On Mon, 28 Sep 2015 09:29:08 -0700, Don Y
wrote:

On 9/28/2015 9:03 AM, Moe DeLoughan wrote:
On 9/27/2015 5:10 PM, philo wrote:
On 09/27/2015 04:57 PM, Walter E. wrote:
I am considering a Harbor Freight battery charger on sale for $ 29. The
specs show 10 A charging current, 2 A trickle charging and 50 A
emergency car starting.

Will 50 Amps start modern cars? I thought it was higher than that.



It takes quite a bit more than 50 amps to start a car and a charger
like that could only produce 50 amps for (perhaps) a fraction of a
second.

That said, if your battery is in good condition but simply too cold or
run a bit too dead to start your car...an inexpensive charger like
that would certainly be useful.

Basically you'd need to allow it to charge your battery...at least
partially...to get your car going.


Ten minutes might be enough...might take longer.

Jump packs are becoming very popular now, since the charge lasts for months
(lithium ion battery), you can jump multiple times between charges, and they're
small enough to keep in the glove compartment.

Here's one:
http://www.amazon.com/Nekteck-Multif.../dp/B00MG687JW

Where I work, we can call our company's parking dept. if we need a jump or a
tire change. I once called the assistance guys needing a jump, and instead of
maneuvering their truck next to mine for a conventional jump start, they just
used one of these jump packs. I was taken aback - but it worked.

A neighbor swore by one of these! I've not looked into them in
detail -- and suspect a lot depends on the state of charge in the
battery in question.

Most of the times that I've needed to jump a vehicle I discovered
a dead alternator (which led to the battery's demise) *or* loose
cables at the battery (big IR drop there, poor charging, etc.)

Most for me have been bad batteries that finally gave out on a REALLY
cold day. - or someone left the door open, or the headlights on, or
the trunk open - and drained the battery dead.