Reply To: Variable Regen

Aptera Community Aptera Discussions Variable Regen Reply To: Variable Regen

Aptera Community Aptera Discussions Variable Regen Reply To: Variable Regen

  • George Hughes

    October 3, 2021 at 10:50 pm

    The regen you get when cruising, whether heavy or light, is just a tool you can use to control speed. If you control speed wisely, you can maximize regeneration and often do so using one-pedal driving.

    First, heavy regen is useful for driving where there is a lot of acceleration and slowing, as in running through hilly curves on a secondary road or just plugging along in heavy traffic.

    Certainly most of us remember driving an ICE car down a long steep hill. In those circumstances, truck drivers often shift to a lower gear to avoid over-heating the brakes.

    We all know that it takes energy to go up hill and one of the advantages of an EV is that it will generate energy on the way down which ICE vehicles can’t.

    Regen feels like a lower gear going down hill and is strong enough to slow the car when going down hill on most hills.

    In the Spark EV I drive, there is negligible difference between high and low regen, as measured by KW generated, when going down mild hills at a speed set by cruise control. When going down steeper hills, the normal regen found in “D” on the Spark, will be overwhelmed by gravity and it will accelerate. However, in “L”, my EV is capable maintaining the speed set in cruise with an increase in the KW generated number on steeper hills.

    The instrument display of the Spark allows the display of +/- KW in real time in one of its screen options. This provides a precise instrument to gauge your power use.

    For instance there is about a six-mile run from the western part of the county to the center that is largely downhill. Of course it includes up-hill portions but on average, you lose 150-200 ft. of elevation going west to east. I set the car’s cruise at 55 at the first hill crest. The motor is generating at about 4-5 kw as I head to the valley. As I head up the next hill, I limit my kw power to no more than 20 kw. This costs me maybe three mph by the time I hit the crest of the next hill where the decline is significantly larger. I add enough KW (no more than 30kw) to regain my speed which results regen in “L” rising to 20-25KW in following 40-60 seconds of regen. The next rise is relatively mild and I let the cruise maintain 55 mph as the KW output to power the motor remains under 15kw … and so on with adjustments made with the cruise controls.

    The point is by the time I’ve reached town, my GOM range has increased 2-3 miles. In another 8 mile run to town on some back roads, I can get the display to report consuming energy at the rate of 6.8 miles/kw using the same technique.

    Bottom line, maximizing regen is a ‘game’ you can play provided you have the instrumentation. I do hope the Aptera will have real-time numeric display of power in both acceleration and regeneration. This allows you to gamify driving with hand controls.

    The funniest take-away of this ‘game’ is that folks in ICE vehicles – particularly Semi’s – tend to exceed the speed limit down hill to make it easier to get up the next hill.

    By my use of gravity to maximize regen, the ICE vehicle driver has to put on the brakes to maintain 55 wasting that energy heat. The funny part is when I maintain 55 uphill they are usually left behind.

    Besides the game, I use maximum regen to maximize my one-pedal experience.