Wiring an Inverter.

[sunquest]

I am fortunate that I can get access behind my distribution panel and have room to fit a Galvanic isolator and an Inverter. This I have wired with a double pole switch so the inverter mains supply is available at all mains sockets. Provisionally the 12v supply is wired directly across the battery terminals at the distribution panel. The problem with this is the current drain is not registering through the ammeter and whilst I can calculate the current drain, it would be useful to see what is being consumed. Any ideas as to where the positive should be connected? Thanks Geoff

 

[Wiggo]

The ammeter derives its reading from a small shunt which will be located on one of the battery terminals (can be on either the +ve or -ve post). The shunt will probably look like a small block attached to the post with the main cable bolted to one end of it and two small leads going to the ammeter. If you wire direct to the battery posts you will not register your current draw, so you need to ensure that you connect to the 'distribution' side of the shunt rather than the 'battery' side.

Having said that, if you are picking up both +ve and -ve from the main panel, it should be registering. How big's the inverter?

 

[KevB]

The galvanic isolator should be wired at the point of mains entry to the boat as there is no telling where the earth is attached throughout the boat.

 

[jfm]

Or, an alternative to wiring through the shunt is to use an induction coil ammeter, where the wire whose current you want to measure is threaded through a loop (like a big polo mint) connected to the meter. I have this type on my boat. If you have or fit one of these you simply need to thread the +ve to the inverter through this polo mint loop and its current will be added to the current of any other wires also threaded through the loop, without any actual proper "wiring" of the ammeter or shunt

 

[sunquest]

Thanks for your response Wiggo. Your solution is viable and I will alter the wiring at the weekend. The Inverter is only 350W
and will be used to power the TV and/or a laptop when shorepower is unavailable. Geoff

 

[sunquest]

Thanks KevB. The shorepower feeds from the meter socket to the bus bar, I was able to test the cable for continuity, ensuring I didn't have more than one. I also did a test across the isolator terminals using a diode tester and the readings registerd both ways as to the manufacturers instructions. Geoff

 

[sunquest]

Thanks for your input jfm, I will use Wiggo's suggestion but it is good to have options. Geoff