GRT Sport EX install

Gents, I am upgrading my steam gauge panel on my RV9A with a 7" Sport ex and a GRT EIS, which I plan to mount on the panel above the radio stack as well.
I have the new sub panel cut and ready, and plan to install a switch from the power source to the Sport EFIS, so it can be off during engine start. I am wondering about the Engine information panel. (EIS 4000).
how did you guys do it?
Did you run both the EFIS and the EIS from the same switch?
Seperate them ?
Switch one and not the other?
The manual recommends a switch, but also I watched the videos and multiple power sources are also recommended, with the backup source being on all the time. Wont this defeat the purpose of having a switch on the primary power? Wont the EFIS power up from the backup wire during engine start when the master is on?

Another thing..I have tried to register on the GRT forums, and post questions there, but I cant get thru the registration page..it asks for the "registration code of the day" as the last question. I cant figure out where to get that. anybody know?
Thanks!

N333M said:

multiple power sources are also recommended, with the backup source being on all the time. Wont this defeat the purpose of having a switch on the primary power? Wont the EFIS power up from the backup wire during engine start when the master is on?

Click to expand...

I had dual batteries, little one powered up the EIS and EFIS so I could start the engine on the big battery, and not brown out the avionics. There was a diode that prevented current back flow from the backup battery to the main battery.

The advantage was I could boot up the panel, then watch the fuel pressure build during priming (fuel injection) prior to start, then check oil pressure and other engine factors as soon as the engine started, and not wait for the electronics to boot up.

My rv

I have the EIS on the master bus, other than a circuit breaker, no switch. I have the GRT EFIS on the avionics bus switch. Since the GRT EFIS has multiply power inputs, I have a second power input on a backup battery with a switch. One advantage of this backup battery is I powered up the EFIS off the backup battery for engine start. This has worked for me.

The EFIS has a primary and secondary power input. Wire the main bus to pin 1. Wire your backup power supply to pin 2. Turn on both prior to start. The main bus voltage will oscillate during cranking, but the pin 2 power will prevent brownout, as the two power sources are connected internally with diode isolation.

You can do the same thing with the EIS, externally. Mine is wired through a junction block. "MAP" is power to the manifold pressure sensor, which also taps dual power:

My EIS does not brownout or restart when my Sport SX would. I have since used the EFIS second power input and a small supporting battery- issue resolved.

I used the same two power sources and two external diodes on a Trutrak PFD install and it functions well, no brownout or reboot at engine start.

EIS manual calls out 10.5v minimum in the wiring harness diagram, but doesn't it function to about 9V?

I've never seen it brown or blackout or restart.

ahhh..battery

So, I gather from these answers, that when the manual mentions secondary power, it means backup battery power. I didnt get that before. Perhaps I need to consider obtaining a battery.
Any recommendations?

Anything 12v can work.

I use a small sealed lead acid, small as in 800mAh.

A double pole, single throw switch connects it to the GRT EFIS secondary input. The other pole is my battery contactor bypass endurance circuit. You don't need anything but a 1.5 to 5 amp fuse or breaker and a single pole, single throw switch. Each unit uses about 1 Amp per hour per the install manual.

I happen to have the backup battery trickle charge in flight, but you can skip that also. Mine is on an RC quick disconnect and mounted below the left seater's left calf on the left sidewall. Easy to grab leaving the plane and recharge if you don't want to bring the recharging to the plane or add a charging circuit.

There are many ways to utilize a secondary battery, I went with the smallest single sealed battery I could find around 1AH. Four of the AA-sized 3.7v lithium cells would be smaller, but I wanted a SLA. Mags and carb on my -6, single Denso and single Deka SLA main battery

RE: Wiring GRT

What Moosepileit said about brownout of the EIS. My GRT EIS is only connected to the main 14V bus via a ckt breaker and it stays powered up during engine start. Actually it's nice feature of the GRT EIS.

With regard to back up power battery, GRT recommends TCW Technologies BU battery products. They are maybe a little expensive but the charging, status reporting etc. are designed into the backup battery unit which helps simplify the installation, maintenance of back up power etc.

I initially installed the TCW "IBBS-12v-3ah" battery to provide backup power to both of my Sport EFIS units and the external Arinc 429 module, but you have to remember to switch the BU battery on before engine start and shut it off after shutting the engine down.

I replaced the battery unit with a TCW "IPS-12v-4a" Power Stabilizer. Once installed, the Power Stabilizer device doesn't require any operator interaction, doesn't require any maintenance and keeps my EFIS units from resetting when the primary bus voltage sags during engine start and which is all I need.