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Are you looking to buy a set of car jumper cables and wondering what the best length for your car is?
In this post, I cover:
- the best length of jumper cable to get depending on the size of your vehicle,
- whether you should extend jumper cables by combining them,
- the associated dangers,
and the alternatives available to you instead of combining 2 sets of jumper cables.
1. The Best Length for Car Jumper Cables
What is the Best Length of Car Jumper Cables?
You should aim to get between 12ft – 20ft of jumper cable to jumpstart your car depending on the size of your car and where the battery is located under the hood in relation to the car being used to jump.
For smaller cars, 12ft should be enough. It is sufficient length to extend battery power to a drained battery even when the car whose battery you are using to jumpstart is parked behind or in front of the one with a drained battery.
Shorter cable lengths may work but they limit you to jumpstarting your car’s battery using a car that is parked side by side to the one with a drained battery.
For larger vehicles like trucks or vans, you should probably get at least 20ft of cable to jumpstart them.
This way, you can jump them even when the car with the good battery is parked behind or in front.
Indicative Jumper Cable Lengths for selected vehicle size
| No. | Size of Vehicle | Indicative Length of jumper cable (ft) |
| 1 | Small cars like | 12-16 |
| 2 | SUVs, Mid-sized cars like | 20 |
| 3 | Pickup trucks, Vans | 25 |
Note: These cable lengths are long enough to extend power to the drained car’s battery using a car that may be parked in front or behind it
2. Common Jumper Cable Lengths Available
Is there a Standard Length for Jumper Cables?
You are more likely to find at least 12ft, 6-gauge car battery jumper cables.
These can work perfectly for small cars if the car whose battery you are using to jump is parked at the side of the one with the drained battery.
The reality is that this is not always possible if you have constrained spaces, for example in your garage.
So, it is a good idea to get at least 16 ft of jumper cable if not longer.
3. The Danger in Combining Car Jumper cables
Can you Extend Jumper Cables?
Yes, it is possible to extend a pair of jumper cables by connecting the ends of one to another (taking care to connect the positive clamp with the positive and the negative with the negative clamp).
This can particularly come in handy when there is limited access to the drained car’s battery so it is not possible for another car to park alongside it unless you push or tow it where there is more access.
If you have two sets of car jumper cables to get a longer length. (Note: the safety concerns)
Should you Extend Jumper Cables?
Much as it is possible to combine 2 sets of jumper cables to get a longer length, there are higher safety concerns around the joint where the two cables connect, and would not recommend it unless you really know what you are doing.
Risks of Extending Jumper Cables
There are serious dangers of injury to yourself, and damage to the good battery if you make a mistake when connecting the 2 sets of jumper wires wrong ranging from damaging the car’s battery to shorting and causing the battery to explode.
- Damage to and risk of explosion of the good battery.
Combining two sets of jumper cables introduces another potential point of failure – the joint where the cables are combined.
It is possible for the battery clamps to connect, short-circuit the battery and cause an explosion damaging the battery and possibly causing injury to you.
Damage to the car’s alternator if the cables are wrongly connected.
If the jumper cables are wrongly connected at the point where they are combined, i.e. positive to negative and negative to positive, there is a danger that the car’s electrical system may be damaged from subjecting it to a higher voltage.
4. How to Safely Extend Jumper Cables? (3 Tips!)
If you must extend the jumper cables (check potential risks), follow the steps below to reduce the likelihood of injury, damage to the battery and the car’s electrical system.
# 1. Use jumper cables of the same wire gauge or at least one of the other jumpers should have a lower gauge (thicker wire) than the minimum required to safely jumpstart the vehicles.
For example, if the minimum required wire gauge is 6 AWG, you can connect to a 4 AWG or lower but not more than 6.
# 2. Wrap insulation at the point where the jumper cables are combined to minimize the risk of a short-circuit when the sets of clamps accidentally connect.
# 3. Make sure that the clamps at the point of the connection are firmly connected to prevent high resistance and voltage drops that can prevent the dead battery from charging.
To combine the two sets of jumper cables, first:
- connect the black clamp of one set with the other black clamp and secure wrap them with insulating tape.
- Next: connect the red clamp of one set with the other clamp and secure wrap them with insulating tape to prevent an accidental short-circuit.
- Double-check that the red cable is connected to the red cable and black is connected to black.
5. Alternatives to Combining Car Jumper Cables
Instead of connecting two sets of jumper cables, you can borrow or buy a longer jumper cable instead to prevent the dangers associated with combining jumper cables.
Or, you can use a charged jumpstarter box or pack to successfully jumpstart the car and then drive it for 15 – 30 min to fully charge the battery.
Final Thoughts
The best jumper cable length for your vehicle is probably anywhere from 12-25ft feet depending on the size of your vehicle.
You may be able to use shorter cable lengths but this limits you to jumpstarting with another car parked at the side.
For larger vehicles, your need about 20-25ft of cable length to extend battery power from a car that may be parked behind or in front of the one with the drained battery.
While you can combine two sets of jumper cables, I would advise against it because of the associated dangers introduced at the joint where the two sets of jumpers connect.
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