Battery Percentage Use

[drt135]

I have been doing a number of flights this winter attempting to catch wave in the mountains of Utah.  Great fun, but I am hesitant to use the motor beyond 50% battery power.  Rather like the back-up buffer....   There have been a few times when I could use the additional lift, so I'm curious if any FES users have taken their battery below 50% power on a single flight (while maintaining battery above 90V minimum).  If so, how low of a percentage have you taken it and did you have any issues when recharging back to 100%?  

Much thanks!

Dan Thirkill

[Luka Znidarsic]

Dear Dan and others,

It is not a problem to use battery below 50% SOC however you need to know that when battery packs are cold their internal resistance is higher and this means there will be higher voltage drop when using higher power settings. For winter flights make sure to put warm (and freshly charged) battery packs into the glider before flight and do not use high power settings below 50% SOC, as otherwise voltage drop can trigger critical voltage level 90V, much earlier then expected.

With 4-5kW power setting for level flight is no problem to go down to 90V, and remaining number of bottles will be in line with remaining endurance time, but rather not use it for climbing.

If you want to use high power settings while battery packs are cold, FCU might still indicate 30 or even 40% remaining battery SOC, but voltage drop can easily trigger yellow 95V message "reduce power" or even red critical 90V message "stop engine".

Regards,

Luka

www.front-electric-sustainer.com

-------- Izvirno sporočilo --------

Od: drt135 <drt...@gmail.com>

Datum: 12. 3. 22 01:56 (GMT+01:00)

Za: FES Owners <fes-o...@googlegroups.com>

Zadeva: Battery Percentage Use

I have been doing a number of flights this winter attempting to catch wave in the mountains of Utah.  Great fun, but I am hesitant to use the motor beyond 50% battery power.  Rather like the back-up buffer....   There have been a few times when I could use the additional lift, so I'm curious if any FES users have taken their battery below 50% power on a single flight (while maintaining battery above 90V minimum).  If so, how low of a percentage have you taken it and did you have any issues when recharging back to 100%?  

Much thanks!

Dan Thirkill

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[drt...@gmail.com]

Excellent and good to know.  I do ensure batteries are both warm and freshly charged prior to the winter flights.  Makes good sense.  Keeping the power settings low after 50% SOC is great info. 

Much thanks!  Here’s to reaching a bit higher while chasing lift 😊. 

 

Dan

[Scott Manley]

Luka,

Thank you for the quick, thorough, and very informative response.

SRM

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