If It Ain't Broke ...

The patron saint of aging do-it-yourselfers, Red Green, said it best. After a summer with no break downs or other excitement, I was feeling the itch to make some "improvements". After all, projects like EV conversions are never really finished, they're just waiting for the next opportunity for skinned knuckles and sore backs. The internet presents all kinds of temptation, and I'm a sucker for amazing Chinese technology.

I found this little gem on Amazon and it seemed too good to pass up: a voltmeter/ammeter with simple amp hour counting to drive a battery gauge for a remarkable price and available in the US with free delivery for Prime customers.

The illustration shows a USB connection from the shunt/logic unit to the display, but it also has a built-in wireless link. The font is a nice size and can be reversed (black on white) for better visibility. While it caps at 300 amps it has a 500 amp shunt. I have never seen over 300 battery amps on either the MG or Porsche, so at 400 volts it should be just right.

You may recall that the PorschEV dashboard was built around an EVIC display for most of the system monitoring. As it turns out, there were several factors that have made it less than optimal as I lived with it for the last three years. First, it is very difficult to see in any kind of sunlight. The only time it's really visible is during night driving. Second, since I revamped the cooling system, the temperature read-outs have been largely irrelevant. If I need to check the temps, I can access the wireless GEVCU data from my iPhone. Third, while it accurately displayed the pack voltage, the amp hours and battery capacity display never worked correctly and for reasons I fully understand and accept, were not going to get fixed. Finally, after reconfiguring the GEVCU for full power, I learned that the Siemens motor had plenty of torque to essentially go direct drive. I wired in a switch for electronic reverse and simply leave the transaxle in fourth gear. That makes the rev counter display uninteresting. The net result is that the EVIC display was not adding much value to the driving experience.

The original dash panel was still gathering dust under my workbench, so a little fun with a hole saw made it a nice place to reconfigure the driving info center.

Black paint makes the base disappear. The speedometer was mounted in the center with the Volt/Amp meter on the right and the air conditioning control to the left. You may recall that I originally placed the AC controller on a windshield suction mount because there was no room on the dash. Now it's nicely integrated and in the line of sight.



You may also recall that I cobbled together a charging display for the rear of the car so I could keep tabs on charging progress. That required an extra contactor, a shunt, a couple of relays, and a box to mount the display and hide the spaghetti wiring. Oh, and it burned out pretty regularly. Not terribly expensive, but not the kind of reliability you'd want for a plug and play function. 

Since the shunt/logic unit supports multiple displays, I replaced all of that paraphernalia with a single piece. Wireless is very cool!