Jump start packs.

i have one in a service van and use it about 1 - 3 times a month and charge it every three months or so. i have had it for two or so years and still working good, ps. also use it for camping some times..

The instructions with mine say fully recharge every 3 months and/or after every use. Don't let it drop into the red.
Using ours for a fleuro light while camping it lasts ages. Using it to run a double A battery charger sucks the juice.
Using it to start the diesel after using it for other things is yet to be experienced.
Also we have the option of charging it 12v but find this very average; a couple of hours driving didn't seem to raise the needle much. Then again, it takes a good few hours to recharge on 240v.
I need solar panels or a generator to charge my charger LOL

Harry,

I think you are spot on in your observations.

i started off with a Projecta brand unit with the intention of providing an "emergency" method of starting the vehicle if I ran into difficulties.

This gradually grew to a requirement for a "portable" supply for a 12 volt light when camping and the Projecta unit, with a 17Ah level of supply was OK.

Then the requirement grew to the inclusion of providing a portable source for powering my Fridge as well as a camping light and at the same time giving me the backup of a means of jump starting the Jack if the primary battery "played up".

Now the auxiliary battery in the Jack has been limited to around the 50-75Ah range depending on what battery type I had at the time.

I started out with a 75Ah capacity "wet cell" auxiliary battery which I ran the fridge of whilst travelling and while camping. The main problem I experienced was that the wet cell battery tended to drop its electrolyte level over a period of time (probably due to my own negligence) and I decided to "upgrade" to a lower capacity AGM battery which didn't require checking for electrolyte level, but due to the physical size gave less Amp Hour capacity.

So entered my decision to "split" the requirements in to an "on board" auxiliary battery with the construction to enable a reasonable capacity of Amp Hours to run the fridge whilst travelling and for an indeterminate time whilst stationary.
At the same time I recognised the need for a reasonable capacity "portable" system that would allow the removal of the fridge from the vehicle and its dependent "auxiliary" supply of power to run independent of the vehicle.

And so entered one of the best investments I have made in camping equipment in the form of the "Thumper" brand of portable 12 volt battery solution.

The "Thumper" gives me the option of a minimum of 75Ah of 12 volt supply for the fridge and one or two low drain light sources for "stand-alone" camping.
Backed up by a modest 40watt Solar power cell to return a reasonable level of power to this portable power source this has given me the "ultimate" choice of power supply to suit my current needs. When incorporated with the "In-car" high capacity charging system for the "thumper", whilst at the same time charging the auxiliary battery, both at the same time from the vehicle alternator whilst driving, I am confident that I have the "ultimate' solution to suit my needs, given the limitations for auxiliary battery size that I can fit into the cradle in my vehicle.

All things considered and all things working well, I currently have the capacity to run the fridge/lights for a minimum of 3 days off the auxiliary battery of the vehicle (70Ah) and a further 3 days + from the "Thumper/Solar Cell" combination I employ.

All things considered, I have yet to reach a point where the output from the "Thumper" has exceeded the input from the 40watt solar panel when employed.

So, I can state in all honesty "my piece of string is considerably long" in not only giving me an adequate level of 12 volt supply (and recharge capability) for an indefinite period of stationary camping requirements, but a practical and "cheap" method of recharging all sully sources while "on the road".

The solution I have outlined above, both use the method of AGM technology, combined with quick and total recharging of battery sources and in the case of the "portable" battery source a high output backup for "jump starting" the vehicle, should the primary battery "fail".

Yes, the solution comes at a price. But the price I have outlaid gives me total confidence in venturing into the "great outdoors" with confidence, without undue
worries and without the added expense and concerns for an additional "generator' type solution.