These ‘new’ lithium powered jump starters are amazing. I had been thinking of installing a dual battery system in the (’95) Discovery but it is difficult though not impossible to fit one in, as well as very fiddly. I already have one in the Defender. Anyway I realized that the main reason I would need one would be if the battery went flat when I left it parked up the bush which I often do for a week or more in very cold weather. Of course I always try to leave it on a bit of a slope so that I can roll start it if the need arises (and it has) – but sometimes there just isn’t any convenient appreciable slope to use. I haven’t been stuck yet, but eventually I would be.
There have been jump starters for some time usually utilizing a fairly bulky sealed lead acid battery, but the range now includes pocket sized models which will nonetheless start large diesel engines. The one I bought is an 18,000 mAh one which also includes a very bright torch (which would clearly run for weeks!) and a couple of USB outlets for charging other things, like your phone or satellite messenger. It is probably a bit of overkill as a supplementary battery for charging your electronics whilst hiking, but the smaller 10,000 mAh ones would do such dual service admirably even on a long trip. These things will jump start your car up to a dozen times – which is pretty amazing for something you can fit in your back pocket!
Antigravity Batteries were apparently one of the first cabs of the rank with this type of product, and reputedly are still one of the best eg http://themicrostart.com/xp-10/ Their 18,000 mAh jump starter weighs 510 grams. This is not such a bad weight that it could not see double use as a hiking (or everyday) power supply. Of course most people will not need that many amp hours. Small 2.5 .litre diesels will only need 10-12,000 mAh which would be a considerable weight saving – probably over 100 grams, and of course smaller petrol engines might get by with much less.
I bought an 18,000 mAh unit from Total Tools for around A$240. This one has an amazing 1200 cranking amps! They had a smaller unit available for less than A$200 but were out of stock on the day when I was heading up the bush. Anyway this will be more than adequate to start either of my two Landrovers should I leave them up the bush for a couple of weeks in the middle of winter whilst I am off hunting – and supposing their batteries go flat.
Everything you need in this neat little bag.
You can just charge them at home or with the cigarette lighter socket when driving. They remain charged for eg a year, so they are just great to have in the car glove box in case something goes wrong. They come with all the leads, etc in a neat little box.
Of course they are just great for starting all those other things whose batteries go flat around the place too: ride on lawnmowers, motor bikes, mulchers, generators & etc.
PS: I have now had occasion to use this amazing device (on a couple of old cars which needed moving around the farm with flat batteries). Let me say I have never seen anything which spun an engine over faster (one is a diesel too), or that started a car which has not been run for months the very first second. Wonderful. Do get one.