Red (+) lead of the supplied USB sense cable, plugged into the supplied USB adapter in any 120V outlet on the generator (a 5-20R)
USB cable lead
SENSE −
Black (−) lead of the same cable
USB cable lead
— (no GenStart terminal)
L14-30 → EG4 GEN AC input stays exactly as it is today
Existing cable
Start Signal — Three Ways
Option
How it works
Use it when
1. Dry contact (wired)
A 2-wire contact wired to START SIGNAL IN (SIGNAL and COMMON): your inverter's or transfer switch's generator-start output, or the normally-closed contact of a relay whose coil is powered by utility power. Closed = run the generator, open = stop it.
The inverter or transfer switch is close enough to run two small wires to GenStart. Available now.
2. Wireless
The Wireless Dry Contact Bridge Kit: a signal-source board at the inverter reads its contact and sends it by radio to the GenStart board at the generator, which then starts and stops the generator exactly as shown on this page.
The inverter is too far from the generator to run the wire. Available now (the kit replaces the controller).
3. Utility power loss
A second supplied 5V USB adapter plugs into an outlet powered by the utility, not by the generator. Wire its USB cable's red (+) lead to START SIGNAL IN SIGNAL and its black (−) lead to BATTERY − (ground). Do not use COMMON for this: on GenStart, COMMON is a +5V output, not ground, and wired there GenStart cannot see the outage. In GenStart's web page, open Settings > Start signal and set Start signal type to Utility power loss (5 V adapter). When the adapter's 5V is gone for the Start delay after loss (default 10 seconds, 1–600), GenStart starts the generator. Once utility has been back for the Stop delay after return (default 300 seconds, 0–7200; 0 keeps it running until you stop it), GenStart stops it.
Backup for utility power through a transfer switch, with no separate relay. Available now in firmware 3.15.8. A GenStart uses one start signal: the inverter dry contact (option 1) or utility power loss, not both.
UTILITY POWER LOSS: Anything that removes power from the utility adapter looks like an outage to GenStart: unplugging it, a tripped breaker on its circuit, or a damaged or disconnected cable will start the generator. Plug it into a dedicated utility outlet that stays on and that the generator does not feed (if the generator powers that outlet, GenStart never sees the outage end). Use the start delay after loss to ride through short blips.
Settings — GenStart Web Page
Setting
Value for the XP9500iH
Why
Start Mode
Button
The XP9500iH has no two-wire start input; its panel button is the control point
Double-Press Gap
Off (single press)
One press-and-hold starts this generator
Press Length (Start)
3 seconds
Manual: hold the START button until the light turns green
Press Length (Stop)
3.5 seconds
Manual: hold the button about 3 seconds to shut down
Start Confirm Time
15 seconds
The 5V running-sense signal must appear within this window or the attempt counts as failed
Retries / Retry Delay
3 / 10 seconds
Automatic re-try; after 3 failures GenStart stops and reports a fault
NOTHING FACTORY IS MODIFIED: The two START/STOP wires splice alongside the existing button wires (posi-taps or solder and heat-shrink). No wire is cut. The choke (automatic), ignition, fuel system, and wireless key fob are untouched and keep working. RUNNING SENSE — 5V USB, NO 120V INTO GENSTART: The supplied USB adapter plugs into a 120V outlet on the generator, and the supplied USB sense cable carries its 5V to SENSE + and −. It only has power while the generator is producing power, which is how GenStart knows the engine actually started; without it it cannot verify a start or retry a failed one. If your generator has its own USB port that is live only while the engine runs (check with a meter: 0V engine off, about 5V running), you can plug the USB sense cable into that instead and skip the adapter. Never wire 120V or 240V to any GenStart terminal. SOC THRESHOLDS: Set 45% start / 90% stop in the EG4's own menu. GenStart simply follows whatever the EG4 contact does. PROPANE: If you switch fuels, the tank valve must be left open for unattended starting to work. SAFETY: Disconnect the generator battery before you begin wiring.