Parry

If you are near Canberra I am almost finished a Waiex Model B. Would be happy to show you around

A few observations on EarthX batteries, specifically the ETX680

 

This was installed in an aircraft with a 912ULS and standard regulator mounted on the cockpit side of the firewall.

 

The fault line was connected to the EFIS so any fault condition was immediately apparent.

 

Not long after install a fault condition was reported which after consultation with the manufacturer it was decided that the fault was indicating that the cells were not quite balanced. The suggested solution was to charge the battery at a slightly higher voltage (14.2v) instead on the 13.8v which was output from the rotax regulator. The battery was removed and charged at the higher voltage and the fault disappeared.

 

I decided that because the charging voltage was on the bottom end of the spec (13.9v to 14.6v), that the charging voltage on the rotax regulator would be increased to 14.2 volts.

 

At this increased voltage there have still been 3 occaisons over 50hours of flying where a fault has been indicated, but the fault condition soon clears after 5 or 10min or so. Possibly a slightly higher charge voltage would stop this but I havent bothered. My suspicion is because of the cell balancing circuitry, a higher charge voltage is beneficial in helping the cell balancing operate. ( no higher than 14.6v of course)

 

Although the manual says “no jump starting from a car battery” the warranty section clarifiies no jump starting from a battery of significantly higher capacity. It does not rule out jump starting persay. This indicates to me that jump starting from a small lithium powercube would not be a problem.

 

The battery cranks the rotax so well I think more care needs to be taken in choke/throttle settings so that as the engine fires up excessive load is not placed on the sprag clutch.

 

As an aside, when the battery is partially flat, the battery charge current in the above environment is about 8amps. Under this condition with all the other loads the regulator temperature reaches about 70deg on a 25deg day. (regulator output approx 18amp under this condition)

 

Very happy with this battery, saves a few kgs, fantastic cranking regardless of ambient temperature; except of course for the price, although it is supposedly lasts a lot longer.

 

Franky

 

Franky,

Could you let me know how you changed the voltage to 14.2 volts as I am thinking of doing the same in my 912 ULS

Murray