If you've been keeping an eye on the Amber app lately, you've probably noticed something pretty spectacular: daytime energy prices dropping to zero, or even going negative.
This isn't a glitch. It's what happens when Australia's rooftop solar systems are pumping out so much energy that the grid has more than it needs. Energy companies are essentially paying you to use power during these windows.
For Amber customers with batteries, EVs, or both, these moments are gold. Charge up for free (or get paid to do it), store that energy, and use it later when prices spike. It's one of the best features of being connected to wholesale prices rather than locked into a fixed retail rate.
But here's the thing: if you try to charge everything at once at full speed, you might overload your home's electrical system and lose power to your whole house. Not ideal when you're trying to be clever about energy.
The good news? Avoiding this is simple. A few small tweaks to your charging settings mean you can safely soak up all that cheap energy without any drama.
Understanding your home's electrical capacity
Most Australian homes run on what's called a single-phase connection. Think of this like a single lane of traffic: there's only so much that can flow through at once before things get jammed up.
For most single-phase homes, the limit is around 16 kW of power draw at any given moment. That might sound like plenty, but high-power devices like battery chargers and EV chargers can chew through it surprisingly fast.
Here's a typical scenario:
- Your home battery is charging at 10 kW
- Your EV is charging at 7 kW
- Total power draw: 17 kW
You've just exceeded your home's capacity. The safety switch in your switchboard will flip, cutting power to protect your wiring from overheating. Everything shuts down: your chargers, your lights, your fridge, the lot.
This isn't dangerous - the safety switch is doing exactly what it's designed to do - but it is annoying. And it means you're not actually taking advantage of those cheap prices because nothing's charging anymore.
The simple fix: dial back your charging speeds
The solution isn't to avoid charging during cheap periods. It's to charge a bit slower so you stay within your home's limits.
Here's what we recommend:
For EV charging: Set your charger to around 20 amps, which works out to roughly 4 kW. Most EV chargers and car apps let you adjust this. You're still getting cheap energy, you're just filling up a bit slower.
For battery charging: Limit your battery to charge at around 8 kW maximum. Most battery systems let you cap the charging rate through their app or settings.
With these settings, you're using about 12 kW total, which leaves around 4 kW of headroom for everything else in your home: your kettle, aircon, oven, pool pump, whatever you need.
Your EV and battery are still charging during those cheap or negative price windows. You're still saving money. You're just doing it without overloading your home.
How Amber SmartShift helps
If you're using Amber SmartShift for your battery, it's already working to charge your battery during the cheapest periods and discharge during high-price evening peaks.
SmartShift is smart enough to respond to price signals, but it can't know your home's electrical limits unless you've configured them. That's why it's worth checking your battery's charge rate settings and making sure they align with what your home can handle.
The beauty of SmartShift is that once you've set sensible limits, it handles the timing for you. You don't need to manually start and stop charging. It automatically buys low and sells high, within the boundaries you've set.
If you've got solar, you're in an even better position
Here's where things get interesting: if you have solar panels, they change the equation entirely.
Solar power generated on your roof powers your home first, before any energy flows through your main connection from the grid. This means your solar effectively reduces the load coming through your switchboard.
Let's revisit that earlier example:
- Your battery is charging at 10 kW
- Your EV is charging at 7 kW
- Total: 17 kW
Normally, this would overload your 16 kW limit. But if your solar panels are producing 10 kW at the same time, here's what actually happens:
- Solar provides 10 kW directly to your chargers and home
- Only 7 kW flows through your main connection from the grid
- You're comfortably under the 16 kW limit
This is why sunny midday charging is such a sweet spot for solar owners. Not only are wholesale prices typically low or negative during peak solar hours, but your panels are also doing the heavy lifting, keeping you well within your home's capacity.
Practical tips for managing your load
Here are some straightforward ways to make the most of cheap energy periods without running into issues:
Stagger your charging. If you've got both a battery and an EV, you don't need to charge them both at full speed simultaneously. Let your battery charge first, then top up your EV. Or vice versa. SmartShift can help automate this for your battery.
Avoid running other high-power appliances during charging. If you're charging your EV and battery during the day, maybe hold off on running the clothes dryer, oven, and pool pump all at once. Spread things out a bit.
Check your settings before negative price events. When you get a notification that prices are about to go negative (yes, you can actually get paid to use energy), it's tempting to crank everything up. Just make sure you're not exceeding your limits.
If your power does cut out, reduce the load before resetting. If you've tripped your safety switch, don't just flip it back on. Turn down one of your chargers first, then reset. Otherwise you'll just trip it again.
Consider three-phase power if you're constantly maxing out. If you're regularly hitting your limits even with these adjustments, it might be worth chatting to an electrician about upgrading to a three-phase connection. This effectively triples your capacity, but it's not cheap and not always necessary.
How it works in practice
Let's say you're an Amber customer in Sydney with a 10 kWh battery, a Tesla Model 3, and a 6.6 kW solar system.
It's a sunny spring afternoon. Wholesale prices have just dropped to -$0.05/kWh (you're getting paid to use energy). Your solar panels are producing 6 kW.
Here's how you'd set things up:
- Battery: Set to charge at 8 kW maximum
- EV: Set to charge at 4 kW via the Tesla app
- Total draw: 12 kW
But remember, your solar is producing 6 kW, which powers your chargers first. So only 6 kW is actually flowing through your main connection from the grid. You're well under your 16 kW limit.
Your battery fills up over a couple of hours. Your EV charges a bit slower than it could, but who cares? You're getting paid to charge it. And your power stays on the whole time.
Later that evening, when wholesale prices spike to $0.80/kWh, SmartShift automatically discharges your battery to power your home and even exports some back to the grid. You're earning money during the evening peak, all thanks to the cheap energy you stored during the day.
This is how wholesale energy is supposed to work.
When to call in an electrician
Most of the time, adjusting your charging settings is all you need. But there are situations where it's worth getting a professional involved:
If your safety switch keeps tripping even with reduced loads. This could indicate an issue with your wiring or switchboard that needs attention.
If you're not sure what your home's actual capacity is. An electrician can check your main breaker rating and tell you exactly what you're working with.
If you want to add more high-power devices. Planning to add another EV charger or upgrade your battery? Get an electrician to confirm your home can handle it before you buy.
If you're considering an upgrade to three-phase power. This is a significant electrical job that requires proper planning and approval.
The short version
Cheap and negative wholesale prices are one of the best reasons to be an Amber customer. They're becoming more common as Australia's solar capacity grows, and they represent genuine opportunities to slash your energy costs.
Taking full advantage doesn't mean charging everything at maximum speed all the time. It means charging smarter: staying within your home's limits, using solar when you've got it, and letting automation tools like SmartShift do the heavy lifting.
A few simple settings keep you safely under your capacity while still soaking up those bargain prices. Your bills go down, your battery and EV stay charged, and your power stays on.
That's the whole point of wholesale energy: putting you in control, giving you the tools to make smarter decisions, and rewarding you for using energy when it's cheap and green.
If you haven't already, jump into your EV and battery apps and check those charge rate settings. Set some sensible limits. Then sit back and let cheap energy roll in.
