Battery monitor upgrade

GHA said:
....The smartgauge does seem very accurate and would be another nice gadget to have......, IMHO amp counting and an accurate voltmeter direct to the battery are much more useful.
For a boat plugged in regularly a smartgauge could well be the best way forward, especially for those non liveaboard who aren't so obsessed with electrons :)
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The SmartGauge does also measure the voltage on two battery banks, and coupled with an Ah digital counter will be a better battery monitor, especially for those non liveaboard who aren't so obsessed with electrons. The other very key factor is the simplicity of the installation.
 
GHA said:
Would still be nice to have one, but there an awful lot of things it would be nice to have :)
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I have sufficiently large solar panels (100W), sufficiently large battery bank (130Ah) and sufficiently frugal usage (GPS, radio and all LED lighting) that battery condition just isn't an issue. It's a bit like the VW attitude to gauges on the air-cooled Beetle ... they didn't see any point in putting in a temperature gauge when you could just fit a cooling system that worked.
 
sailinglegend420 said:
The SmartGauge does also measure the voltage on two battery banks, and coupled with an Ah digital counter will be a better battery monitor, especially for those non liveaboard who aren't so obsessed with electrons. The other very key factor is the simplicity of the installation.
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How does the Smartgauge distinguish, by battery voltage alone, between a single 100Ah battery and a pair of them in parallel feeding precisely twice the load?
 
The sterling version for me, I have had one aboard for six years, only stopped working, because a wire snapped, which I had fitted, repaired that works fine again. I would not be without a battery monitor, being a liveaboard it is vital to my power management.
 
JumbleDuck said:
How does the Smartgauge distinguish, by battery voltage alone, between a single 100Ah battery and a pair of them in parallel feeding precisely twice the load?
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You have to understand the difference between CAPACITY measured in Ah, and State of Charge (SoC) measured as a % of the ACTUAL maximum capacity not the capacity you think the bank is. That is where the a Battery Minitor falls down, it assumes the Ah Capacity is still the value you entered when you programmed the unit. Reducing this 5% each year may help the BM accuracy, but changing Peukerts and the battery efficiency as the batteries age is not so easy!

So connecting two 100 Ah banks together with the same SoC doesn't make any difference to the SmartGauge.

One very important thing to know about the SmartGauge is it doesn't just measure VOLTAGE. With two wires you can do a lot more, as this posting from Chris Gibson(the inventeor) let out of the bag in 2005. It gives you some idea of how the device MIGHT be working:

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 known as AC impedance spectrography.

http://www.ybw.com/forums/showthread.php?73924-Smartbank-battery-management/page2
post number #42
 
JumbleDuck said:
So it gives state of charge as a percentage but doesn't what it's a percentage of?
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Never had a problem interpreting one of these:

Smiths_Cobra_Fuel.jpg


Of course you had to know the car and having a general idea about its fuel capacity and milage at a given speed certainly helped.
 
JumbleDuck said:
So it gives state of charge as a percentage but doesn't what it's a percentage of?
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But you should be bright enough to add 100 +100 and make 200 Ah. No battery monitors calculate the Ah capacity, some can give you a percentage because you told them what you think the capacity is. If you like counting Ah out overnight and you've lost 50, then you immediately work out in your head you are down 25%. SmartGauge gives you the same info but should be used with an Ah counter. Then you can have Amps or Ah in/out on one meter and next to it the % SoC or the voltage, and you don't have to push any buttons!!!
 
sailinglegend420 said:
But you should be bright enough to add 100 +100 and make 200 Ah. No battery monitors calculate the Ah capacity, some can give you a percentage because you told them what you think the capacity is.
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Battery capacities decrease quite a lot over time, and I thought I had read that Smartgauges were capable of deducing the current capacity.
 
JumbleDuck said:
Battery capacities decrease quite a lot over time, and I thought I had read that Smartgauges were capable of deducing the current capacity.
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Correct, they'll give you a percentage reading of the actual capacity. My battery is just a few weeks old though, time will tell.
Just like on a laptop the battery ages but you should still be able to make sense of the little symbol on your iconbar.
 
JumbleDuck said:
Battery capacities decrease quite a lot over time, and I thought I had read that Smartgauges were capable of deducing the current capacity.
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Nope, just percentage of actual capacity, no hint what that capacity might be. And apparently very accurate on discharge but not quite so much on charge Which relegates them to "would be nice to have one day, maybe" on a full time cruising boat. IMHO.
Comprehensive test here....
http://www.pbase.com/mainecruising/smart_gauge
 
2nd_apprentice said:
Correct, they'll give you a percentage reading of the actual capacity. My battery is just a few weeks old though, time will tell.
Just like on a laptop the battery ages but you should still be able to make sense of the little symbol on your iconbar.
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Laptop batteries are much cleverer! Mind you, in a few years time when we'll all have smart Li-ion batteries we'll look back at all this alchemy and laugh.
 
JumbleDuck said:
Laptop batteries are much cleverer! Mind you, in a few years time when we'll all have smart Li-ion batteries we'll look back at all this alchemy and laugh.
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They don't last all that long in my experience though :-(
A few days ago I had a look at Torqueedo and their batteries btw, luckily I wasn't standing!
 
2nd_apprentice said:
They don't last all that long in my experience though :-(
A few days ago I had a look at Torqueedo and their batteries btw, luckily I wasn't standing!
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True. I've got a friend with a Tesla Roadster, which has fantastic performance but uses up its battery pack at ten thousand pounds per year.
 
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