Battery car jump starter

[Shnozz]

I want to buy a portable car jump starter. Amazon have a plethora of them ranging from about 10k mAh up to 20k or so. In the descriptions they talk of 12k being enough for "up to 4.0L" and the 18k ones "up to 7.5L" etc. How realistic is this? I will need it for a 4.3L and a 6L - will the 18k mAh ones be sufficient as they say? Or is it ambitious in their advertising? Any links to what people have bought and been happy with then I am all ears.

[Shnozz]

Olas said:

An isolator switch and trickle charger suit this usage pattern

I don’t have an electricity in the car park where the vehicle is kept. A solar charger can cope in summer months if I am away a month but in winter it can’t.

Thanks to the suggestions so far.

[Shnozz]

Sheepshanks said:

Shnozz said:

I want to buy a portable car jump starter. Amazon have a plethora of them ranging from about 10k mAh up to 20k or so. In the descriptions they talk of 12k being enough for "up to 4.0L" and the 18k ones "up to 7.5L" etc. How realistic is this? I will need it for a 4.3L and a 6L - will the 18k mAh ones be sufficient as they say? Or is it ambitious in their advertising?

I wondered what the cc of the engine had to so with anything - seems a bit of a random way of estimating their capability.

Reading the reviews is a nightmare of contradictory results, but apparently it's important to connect them properly and faithfully follow the instructions.

I guess its probably just the easiest gauge of the battery size needed to turn over the larger capacity engines. But I agree, all of it seems random, the reviews included! Hence the post on here seeking PH recommendations.