back to inline meters

100v 100a inline meter project:




I've been needing a way to easily measure higher DC current than my usual 20 amp power meters (and also the
cheap inline meters that CLAIM high current but ship with 18ga wire) so a project for an improved power
meter was long overdue.

For this project I used a power meter similar to the one in my 20a deluxe inline meter project, but went with
the upgraded 100a version that uses an external shunt. I also need to go with the bigger SB50 connectors, and
I don't like the idea of trying to use hot glue to mount them, so I had to track down some panel-mount SB50
connectors. Since both the shunt and the internally-mounted SB50 connectors were going to consume a lot of
space, I had to go with a larger box too. Everything's bigger it seems!

I also used 6ga welding cable internally, the same stuff I recently upgraded my battery harnesses with, so
everything should have no problem supporting 100 amps. The shunt only produces 75mV at 100 amps, so the
wires to the meter can all be skinny. I didn't need to make any big splices, but the propane torch still got
a bit of a workout with those 6ga powerpoles and thick copper wire.

I installed the gasket on the box, but I haven't bothered to waterproof the meter since this one isn't intended
to be left out in the rain. It's s a chunky monkey, all that copper and the shunt puts it at close to 2 lbs.

If I was going to make another one of these I would move the SB50 mounts as far away from the shunt as possible
instead of centering them, to give myself a little more room working with the shunt. Or find a variation on
this meter that uses a pass-through (inline hall-effect) sensor for current measurement instead of a shunt.



100a LCD power meter (in meters)


pinfox medium project box (in project boxes)


SB50 panel-mount (in SB series (50,120,175,350))

01 measure and tape box	02 all this has to fit inside	03 drill holes	04 carving starts	05 carving done	06 fit test external
07 fit test internal	08 builkheads and shunt installed	09 shunt feeds are a tight squeeze	10 wiring complete	11 smoke test maxing my lab supply

highest resolution images
last updated 02/16/2025 at 18:46:08 by make_www_index.command version 2025.02.14.A