ammeter

[David Hale]

Here's another one for you guys... has anyone checked the accuracy of the supplied shunt and ammeter from the ElectroAuto kit? I'm talking about the +/- 200A gauge for the traction pack. I always trusted it, but never verified. It seemed reasonable. Until now.

Now I have a Hall effect current sensor which I've added so that my Elithion Pro can read the current. This is the sensor, L03S400D15, from Tamura. However, the reading from their sensor is low by a factor of 2. There is a gain factor to apply to this sensor but I'm using the correct gain as given by Elithion. I suppose all I can really do is get a third independent measurement now, but wondered if anyone has ever checked the EA shunt/ammeter, or if anyone has experience now with the Elithion.

Dave 

[Peter Thompson]

The meter from EA is crap.  It is only accurate to 100A or so, above that, it is worse than useless.  When I was using the DMOC, I was able to get current readings from it, so was able to verify the lack of reliability of the meter.  

Of course, I still need to replace it, but for now, I just ignore it and pay attention to the voltage sag instead.

Cheers!

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[David Hale]

Sears has a clamp on ammeter that works with DC, good to 400A, for $45. I'll pick one up on the way home and (hopefully) resolve this tonight. Thanks, Dave.

[David Hale]

The Sears Craftsman 82369 seems decent. It confirms the reading by the Elithion BMS' current sensor. Of course, now we are talking about the fundamental measurement and which technique is accurate. The Craftsman DC clamp-on is using a Hall effect sensor, as is the Elithion BMS. So I'm using a Hall effect sensor to check another Hall effect sensor and a shunt. I don't know what the true accuracy is. The Craftsman manual states that the accuracy is +/- 2.5% -- even if it is 10%, I'm looking for a 100% error, as the ElectroAuto shunt-ammeter is reading 2x what the Hall effect sensors are reading.

I've got to say, the Craftsman is probably not going to be 100% off; I think I'm going to trust the two Hall effect sensors over the EA shunt-ammeter.

Dave

[Peter Thompson]

Probably better to get a different shunt ammeter - I suspect that EA put in the wrong shunt. It would also be nice to get their ugly logo out of my car.  :)

[David Shields]

I have had similar problems. I've never had a working ammeter in my car. I thought I was just too stupid to figure it out.
 
Misery loves company.
 
I plan to take my dash board apart this spring  and change some of my instrumentation. An ammeter is certainly on my list.
 

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Date: Mon, 8 Feb 2016 21:18:41 -0800
Subject: Re: [914ev] ammeter
From: pthomp...@gmail.com
To: 91...@googlegroups.com

[David Hale]

Well, with two meters reading the same I feel I can trust the Hall effect sensor. The current sensor for the BMS is all that really matters. I'll just keep the shunt+analog ammeter on the dash for now. The absolute value isn't important for me to know while I'm driving but I can use it to see how hard I'm accelerating (and if I really want, just /2 in my head!). Dave.