Mark F wrote:Hi Jeremy,
Thanks for your back channel help. I'm still a bit in the dark. My electrical knowledge is minimal.
I've got the Turnigy Watt Meter and want to mount it near the helm of my sailboat. This will require mounting the shunt remotely. I see the the photos of the removed shunt and reattached wires but I'm not clear on where the wires go. Where do I reconnect to the inside of the Watt Meter?
When you remove the shunt from inside the controller, you run two thin leads from the pads where it was connected down to the new shunt location. The shunt is in the negative lead, so all you have to watch is that you keep the connection (load and supply) sides correctly wired.
Mark F wrote: If I unsolder the red wire will the shunt lift out?
The shunt isn't connected to the red wire, it is under the circuit board and has black wires running to each side of it, one from the load side (which normally goes to the controller negative terminal) and one for the supply side (which normally goes to the battery negative terminal).
The thick red wire can be discarded and replaced with a thin red wire to your battery positive terminal, preferably via a switch so that the meter isn't on all the time (you could connect it to your controller positive terminal, as that will be switched).
Mark F wrote:I have a Sevcon controller, can I connect directly to the +/- contacts (B+ and B-) on the Sevcon? Basically short wires attached to the Sevcon B+ and B- with a connector and plug the shunt in there?
The shunt has to connect between the battery negative terminal and the controller negative terminal (B-), with the thin wires from the shunt fed back to the meter. The new thin power feed wire to the meter can be fed from the controller positive terminal (B+).
Mark F wrote:As an aside, would I be able to move just the display? Are there just 2 wires to the display - A and K on the circuit board?
The display circuit board has a lot of connections to it (the long row of pads on one side) and the signals won't run happily over more than a few feet of wire. It's far easier to just remotely mount the shunt.
One thing to watch with your application is that the shunt doesn't get too hot. It's a 0.001 ohm 1% shunt, so at a continuous current of 20 amps it's OK, as the power dissipation will be 20^2 x 0.001 = 0.4W. The shunt has a power rating of 3W, I believe, so should be OK for a continuous current of around 54 amps; anything over that for more than a short burst will risk overheating the shunt. It's fairly easy to increase the power rating of the shunt by soldering it to some big copper tabs. This also makes it easier to create bolted connections to it. I've modded a shunt by doing this, then bonding the shunt to an alloy block (with a very thin bit of mica sheet under it and with one terminal insulated from the alloy block) to make a high power shunt capable of working at around 100A or so.
Please ask questions on the forum, rather than by PM, as it helps others and you'll get a better range of answers.