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The SmartGauge is an interesting product and I have ordered some for the store I work in. I may try one myself. Currently I have a Link 10.

There should not be any reason to not be confident of the Victron though. As long as it knows the bank size in AH, has the correct Peukert programmed, and is reset when you know the batteries are fully charged it should be very accurate. The failing of the Victron and others like it is that they become less accurate unless synchronized regularly.

Here is the link to Maine's review of the SmartGauge:
Smart Gauge Battery Monitoring Unit Photo Gallery by Compass Marine at pbase.com
 

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Discussion Starter · #5 · (Edited)
Interesting writeup here which describes using the Smartguage in conjunction with an AH counter like the Victron 600 (which I have also). Basically, the AH counter is programmed with Peukert = 1.0, charge efficiency = 100%, etc., and is simply used as a straightforward ammeter and AH consumption counter (where it excels), while leaving all the SOC calcs to the Smartguage (where it excels).
 

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The SmartGauge is an interesting product and I have ordered some for the store I work in. I may try one myself. Currently I have a Link 10.

There should not be any reason to not be confident of the Victron though. As long as it knows the bank size in AH, has the correct Peukert programmed, and is reset when you know the batteries are fully charged it should be very accurate. The failing of the Victron and others like it is that they become less accurate unless synchronized regularly.

Here is the link to Maine's review of the SmartGauge:
Smart Gauge Battery Monitoring Unit Photo Gallery by Compass Marine at pbase.com
Another great article by Main Sail.

I too have a Link 10. I would probably have more confidence in it if I followed the instructions and periodically re-synced it when I knew the battery banks are fully charged. Problem is I believe that batteries need to "settle" for a period in order to get an accurate read on their charged state. Usually, after a long motor, when I feel confident that the batteries are fully charged you start putting on the juice, radio lights, water pump, etc.

The SmartGuage seems to be a much simpler option. It looks like the SmartGuage can also operate a relay. I would like to be able to run my Espar heater without the concern of running down the house bank. I'm thinking it might be fairly easy to swap out the Link 10 for the SmartGuage given that it appears that Link has more lines run to the batteries and shunts than appears to be needed for the SmartGuage. Maybe some reconfiguration and elimination of unneeded wires.

I'm smart enough to know there is a lot I don't know but not smart enough to know what I don't know.
 

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Another great article by Main Sail.

I too have a Link 10. I would probably have more confidence in it if I followed the instructions and periodically re-synced it when I knew the battery banks are fully charged. Problem is I believe that batteries need to "settle" for a period in order to get an accurate read on their charged state. Usually, after a long motor, when I feel confident that the batteries are fully charged you start putting on the juice, radio lights, water pump, etc.

The SmartGuage seems to be a much simpler option. It looks like the SmartGuage can also operate a relay. I would like to be able to run my Espar heater without the concern of running down the house bank. I'm thinking it might be fairly easy to swap out the Link 10 for the SmartGuage given that it appears that Link has more lines run to the batteries and shunts than appears to be needed for the SmartGuage. Maybe some reconfiguration and elimination of unneeded wires.

I'm smart enough to know there is a lot I don't know but not smart enough to know what I don't know.
No need to get rid of the Link. Keep it and use it for monitoring current, charging or loads. Ignore the % charged and Ah screens and use the Smart Gauge for that...

For an Ah counter to be accurate for SOC is much harder than most folks are willing to work for...

At a bare minimum they need to know:

Bank capacity = ACTUAL not THEORETICAL (CWA)
Battery Temp = Or a known "ballpark"
Charge Efficiency = Can't even begin to be accurate without this. (CWA)
Peukert = If this is wrong there is no way it can even get close. (CWA)

*CWA= Changes With Age

On most boats auto-synch should simply be disabled and "known full re-sets used.

To properly use an Ah counter the bank should ideally be 20 hour capacity tested once per year. This can be done two ways:

Method #1 (at a battery temp of 75F - 80F):

#1 Apply a load of C/20 to a FULLY CHARGED battery and start a stop watch. C/20 is the 20 hour Ah rating divided by 20. So a 125Ah battery would get a load of 6.25A for 20 hours before hitting 10.5V.

#2 Connect a DVM to the battery terminals.

#3 Adjust the load/current as voltage falls to maintain the C/20 rate as precisely as possible.

#4 Monitor battery & load until terminal voltage hits 10.5V then hit the stop watch and record the hours & minutes.

#5 Determine what % of the 20 hours it was able to deliver the 20 hour rate.

Method #2

Replace the stop watch with an Ah counter such as the Victron BMV-600 and count the actual Ah's delivered before hitting 10.5V. What percentage of the rated Ah capacity did you get? Use this as your new Ah capacity and you will be much closer in accuracy. You can also use the Victron to drive a relay and cut the "load" at 10.5V.

*In both methods the "load" needs to remain as constant as possible and requires human intervention to keep it steady as the voltage decays.

*After any discharge capacity test you must immediately recharge the battery bank!

Or just use a Smart Gauge and let it do its thing...;) The best readings for a Smart Gauge are in the am when there is no charging and the bank has been discharging all night.. You really don't need to know SOC more than once ever 24 hours....
 

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No need to get rid of the Link. Keep it and use it for monitoring current, charging or loads. Ignore the % charged and Ah screens and use the Smart Gauge for that...

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Main Sail

Both the Link 10 and SmartGuage can be used to operate a relay, correct? If that is correct would the SmartGuage be a better option than the Link 10 to turn off an Espar heater?
 

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Main Sail

Both the Link 10 and SmartGuage can be used to operate a relay, correct? If that is correct would the SmartGuage be a better option than the Link 10 to turn off an Espar heater?
You can't just cut + to an Espar without allowing it to run through the proper shut down procedure. Doing so can potentially damage the heater... Best to use the SG to drive an audible alarm so you can manually shut it down at the control panel..
 

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You can't just cut + to an Espar without allowing it to run through the proper shut down procedure. Doing so can potentially damage the heater... Best to use the SG to drive an audible alarm so you can manually shut it down at the control panel..
Makes sense as the blower always runs for a bit after it is turned off. I'll see if I can find a wire diagram for the thermostat to see if it could be wired to the relay?
 

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Thanks MaineSail, I just ordered a SmartGauge from the Compass Marine Website.

Here is a simple question; does the SmartGauge come with AWG 14 leads and fuse holders for connection to the batteries, or do we need to buy our own?

Also - I understand that the positive leads need to be run directly to the battery terminal. However, the negative lead is shown as being run only to the house bank. Could I run the negative lead to my negative buss bar, instead of to the battery? (there are no shunts in my electrical system) In my case, this should be the same as running it to either battery's negative post.
 

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Thanks MaineSail, I just ordered a SmartGauge from the Compass Marine Website.

Here is a simple question; does the SmartGauge come with AWG 14 leads and fuse holders for connection to the batteries, or do we need to buy our own?

Also - I understand that the positive leads need to be run directly to the battery terminal. However, the negative lead is shown as being run only to the house bank. Could I run the negative lead to my negative buss bar, instead of to the battery? (there are no shunts in my electrical system) In my case, this should be the same as running it to either battery's negative post.
Comes with a fuse holder but no wire.... Negative must go to the battery terminal..... Every connection adds voltage drop and this is a highly accurate device that requires battery terminal voltage for the best accuracy.....

Shipped out this morning BTW..
 

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Thanks for the follow up, and the fast shipment. I expect it tomorrow.

After more reading, and more learning, I now believe that I will need to do some (minor) rewiring. I had been using battery 2 as the house bank, and battery 1 as the start. I will have to change these.

It seems that the SmartGauge only tracks and displays the State Of Charge (SOC) for Battery (Bank) #1. It will display the voltage for battery 2, and this is printed on the button which selects battery 2 (thus necessitating the wiring change), but it will not display the SOC for battery 2. I believe that this explains why it must be directly connected to the battery terminal for Bank 1.

This is still MUCH better than the old analog volt meter that came with the boat.


See here for a LOT of great technical info on the SmartGauge: SmartGauge Electronics - Products

Please correct me if I am wrong.
 
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