The choice is simple. Either I play safe and turn left on to the M58 and go on a 30km detour, or I push on up the M6 and hope my electric car's fading battery will make the 45km to the next service centre outside Wigan.
This is the sort of arithmetic increasingly being played out on Britain's roads as drivers of electric cars attempt to make use of the expanding fast-charge network.
I'm on the M6 to Glasgow from London to test the new Electric Highway. Provided free by the green energy firm Ecotricity, it's the country's biggest inter-city network, covering 89 per cent of the motorway system and due to be completed by April.
In theory, the battery in the new VW e-Golf I'm driving has enough range to reach Wigan, but the sun has set, it is raining, and the temperature is dropping.
Cold weather is a killer for electric-car batteries, dropping the theoretical range of the e-Golf from a respectable 190km in summer to somewhere closer to 100km in winter.
Unlike hybrids, the e-Golf is purely electric. I have no engine to fall back on, and my energy-thirsty headlights and wipers, plus the inclines ahead, are already making trouble for my lithium-ion battery.
Once this sort of long-distance trip would have been impossible, but thanks to Ecotricity and its network of 207 rapid chargers, it's fast becoming a reality - as long as you are willing to stop 30 minutes to charge every 140km or so.
"What we are offering electric car owners is the chance to drive the length and breadth of Britain. Three years ago, it took eight hours to charge an electric car, which we knew was never practical, but now that's down to just 30 minutes," says Dale Vince, the founder of Ecotricity.
"There has been a quantum leap in car and battery technology, and now we are seeing an exponential rise in demand."
New figures are expected to show a massive surge in electric car sales in 2014, thanks to new models from VW, BMW and Tesla.
Tesla has its own network of 15 super-fast charging stations for its luxury car owners, but they are in the minority among more than 3000 fast and slow public charging locations across the UK.
I've covered 300km on the M6 with three charging stops, but at Knutsford services my luck runs out, and I arrive to find only an error message and a dead terminal.
I had expected this, as Ecotricity has freely admitted that it has had some problems perfecting the so-called "electric handshake" between the e-Golf and "Combined Charging System" (CCS) it uses. It's one of the several types of fast chargers used by the firm in a form of VHS versus Betamax situation.
The firm says the problem will be fixed by April, but at the side of the M6 this offers little consolation - with a nervous run to Wigan ahead of me on a reduced charge.
The digital display on the dashboard says I have 50km of range left, which should technically get me to the next CCS point 45km away at Charnock Richard, just north of Wigan; but so far the e-Golf's display has seen the range drop far quicker than the distance readings.
In desperation, I call Mark Tebbutt, an electric car owner who took delivery of the third Nissan Leaf to come to Britain in 2011.
He advises me to "turn off the heater and stick in the slow lane at 75km/h". His kind advice does little to reduce my anxiety.
Amazingly, I make it to the service centre ready to celebrate with Tebbutt, who comes to meet me.
We pull into the bays at the same time and he leaps eagerly into the seat of the e-Golf to compare it to his Leaf.
I'm not so happy; the Ecotricity charger is ominously dark, and won't read my charging card. This time, I'm well and truly stranded.
"It's a shame you didn't make it to Glasgow," says Tebbutt.
"In the early days, this sort of thing was fairly common, but it's actually not that hard to get around the country these days."
He suggests I sneak down an access road to try the other carriageway's charger, but that is out too. As I don't have enough charge to take up his offer of an overnight charge at his Chorley home, I am forced to call the AA and return to London by train as the blameless VW e-Golf makes its way home on the back of a recovery lorry driven by a somewhat confused petrolhead.
Speaking to Vince the next day, he's still upbeat about my experience.
"When petrol cars came along, there wasn't a national network of petrol stations; overnight, they had to be built," he says.
"It's important to remember this is just the start of a revolution."