Jump starter

I'm looking for one of those portable jump starter units, the sort of thing the AA carries with them.

Plenty on the market but most only offer a rating of being capable to start 1 to 2l engine cars and presumably that's petrol, not diesels.

I'm after something that's capable of starting a 3.5l diesel. My van is a 2.2, pickup 3.2, other cars in the family range from 602cc to 4l so something that can cover all bases would be nice.

Any recommendations?

You get what you pay for in this area, I'd probably try one of the newer type, they look interesting.
https://www.halfords.com/workshop-t...rs-jump-starters/gb70-2000a-noco-jump-starter

Some years ago now, I bought one of these:
http://www.car-pow.com/products/5.html#.XFIx7Fz7SUk

I can't remember how much it cost, but I'm sure it was a lot cheaper than the Halfords one.

To be honest, I have used it only for recharging mobile phones and have never actually used it to jump start a car, though the manufacturers claim it is suitable for doing that, and I remember reading reviews written by people who have.

One thing, though. This was several years ago now, and it is encouraging that exactly the same model is still available. If it were rubbish, I'm sure it would be.

I've no experience of those starters, it was just an example of how things have moved on. They look very good though as they hold a charge for a long time.

A 12 cylinder 4.2 litre engine is likely easier to turn over than a 4 cylinder 850 cc so hard to say what size is required, but my 20 Ah starter seems ample for most jobs.

Today there are three types of jump starter, lead acid battery, Li-ion battery, and capacitor. I have never tried the last two, theory is the capacitor charges its self from the main battery and then gives the extra required on cranking, or charged from another car or mains. Advantage is it can be left for years unused, and will still work when required. I don't like large Li-ion batteries because of fire risk, however the jump starters with these are far lighter and I can see the advantage. The lead acid type need charging every 4 months or less as they get older, as a jump starter often you find when wanted it is discharged and useless, however I use one with a cig lighter output and tyre pump and inverter a lot, from powering lap top to pumping up bike and caravan tyres, because used a lot it is kept charged, so ready to use as a jump starter.

There are some with just 16 Ah batteries which is a bit too small, but the multi-function models tend to have the larger battery fitted, mine also has a cig lighter to cig lighter lead so can be both charged from the car, and can be connected to equalise car and booster battery, so plug in wait 15 minutes and then crank.

As to how any car with stop start works I don't know, as engine management monitors battery voltage and switches things off etc. I am sure using a Smart Charger on the Jag made it worse not better as it messed up the engine management?

"A 12 cylinder 4.2 litre engine is likely easier to turn over than a 4 cylinder 850 cc "

Can you clarify please ? It's far from evident to me .

I'm not sure what the OP is hinting at but the advantage of a multi-cylinder engine is that even if it only fires on some of the cyls. they in turn will help the starter crank the engine, ie on a very cold start-up. I've no experience of these modern tiddly engines, but perhaps they have a very high compression ratio ?