I don't sell any of these nor do I receive any remuneration if you buy them, and I have not personally reviewed them, they are listed here to give you perspective
Introduction
traditional jump starter batteries are lead acid chemistries excluding most deep cycle batteries
most 12V lithium batteries are NOT suitable for jump starting cars as they are not able to deliver over 200A currents (usually at least 400A is needed)
a jump starter which uses a LiFePO4 battery will be more efficient than one that uses a Li-ion or Li-Po battery
this page outlines some options for batteries which can jump start cars as well as battery-less options
in essence it needs to send a transient initial very high current perhaps 400A to the starter motor to overcome the inertia of the flywheel (which will usually drop the battery voltage from over 12V down to ~8V), then it sends spikes of around 100-150A (battery voltage will generally be down to 10V in this stage) to the spark plugs
the higher the current spike, the more compression pressure is being generated. A low current spike would suggest leakage from the cylinder and failure to achieve adequate compression (eg. worn piston rings)
each spike represents one piston in sequence
a failure of a spike in the sequence on an oscilloscope doing a relative compression test may be due to a faulty spark plug or a fault in the starter motor such as a solenoid tripping for that cycle
will the jump start device actually work for my car?
most devices have a peak amp rating
in general this is not very useful as it is only the maximum current for a few secs not the 30secs you may need to crank your engine
however, it is likely that a device rated at 1000 peak amps will do better that one rated at a lower peak amperage
some devices give the cold cranking amps (CCA) rating
this is better but perhaps not in Australia - the rating is for 30secs current at 0 °F (-18 °C)
a small car needs 150 CCA
a SUV may need 450 CCA
500 CCA should start most vehicles
a better measure is the cranking amps (CA) rating
this is how much current it can put out for 30 secs at 32℉ (0 °C)
presumably this is what manufacturers are referring to when they state starting current
a small - medium car with 6 cyl petrol engine or 4cl diesel engine will draw a peak current of 300-400 CA
a 4WD, especially if diesel will require at least 400 CA
most of the devices below provide at least 500CA which is adequate for most vehicles
how much cranking amps do I need?
the larger the engine the more energy needed to turn it over
the older the engine the more energy you need
the colder the device the less it will output at zerodegC the max output may be reduced by around 35% for a lead acid jump starter
the colder the engine the greater the cranking amps you will need at zero deg C you may need 50% more power
a device with greater capacity will give more jump starts
Small lithium power banks with jump start capability
as a minimum, these generally have:
a lithium polymer battery
LED torch with SOS mode
power indicator
12V or 15V 1A (or sometimes 2A) input for charging
12V 10A output
12V jump start port and jump start cables
USB 5V 2.1A out
PREFERABLY USB-C PD for fast charge input/output
Rooboost™ RB-PRO1500 1500A Peak Car Jump Starter
16000mAh 5V; 120W; QDSP Quick Discharge Start Power technology jump start; peak 1500A; torch; wireless smartphone charging; QC 3.0 USB-C; DC out; USB charge in 3-4hrs;
19.3 x 3.3 x 8.9 cm; 1kg;
$AU149
GOOLOO GP37-Plus 1200A Peak 18000mAh Portable Car Jump Starter
as per minimum specs above plus USB Quick Charge out; charges within 5hrs and holds charge for 3 months;
20000mAh 3.7V battery; can hold its charge for up to 6 months; peak 1000A; starting current: >500A; 12V 8A output; can also charge 12V, 16V and 19V DC devices as well as USB out;
20000mAh 74Wh 3.7V battery can hold its charge for up to 6 months and chargeable via 12V DC or 240VAC taking 4-5hrs; peak 2000A; 10W QI wireless charger for smartphones;one QC 3.0 USB; one USB-2 out; 12V 8A out but no 16V/19V out;
195x85x45mm 650g for unit itself (whole package 1.4kg)