User: Brownetown, Location: Va
Asked on: Saturday, June 7, 2025 at 10:45 pm EDT
Answered on: Saturday, June 7, 2025 at 10:45 pm EDT
Question: Recently ran across an older Eaton ATS/load center. Had the 240v sensing wires and 2 low voltage transfer terminal blocks. Long story short it didn’t have the normal T1 terminal for battery charger. Genartor is a honey well older model as well. My question is to get a 120v to the battery charger, I should jumper of normal power load side correct this way there is always 120v going to battery charger?
You're on the right track, but let's clarify to ensure safety and proper functionality. Here's a breakdown of how to approach connecting a battery charger to an older Eaton ATS (Automatic Transfer Switch) and Honeywell generator setup, focusing on safety considerations
Understanding the Problem
No Dedicated T1 Terminal
Older ATS units might not have a specifically designated "T1" terminal for battery charging. This is common, and it just means you need to find an alternative power source that is energized when the generator is NOT running to power the battery charger.
Generator Battery Charging
The generator needs a reliable battery charging system to ensure it's ready to start when needed. Typically, a battery charger is powered from the normal (utility) power supply so the battery remains charged when the generator is idle.
Best Practice: Powering the Battery Charger
The safest and most reliable method is to power the battery charger from the Normal (Utility) Power Source, BEFORE the ATS transfer switch. Here's why:1. Reliable Charging
The battery charger will always have power whenever the utility is available. This keeps the generator battery topped off and ready for emergencies.2.
Avoids Generator Load
You don't want to draw power from the generator to charge its own battery when the generator is already running. This is inefficient and can introduce unnecessary load fluctuations on the generator, and you definitley don't want to draw power from generator once utility comes back on.3.
No Transfer Switch Issues
You don't want the battery charger to switch between utility and generator power. It's designed for continuous charging, and constant switching could damage the charger or affect its performance.
How to Connect (Safely)1. Identify the Utility Power Source (Before ATS)
Find a readily accessible 120V circuit on the utility power side before it enters the ATS. This could be a spare breaker in the main panel or a junction box before the ATS. This is ideal.2.
Install a Dedicated Circuit (Recommended)
Ideally, install a new, dedicated 120V circuit (with its own breaker) from your main panel to a receptacle (outlet) near the ATS. This is the safest and most reliable solution.3.
Connect the Battery Charger
Plug the battery charger into the receptacle you've created (or connected to the existing circuit).
Important Considerations & Warnings Safety First
Work with electricity ONLY if you are qualified and comfortable doing so. If not, hire a licensed electrician. Electricity is dangerous and can be lethal. Turn off power to the circuits you're working on before making any connections.
Code Compliance
Make sure your wiring meets all local electrical codes. An electrician will be familiar with these requirements.
Overload Protection
Ensure the circuit you are tapping into (or creating) has adequate capacity (breaker size) to handle the battery charger's current draw in addition to any other loads already on that circuit. Overloading a circuit is a fire hazard.
Proper Wiring
Use the correct wire gauge for the length of the run and the amperage of the circuit.
Grounding
Proper grounding is essential for safety. Ensure all grounding connections are secure and compliant with code.
Don't Modify the ATS
Avoid making any modifications to the ATS itself unless you are a qualified electrician and understand the potential consequences. Modifying the ATS can void its warranty and compromise its safety features.
Read the Manuals
Consult the manuals for both the Eaton ATS and the Honeywell generator. They may contain specific recommendations or warnings related to battery charging.
Consider a Transfer Relay
If you want to get fancy and have a very robust setup (or if you absolutely cannot find a suitable utility power source), you could use a transfer relay. This relay would be energized when utility power is present. When energized, it would switch the battery charger to the utility power source. When utility power is lost, the relay would de-energize, disconnecting the battery charger completely. This adds complexity but ensures the charger never draws power from the generator. This is usually not needed, but it's an option.
Why Your Idea (Jumpering off the Load Side) Is Risky
While "jumpering off the normal power load side" might seem like a quick solution, it's generally not recommended because: Potential for Backfeed
Depending on the wiring configuration, you could potentially create a backfeed situation where the battery charger is trying to send power back into the generator when the utility power returns. This is unlikely but possible and could damage components.
Interference
The battery charger's operation could potentially interfere with the ATS's sensing and transfer logic.
Unpredictable Behavior
In some ATS designs, the load side is not reliably energized when the utility power is present.
In Summary
The best approach is to connect the battery charger to a dedicated 120V circuit on the utility side, before* the ATS. This provides reliable charging, avoids overloading the generator, and minimizes the risk of electrical problems. Always prioritize safety and consult with a qualified electrician if you are unsure about any aspect of the wiring. Flag for review