Stupid electric aircraft question

Pi1otguy

Pi1otguy

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Will electric aircraft have better "fuel" gauge requirements than conventional aircraft?

Somehow dubious accuracy of current fuel gauges sounds scary when one can't visual check electrical charges.

Also, are they going to low voltage cut offs? The whole issue that some chemistries are damaged if over-discharged.
 
Pi1otguy said:
Will electric aircraft have better "fuel" gauge requirements than conventional aircraft?

Somehow dubious accuracy of current fuel gauges sounds scary when one can't visual check electrical charges.

Also, are they going to low voltage cut offs? The whole issue that some chemistries are damaged if over-discharged.
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I've been driving a plug in hybrid for the last seven years. My experience is that the percent of battery left is accurate. How far that percent will take you is not, because it varies greatly depends on your speed and the terrain, it takes a lot of energy to climb. There is a battery management system that determines when you are out of battery, in automobiles, this prevents the overdischarge of the battery. I would guess in an airplane it would let you know the percent left until the management system would consider the battery fully discharged, but would let you continue pulling power out of the battery until there was no more, and then tell you to have the batteries checked if you went past the point of a normal full discharge.

I suspect it will be quite a while before there are electric airplanes for cross country use.
 
i've heard the batteries have a little glass window so you check when it's full of electrons.

In seriousness, electric car batteries get measured as %full and I expect airplanes will do the same. As mentioned above, how far a set percentage will take you will depend on altitude and what you're doing - climb, cruise, descend. I'm sure the POH will have the numbers to compute this.

Keep in mind that you still have to have a reserve. As long as you're doing that, the battery should never get down to a low voltage cutoff. Deep discharges can cause damage to a battery, but I expect that level will be far below the 30 minute reserve. Once I took my car battery down to 12%, which equates to about 25 minutes of driving. It doesn't seem to have caused any loss of capacity for me.
 
bflynn said:
electric car batteries get measured as %full and I expect airplanes will do the same.
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I hope so. Surly you've flown a rental with dubious fuel gauges. The gauge that maxes out at 3/4, then waves around like that inflatable sock guys at a car dealer.
 
You won’t need gauges in an electric plane anytime soon. Set the timer for30 minutes and be sure you’re over a runway when it goes off.
 
Probably will read 98% full for 45 minutes then drop to 2% in 5 minutes.
 
Pi1otguy said:
Will electric aircraft have better "fuel" gauge requirements than conventional aircraft?

Somehow dubious accuracy of current fuel gauges sounds scary when one can't visual check electrical charges.

Also, are they going to low voltage cut offs? The whole issue that some chemistries are damaged if over-discharged.
Click to expand...
What do you mean by "better fuel gauge requirements than conventional aircraft?"
Among other things, 14 CFR Part 23, §23.1337(b) states: "Fuel quantity indicator. There must be a means to indicate to the flightcrew members the quantity of usable fuel in each tank during flight. An indicator calibrated in appropriate units and clearly marked to indicate those units must be used." What more do you need?

My plane also gives constantly updated fuel total distance and reserve rings on the chart calculated for wind and fuel burn, don't have to wait for electric planes for that.
 
I don't have a link but I know there is more than one YT video of the European certified Pipistrel Electro out there that specifically talks about the power gauge at some point in the video. I remember that remaining current is dependent on throttle settings and other factors (may be half on climb out and then go to 75% at cruise). Bye Aerospace also has quite a few videos on their eFlyer. Both are amazing and I'd be thrilled to fly one.
 
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