[Closed] Jump leads - zzzzz content

Jump starting my own thread 😉

They're the ones I've got and they do the job. To be honest I've never had a jump lead that doesn't work. I went for the extra length so you don't have to mess around so much when maneuvering into position.

We went with the RAC ones from Screwfix. Only had to use them once to help a fellow camper out at a PMBA event.

https://www.screwfix.com/p/rac-red-black-400a-booster-cables-3m/4148R?tc=AA9&ds_kid=92700046638549236&ds_rl=1243318&ds_rl=1241687&ds_rl=1245250&ds_rl=1245250&gclid=CjwKCAjwtdeFBhBAEiwAKOIy5-heOnQreZbnic2K2SYZ32MNMtedW1WJR9XOYPJFXu7uVo-bXkYGSRoCk3UQAvD_BwE&gclsrc=aw.ds

They’re the ones I’ve got and they do the job. To be honest I’ve never had a jump lead that doesn’t work. I went for the extra length so you don’t have to mess around so much when maneuvering into position.

Indeed - being too short is the only thing that can really go wrong with them - its not always the case that the battery is somewhere overly accessible (either on your vehicle or on the friendly soul who'll lend you some electrons)  - perhaps more so with vans and campers where they are often under the seat or somewhere hurried under the floor. And given you can't really move one of the vehicles getting the other one close can sometimes be tricky

What you may find a challenge though is finding someone willing to give you that jump - people are increasingly worried that ever more complex cars are unable to 'do' jump leads. On several occasions potential jumpees have declined to help me or others because their car is 'modern' and 'one of the ones that can't be jump started'. And while I've heard and read that often its never in reference to any actually specific makes / models that this constraint would apply to. I'm sure there are elements of modern cars that are especially vulnerable to trying to jump start incorrectly but I can't find an example of one that can't be jumped correctly -  but for many people that's just enough doubt and they don't feel informed enough to want to risk it.

Obviously what you really mean to ask is what mini jump starter? I recommend these and not jump leads. They really are liberating, pathetically beg strangers no more!

I went with convenience and popped down to everybody's favourite motor vehicle & bicycle place - desperate times. The great thing about it is now that it's rarely needed for jump starting the car, it can still be used it as a battery pack for whatever USB device I forgot to charge right before I need it - can't do that with jump leads!

Collared a mate once at Heathrow airport for ‘a jump’ 🤔 after a work trip. Could I find the terminals in his Porsche truck, could I bollocks. Random punter in 1.1 Fiesta to the rescue. Special cars for special people.

Range Rovers specifically tell you not to jump start the car or even charge the battery in situ. Apparently it will mess up the electronics which are pretty flaky to begin with. Not sure this helps but is why the AA wouldn't just jump start my RR and I sat there for 20 minutes while he 'fast charged' the battery having removed it to the safety of his van.

Obviously what you really mean to ask is what mini jump starter? I recommend these and not jump leads. They really are liberating, pathetically beg strangers no more!

They're great in principle.... they die from lack of use though and as a tool that you plan never to use then lack of use is sort of designed in. They've helped me sometimes and also let me down. Something to have as well as jump leads rather than instead of.

A 2 litre engine would be on the limit of what those little jump packs can power was well - mine states 2 litre as the top of its range and I'd say that's right on the limit of its abilities (if it can do that) as it certainly can't make a dent on the 2.1 litre in my van

Ah. Yes I only really used it for a few days while we got the car sorted, but it seems to charge USB devices fine - but expensive and bulky for a USB power bank 😀

Lack of use... or the li-ion battery discharging too much and it sitting uncharged? Sort of like Exposure recommend their lights be charged every month (is it, oops)?

Lack of use… or the li-ion battery discharging too much and it sitting uncharged?

I bought two to have them on hand in two of our cars - one was charged on arrival and the next time we tried to charge it after a few month- dead. The other has managed a few jump starts over the last couple of years (and occasional use as a powerbank but its just that bit too bulky to be used that way really - but now when charging only ever gets to the forth bar so hard to tell how much meaningly ooph it has left

Ur Range Rever iz sarcin

I once killed my wife's battered old clio by bump-starting it. RAC said that the ECU had got fried in the process. It still comes up in conversation...

It’s best to have jump leads with a really thick cross-section copper cable, and clamps with relatively narrow jaws without plastic surrounding them, this is because many leads are very thin and just can’t carry current, and many cars have the terminals of their batteries surrounded by plastic making it very difficult to get a decent grip on any metal, some batteries are tucked right under the scuttle, so the negative is often a silly little prong attached to the bulkhead. We’ve had vehicles so flat we’ve had two big heavy-duty jump-packs and a set of jump-leads attached before they’ve eventually struggled into life. Some of our cars and vans can be sat around literally for months before they get sold, which does wonders for the batteries!

Range Rovers specifically tell you not to jump start the car or even charge the battery in situ. Apparently it will mess up the electronics which are pretty flaky to begin with.

I’ve jump-started several Range Rovers and Land Rovers, Discos, Evokes, and the big Range Rover Sport, none suffered any ill-effects. Mercedes, on the other hand, will brick themselves if the batteries go flat, and they cannot be started at all. You get a galaxy of warning lights on the dash, and sometimes the car gets stuck in ‘Park’, as well. We have full diagnostic kit, but Mercs require the car to be hauled onto a flatbed and carted off to a dealer - I’ve seen four taken away, it’s not happened to any other make that I can think of in the three years I’ve been working where I am.
What does happen quite often after a jump-start is the engine management light comes on, along with most of the others, which means a Snap-on Tools diagnostic box has to be used to clear all the error messages, before the car will run properly, but no damage is done, it’s effectively a re-boot of the electronics.
We did have one car have the battery go flat on arrivals, before it could be taken to the inspection unit, and I tried everything, but even the really heavy-duty leads wouldn’t work, in fact they started smoking, which was worrying. We ended up getting an AA bloke in, he checked it, and the battery had 3.5v in it…
He said I was effectively trying to put juice into a block of lead. He managed to get it started but he had a second battery on his truck with jump-leads that plugged into terminals on the truck.
Hybrids can be problematic at times, and full EV’s have to be treated very carefully, for obvious reasons, there are some very high voltages in play. I don’t think we’ve had a Tesla with a flat battery, but we have full EV chargers installed now for all EV’s, so shouldn’t be an issue.
I’ve just had a thought, we usually try to use a donor car that’s got a decent size Diesel engine, they seem to produce more current than most petrol cars, and I guess they have bigger batteries anyway.

Soon as it starts put lights on full.

Some smart charge altenators will just dump loads of volts in if the battery is so low.

Jump started 100s of cars and trucks never had an issue

I left my Merc CL600 to go flat once. Recharged the battery on a slow trickle overnight and started it in the morning. 64 engine faults. Left it to run for a while before switching off, leaving it for 1/2 an hour and trying again. 43 faults showing. Did a 5 minutes drive to check everything was working. Turned off, waited 5, turned back on and just 5 faults. Needed a Merc garage to reset the airbag and abs warnings from memory.