Voltmeter Wiring Question

[Ward H]

I am finally going to install the Blue Sea 8 Position DC Breaker panel, replacing the stock O'day panel. Bought the panel 2 years ago but now I have added a few electrical things installation is top on the priority list.
I have read Maine's articles on battery monitors and decided on installing a analog voltmeter. I understand it will only be accurate after the battery as rested for 24 hours. I plan to use it to check the battery charge state when I first get to the boat.
Our normal sailing plan is 2 to 4 hr day sails using power only for auto tiller and GPS power. The battery goes in fully charged when the boat is splashed and has lasted all season only being charged by the OB for the 45 minutes we use the OB per trip. (out to the sails up area and back)
I'm hoping the volt meter will give me some warning if I start to drain the battery lower than the OB can recharge.

I bought the Blue Sea Analog Voltmeter. The wiring instructions show it wired to the battery positive and the negative to a negative bus bar. It has a switch to select 1 of 3 batteries.
I believe I should run the wires directly to the battery, not to the battery switch, to avoid voltage drop in wiring and connections.
What the diagram does not show is whether you put in a switch to turn it off or on. I can't imagine leaving it on all the time.

Here is the link to the instructions.http://assets.bluesea.com/files/resources/instructions/9310.pdf

Thanks

 

[John T1594]

I installed the same meter back in 2006 and have used it continuously. I have a three battery bank, with two Gp 27 deep cycle units in parallel as my house bank and a separate Gp 24 starting battery as an emergency reserve. Yes, I wired the meter directly to each battery and yes it is on all the time.

 

[centerline]

I bought the Blue Sea Analog Voltmeter. The wiring instructions show it wired to the battery positive and the negative to a negative bus bar. It has a switch to select 1 of 3 batteries.

What the diagram does not show is whether you put in a switch to turn it off or on. I can't imagine leaving it on all the time.

With a 3 position switch wired into a two bank system, the volt meter does not need to be on constantly....

Wire bank 1 to switch position 1... and bank 2 to switch position 2.... switch position 3 will not be connected to anything so when you dont care to have the meter show the voltage, place the switch on 3 and it will be off...

 

[caguy]

What is the typical way to wire a volt meter if you have solar? Do you have to hookup a switch that will disconnect the controller or panel when you test with the meter? Or does it not matter?

 

[Ward H]

John,
good to know it should have a long and simple life and was designed for constant on.
CL,
That's my real plan. Just thought It strange that Was the way it was designed.

Thanks

 

[Maine Sail]

Direct to the batteries is best but you'll want a fuse in the positive conductor within 7" of the positive battery terminal.

With a three way toggle switch you can also add.

Batt 1 Volts
Batt 2 Volts
Voltmeter OFF

 

[woodster]

i used a mon-noff-mon toggle and it always goes to off when not used

 

[caguy]

Direct to the batteries is best but you'll want a fuse in the positive conductor within 7" of the positive battery terminal.

With a three way toggle switch you can also add.

Batt 1 Volts
Batt 2 Volts
Voltmeter OFF

Yes, but should the solar panels be disconnected when reading the battery voltage. Otherwise aren't you also reading the controller output as well?

 

[Maine Sail]

Yes, but should the solar panels be disconnected when reading the battery voltage. Otherwise aren't you also reading the controller output as well?

You can read the battery voltage anytime you want but the only time it really relates well to SOC is after being disconnected from all charging and system loads for 24 hours at 70-80F.

With volt meters don't let your batteries drop below 12.1V, under normal house loads, and you'll do okay...

 

[Bill Roosa]

SOC without waiting for batteries to rest

I would have to disagree with most. You can tell SOC while the battery is charging and discharging. You only need to know the voltage, battery capacity (C) and the total amps flowing into/out of the bank. Then use the charts below. C/10=battery amp hour capacity/10. The graphs are for standard flooded cell lead acid batteries, AGM or other chemistries can't use them.