Install shunt for battery monitoring

[Ray K]

I looking into the possibility to install battery monitors that requires a shunt in the negative line just before the battery. On my last boat it was easy as the boat had a large dedicated house bank. Engine batteries were separate and each had a dedicated battery. The boat in question this time is a Sea Ray 44 Sedan Bridge which like most Sea Rays do not have a dedicated house bank. They split all DC system and load between 2 banks, Starboard and Port. I'm looking at installing a monitor for both banks but am concerned about the amperage going through that circuit when the QSC500 engines start. Is it safe to put a shunt in negative circuit for this type of setup with a high current draw like a large diesel engine? I would really like to have a separate house bank but this would be too much work if not impossible to separate all the DC now split between the port and starboard banks. I don't know how much the engines draw when starting. The standard shunt is 500A but a 1000A is available.

 

[Ctsearay]

That's a good question, we installed a Balmar Monitor and its done everything we have wanted so far.



http://www.panbo.com/archives/2014/04/smartgauge_battery_monitor_rc_proclaims_paradigm_shift.html
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[Doc O Rock]

Hmmm

 

[Bt Doctur]

starters draw typically 80- 200 amps but all you need is a voltmeter gauge and a double pole double throw toggle switch across the banks

 

[ttmott]

Why not install the shunt on the positives to the boat's systems (should be two) rather than neg battery main wire? This way you can meter the boat's usage within a reasonable range and not worry about the starting current.

Question - why interested in amperage? Are you measuring watt hours for battery load?

 

[Ray K]

The shunt needs to be installed on the negative to capture all power consumed and recharged. Due to the way Sea Ray sets up the battery banks the 2 banks are both to start the engines and be house banks. I am going to try and get a complete wiring schematic to see if there are other alternatives. The problem is if you try to omit some of the current going out of the battery (ie engine starting) you are really not going to get an accurate reading of amp hours used and charged. I was just concerned that the 500A shunt would maybe not be enough for the engine starters.

Question - why interested in amperage? Are you measuring watt hours for battery load?
Installation of a battery monitor to monitor all loads and recharging. Will also be installing and inverter and increasing the size of the battery banks. Had a monitor on my last boat and it gave all info on batteries and there state. Was very usefull when off the grid for a few days and relying on the generator to recharge. Interested in amperage due to the 500A shunt. Don't want to exceed that and damage it. There is a 1000A shunt available but if not necessary I don't need that one.