Use and storage of auto jump-starter - portable power

 I've got a Sears DieHard Portable Power 1150 unit.  It can be used to jump
start a car, has an air compressor, and even a small inverter.
Does it make sense to always have the unit plugged in and charging
constantly or to charge it to 100%, take it off the wall outlet until I use
it and then charge it again?  The instructions say to charge the internal
battery every 2 or 3 months -or- leave it permanently connected to the AC
wall outlet.

Just wondering if one way might prolong the internal battery more than the
other.

Thanks,
Walt

 
I would assume it uses gel type sealed batteries. I would just plug it 2-3
months.
As used in emergency lighting, they only last so long, perhaps 6 years or so.

greg

 
that depends on how the internal charger is designed..

if it is designed poorly, having it plugged in all the time may
overcharge the battery and boil away the electolyte...  if this is the
case then you are better off pluggin git in for 1 day per month or
something like that...


If you have a good DVM check the volatge across the battery while it
is plugged in and has been plugged in for a day or so..  if it is much
above 13.8V then it is probably overcharging.


If the charger is designed correctly and holds the voltage to 13.8 V
then you can leave it plugged in all the time...

Mark

 
13.8 is 100% but if he lets it go below 12.6 or so as it sits months
it will sulfate. I bet those cheap units are not very good at proper
battery maintenance, that might need a maintainer. www.batteryuniversity.co=
m
might help him learn what he needs

 
Hi Walt,

I have a similar jump-starter and air compressor combination that I
keep in my car for one or two months at at time between charges. While
I have used it during a recent two-week, 4500 mile road-trip with
minimal charging, it has served me well.

Mine has a sealed lead-acid battery that likes to be charged every two
or so months. As long as I take care of its needs, it takes care of my
needs. If your model uses a lead-acid battery, it's better to fully
charge it every 2-3 months or so. That's been my experience using a
similar device during 2-3 month periods over the course of one year.

Brian