trickle-charging quandry

I never have figured out just how those are supposed to work...

'Most' vehicles need the key on to use the lighter. Even in the ACC key set, some power can be drawn if you aren't real careful with things like the heater controls or radio.

Then even if you can get 0 draw, you are making sure the thief has a nice charged battery for when he turns the key to start and drives away....

I have used the small trickle chargers lots when I lived in the -40 winters. These ones fit under the hood and were hardwired to the battery. When the block heater got plugged in, so did they.

If it was mine, I would be cutting off the lighter plug and putting it on the battery.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Dave Gower wrote:

Dave Gower wrote in rec.autos.tech

Why are you turning the key on? Leave the key off, and let the trickle charger do what it is supposed to do, put a small current into the battery to either bring it up to full charge, or keep it there.

I think you have answered your own question. A trickle charger is just thank, a very LOW current charger designed just to keep a battery topped off. When you put your car in run or accessory position, you turned on many systems in your car whether your realized it or not. So the end result is the trickle chargers output is not greater than the load being required by the vehicles systems. So in that scenario, you could still run the battery down. You need to have the trickle charger connected directly to the battery with nothing turned on to be effective. Even then, there will be some parasitic load on the battery.

Bob

"Mike Romain" wrote

The specs on the charger say it puts out 65 watts (5 amps at 13 volts). Since I turned off the radio I figured this should be plenty, but I guess you're all correct, there must be a greater current draw than that.

I wonder whether "most" vehicles DO need the key for the lighter. It isn't true of my 2000 Focus, nor as I recall the 92 Voyager I got rid of last summer. I was surprised to find that on my 98.

Anyway thanks for the reply.

Many current-production vehicles are wired so that the lighter socket is not "hot" unless the ignition or accessory switch is on. This was NOT the case years ago. The manufacturer of your charger has not taken current practice into account. It's almost certain that your vehicle systems draw more current than the charger can provide, when the accessory switch is on. Arrange to connect your charger's output directly to the battery posts, and leave the key switch in the "off" position.

I have never seen a vehicle where the cigarette lighter required the ignition to be on or even accessory on. I'll take it on faith that some are. So I'd just wire the thing to the battery area or to something that is on constantly.

Is this a charger or battery eliminator? A charger typically charges at least a volt over the battery voltage. If its really just 13 volts DC, that may be low to charge the battery. Did you measure it with an accurate Digital volt meter?

Bob

And somewhere around the time of 02/14/2004 10:13, the world stopped and listened as Dave Gower contributed the following to humanity:

Well, if you put the key to the ACC or RUN position, then there's alot more circuits being powered than with the key in the OFF position. Can the current output of the charger supply the current to all these other circuits AND have enough left over to charge the battery?