Our customer's aircraft (2008 Flight Design CTLS) has a quirk in the amp section of the D-120. Upon initial delivery, the factory had us disconnect the "keep alive" wire to the 120 ( boot-up problems?) The amps float from +15 to -20 amps and sounds the alarm after it exceeds the factory alarm settings (we verified the correct setting earlier). Battery voltage runs 12.5v to 13.5v. We've checked all connections This has been a recurring problem since initial delivery. Any suggestions?
D-120 Amp floating
- Thread starter flyguy1
- Start date
Your amps and voltage move roam too much. I have a CT and work on many. My voltage stays at about 13.4-13.6. The amps on my CT move between -2 to +3 depending on my power usage.
Dealing with many CT's I would go after the grounding block and wires. This has been a problem with many CT's even when you think they are tight. This cause many guage problems, too. Tighten the through the firewall screw to the grounding block in the instrument panel. I even put an extra washer under it if they have the firewall to make a better connection. The screws on the grounding block that holds everything together get loose. Put a screwdriver to each screw and you may find some loose. I would do these checks first before doing anything else.
p.s.
Any other guage or panel issues that point towards voltage issues?
Dealing with many CT's I would go after the grounding block and wires. This has been a problem with many CT's even when you think they are tight. This cause many guage problems, too. Tighten the through the firewall screw to the grounding block in the instrument panel. I even put an extra washer under it if they have the firewall to make a better connection. The screws on the grounding block that holds everything together get loose. Put a screwdriver to each screw and you may find some loose. I would do these checks first before doing anything else.
p.s.
Any other guage or panel issues that point towards voltage issues?
Greetings Roger,
I've seen many of your posts on numerous blogs. We have run into the ground issue before on other CT's and have done the very thing you suggest. We had an SW that would loose oil pressure when you turned on the landing light
go figure!.
Back to the LS...he does have his 496GPS blink out occasionally, but it does not coincide with the amperage fluctuations. This is probably a software issue with Garmin. We'll go back and supplement the grounds and see if that doesn't straighten things out.
Thanks for the input!
JS
I've seen many of your posts on numerous blogs. We have run into the ground issue before on other CT's and have done the very thing you suggest. We had an SW that would loose oil pressure when you turned on the landing light
go figure!. Back to the LS...he does have his 496GPS blink out occasionally, but it does not coincide with the amperage fluctuations. This is probably a software issue with Garmin. We'll go back and supplement the grounds and see if that doesn't straighten things out.
Thanks for the input!
JS
Sounds to me like one of the two current sense wires going to the current shunt have been broken or disconnected, possibly an open fuse since each of these two wires should have a small 1 amp or so fuse inline close to the shunt. I would not think this is a ground problem since the current reading is a differential measurement across the shunt and is not relative to ground. If either of the two shunt sense wires were disconnected you would probably see the exact readings you describe. Your voltage readings which ARE referenced to ground sound about right to me.