Sanyo MQH03 + auto battery draining ?

[Sarratt]

Will using the cigarette lighter plug-in drain a cars' battery if its not running?
The output on the Sanyo auto adapter says:
Output 1.5A/12-24V

I'm trying to keep in mind the phrase ''there's no such thing as a dumb question, only dumb answers'' but I'm guessing my question comes close.

Thanks for any advice.

 

[bcwang]

Considering a typical car battery holds 45 amp hours, and the reserve capacity label on your battery is how long it can supply 25 amp while still holding above 10.5v, I'd say your 1.5 amp load to charge your batteries should be ok as long as you aren't running for the whole day at max output.

But the thing to keep in mind is lead acid batteries should not be deep cycled, nor stored in a state of partial charge. So as soon as possible you should drive the car to let the charge get back to full.

 

[tabetha]

Depends on size of car battery, how long you use charger for, remember that as chargers and other electronics are not 100% effecient it will actually take out more than you think from a simple calculation, work on the assumption of double the amperage out that it works out to as a rough rule.
Eg my 2L car has a 92AH battery, so if I was drawing a rated 5 amps hour for a charger, I would assume 10.
Invertors really sup the power from batteries, as use these myself.
Maybe if worried just try at home to start or maybe take a spare battery.
tabetha

 

[Radiophile]

Switching power supplies are relatively efficient, so I wouldn't bother with the 2x assumption. It's probably more like 1.1x or so. Of course that's assuming it uses switching at 12v and not voltage regulation which would be terribly inefficient with the voltage drop necessary. If that is the case, then 2x is a good assumption.

Also as a note on car batteries - sulfation doesn't really present itself as an issue until the voltage drops below 11v, so my primary concern would be having enough juice left to start the car. Certainly one charge cycle shouldn't be a problem. Even multiple charge cycles over the course of a few days wouldn't be a problem as long as the battery was working properly and not damaged in some way.

If the capacity of the battery is reduced because of abuse or neglect, you may want to be cautious and run the engine briefly after a charge cycle. No more than a few minutes should be necessary unless the alternator is very underdriven at idle speeds.

As a former glow plug equipped diesel car owner I'm painfully familiar with auto battery issues. Add to that a radio hobby that required a mobile amplifier, and I would kill a battery about every 18 months even with a great deal of knowledge and care taken to prolong the battery's life. I'll never understand why diesels don't come with dual batteries!

 

[tabetha]

If it's a AGM battery, then sulphation won't be an issue at any voltage, even completely drained, esp if spiral core AGM.
The time needed to put back into a battery what 1 start of the engine takes out is a hell of a lot longer than 2 minutes, at idle, unless the alternator is DELTA phased, which is very unlilkely, though can be converted, most are STAR phased.
Best bet would be spare battery, I know the conversion rate when using a invertor on my car worked out at 2.8, ie it used 2.8 times as much energy to convert 12-240.
tabetha

 

[Sarratt]

Thanks for the answers ... and for a bit more information than I understand but I think the answer is yes.
I can run the AA cell charger for say ..an hour without killing the car battery.
It's a camping trip and I'm not sure there is regular power anywhere nearby.
The eneloop charger says it takes about an hour to recharge 2 aa cells 2 hours for 4.
It'll be a rental car *fingers crossed* but generally they have all been in very good shape.

 

[Marduke]

Will using the cigarette lighter plug-in drain a cars' battery if its not running?

That depends entirely upon your car. Most cars completely turn off all outlets when the car is off. If you car happens to have a "hot plug" that maintains power while off, follow the advice given.

If you have to turn the key to power the outlet, and hence powering many of the car accessories, your battery drain can be much higher than that of the charger.

 

[VidPro]

with large gaps in driving a car, i often have to top off my battery to keep it alive even without anything pluged in.
i have Never had a little plug in device completly drain the battery While Using the car normally, but without the car being driven often (recharging it), like the one kept in the garage i would never leave a device plugged in.

after the batteries charge the total power consumption will drop , but there will still be a minor discharge from almost ALL of the ciggy plug in devices. Assuming the power outlet doesnt turn off (with the ignition).

anyone driving a car at least once a week, shouldnt have any problem with any of the minor charging device items, and if they did they probably need a new battery.
if your not using the car, then not only will a small device like this take the battery down over months, but you need to maintain the battery anyways.

if it was running the stereo or tv , or a AC converter running 100W out of it, Then you can take a battery down in no time, and be left stranded, but devices like this when finished doing thier charging, and just parked will take much more time than a few overnights.

Get a manuel transmission and park on a hill