Brian,
I was not thinking about removing both SOC alerts, just
the fixed one, and maybe then default the configurable
to 5%.
Self discharging rates are very low on lithium cells in
general, and the BMS will normally cut off the battery
long before reaching critical voltage levels, leaving
several months of self discharging without damage. All
third party BMS systems I checked during the last year
or so support this.
I understood from reading a web report on this, that the
roadster BMS does not cut off the battery by a relais,
the car electronics will continue operation until the
battery is dead. The first gen Twizy has the same
problem on the 12V aux battery, that's why I introduced
the 12V alert. That's also a bug, consequences are just
not as expensive.
I don't need the low SOC alert at all, I use the car
nearly every day (the Twizy is my only car), I always
know the SOC and take care to charge it up as soon as
possible, to keep cycles shallow and charge while the
battery is warm. Parking at 100% SOC is also no problem
on the Twizy, as the 100% mark is at ~ 4.12 V per cell,
well below spec max.
But the situation is of course different when you've got
plenty of capacity and fast charging capability.
Regards,
Michael
Am 20.04.2016 um 09:15 schrieb HONDA S-2000:
Michael,
Any battery will continue to self-discharge, even
after it is disconnected from everything.
The Tesla Roadster does disable driving when the
battery is below the single-digit cutoff, but I would
still want a warning so I can come rescue the car! For
example, if it were parked somewhere for a long term
and the charge reached 5% (or even 7%), then I'd want
to know about that because it's not a good idea to
ignore the system and leave it when the charge is that
low. It's certainly a warranty-voiding situation
(although surely no Roadsters are in warranty any
longer).
In other words, it's not a BMS bug. Chemistry dictates
that all batteries will self-discharge, even if very
slowly.
What I'm curious about is why other electric car
owners would not also want to know if their battery
was low enough to trigger an automatic cut-off.
Brian
On Apr 18, 2016, at 2:23 PM, Michael Balzer <dexter@expeedo.de>
wrote:
Tom,
so the roadster doesn't cut off the battery to avoid
deep discharging?
Sounds like a bad BMS bug...
Ok, that's a very good reason why this kind of alert
should be sent out
on all channels available.
Thanks & regards,
Michael
Am 18.04.2016 um 20:56 schrieb Tom Saxton:
Personally, I like
having the second backup warning that doesn’t
depend on a setting being right. It’s a big deal
if our Roadster gets down to 5% accidentally.
Tom
On 4/18/16, 8:35 AM, "Michael Balzer" <ovmsdev-bounces@lists.teslaclub.hk
on behalf of dexter@expeedo.de>
wrote:
Hi everyone,
we've currently two low SOC alerts in the
framework, one is the
configurable (feature #9) min SOC alert in
vehicle_ticker(), the other
is the OVMS_SOCALERT code in
net_state_ticker600().
The latter is fixed to 5% and does not respect
user channel &
notification configuration. Is there still a use
case for this or is it
obsolete?
Regards,
Michael
--
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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