Cor van de Water via EV wrote:
It does not matter if the meter is powered from the aux battery or from the
pack,
it will draw something down to zero if the vehicle is parked too long with the
meter running (idle)...
OR, if the meter is switched off, it will lose its current state of
charge no
matter from where it is powered either...
so there is no benefit or drawback from using a non-isolated DC/DC converter
to power the meter from the pack
Yep! Additionally, these meters ignore current under about 0.5 amps
(they treat it as zero). Even if you leave it powered, its reported
amphour capacity will STILL be wrong, because it's not counting the
current that the meter itself draws (because it's below 0.5 amps).
This is a classic problem with *all* SOC meters. If they can measure
high currents (like 500 amps), then their current sensors and A/D
converter simply can't accurately measure low currents (like 0.5 amps).
You could accurately measure currents this low with a really good
6-digit accuracy Agilent or Fluke meter for $1000; but not with a $100
consumer product.
--
Pollution is nothing but the resources we are not harvesting. We
allow them to disperse because we've been ignorant of their value.
-- R. Buckminster Fuller
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
For EV drag racing discussion, please use NEDRA
(http://groups.yahoo.com/group/NEDRA)
