Battery Charging

DEpointfive0

*Mods, I don't think this fits in any of the tech areas, but feel free to move*


Anyways, is hooking your car up to a charger every day a bad thing?

For the last few weeks for shitz n giggles I have been charging the battery with the charger I already had, 6AMP, 12V

Is this a bad thing? Is there any other risk? Or will it prolong battery life?

I DD my car, so it's not sitting, but when I plug it in, it does take a fair amount of time for the gauge on the charger to say 100%



Thanks for your input!

Mr&Mrs

After it gets fully charged you just want a trickle charge going to it. Im not sure if 6amps is to high or not though. I just use a motorcylce tender and leave them on 24/7.

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DEpointfive0

I think my charger automatically does that because it makes a totally different sound once the gauge says 100%

SouthArk370Z

Assuming you have a good charger and your car's charging system is up to snuff, all you're doing is wasting time. A good charger will not over-charge the battery, so it does no harm. If your car is properly charging the battery (charging system working and putting enough miles on it), there is no need to put a DD battery on a charger. I don't think it will increase battery life (enough to matter), but I'm not sure. Ie, you're not doing any harm, but you're not doing any good.
As for why the charger charges a fully charged battery at all: the charger setpoint may be a tenth or two of a volt above the car's and it takes longer to charge the last little bit. Or it may take it a while to realize it is already at the setpoint. YMMV

DEpointfive0

Fair enough, I think I started doing it too because my crank pulley is 20% underdriven and I have the stock alternator pulley. And sometimes while stopped at a light or something, you see the voltage dip from 14.2 to like 13, which is still good, but I just wanted to know if topping off the battery is bad in any way

Waiz

I would have to agree with this assesment, you're just wasting your time Andrew

SouthArk370Z

If you want to be sure you are getting enough charge (if you do a lot of idling with an underdriven alternator, it's possible you are not), just put a voltmeter on the battery when you get home. A 100% charged lead-acid battery will read 12.6V and drops to 12.35V at 75% charge. Edit: Anything above 12.4 is usually called "charged".

DEpointfive0

Legit answer! Thanks for putting it quantifiably! Rep added
My battery is reading 12.99!
Looks like I won't be hooking it up anymore...

And not bad for an 2009 OEM battery that has spent most of its life in the heat of the South

Edit: Locking thread, thanks for the replies guys

DEpointfive0

Because member SouthArk370Z is an amazing and helpful member, after I had posted my response and closed the thread, he sent me a PM stating:

I got to thinking about you getting the high (12.99V vs 12.4-12.6V) reading on your battery when not being charged. Lead-acid batteries will hold a "residual" charge for a few minutes - something about local spots of higher potential on the battery plates IIRC. The "extra" charge will equalize over time - I've seen claims of from 5 minutes to 12 hours. You may get a more accurate reading before you crank up in the morning. There will be some drain on the battery from the always-on electronics, but it shouldn't a large drain so voltage should still be above 12V after sitting all night (but I'm not sure just how much drain is involved, so don't hold me to that figure).
Probably not that important but thought you might want to know.


I replied:
Man oh man, you're awesome for coming back to shoot me a PM!
I really appreciate it. I got the 12.99 after about half an hour, but tomorrow morning I'll check before I fire it up!

Today after the car has been sitting all night it's at 12.82V, and I tried 2 voltmeters, and they tested the same, and they both tested a brand new Duracell AA battery at 1.79V, and my home AC outlets are at 112V... The car/garage is around 60 degrees F, sooooo, not sure how much that makes a difference, but I assume colder would have a lower readout vs before when the garage was 70 degrees F, and under the hood was quite warm.

Mt Tam I am

How long can the rest of you leave an interior light on for? i was packing the car for a trip and left the hatch open for up to 4 hours and the car would not start. If I leave the music box on to record too (3-4) many albums it did the same.

This seems weak. Is it normal or shared by others?

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DEpointfive0

Yeahhhhh... That seems weak... I have had my hatch open for HOURS, and no issues (I do have LEDs, they do get pretty hot though, so it still burns electricity) but I have slept in my car with my phone charging while listening to music (Bose system) for about 4 hours and my car started up fine...

You can go to any Sears (with an automotive department) or MOST Sam's Clubs, or Walmart, or the dealershit and they can check your CCA (Cold cranking amps) Since I'm not the battery expert, maybe someone can chime in, but in all my battery changing experiences, that's what they always complain about... (I'd suggest a local automotive store, but usually you have to bring the battery in, which isn't exactly fun on the 370...)