Safe to connect two sets of jump leads together?

Pininfarina · 31-07-2008 6:43pm #1

Got a car with a flat battery in a position such that it's impossible to get another car close enough to it for a set of standard jump leads.

Is it safe to link up two sets of jump leads? Obviously, keeping the polarities right.

Thanks!

Plug · 31-07-2008 6:44pm

Pininfarina wrote: »

Got a car with a flat battery in a position such that it's impossible to get another car close enough to it for a set of standard jump leads.

Is it safe to link up two sets of jump leads? Obviously, keeping the polarities right.

Thanks!

Yes, its perfectly safe BUT make sure they can't come apart easly or battery could short.

Pininfarina · 31-07-2008 6:52pm

Cool, thanks.

bbbbb · 31-07-2008 7:08pm

I would be very careful doing this. My first thought is that where the leads join (i.e. where they're clipped together) is exposed, the same as if the insulation was exposed in the wires. Probably ok for the -ve terminal, but probably not so good if the +ve touches off one of the cars bodies? :eek:

peasant · 31-07-2008 7:11pm

"Perfectly safe" is debatable.

If you just clip together the two sets of crocs teeth like connectors ...keep in mind that they are not perfectly insulated ...don't let them touch anything.

Also, if you only have two thin/cheap sets of jump leads, the resistance in them might be too high and they could get hot, hot, hot

Any chance of pushing the disabled car out a bit?

crosstownk · 31-07-2008 7:51pm

peasant wrote: »

"Perfectly safe" is debatable.

Agreed.

Where the two sets of croc clips connect you will (unavoidably) have increased resistance across the connection. This will limit the current that can pass and could possibly result in overheating the cables. The best solution would be to beg or borrow a longer set of leads or get a lend of a booster pack.

As previously stated, if you do use the two sets of leads pay close attention to keeping the + cable away from anything metal on both cars.

colm_mcm · 31-07-2008 7:54pm

just take the good battery out of the other car, then jump start the bad one, then reinstall the good one.

Pininfarina · 31-07-2008 8:02pm

All points taken on board. Will be swapping the battery methinks.

crosstownk · 31-07-2008 8:04pm

colm_mcm wrote: »

just take the good battery out of the other car, then jump start the bad one, then reinstall the good one.

Yep - the simplest solution. Just be sure you have the radio code before removing the battery.......

colm_mcm · 31-07-2008 8:04pm

by taking out the battery, I mean remove the good battery from the good car, leave the bad battery in the other car. jump start using 1 set of leads. reinstall good battery.

endplate · 31-07-2008 8:11pm

Is the car an automatic? can you not push the car into a position that you can make a jump lead connection?

Run_to_da_hills · 31-07-2008 8:26pm

Safe if you get some elephant or duct tape and wrap it around the exposed two joining positive crock ends. If the poz end touch any metal part of the car it will short out and could cause damage.

peasant · 31-07-2008 8:28pm

and for those that don't know what kind of power lives in a car battery:

https://www.youtube.com/watch?v=79dauuviLe4

https://www.youtube.com/watch?v=8cXN7ic_L9A

Plug · 31-07-2008 8:29pm

colm_mcm wrote: »

just take the good battery out of the other car, then jump start the bad one, then reinstall the good one.

OP make sure you have a radio code;)

Plug · 31-07-2008 8:31pm

peasant wrote: »

and for those that don't know what kind of power lives in a car battery:

https://www.youtube.com/watch?v=79dauuviLe4

https://www.youtube.com/watch?v=8cXN7ic_L9A

I was puting a battery back in a car before when I crossed + and -.:D
not nice.

crosstownk · 31-07-2008 8:38pm

Good post peasant!

To put it in perspective, a car's starter can draw in excess of 150 amps @ 12VDC (depending on the engine size). The main fuse in your house is 63 amps @ 220VAC. The lower voltage in a car requires a much larger current to do the same work. Car batteries can deliver an almighty punch.

Esel · 31-07-2008 8:44pm

endplate wrote: »

Is the car an automatic? can you not push the car into a position that you can make a jump lead connection?

What's the relevance of your 'automatic' question?

crosstownk · 31-07-2008 8:48pm

esel wrote: »

What's the relevance of your 'automatic' question?

If it's an auto, then it's possible that it can't be taken out of 'park' without the brake pedal pressed - this requires electricity to operate the brake pedal switch.

Plug · 31-07-2008 8:51pm

OP another thing to remember always take off -(black) first and the when your putting it back put on the +(red) first;)

crosstownk · 31-07-2008 8:59pm

Plug wrote: »

OP another thing to remember always take off -(black) first and the when your putting it back put on the +(red) first;)

Positive/red/+ connects to donor car first then to + on stricken car. Negative/Ground/Black/- connects to donor car once + leads are connected. -/black should not be connected to the battery post of the stricken car but to well grounded metal at least 18 inches from the battery.

colm_mcm · 31-07-2008 9:07pm

GaBLE

Good and Bad, Live (+) then Earth (-).

1 Connect a 'good' battery to your 'bad' one using the live (+) lead and terminal. Then attach the earth lead to the engine block or chassis member (DO NOT attach it to the negative (-) battery terminal of the 'bad' battery.)

2 Once connected, start the 'good' car first and leave its engine running, then try turning on the ignition of your car.

3 Once your engine is running smoothly, remove the leads in reverse order, one at a time.

4 Whatever you do, don't switch you engine off now. It'll take a 20 min drive with the radio and other non-essential electricals off to fully recharge the battery - so you won't have to repeat the process all over again when you stop

Plug · 31-07-2008 9:15pm

crosstownk wrote: »

Positive/red/+ connects to donor car first then to + on stricken car. Negative/Ground/Black/- connects to donor car once + leads are connected. -/black should not be connected to the battery post of the stricken car but to well grounded metal at least 18 inches from the battery.

I was on about taking out the good battery and reinstalling it:o

crosstownk · 31-07-2008 9:21pm

Plug wrote: »

I was on about taking out the good battery and reinstalling it:o

I know - I was just adding the jump start version - apologies if you misunderstood.

Plug · 31-07-2008 9:33pm

crosstownk wrote: »

I know - I was just adding the jump start version - apologies if you misunderstood.

no bothers:)

knifey_spoonie · 31-07-2008 9:37pm

peasant wrote: »

.
Also, if you only have two thin/cheap sets of jump leads, the resistance in them might be too high and they could get hot, hot, hot

I can vouch for this, once using a mates "Homemade" jumpleads, i proceeded to take them off the battery, but in that process i welded them my fingers, hot hot hot + sore

ON TOPIC

The chances of the brakes not being siezed are slim so pushing aint an option im guessing.

Colm's idea of taking out the good is the safest option

Safe to connect two sets of jump leads together?

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