Keep Alive Power

[Don A(Guest)]

Is the keep alive power lead necessary on the engine monitor? I plan to not use this power lead on the EFIS, but didn't know if it was critical on the EMS.
Regards,
Don

 

[dynonsupport]

It is used solely to keep the current time on the clock when master power is not there. So if you don't care about the clock resetting every time the EMS is power cycled you can leave the keep alive line disconnected.

 

[godspeed]

will the ems get power from the battery on the efis if so connected ? to keep the clock time, or will it get the corrected time from the efis ?

Danny..

 

[dynonsupport]

The EMS can not draw power from the EFIS. However, the EMS keep alive line, which is wired directly your aircraft (or other) battery, exists solely to keep the EMS's clock powered so that it does not need to be reset.

 

[alfons]

Alfons

Is it possible to take the keep alive power from the master relay coil?
This coil is connected direct to the batterie and switched to ground if the A/C power is switched on. So when the A/C is off pin 2 on the MDS-D10 will receive power via the coil as your info it will pull only a view mA to stay alive but when the power is switched on then this power source will be short to ground but now the supply via pin 1 will take over!
Is the short to ground when A/C power on causing any problems with the EMS-D10?
I can live with the fact that when pin 2 shorts to ground EMS-D10 internally the A/C power will be switched on.

 

[dynonsupport]

The keep alive's sole purpose on the EMS-D10 is to keep the clock running so that it does not reset to 12:00 every time you cycle master power. If you connected keep alive so that it switched on and off opposite master power, you would likely have brief instants during the master power cycle that there is no power coming in to the EMS. In this case, it would behave exactly as if there was no keep alive line connected at all. That is, the clock would reset. It's not clear to us why you would want to have the keep alive line switch on and off at all though. Most people run this line right to the battery.

 

[fabjab]

What current draw on keep-alive power should I expect to see for the D120?

 

[fabjab]

I am helping with an aircraft where the pilot had installed his battery with reversed polarity after charging it.

Both the D100 and D120 was connected via keep alive power to this setup. Could this have caused any damage to the units or to the internal battery of the D100?

 

[dynonsupport]

The D120 draws milliamps for a fraction of a second at a time - just enough power to keep the clock running when the EMS is not powered on. It is practically undetectable with a multimeter.

Neither the D100 nor the D120 will be damaged by reversing the polarity to the unit.