Any - Car Battery/Starter - chesterfieldhouse

Recently, my daughters car (Peugeot 307 auto) had a flat battery, turned out she'd left the interia light on. For last Christmas my son had bought me an RAC Jump Starter Heavy Duty 400 amp. However, it would not start the car & we ended up taking the battery off & charging it overnight.

Having a closer look at the specifications of the jump starter, it states for vehicles up to 1500cc & as the Pug is a 1.6; it was asking a lot.

l don't want to offend my son & buy another, so my question is could l buy another starter of the same model/output & connect both to a battery?

Any - Car Battery/Starter - galileo

Petrol or diesel? 1.5 or 1.6 is not a significant difference.

Have you ever charged the Jump Starter? If it has stood since last Christmas it will have lost a lot of charrge. If you read the instructions, it probably says "Charge at least once a month" (which is what I do with mine).

Any - Car Battery/Starter - elekie&a/c doctor

Most of these jump start packs are only useful as a doorstop. If you want something that does the job,then I would suggest one of these.I started a LR Disco with one of these.

Any - Car Battery/Starter - chesterfieldhouse

It's a petrol vehicle.

The starter has been charged every month or so since Christmas & fully charged when used.

My logic is connecting in parallel will provide quite a kick.

Any - Car Battery/Starter - liammcl

..or one of those , voodoo, lithium small starter packs...
or their ilk, starting£40+


Edited by liammcl on 17/09/2017 at 03:03

Any - Car Battery/Starter - John F

My logic is connecting in parallel will provide quite a kick.

Your logic is correct, but apparently you only need a current of 200amps to start a 5 litre V8

You need really thick copper wires and excellent connections to carry such a current, although far fewer than 2,400watts should be needed to start your tiny engine. Try clamping the clamps firmly into the battery terminals with a mole wrench (take care not to inadvertently earth it at the positive terminal!).

Any - Car Battery/Starter - chesterfieldhouse

OK thanks.

So the one starter pack should do the job, with a better/firmer connection?

Any - Car Battery/Starter - hardway

I'm wondering if you hooked up the jumper like every other b***** I've seen,

red to battery pos and black to battery neg?


Not the way to do it,

All that does is make the jumper try to "charge"the dead battery.

You loose voltage Amperage that way

Not to mention battery internal resistance.

The correct way to jump a vehicle is jumper red to battery red/pos.


And I know I'm shouting.

What most don't know or remember is the stuff that comes out of a DC battery is negative charged.

So that means THE most important eletrical connetion is the ground/earth.

So next time try to connect the jumper groud as close to the vehicle ground/earth strap as possible.

The one I'm on just now is a Peugeot Partner and the ground lead bolts to the gearbox for example.

Any - Car Battery/Starter - John F

You loose voltage Amperage that way

Not to mention battery internal resistance.

Nonsense. You would only lose power if the recipient car's connection from its battery to 'earth' is dodgy. The anachronistic reason for connecting to the earth strap, body or block is to avoid a spark igniting hydrogen from the battery being charged. It's a pretty remote possibility these days of sealed batteries, but this advice is typical of dogma that persists from 50yrs ago and continues to be solemnly and sometimes SHOUTILY dispensed.

Edited by John F on 24/09/2017 at 19:05

Any - Car Battery/Starter - chesterfieldhouse

So.........l either buy the same jumper (which costs approx' £50) & have to keep the two charged. Or alternativly, spend around £100 + for a recommended one.

Any - Car Battery/Starter - gordonbennet

I've had one of these for years,

it will still start almost anything, this is the best price i can find at the moment with it looks like free delivery (if you can find it cheaper then buy it quick), and a replacement battery is available when it eventually dies @ around £75, it's a no frills jump pack though, all it has is an all important isolator switch a light and a cigarette lighter sized socket power output, can be charged with its own charging pack or faster via a normal battery charger.

Note though its heavy, its twice the width and weight of a typical jump pack because it has twice the battery inside, but the leads are long and very thick so you won't need to balance this one somwhere in or on the engine bay which can be a problem with some of the cheaper units which need shorter leads.

edit, that one linked to by Elec Doc is a bargain.

Edited by gordonbennet on 26/09/2017 at 12:33

Any - Car Battery/Starter - liammcl

Interesting ...

I didn't know what the resistance of a "dead" ie 11.9v battery would be....
and whether the good battery would throw mega amps (100a) at trying charging it up,
thus not having much oomph for the cold cranking amps to start the car...

read this,elsewheres..
"The minor voltage difference is between a full and an empty car battery is not enough to charge the empty one in reasonable amount of time. Assuming an internal resistance of 25mOhm, you would have a charging current of ~7A, which would be a pretty meager charge current for a car battery which typically has 40Ah-50Ah.

Also, if you waited long enough (hours and hours )
then you would end up with two batteries that are half full

The reason the good battery works, lies in the behaviour of the battery under load.
it may be supplying 7amp charging the dead battery, but the good battery still has Hundred(s) of amps in reserve to cold crank the start motor...starting the car .. "

I imagine connecting the negative to the car battery negative, is excatly the same as connecting it yo the there is a lead or three from the chassis direct to the negaive terminal.


Edited by liammcl on 27/09/2017 at 02:08

Any - Car Battery/Starter - gordonbennet

I've seen hundreds and possibly thousands of cars jump started in my previous work, the 'yardies' who move the cars in vast compounds at docks and storage facilities often have a minubus with permanently wired heavy jump leads ready at all times clamped to a rubber insulated rail bolted to the front of the vehicles.

They don't have time for all these niceties, they very often don't even use the clamps at all but one of the lads will raise the bonnet and hold the leads against the two flat battery terminals whilst another starts the car, and leaves the flashers on if they're going to leave it running assuming its got some fuel, if for example its due for transporting, both to give the charging system a reason to work and so others know what the score is there, plus if left it could still be days later if it had enough fuel, and this has happened hence the flasher practice...the minibus engine almost never got stopped during the working day.

I too don't usually bother earthing to the engine, simply clip both terminals on the dead battery, i'm more concerned about the donor vehicle in all honesty if its a modern with the devils electronics, so for me i'd rather use a jump pack with an isolator switch than jump leads these days.

I've only ever seen one battery explode, and that was a lorry battery on an old Leyland lorry around 1977, the clot connecting up the freshly charged battery managed to short a spanner across the plates (remember when batteries had exposed metal plates between the cells?) and the spark from that contact must have ignited the hydrogen with predictable results, he got covered in acid but luckily no permanent damage, my clothes got splashed and were in effect bleached.

Edited by gordonbennet on 27/09/2017 at 09:04


Ask Honest John

Value my car