[Ovmsdev] Roadster cooldown again

Stephen Casner casner at acm.org
Thu Aug 1 00:24:12 HKT 2019


Thanks.  I've changed the templimit to 30.  The setting of 25 was
probably left over from the testing we were doing last winter.

                                                        -- Steve

On Wed, 31 Jul 2019, Mark Webb-Johnson wrote:

> Steve,
> The output looks correct. The car just only turned on the HVAC twice (2 cycles detected) in the hour.
> The behaviour of the VMS is pretty much voodoo in this. The cycling of RANGE/PERFORMANCE seems to work once every ten minutes or so for hot packs, but In your case it didn't seem to want to go below 30C. That is average temperature - perhaps the control is more on min/max brick temperature? The conjecture Is that too much / quick cooling would be a bad thing as it would cause condensation within the pack/
> Below 31C should be fine to turn off the little coolant pump.
> Regards, Mark.
> > On 31 Jul 2019, at 5:58 AM, Stephen Casner <casner at acm.org> wrote:
> >
> > Today my coolant pump was running continuously even though the charge
> > level was only 55% and the ambient temperature was only 77F, although
> > the battery was at 89F (32C) left over from a drive last evening.  So,
> > I decided to try cooldown again.  The log is below.
> >
> > This time the charge current was properly managed at 12A and Range
> > mode.  The A/C fans came on soon after starting and the battery temp
> > was reduced from 32C to 30C in 3 minutes.  However, after that the
> > temperature did not drop further, even though the templimit is
> > currently set to 25C, except for a brief period at 29C for 3 minutes
> > about halfway through the hour time limit before returning to 30C.  I
> > didn't monitor the whole time, but I didn't notice the A/C fans on any
> > more.  Does the Roadster not try to cool below 30C?  Yet when we were
> > testing last winter while the ambient temperature was cooler, I was
> > able to set the templimit to 19C and the car did cool the battery from
> > 20C to 19C in the test.  Perhaps the car's goal temperature is based
> > on some delta from the ambient temperature.
> >
> > This time the session correctly did not turn into a regular charging
> > session after the cooldown time limit was reached, and the coolant
> > pump did stop running.
> >
> >                                                        -- Steve

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