Best battery monitor system?

[William_H]

Call me ignorant but that seems like a load of bovine product. Present an AC voltage across a battery you get in the positive cycle that will tend to charge the battery. On the reverse part of the AC cycle you will tend to get a discharge. There is no reason to get a phase change and nothing is going to change at varying frequencies. You could measure the current on both cycles but what will that tell you? " AC impedance spectrography" sounds like the names doctors gave to various illness a long time ago when they had in fact no idea what was going on. olewill very sceptical

 

[GHA]

Call me ignorant but that seems like a load of bovine product. Present an AC voltage across a battery you get in the positive cycle that will tend to charge the battery. On the reverse part of the AC cycle you will tend to get a discharge. There is no reason to get a phase change and nothing is going to change at varying frequencies. You could measure the current on both cycles but what will that tell you? " AC impedance spectrography" sounds like the names doctors gave to various illness a long time ago when they had in fact no idea what was going on. olewill very sceptical

The device seems to ignore your scepticism and provide accurate data....

http://www.pbase.com/mainecruising/smart_gauge

 

[sailinglegend420]

Call me ignorant but that seems like a load of bovine product.....

I very rarely use my signature here but your response demands some comment! For those who have signatures turned off here is mine.

Ignorance isn`t what you don`t know, but what you think you know that is incorrect.

 

[aluijten]

This is the basis of what he said - 10 years ago!

Obviously I am not prepared to disclose how SmartGauge works. Anyone who asks me to do so is simply being totally unreasonable.

But 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.

The full Chris Gibson post is at,

http://www.ybw.com/forums/showthread.php?73924-Smartbank-battery-management/page2
post number #42

As said by other, this sound fishy at the very least. Moreover if Mr. Gibson was so clever in his algorithm he could have patented it for protection. Being mystical about it builds very little confidence in my book. To me this feels like the discussion on loud-speaker cables and the effect on sound quality.
If the smart-gauge uses some impedance measuring trick so determine the SOC, fine but there are so many different types of battery construction all with different impedance characteristics making it hard to tell the SOC. Even the wires connecting the gauge to the batteries could influence the result.

By the way I'm using a Mastervolt battery monitor that does have some aging algorithm in place as well, so the SOC is reflecting the actual capacity of the battery instead of the new capacity.

 

[sailinglegend420]

.....If the smart-gauge uses some impedance measuring trick so determine the SOC, fine but there are so many different types of battery construction all with different impedance characteristics making it hard to tell the SOC. Even the wires connecting the gauge to the batteries could influence the result....

You have to tell SmartGuage what type of batteries you have but not their Ah capacity and you have to use 14 AWG wire to connect it. I suggest you read the manual before you make any more comments.

EnerSys, who make Odyssey batteries, tested SmartGuage and found it to be amazingly accurate to within less than
3% error. The longer it measures the batteries the more it learns about them and the more accurate it gets. With a shunt based Battery Monitor exactly the opposite happens!

 

[pvb]

EnerSys, who make Odyssey batteries, tested SmartGuage and found it to be amazingly accurate to within less than
3% error. The longer it measures the batteries the more it learns about them and the more accurate it gets. With a shunt based Battery Monitor exactly the opposite happens!

Many shunt-based monitors automatically reset themselves, provided the batteries are allowed to become fully charged, and therefore remain accurate.

 

[prv]

As said by other, this sound fishy at the very least. Moreover if Mr. Gibson was so clever in his algorithm he could have patented it for protection. Being mystical about it builds very little confidence in my book.

I'd usually agree - being coy about how something works doesn't inspire confidence. However, there have been a number of independent tests which report favourably on the SmartGauge, and I have never seen anybody saying "I tried it and it didn't work". Anecdotally I've used them on two boats now and the display has always been believable - although of course I don't have any other facility to measure the "true" state of charge for comparison!

Trade Secret is recognised as a legitimate alternative to patenting, and I can think of two reasons why he might have preferred this option: 1) he's a bloody-minded old sod , and 2) the Chinese make a lot of electronics and generally don't respect patents.

Pete

 

[ianc1200]

On Straight Across I have a Smartguage & a Sterling amp hour meter. Find the Sterling interesting to see what's going in & going out, but the Smartguage every time for what charge is in the batteries.

 

[ditchcrawler]

On advice from a marine commercial electrician I bought a volts only read out LCD which is connected so I can get a reading from both my domestic and starter batteries by using my 1/2/both switch.Total cost just over £9 off E Bay.Dead easy to wire in as only two wires.It seems to do the job.Of course it does not monitor amps etc but the voltage gives a good indication of battery state.I can see a bit over 14.2 volts when my Sterling charger is on going into the battery.
He fitted 3 of them when he rewired his boat as he has 3 battery banks with individual switches.
Cheap and cheerful I know but for the price of some monitors I can buy a couple of batteries.
I have a Red Flash AGM just for starting and a couple of Numax 110a/h batteries as my domestics.

 

[pyrojames]

I used to have a BM1 on a previous boat and was extremely sceptical about the Smartguage. I thought long and hard about what to fit on the current boat. The BM was OK but it clearly didn't really get the state of charge right, and it got worse as the batteries aged. I have had the Smartgauge for around 4 years with a period of 9 months cruising. For state of charge I can't fault it.

As a reasonably scientific/engineering individual I consider the that the advertising that goes with Smartguage sounds plausible and the results speak for themselves. I don't know exactly how it works, but it does!

 

[pvb]

I used to have a BM1 on a previous boat and was extremely sceptical about the Smartguage. I thought long and hard about what to fit on the current boat. The BM was OK but it clearly didn't really get the state of charge right, and it got worse as the batteries aged. I have had the Smartgauge for around 4 years with a period of 9 months cruising. For state of charge I can't fault it.

I'm sure lots of people are happy with their SmartGauges, but I still want to see a reading of current. As for "state of charge", I'm not sure what that really tells you - you don't know the actual capacity of the batteries (which drops with age), so knowing that they're say 85% charged doesn't mean a lot. Certainly no more information than seeing that the charge current had dropped to a low level. So if I were to fit a monitor to my newish boat, I'd still go for a good quality traditional shunt monitor such as the LinkPRO or Victron, as the current readings and amp-hour count are very informative.

 

[sailorman]

State of charge chart for 12v batteries

http://www.mmbalmainauto.com.au/PDF/State_of_charge_12_volt_batteries.pdf

 

[pvb]

State of charge chart for 12v batteries

http://www.mmbalmainauto.com.au/PDF/State_of_charge_12_volt_batteries.pdf

For most boat owners, that's effectively useless, as the voltage has to be measured after the battery has "rested" with no charge or discharge, for a number of hours.

 

[pyrojames]

I'm sure lots of people are happy with their SmartGauges, but I still want to see a reading of current. As for "state of charge", I'm not sure what that really tells you - you don't know the actual capacity of the batteries (which drops with age), so knowing that they're say 85% charged doesn't mean a lot. Certainly no more information than seeing that the charge current had dropped to a low level. So if I were to fit a monitor to my newish boat, I'd still go for a good quality traditional shunt monitor such as the LinkPRO or Victron, as the current readings and amp-hour count are very informative.

If you monitor SOC during the day, and it drops from 90 to 75 you are OK for another day. If your AH drops by 50, how much power do you have left? You need to know what your actual capacity is. In my experience, the Smartguage gives you a better way to judge actual reserve capacity than a traditional battery monitor does.

 

[pvb]

If you monitor SOC during the day, and it drops from 90 to 75 you are OK for another day. If your AH drops by 50, how much power do you have left? You need to know what your actual capacity is. In my experience, the Smartguage gives you a better way to judge actual reserve capacity than a traditional battery monitor does.

Most traditional battery monitors also include a "bar graph" indication of state of charge. Many traditional battery monitors also give a "time remaining" figure at the current discharge level.

 

[William_H]

On the subject of battery monitors this little device might be useful. Limited to 20 amps, however. Certainly cheap. I have not seen one but the specs seem to indicate it has a cumulative "watt/hour" readout which can be reset. Watt hours being roughly Amp hours when divided by 13. Could be useful for getting an idea of how much charge you have put into a battery in an engine run or how much charge you have used eg overnight.
Has anyone bought one or seen one? Not sure if it will measure amps and power both in and out possibly not. If not then could be useful for monitoring fridge or other load or have 2 one for alternator charge one for load. It seems like it might have an alarm function for low battery volts also. As with so much Chinese stuff the documantation is often lacking.
http://www.banggood.com/20A-DC-Digi...d=EzQIH4eJFS&emst=EzQIH4eJFS_57040_1520058_42
olewill

 

[dune16]

Sorry to resurrect an old thread. I'm not happy with the battery gauge on the the standard panel on my Jeanneau 389 and am therefore looking to add a standalone battery monitor. Is Smartguage still a good choice 2 years on from this thread or are better options now available?

 

[PaulRainbow]

Sorry to resurrect an old thread. I'm not happy with the battery gauge on the the standard panel on my Jeanneau 389 and am therefore looking to add a standalone battery monitor. Is Smartguage still a good choice 2 years on from this thread or are better options now available?

I fitted a Victron recently. Tells me volts, net amps, SOC, Ah used and lots of other stuff. Has a configurable alarm and a built in configurable relay, which i have set to turn the mains charger on at low volts. A Bluetooth dongle will send it all to your phone or tablet, whilst a cable will send it to your PC (dongle or cable, not both).

 

[RobbieW]

I fitted a Victron recently. Tells me volts, net amps, SOC, Ah used and lots of other stuff. Has a configurable alarm and a built in configurable relay, which i have set to turn the mains charger on at low volts. A Bluetooth dongle will send it all to your phone or tablet, whilst a cable will send it to your PC (dongle or cable, not both).

Whilst we dont know explicitly how the Smartgauge does its magic it does seem to work as attested by those who use it, but it only does SOC. Do you know how the Victron system determines SOC ? Maybe they've licensed the Smartgauge algorithm, maybe it uses a current counting technique. Either way you cant really compare the two without knowing something of the way they work.

I've not come across anything else that does SOC the same way that Smartgauge does.

 

[PaulRainbow]

Whilst we dont know explicitly how the Smartgauge does its magic it does seem to work as attested by those who use it, but it only does SOC. Do you know how the Victron system determines SOC ? Maybe they've licensed the Smartgauge algorithm, maybe it uses a current counting technique. Either way you cant really compare the two without knowing something of the way they work.

I've not come across anything else that does SOC the same way that Smartgauge does.

I didn't make a comparison, i just stated what i fitted and what is showed

I'm not sure exactly how the Victron works out SOC, but you have to program battery capacity and it has an algorithm to tell when the battery is charged. Add to that the ammeter shunt and it's surely simple maths to work out that x capacity - used ah = SOC ?