Get more out of your car battery
Q: Our 2010 Holden Calais V Series 2 Sportswagon uses around 9.3 litres/100km on the highway, and around 11 litres/ 100km with bikes on the roof.
We do have permanent roof racks and bike carriers fitted.
It has done 6900km. Should I be getting better fuel economy or is the motor still stiff and running in?
A: It’s a little higher than I would expect, but roof racks and bikes carriers would have an adverse effect on the fuel consumption, and it would be even more affected by carrying bikes.
Q: I amafter a company that can test the speed of my Lexus 250 against what is shown on the speedometer.
When I am driving along, it seems as though cars are going past or are tailgating me while, according to what I see in front of me, I am sitting on the speed limit.
This gives me the impression that something is wrong with the speedometer.
What could I expect the cost of such a test to be?
Ray Williams, email.
A: Normally I would expect your speedo to be around 5 per cent fast – in other words, it’s reading 5 per cent higher than the actual speed you’re doing.
Under the law, it could be as much as 10 per cent fast, but on average most cars appear to be closer to 5 per cent.
You could have the speedo checked by an instrument maker, but I would suggest you first check it against an overhead speed indicator on a nearby highway.
While they are not necessarily 100 per cent correct, they are a good guide. You could also check it against a GPS unit, which would give you a good indication of a problem.
Q: How long should a car battery last? The one that came as original equipment in my low-kilometre, short-trip 1999 Jeep Wrangler Renegade has just given up the ghost after 11 years.
My husband, who is a car nut, showed me how to prise the cell caps off the top of the battery to check the electrolyte. Even though it was supposed to be maintenance-free, it still needed topping up every now and then.
Also, the car came with an insulation blanket around the battery. Is this to keep it warm or cool?
Would any of this extend the life of a battery, or is it just good luck?
My husband replaced the battery with a new Optima Spiral Cell, which he said will most probably outlast the car.
Carol McKenzie, email.
A: You’ve done well in getting 11 years from a battery. They often give up much earlier than that.
No doubt checking the electrolyte and keeping it topped up would have helped to keep the battery going for longer.
The insulation blanket would also help to keep it at a more consistent temperature and make it more effective, particularly at low temperatures. It’s also important to understand when replacing a battery that you buy one that has the power your car needs.
Simply buying a cheap battery might mean another visit to the battery store in quick order when it proves unsuitable.