On Sun, 27 Sep 2015 14:57:54 -0700, "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.


I've bought two of those. They work great. Here's a tip if you buy
one. If your battery is really low and you use the charger on the
logical settings, like "charge" on the 10 amp setting, you may fine
the "charge complete" light will come on right away but it won't have
charged the battery. That's got something to do with how the thing
senses the ability of the battery to take current, apparently really
low batteries fool the charger into thinking no charge is needed. The
way around that is to leave it on the 10 amp setting but put the other
switch on "boost" instead of "charge". As to the 50 amp thing, that's
about all you are going to get out of that small a transformer in a
small charger. I know when a battery is low and you put it on boost
the meter needle bangs over to the right from the high current. A
starter on old V-8s typically would draw 150 amps to start the car. I
would guess a 4 cylinder with a battery too weak to start it, but not
ruined and shorted, could be started with the 50 amp boost. You might
need to give it a 10 amp charge for 15 minutes first and then switch
to boost. Or a few minutes set on 50 amp boost to force some charge
quickly into the battery. I would expect the charger to overheat if
you used it that way very long.