Wire heating is very real - hence there are derating tables for selecting
wire gauge for an application - ampacity. 4% change in resistance over
10°C is significant Insulation severely derates copper conductors.
I am familiar with Allegro Microsystems Hall sensors and most are
temperature
From: Michael K Johnson via EV ev@lists.evdl.org
That AH meter at lightobject looks very interesting. It doesn't say
what shunt or range of shunts it can use that I can see.
I have a buck converter that I can put on my tractor to power the
meter, but obviously I'd need to use a shunt to
Because the resistance of copper changes 4% for every 10 degree change in
temperature.
Manganin, which shunts are made of, barely change at all. Typically it's
less than 0.05% in the normal temperature range and 0% around 30-40C.
Here's a graph http://images.elektroda.net/89_1304228034.png
Copper
I don't use manganin battery leads (no one does), but I like a
temperature-stable reference, and 10-15mV drop in normal operation is
noise. ☺ And my longest battery lead is in the middle of my pack so
it's biased by half the pack, which would mean that it would be more
of a pain to measure since
The problem is that 10-15 mV is noise on a battery cable, but 20-30% of range
for a typical meter with 50 mV input sensitivity. That's why you need a shunt
that is very stable.
Mike
On May 14, 2014 6:26:15 PM MDT, Michael K Johnson via EV ev@lists.evdl.org
wrote:
I don't use manganin
Thanks for bringing that to my attention, Peter, although ±4% for 90% of the
typical annual temperature change here isn't TOO bad! I'm guessing temperature
affects on battery capacity are of a similar magnitude.
I think I like the hall-effect torus sensor better. A 50 mV drop at 500 A is 25
Jan Steinman via EV wrote:
Thanks for bringing that to my attention, Peter, although ±4% for 90% of the
typical annual temperature change here isn't TOO bad! I'm guessing temperature
affects on battery capacity are of a similar magnitude.
Keep in mind that the wire also heats up from the
