NomadEpitro

I am using a Sears Battery Maintainer (DieHard series: #02871219000 Mfr. model #71219) . This power inverter / charging device differs from most conventional battery chargers in that it doesn't overcharge the battery, but rather, maintains and 'tops off' the voltage as needed (since, as we all know, most newer vehicles have so much aux-power-draining electronics on board that most conventional undercharged (by alternator) batteries don't last quite that long (maybe two years, tops[avg]?).
When it's plugged into one of the cigarette lighters, however, the message display reads: 'mazda rx8', then goes blank, but I can hear a quiet hiss from the speakers, as if some audio something-or-other is then turned on, even though I have everything turned off (key out of ign).
If this sort of thing happens, then it more or less defeats the purpose of using the maintainer through the socket outlets, as the power it's supplying to otherwise maintain the battery is being consumed by this 'hiss' and backlit information panel.
Does anyone else experience this?
The only other remedial thing is to go directly off of the battery terminals themselves to the maintainer. But it's somewhat cumbersome, removing the plastic cover and getting the connectors just right in each post, then leaving the hood up overnight, everytime I want to do this. Advise...

ken-x8

Not to be rude, but that description is a bunch of hooey. Batteries last as long as they ever did, and that is not at all affected by the amount of electronics on the car. Sounds like a copywriter at Sears has taken a cue from late-night infomercials.

The charging system on your car is designed to keep the battery charged, without overcharging. As are conventional battery chargers. There is no need for a device like what you've described.

I would suggest that you put that charger on the shelf. Bring it out if a) you actually have a dead battery that needs to be charged, or b) you're going to park the car for a month and need a trickle charger. In either case, the effort of opening the hood and removing the battery cover isn't such a big deal.

Ken

Charles R. Hill

iTrader: (7)

I would agree with Ken and only add that if battery condition, i.e. long storage, is a concern then you could do what I did. I just made sure the battery was fully charged, removed it from the car, and stored it off the floor and on a shelf in my basement. 3-4 months later it started the car with no problem.

StealthTL

iTrader: (1)

I won't comment on the need for a trickle charge, but it's pretty obvious why everything on the dash lights up.....

The lighter is on the circuit that is controlled by the accessory relay. When you send power in with the key off, everything on that circuit (that should be off) is on.

You could wire a lighter socket into the battery, or into a circuit that is supposed to be on at all times.

S

Nubo

Actually there is truth amid the fiction. Most newer cars consume dark current nowadays, compared to older cars which, once they were off, they were OFF. Any number of posts in the forum from owners whose cars were dead or unable to start after sitting for as little as 2 or 3 weeks. Now, some of the 2004 OEM batteries were crap, but still true that your battery will eventually run down unless its driven regularly.

Add to that equation, the fact that most auto batteries are not designed to handle deep dischage -- it weakens them and permanently removes capacity. If you're like most people who drive their car daily or at least a couple of times a week, your batteries will probably last as long as they ever did. If you have cars that you only drive once in a while, your batteries won't last as long as they once did under that circumstance.

And so, a float charger can be a good idea for folks who don't drive their car regularly.

Also, if one only drives very short trips, the battery will remain undercharged because there is not enough time for the alternator to replace energy lost to starting and from dark current drain. Admittedly, with a 90-amp alternator it shouldn't take too long

Finally, even if you only want a device for occasional battery-charging duty, it makes sense to have one that can tell when the battery is fully charged. The three enemies to battery life are

over-discharging
over-charging
heat