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Old 01-24-2010, 11:58 PM   #38 (permalink)
bwilson4web
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Join Date: Mar 2009
Location: Huntsville, AL
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17 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

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Quote:
Originally Posted by orange4boy View Post
. . .
Apart from parking lots and warm up, Should I be avoiding EV on my trips . . .
Heat is the enemy of batteries and the primary sources:
  • Parking in sun in the South - the battery works most efficiently at 'nice' temperatures.
  • Avoid high charge events - descending hills or mountains, say 500 ft or more, be sure to use "B" to minimize overcharging the battery.
Charging NiMH batteries is exothermic and generates some H{2} and a little O{2} leakage. This increases the internal module pressure and strains the terminal "O" rings. All of the failed and weak modules I've tested are low on water and I'm sure it is from gas leakage exasperated by high temperature.

Quote:
Originally Posted by orange4boy View Post
. . . and P&G instead?
Uh, once I'm in Stage-4, I only drive using cruise control ... all the time. I do use "N" when the ICE is warming up before Stage-4 and when stopped to minimize fuel burn. But in all other cases, I used cruise control and seek:
  • speeds 38 mph or under
  • speeds 45 up to 65 mph
  • avoid all others
Quote:
Originally Posted by orange4boy View Post
. . . It's so hard to resist the ev mode but am I cycling the battery too much?
Go by battery temperature. If you are keeping it moderate, say +5 of ambient, no problem. If you are heating the traction battery much higher, see if you can reduce the heat-up. Otherwise, I see no problem with EV.

My approach on EV is:
  1. use the 45 seconds to maximum effect
  2. all but last 1-2 miles, ordinary driving avoiding the bad speed ranges (39-44 mph and above 65 mph)
  3. maximum range speed, ~18 mph
  4. 38 mph works very nicely with a mix of ICE and EV power
  5. 65 mph is an excellent highway cruise speed
  6. 55 mph is an efficient hill or mountain climb speed (follow trucks!!)
  7. ~22 MPG at 100 mph but I don't recommend it more than once per year
  8. maximize EV on the last 1-2 miles, speeds of 30-25 mph work great

Bob Wilson
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2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL
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