Why Power Logging Should Happen Before Adding EV Chargers, Solar or Batteries

Why should power logging happen before adding EV chargers, solar or batteries? Because it shows how much power your property actually uses, on each phase and at what times, so new equipment is sized to your real load and your supply's limits. Without it, installers are guessing, which leads to chargers that trip the main switch, needless supply upgrades, solar inverters that shut down on high voltage, or batteries sized for a load profile you don't have.

1. What a power logger actually measures

A power logger is temporarily connected at your main switchboard by a licensed electrician. Over the logging period it records current on each phase, voltage, power factor and demand at short intervals. The result is a clear picture of your baseline load, your true peak, when it happens, how evenly your phases are loaded and whether your local voltage runs high or low. That's information a switchboard inspection or a quick calculation can't give you.

2. EV chargers: will your supply cope?

A 7 kW single-phase EV charger draws around 32 amps for hours at a time. On an older Inner West terrace with a modest single-phase supply, electric hot water, air conditioning and cooking, that can push peak demand over what the supply or main switch can carry, especially on a winter evening. Logging shows how much headroom you really have. Often the answer is a charger with load management that throttles charging when the house is busy, rather than a supply upgrade. For strata buildings, logging is essential before planning shared charging; see our guide to EV charging in shared basement car parks. Our guide to what an EV charger installer should check covers the rest of the assessment.

3. Solar: voltage and export

In parts of Sydney, local network voltage can already sit at the high end of the allowed range. Add a solar system exporting on a sunny afternoon and the inverter can trip off on over-voltage, costing you generation you paid for. Logging voltage before installation lets the designer size the system and cabling to reduce voltage rise, and flag a network voltage issue early. It also shows your daytime usage, which determines how much solar you'll use yourself rather than export. Our guide to solar and batteries on Inner West terrace roofs covers the roof side of the design, and our explainer on solar export limiting and zero export covers what happens when the grid can't take your surplus.

4. Batteries: sizing to your evening load

A battery earns its keep by covering your evening and overnight usage. Sizing one well means knowing how much you use between sunset and morning, and how high your evening peaks go. Logging gives you that profile, so you don't overpay for capacity you'll never cycle, or buy a battery that runs flat by 8pm. It also shows whether your backup circuits can realistically be supported during an outage.

5. Businesses and strata: evidence before spending

For Inner West businesses and strata buildings, logging is the evidence behind any big electrical decision: adding EV chargers to a car park, installing commercial solar, replacing a main switchboard, or applying to Ausgrid for more capacity. It feeds straight into the AS/NZS 3000 maximum demand calculation and often shows that better phase balancing or load management avoids an upgrade altogether. Our guide to commercial three-phase supply upgrades explains how that works, and strata electrical upgrades covers the building side.

6. What happens after logging

1. We review the data with you: peak demand, phase balance, voltage and usage patterns.
2. We calculate the added demand of the EV charger, solar or battery you're planning.
3. We recommend the simplest option: install as planned, add load management, rebalance phases, upgrade the switchboard, or upgrade the supply.
4. You get a written recommendation to share with your installer, strata committee or landlord.

How Does High Demand Electrical Help With Power Logging?

We're a Level 2 ASP team (Licence 397193C) working across the Inner West. We install and remove loggers, interpret the data in plain English, and if an upgrade is needed, we handle the switchboard, consumer mains and Ausgrid side ourselves. That means your EV charger, solar or battery goes onto an installation that's ready for it.

Frequently Asked Questions

Book Power Logging Before You Buy

Planning an EV charger, solar or battery? Book power logging first, or call 0402 808 808. It's the cheapest way to make sure the expensive part goes right.