Had a 600A continuous/900A surge portable jump-start (with
built-in voltmeter & flashlight) four years ago. In
hindsight, I should have just purchased another battery
(identical to the one I was jump starting) because they have
much more ooomph than the portable. You have to consider
the Ampere-hour rating: after three SHORT attempts at
jumping with the portable, the unit was useless (A-h rating
is 7Ah: can be up to 14 Ah depending on the portable unit).
Sure, you can recharge it, but it's still useless until
then.

With a "real" second battery, in the event the first battery
has to be replaced, you've got your replacement then and
there. If you don't need to replace it, you've got a more
POWERful spare/jumper, literally (~200Ah?). Stick a battery
carrier/strap and you've got a portable... Invest in a good
charger (~ $35) and an electronic trickle charger/maintainer
(~$25) and that's the most bang for the buck, IMHO. BTW,
the portable's 7Ah battery died after one season.

Regards,
Franko

"Bryan" wrote in message
m...
Tell me about the portable battery packs for jump starting
a weak battery?
Who carries them? Which one is the most bang for the
buck?