2G wrote on 12/13/2020 4:47 PM:
On Sunday, December 13, 2020 at 2:49:43 PM UTC-8, Matthew Scutter wrote:
Once I get to about 40% remaining, I can only get ~15kW instead of 22kW. Around 30% it warns me to reduce power below 8kW to prevent battery damage, but doesn't prevent me from continuing. I need about 3.5kW for level flight and 8kW is a ~200ft/min climb. Haven't discharged past 20% yet but it was still able to achieve 8kW at that level.
The default charger is 1200W, so even at 110v 10A should be fine, I also purchased a small 600W 'travel' charger that fits more comfortably in the cockpit with me if I outland at a remote airfield and wanted to recharge overnight, or to tour with.
So since the power (and voltage?) decreases as the batteries are
partially discharged, when it says XX% remaining, what is it a
percentage of? Amp-hours? Energy? Altitude it can climb? And how
accurate is that prediction? (As we know it was disastrously wrong in a
rooftop in CT.)
That glider looked (relatively) intact so I hope the logs from the aircraft will provide some insight when the accident report comes out.
.....
How far you will need to self-retrieve depends upon the flight, not the glider. A Mini-Lak was the glider involved in the case I cited, and the pilot was attempting a 750k record flight. And the oft-quoted self-retrieve distance is way too optimistic - I would cut it in half, and that might be too generous (having to clear a mountain range, for example).
Arguing about the circuit amperage is nit-picking (20A is pretty much standard, but 15A may do as well): you have to have a dedicated circuit is the point.
These electric gliders will perform, just realize that the manufacturer's are not giving you the entire picture on their limitations, particularly regarding safety.
Why does it have to be a dedicated circuit for a 1200W charger? Especially if it's a 20 amp
circuit?
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1