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100v 20a dual meter project:




This project was built for situations where I am trying to measure both battery discharge and charge over the
course of an event. I will be using two 100v 20a meters with watt-hour tracking, wired 'back-to-back' in a
single enclosure. Since the meters only measure current and watts / watt-hours in one direction, one meter
will track charging and the other will track discharging.

This build is pretty standard, with a few exceptions. First, when carving holes for the two meters, the strip
dividing the two meters gets pretty flimsy, so try to go easy on the plastic to prevent it from stretching.
Second, the connector blocks on the meters are intended for wires to lead off to the side, but this box isn't
wide enough to allow for that, so I had to unsolder the block (and the current sense resistor) and flip the
block around so the wires led inward instead of outward.

Also as I don't plan on this box getting exposed to rain, I didn't waterproof the LCDs or the meter buttons.

It should be noted that the 20 amp limit on the meters limits the usability here since battery discharge may
exceed that during normal 100w radio transmission.

I ended up having to do a recalibration on both meters, probably due to having to remove and flip the green
screw blocks. See the link below for instructions on calibrating these meters. I also added clear packing
tape across both meters to make them mostly rain-proof without hindering access to the reset buttons.
(not shown in these pictures)


1 prep

2 hole punch and carve

3 installing bezels and housings

4 wiring and test


multifunction LCD power meters (in meters)


pinfox medium project box (in project boxes)

PZEM meter recalibration (in PZEM-031 power display)


20215.01.17:



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last updated 02/17/2025 at 20:05:34 by make_www_index.command version 2025.02.14.A