Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 26-07-2016, 13:36   #31
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2014
Location: Astoria, NY
Boat: Sabre 38
Posts: 377
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by Paul L View Post
I haven't used one. Does the bolded sentence above then mean that all day long when the solar is charging that the device is inaccurate? Daytime is usually when I decide to additionally charge or not.
I had/have a similar question. From Maine Sail (via his website):

"Solar panels do not continuously charge, if they could we'd not have energy problems...... If you have a few days of wind turn it off when the bank is full and let the SG regain a more accurate grasp on SOC and the bank... Even during charging I only noted it off by 10-12% (best resolution I could measure) and I can assure you this is far better than the vast majority of Ah counters currently in use out there when looking at actual SOC for the bank in use...."

So, yes, the SM will be off while charging from solar. Maine Sail saw 10%, while Dockhead appears to be seeing a difference of almost 40%. Maybe a difference in the strength of the charging source? Perhaps a few hundred watts of solar won't affect the SM as much as a 5kw generator. Keep a "SOC per voltage" table near the SM to check whether you need that extra charge. You'll be able to check your guess once the sun is low and the SM self corrects. After a few rounds, you might get really good at guessing how far off the SM is with your solar set up.
__________________

__________________
Stephen

s/v Carpe Ventum
1983 Sabre 38
My Intro
fallingeggs is offline   Reply With Quote
Old 26-07-2016, 13:41   #32
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,249
Images: 1
Re: SmartGauge -- Real Life Experience

I did a quick Google for "battery specific gravity monitor" & came up with this:

Fiber Sensing to Measure Battery State of Charge | Sensors

If you could constantly monitor each cell's SG,would that lead to a reliable SOC calculation?
http://forum.arduino.cc/index.php?topic=91316.0

Just wondering. / Len
__________________

__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 26-07-2016, 13:50   #33
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 4,124
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by fallingeggs View Post
I had/have a similar question. From Maine Sail (via his website):

"Solar panels do not continuously charge, if they could we'd not have energy problems...... If you have a few days of wind turn it off when the bank is full and let the SG regain a more accurate grasp on SOC and the bank... Even during charging I only noted it off by 10-12% (best resolution I could measure) and I can assure you this is far better than the vast majority of Ah counters currently in use out there when looking at actual SOC for the bank in use...."

So, yes, the SM will be off while charging from solar. Maine Sail saw 10%, while Dockhead appears to be seeing a difference of almost 40%. Maybe a difference in the strength of the charging source? Perhaps a few hundred watts of solar won't affect the SM as much as a 5kw generator. Keep a "SOC per voltage" table near the SM to check whether you need that extra charge. You'll be able to check your guess once the sun is low and the SM self corrects. After a few rounds, you might get really good at guessing how far off the SM is with your solar set up.
Thanks for the info. No way am I going to turn off my solar to make my monitor work better. Thats the tail wagging the dog. I think there's probably a lot of difference to for the use case that mainesails customers seem to often have, close in to docks, short cruises, vs 100% away from docks and recharges. I have a monitor to help understand my charging. Saying wait for a low sun day seems to miss the point. So far, most of the reports I've heard on the SM sure don't inspire me to want one. I do fine with my simple Link.
__________________
Paul L
http://svjeorgia.blogspot.com
Paul L is offline   Reply With Quote
Old 26-07-2016, 13:58   #34
Registered User

Join Date: Mar 2012
Location: On board in Alanya, Turkey
Boat: Hunter Legend 420 Passage
Posts: 579
Re: SmartGauge -- Real Life Experience

A few facts to put the record straight - direct from the MD of Merlin:

They will NEVER fit a shunt to the SG - it would make it difficult to install properly and so would cause errors.

To say that only voltage can be measured via 2 wires is *completely* incorrect.....
Pull a brief current pulse from the battery and measure the voltage drop, this will give an indication of internal resistance.
Present an AC voltage across the battery and measure the phase angle and amplitude of the resultant current. This will show the AC impedance of the battery.
Do the same thing with a wide variety of frequencies and analyse the results. This is know as AC impedance spectrography.

THIS IS A DIRECT QUOTE FROM THE DESIGNER CHRIS GIBSON.

Read the manual and note that the monitoring wires to the battery are larger than they need to be just to measure the voltage.

Also note that you have to tell SG what kind of batteries you have. There are no algorithms for LiPo4 and probably never will be as the military will never use them.

Chris Gibson worked for LINK and got fed up answering the phone and explaining why their battery monitor would become inaccurate as the batteries aged, so he designed the Smart Gauge.

He was bought out by Merlin and now works for them on secret Military projects in the US.
__________________
sailinglegend is offline   Reply With Quote
Old 26-07-2016, 14:26   #35
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 18,248
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by Paul L View Post
I haven't used one. Does the bolded sentence above then mean that all day long when the solar is charging that the device is inaccurate? Daytime is usually when I decide to additionally charge or not.
Yes. The device measures the state of charge very accurately when you're using battery power. It doesn't understand how much you have put back into the batteries. It guesses (often badly), and then waits for the system voltage to come down to the state of charge which it guessed you achieved.

I haven't tried it with solar (I don't have any solar), but I would think that solar would completely confuse it.

It works ok with a generator (like I have) because the rate of charge is highly predictable so you know yourself, more or less, when you've achieved what you need. I usually shut down the generator when the bulk phase is over.
__________________
Dockhead is online now   Reply With Quote
Old 26-07-2016, 14:32   #36
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 18,248
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by deblen View Post
I did a quick Google for "battery specific gravity monitor" & came up with this:

Fiber Sensing to Measure Battery State of Charge | Sensors

If you could constantly monitor each cell's SG,would that lead to a reliable SOC calculation?
Battery Hydrometer Sensor?

Just wondering. / Len
I doubt if that would work very well. The problem is stratification of the electrolyte. Maybe if you put a bubbler in there.
__________________
Dockhead is online now   Reply With Quote
Old 26-07-2016, 15:05   #37
Marine Service Provider
 
Maine Sail's Avatar

Join Date: Jan 2007
Location: Maine
Boat: CS-36T - Cupecoy
Posts: 2,993
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by Dockhead View Post
Yes. The device measures the state of charge very accurately when you're using battery power. It doesn't understand how much you have put back into the batteries. It guesses (often badly), and then waits for the system voltage to come down to the state of charge which it guessed you achieved.
I simply tell my customers to look at SOC perhaps twice per day. You really don't need any more than that. Once in the AM before the sun comes up or charging begins and once before bed at charging has been off for a while. From this you tend to learn the system and what you need in terms of charging time.

So far wind is the only thing I have found that can trip up the typical AM/PM checks.

The SG is not perfect, there is no perfect method for tracking battery SOC, but far better than an Ah counter at predicting SOC, far easier to operate, and no calibration other than selecting battery type..


As far as Ah counters vs. the SG take a look at the event in the link below and then think where your programming for an Ah counter would have left you.. The SG was remarkably accurate with crap batteries that literally fell off a cliff in a few months.

How to Murder Batteries in Half a Year



FWIW I have a very prematurely murdered Lifeline AGM bank in the back of my truck right now, removed and replaced this morning, killed by improper Ah counter programming (Xantrex Link). House bank was 315Ah rated when new and the Ah counter had been programmed for 460Ah. D'oh.. Mistakes like these are much harder if you pay attention to voltage or use a SmartGauge.

The owner was overly confused and hung up on counting "amps" (he meant Ah's). When I left the boat I simply suggested he use the voltage screen and do not discharge below 12.2V. He seemed to think that was simple.

Owner: "What if it drops to 12.2V too fast?"
Me: "You charge longer or the batteries are getting old."
Owner: "OK that seems easier."
__________________
Marine How To Articles
Maine Sail is online now   Reply With Quote
Old 26-07-2016, 15:42   #38
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 15,364
Re: SmartGauge -- Real Life Experience

So he killed them overcharging them? Or undercharging them?
Sorry to be ignorant, only battery monitor I have ever had is this Smart Gauge, bought after reading your review by the way, I've always just watched voltage before, but I would also run Walmart batteries, replace them every year and put them in the RV where they ran another year. Of course with only a year on the boat I didn't need anything scientific


Sent from my iPad Pro using Cruisers Sailing Forum
__________________
a64pilot is offline   Reply With Quote
Old 26-07-2016, 16:19   #39
Registered User
 
Cowboy Sailer's Avatar

Join Date: Aug 2007
Location: on the boat. Gulf Coast
Boat: C&C 38'
Posts: 351
Images: 2
Re: SmartGauge -- Real Life Experience

I have one bank. I don't have a separate start battery. I have a digital voltmeter and a digital ammeter. I have a voltage vs state of charge chart next to the voltmeter. My wife can notice when the batteries are needing charging.
I actually have three battery banks with switches to isolate any one bank. the voltmeter is also switchable. Every few months I run off of one bank and check its ability to run the entire boat. The next day I check the next bank etc. I have never had a problem with this technique for keeping on top of my batteries health. I have only had to replace one battery that started going bad.
__________________
Jerry and Denver
Happy Old cruisers!
Cowboy Sailer is offline   Reply With Quote
Old 27-07-2016, 01:07   #40
Registered User

Join Date: Jun 2013
Location: canada
Posts: 1,561
Re: SmartGauge -- Real Life Experience

first I'll say that I love battery monitors and they are great. I bet I've put in a 100+, but every boat I work on is plugged into a dock 360 days a year. so they are all self resetting after a weekend trip. I bet most boats on avg leave the dock twice a year in my city. and there are 1000's of them. I'm betting most boats in the world are used like this and cruising without dock power is a rarity in the scheme of things. with no dock power and no self resting I bet they would go crazy in time because of peukerts curve. but charging / discharging on a 3 day trip will have little effect. and then plugging in for weeks before doing it again.

I have only put in one smart gauge, and I don't understand how it would work.

so say I leave dock with full batteries. drain while sailing on a rainy day, drain over night. I'm at 70% at 12.5v or whatever. then the sun comes up and my solar takes the voltage to 13.5v. and it sits there for 7 hours of sun. clouds come and go. sometimes my solar is 10a, sometimes 5 amps. HTF is the smart gaguge going to know my SOC an hour later, or 3 hours later, or 7 hours later when my voltage is 13.5v the entire time yet my SOC is changing, by non liner amounts the whole time.

only a amp counter can do this. and also a volt gauge can not. unless you cut off solar and give the batteries no load rest time.

maybe when the sun drops and the voltage stabilizes in a non charging voltage level it can redetermine the SOC. but I can't see it doing it while under a charging state.

this is pretty important while running a generator to charge a battery. without an net amp gauge or SOC while charging, you wouldn't know when to shut off the gen vs when you are just wasting fuel. and charging at a few amps.
__________________
smac999 is offline   Reply With Quote
Old 27-07-2016, 02:14   #41
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 18,248
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by smac999 View Post
first I'll say that I love battery monitors and they are great. I bet I've put in a 100+, but every boat I work on is plugged into a dock 360 days a year. so they are all self resetting after a weekend trip. I bet most boats on avg leave the dock twice a year in my city. and there are 1000's of them. I'm betting most boats in the world are used like this and cruising without dock power is a rarity in the scheme of things. with no dock power and no self resting I bet they would go crazy in time because of peukerts curve. but charging / discharging on a 3 day trip will have little effect. and then plugging in for weeks before doing it again.

I have only put in one smart gauge, and I don't understand how it would work.

so say I leave dock with full batteries. drain while sailing on a rainy day, drain over night. I'm at 70% at 12.5v or whatever. then the sun comes up and my solar takes the voltage to 13.5v. and it sits there for 7 hours of sun. clouds come and go. sometimes my solar is 10a, sometimes 5 amps. HTF is the smart gaguge going to know my SOC an hour later, or 3 hours later, or 7 hours later when my voltage is 13.5v the entire time yet my SOC is changing, by non liner amounts the whole time.

only a amp counter can do this. and also a volt gauge can not. unless you cut off solar and give the batteries no load rest time.

maybe when the sun drops and the voltage stabilizes in a non charging voltage level it can redetermine the SOC. but I can't see it doing it while under a charging state.

this is pretty important while running a generator to charge a battery. without an net amp gauge or SOC while charging, you wouldn't know when to shut off the gen vs when you are just wasting fuel. and charging at a few amps.
You correctly describe a situation where the Smart Gauge will not work.

But it seems to me that you don't understand the problem of calibration of amp counting meters. You do not get a "reset" every time you have a full charge -- the only thing you get is a starting point for counting down.

The problem is that the state of charge of a battery bank is not related in any straightforward way to the amps that you are counting.

First of all there is Peukert, the effect of which can be estimated, but only pretty crudely.

Secondly, the real capacity of a lead acid bank is changing all the time. You might think you have 600 amp hours, and so you might think you have reached 50% SOC when you've taken 300 amp hours out with some correction for Peukert. But a nominal 600 amp hour bank almost never has 600 real amp hours. It could easily be 400 after a couple of years of use. And you will quickly kill them, if you believe in your amp counting meter, because what you think is a 50% discharge is really a battery-killing 75% discharge, or even worse because Peukert is not dealt with accurately.

The Smart Gauge will not know -- as you correctly point out -- what state of charge you have achieved, while your solar panels are putting out output.

But once no charging sources are active, and you are running on battery power, voltage will tell you accurately when you need to charge. You don't actually need a Smart Gauge at all for that. The amp-counting meter will not tell you this with any degree of accuracy. And this is by far the most important thing we need to know about our batteries. Counting amps may be useful for managing your batteries, but you should not judge your SOC during discharge this way.*

As to knowing when to shut off the generator -- this is the way I charge, and I wish I had better information. But I know I've reached exactly 86% charge when my charger goes over to absorption from bulk. That's a good time to shut down the generator if you are on the hook (every few days you'd better get it up to 100%, though, one way or another). So that's not perfect information, but it's pretty much good enough in practice.



* One way to use an amp counting meter for this is to derate your batteries to a capacity you are sure you have more than (in the setup menu of the meter). That's exactly what I did when I was using my Victron amp counter.

This works, but it is wildly inaccurate -- it works only because you are giving up a possibly large part of your real capacity.
__________________
Dockhead is online now   Reply With Quote
Old 27-07-2016, 03:58   #42
Marine Service Provider
 
Maine Sail's Avatar

Join Date: Jan 2007
Location: Maine
Boat: CS-36T - Cupecoy
Posts: 2,993
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by Dockhead View Post

The problem is that the state of charge of a battery bank is not related in any straightforward way to the amps that you are counting.
Some of the problems with Ah counters are design, and most of them are user related to a lack of understanding of what their capabilities & limitations actually are. Some companies are working on better Ah counters, that will work better with PSOC use, but as of yet I have not seen one that could accurately predict SOC and remain accurate for any decent period of time without serious user intervention.

This article hits most of the issues of AH counters and will help users understand how they work and how to stay on top of them. I design systems for long distance cruisers who don't have the luxury of being dockside regularly, and who are using batteries in a PSOC application. Once they are out of my reach they need to understand their own on-board systems and also adhere to my #1 back up / fail safe and that is don't let your batteries drop below 12.15V - 12.2V regardless of what the -Ah's screen says..

Keeping Your Ah Counter More Accurate



.
__________________
Marine How To Articles
Maine Sail is online now   Reply With Quote
Old 27-07-2016, 04:16   #43
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 15,364
Re: SmartGauge -- Real Life Experience

You can tell when your fully charged and when to shut down the generator by watching charge acceptance rate at absorption voltage can't you?
If your charger jumps into float at 86% charge, then that is all the charging your going to get, correct? Little if any charge happens at float voltage?
Why would you not want to hold absorption voltage until batteries at 100%?


Sent from my iPad Pro using Cruisers Sailing Forum
__________________
a64pilot is offline   Reply With Quote
Old 27-07-2016, 04:59   #44
Marine Service Provider
 
Maine Sail's Avatar

Join Date: Jan 2007
Location: Maine
Boat: CS-36T - Cupecoy
Posts: 2,993
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by a64pilot View Post
You can tell when your fully charged and when to shut down the generator by watching charge acceptance rate at absorption voltage can't you?
Yes you can.

For most boaters we tend to accept resetting to full/100% at a tail current of 2% of Ah capacity @ absorption voltage. Sadly this does not actually represent a full battery just a cruiser full battery.

A 2% tail current at absorption leaves capacity on the table so when programming an Ah counter, especially with AGM or GEL batteries that need to hit a 0.5% tail current at absorption (Lifeline) or 0.3% East Penn, Northstar, Odyssey etc.) to attain 100% SOC, we need to account for this lack of capacity in programming. Of course without the proper equipment to know your actual capacity, a catch 22, this rarely happens.


Quote:
Originally Posted by a64pilot View Post
If your charger jumps into float at 86% charge, then that is all the charging your going to get, correct?

Premature Floatulation is a real problem and one that the lawywers have forced on us. Your charge source dropping to float DOES NOT mean your batteries have achieved 100% SOC, and usually far from it. In float the batteries continue to charge however the time to full is now extended dramatically to well beyond 24+ hours.

Quote:
Originally Posted by a64pilot View Post
Little if any charge happens at float voltage?
This is untrue you can fully charge a battery to its actual capacity at float voltage but the time it takes is measured in days not hours.

Some on the net have purported that a battery can't attain 100% SOC without a high absorption voltage but I have tested this numerous times and it is incorrect. It is correct if you expcet to charge the battery in a solar day but even when holding high absorption voltages it is almost impossible to attain 100% SOC in one days solar recharge on a boat.

By lacking a proper and healthy absorption charge, attaining at least 98% -99.5% SOC before dropping to float, you will be damaging the battery health wise if this practice continues..


Quote:
Originally Posted by a64pilot View Post
Why would you not want to hold absorption voltage until batteries at 100%?
You do want to hold absorption that long, but for charger makers they have no clue what size bank you are connecting to thus they often use kitchen timer algorithms to determine max absorption time. A one size fits all is safe for the lawyers but not healthy for your batteries. Best tip is to only buy equipment that allows for full custom charge profiles..

As Dock has eluded to voltage can be used especially if used in conjunction with tail current at absorption voltage.

Voltage is still tough though and you will need to do the homework on your own bank.

Here is an experiment I ran a while ago based on a customers Voltage to SOC chart..

Loaded Battery Voltage vs. SOC
__________________
Marine How To Articles
Maine Sail is online now   Reply With Quote
Old 27-07-2016, 05:30   #45
Registered User
 
S/V Alchemy's Avatar

Join Date: May 2008
Location: Toronto
Boat: Custom 41' Steel Pilothouse Cutter
Posts: 4,505
Re: SmartGauge -- Real Life Experience

Quote:
Originally Posted by Maine Sail View Post
You do want to hold absorption that long, but for charger makers they have no clue what size bank you are connecting to thus they often use kitchen timer algorithms to determine max absorption time. A one size fits all is safe for the lawyers but not healthy for your batteries. Best tip is to only buy equipment that allows for full custom charge profiles..
I just programmed my six L-16s to be charged off shore power (solar, wind and alternator will be hooked in later after I get my external regulator and MPPT installed). My Xantrex RS2000 charger's control panel wanted to know battery type, battery bank size in Ah capacity and other parameters, some of which I can customize. After an initial few hours of bulk and absorption regimes at pretty impressive amperages, it's now in float mode (there are no draws as I have to hook up the AC out for inversion). I will water the batteries as per manual SG observations shortly (I would prefer it to be cooler) and then give the batteries an initial equalization, after which I suspect all three L-16 pairs will start acting as I wish, like one big 12 VDC bank.

I have maximal charger-to-bank wire runs of 4/0 ga. to the charger and 2/0 ga. between batteries. It's not zero resistance, but it's darn close! The charger also has a temperature sensor directly on one of the negative posts.

I can't imagine automating charging through any charge source without the charger being "aware" of the size of the bank, because how else can absorption stage run times be calculated effectively? The "lawyer mode" would suggest "not enough for not long enough"; as you point out, more is better to get to 100% SOC.
__________________

__________________
Can't sleep? Read www.alchemy2009.blogspot.com for fast relief. Can't read? Avoid www.volumesofsalt.blogspot.com, because it's just personal reviews of sea books.
S/V Alchemy is offline   Reply With Quote
Reply

Tags
enc

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: Balmar SmartGauge New in Box Ex-Calif Classifieds Archive 6 22-06-2016 10:28
Real Crew with Real Experience nryder64 Great Lakes 1 17-10-2015 19:09
For Sale: Sterling Batt Charger & Balmar SmartGauge SailRedemption Classifieds Archive 0 04-06-2015 06:08
Crew Wanted: Would you like to be Real Crew on a Real Tallship? ryon Crew Archives 0 19-02-2014 15:57
Crew Wanted: Would you like to be Real Crew on a Real Tallship? (Southern California) ryon Crew Archives 2 18-02-2013 08:22


Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 03:45.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.