Thanks for posting. I learned a bunch.
I'm building my Carbon Cub EX - just finished hanging the engine - now I'm wondering if the EarthX (ETX24C) Lithium Iron Phosphate (LiFePO4) battery is still a good idea. Their website highlights, "In addition to the new physical size of these models, they also come with redundant electronics ['Over Discharge Feature'] on the BMS board and have an LED battery fault light indicator"... Where is the fault light indicator??
EarthX says on their FAQ page... "This battery comes with advanced technology to protect from over discharge, the number one killer of all batteries." A nice feature, no doubt (saves $$). But, below what voltage does the 'Over Discharge feature' kick in?
Lightspeed Ignition says "Plasma CDI systems need a minimum of 6.2 volts to start operation"... What happens if the EarthX Over Discharge Feature has been activated (now 0 volts)? You're strictly operating off the backup battery. Hmmm....
(Sorry for the thread creep)
I was unaware of that feature on the EarthX. That would make it a non-starter (no pun intended) for any airplane with Lightspeed ignition, in my opinion. I want that box sparkin' til the fat lady sings!
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Jon Delamarter
Customer Support Manager
Cub Crafters, Inc.
jond@cubcrafters.com
Office (509)367-5200
We have the ETX36C, there is a comment that I wrote on the battery thread that may be of interest. The protection circuit shuts it down at 11v. The discharge curve is very steep at that point, probably only a few seconds down to 6v if the protection does not cut in. A reason to have a good electrical system monitor and check the backup battery frequently. There is never a question of if the engine will start though.
Thanks. Just got this back from EarthX Support:
Thank you for the question! I want to provide you to the link to the manual that is located on the website as it is full of very useful information. http://earthxmotorsports.com/wp-cont...l_111017_K.pdfThe over discharge feature is activated when the battery is about 98% drained, which is about 11.5V. The discharge curve of a lithium is very different than a lead acid battery and will remain at full voltage (13.3V) and then it will drop quickly.
The most common battery pilots purchase for your plane is the ETX900 but you could use the ETX680 or the ETX1200 depending on your desired performance and spec’s. Let me know if you have any further questions.