Can i use a y to charge my ECU (FADEC) battery that is buired in the belly of my f-15 with the xicoy fadec ecu sence there is no power to the fadec untill the transmiter is turned on i am thinking it will be ok just want to be sure so i don't destroy it by being dumb

thanks
Arden

It says in the manual that you have to disconnect it from the ECU before charging......so no.

mine says to disconnect it

I have just read the manual on the xicoy site and the cd that was sent to me and i did not find anything about charging the ecu (FADEC) battery . can you tell me where it says you have to remove battery to charge thanks
Arden

If the battery is that hard to get to put a deans connector in accessible location and charge from there. Never charge with it connected to the ECU you will fry it.

say if i put a deans plug male /female and used it as a switch to open the circuit on the positive side to the fadec while chargeing and insert the deans plug to complet the circit to the fadec , would that be isolated enough or would the ground also need to be removed while charging


Arden

Leaving ground connected should not present any problem.

It would be best to disconnect and charge to the battery directly, of course.

If you cannot do that and want to have things permanently wired, go ahead and leave the ground connected to the ECU, battery and charge port in a "Y" connection. Then get a small single pole double throw switch (from radio shack) for the "+" or hot side wiring. To hook this up, connect the center contact (com) of the switch to the battery, one end (L1) to the ECU and the other end (L2) to the charge terminal. Then the charger port cannot possibly damage the ECU.

See a SPDT switch diagram here: http://en.wikipedia.org/wiki/File:SPDT-Switch.svg

In the first position of the switch, it connects battery to ECU (this would be the "run" position), in the second position, it would connect the charger to the battery and leave the ECU floating. This would be the "charge" position.

I tried to draw it with ascii graphics but could not get it to survive posting. Looked good with the editor though :-)

The reason you are cautioned not to leave the battery connected while charging is that the charger may take the battery to a rather high voltage at the end of the charge (depends on the internal resistance of the pack, wire sizes, etc). It could easily be much higher than the fully charged battery voltage (e.g. some 5-cell NiCd packs, when charged aggressively, can get over 8V at the charger terminals).

Caution, I have not tried this, so while I believe this is correct, you need to be careful, especially if you use the same field battery and/or charger to simultaneously charge other batteries in the plane, which can in some cases cause odd problems if the charger uses the - side of the battery as the charging lead and uses the + side as common.

Dave McQueeney

I have cured my problem I can now disconect the battery completly by pulling out the deans plug and charge my battery without damaging the fadec thanks guys for all your advice

Arden