind this. For instance, in our testing, showing AH remaining can be misleading, often quite so.

Chris

So why have you changed your mind?

How can you guarantee that your Ah counting will be accurate - can you determine the true Ah count from your SmartGauge software algorithm?

If so that would only solve part of the problem of inaccurate Ah counting. There are many other reasons why the Ah count can be wrong, as Maine Sail - your excellent SG-200 tester - reported in his assessment of shunt based Battery Monitors on his website:

…that about 90% of Ah Counters I come across are NOT properly installed & wired and about 98% of Ah counters I come across are NOT properly calibrated/programmed.

This has been posted many times and I referred to Maine Sail's thoughts in the above SG-2000 thread and only one astute reader - Stu Jackson - acknowledge my post.

So I detail here the Ah reading errors that Balmar can have no control over, which means “...Ah remaining can be misleading, often quite so.”

1. Installation errors and the position of the shunt.

One common problem is the alternator charging current does not go through the shunt when charging the House Bank. This happens because the common negative wire from the house battery to the starter battery must go though the shunt. Wiiring diagrams errors in your Rev A and Rev B manuals will mean many early SG-200s shunts have been mounted incorrectly.


2. Subsequent addition of new equipment that bypasses the shunt.

Many equipment installation manuals say "wire directly to the battery, don’t go via switches and busbars." Many solar controller installations and extra 12 volt load outlets like USB chargers and inverters fall into this category. This potential problem could be made much clearer in your manual "- don't wire to the battery negative go via the shunt." Maybe ‘installation troubleshooting’ should have a whole chapter to itself. 


3. Programming the Ah counter.

Any product with a 36 page manual leaves the possibility for many errors by the inexperienced installer.

Exactly which battery chemistry do they have?
What is a dual purpose battery?

And what battery capacity - whole bank not single battery?
Can users determine which of the three different types of AGM they have? 

And Gel - which some people think are AGMs?

What are the actual manufacturer’s recommended charging voltage for each type of battery - not the generic ones you have chosen? 

Where can yo find the correct Peukert value that may need to be changed to correct ‘time remaining’ calculations?

And can they understand this instruction - charge voltages and tapper current need to be changed if charge termination is not being reached?


All these potential installation errors may mean much of the feedback and problems users have been having may have very little to do with your hardware or software.

The Balmar SG-200 Battery Monitor thread had over 650 posts and nearly 50,000 views and it would be worth refreshing your memory on the feedback expressed there. This contained some very confusing and misleading ideas and it will quickly become clear that you are seeking feedback from many people who haven’t fully understood why a battery monitor can’t always count Ah properly, they are not just a bit inaccurate they can be very inaccurate. These same people are asking for Ah counting because they ‘want’ it - but do they really ‘need’ it?

It is well worth noting that customer installation errors is why the original Merlin SmartGauge, even after countless requests, would never add a shunt to read current and Ah. I do firmly believe a separate digital current meter is essential on a cruising boat - but treat the associated Ah readings with caution and don't compare the two results.

I’m a Liveaboard on a 42 ft sailboat in Greece and added my Merlin SmartGauge 14 years ago after my BEP battery monitor couldn’t accurately show Ah used with older batteries. 450 Watts of solar, 400 watts of wind generator and 630 Ah of new Lifeline AGM batteries.

[Bycrick]

COUNTING amp-hours is simple, easy and accurate. The problem occurs when you try to use that number for anything other than determining how much energy a load consumed. You can’t easily, simply or reliably use amp-hour counting to tell you how "full" or "empty" your batteries are.