Jump Leads Range

Low battery voltage
Cold weather can cause a drop in the specific gravity of lead acid battery electrolyte with a loss of sufficient battery voltage to enable vehicle starting. The battery may need removing from the vehicle for recharging or a replacement battery may be needed.
Accidentally leaving the lights or radio switched on will cause a discharge of current and can mean a flat battery.

Vehicle battery charging system faults :
A faulty charging system may mean your car battery is not being recharged properly eg Alternator faults, wiring faults ,loose connections , high resistance connections, etc, these need further attention.

Vehicle starting system faults :
Corrosion may cause high resistance in wiring connections eq corroded battery terminals, loose connections , can result in a slower than normal cranking rpm making a vehicle engine difficult to start. These need repair.

A worn starter motor can increase the load on the vehicle battery and current demand during starting.

Winter weather = Low temperature =  Cold engine :
Metal contracts as temperature decreases which can increase friction between contacting surfaces making the engine more difficult to rotate under cold weather conditions, this in turn increases the load of the starter motor during cranking requiring greater battery voltage to acheive sufficient cranking rpm.  Water ingress into components such as the alternator can freeze and cause component damage resulting in a discharged battery. Jump leads won't solve the problem in this instance but may assist in getting the vehicle engine started so testing can be carried out.

Using jump leads to aid diagnostics

Jump leads may be used as a temporary link to aid vehicle diagnostics where main battery cables are suspected of having high resistance.

Typical examples:

HGV truck : A bad cab to chassis ground connection causing erratic dash guage operation was confirmed by connecting a jump lead between cab and chassis as a temporary link. A new cable was then made up and fitted on site.

Van Breakdown:

Starter motor cranking slow : A jump lead was used between battery negative and engine block to confirm diagnosis of voltage drop during starter  motor operation caused by a defective chassis to engine earthing cable causing high resistance. A replacement cable was subsequently fitted.

Car Breakdown :

Renault Clio breakdown attended suspected by the customer to be an immobiliser fault because the vehicle starter motor did not crank the engine when the ignition key was turned. A quick check at the starter motor using a simple test light proved that the ignition switch was operating correctly however the starter motor did not operate. Placing a jump lead between the battery negative terminal and metal casing of the engine and trying the starting procedure again , the vehicle engine started instantly proving a fault existed with the negative lead to the engine, which was checked and found to have corroded through. A replacement battery negative lead was manufactured on site and fitted to the vehicle resolving the problem.

Your Review of the Products we Market:

The battery jump leads we market online are delivered directly from a trade only manufacturer and distributor based in the UK .We have a close working partnership with the supplier / manufacturer. The premium quality level of the products is always maintained to a high standard as the same supplier also supplies government and defence establishments and certain major high street retail chains. If you have any comments about products you have purchased, product suggestions, or bulk quantity supply enquiries, please use the email contact enquiry form

Booster Cable Specification

Buyers guide

When considering the purchase of a new set of booster  leads check the cross sectional area of the copper core cables making up the jump leads. Generally bigger is better.

Jump Lead Marketing Tricks of the trade

Some manufacturers use thick insulation around a small diameter cable conductive core to disguise the lower quality of their product.

The products we sell are specified by cross sectional area of the COPPER cable core. Heavier gauge core cable will allow more amps current flow.

Manufacturers may rate by continuous current rating or maximum current rating (surge). The maximum current rating specified by some retailers relates to surge current for a short time period. We specify by continuous current rating though the surge current rating is often much higher.

 To put this into perspective the free run current required by an average car starter motor can be around 40 to 100 Amps. During  cold start of a stationary engine the peak current draw measured to achieve initial rotation  using an oscilloscope and current clamp could be as high as 800 amps.