Charging battery in-car

[Dave Sherman]

I've got the 1-amp smart charger that's regulated, charges up to about 14.5 volts, and drops down to 13.2 to maintain the battery. It's sitting on the Traverse right now, because I had the key, the automagic headlights, and the radio on for a while while I was troubleshooting a flaky door speaker. Trouble is, it takes hours to replenish the battery. Probably doesn't help that the keyless entry module is sucking some of that current.

Then I have the brute-force, 12-amp dumb charger. Totally unregulated. Puts out rectified AC that peaks at 16 volts or more. Have to watch that one because it charges fast but the battery will be boiling before too long. I'm afraid to put that one on without disconnecting the battery first.

The small charger I'm not worried about, it doesn't go any higher than the alternator normally goes. Is it safe to put the big charger on? I think waiting a couple hours sounds better than pulling up the floor panel, disconnecting the battery, charging, reconnecting, resetting the clock, etc.. If I can throw the big charger on the jump starting terminals under the hood safely without having to disconnect the battery, that would go more quickly.

Thoughts? I just have this fear of zapping something if I put the dumb charger on.

 

[Warstud]

Slow charging is best for the battery.

 

[andyd]

u

 

[JHZR2]

Originally Posted By: Warstud
Slow charging is best for the battery.


I agree. While some battery types do you have low enough impedance I thinking collect this a large amount of charge with relatively low over potential, most typical batteries do not. what this means is that as soon as the terminal voltage it's high enough in order to keep a high amount of charge flowing in the battery voltage has to be high enough to dissociate water rapidly.

All that said I wouldn't call 12 and all that high on the battery that's probably at least 60 amp hours.

There is some literature out there that has found that charging at high rates at least in a pulsed fashion, or short-term fashion can help get the surface structure to be more optimum for continued cycle life.

If I were the OP, i'd probably use the dumb charger because 12 A is not all that high. i'd be very hesitant to allow it to get up to 16 V though, and so I keep a rather close are you as well as a multimeter on the charger and stop it when it gets too low to mid 15 V. When that happens you can turn off the charger and let the battery rest and equilibrate because it is polarizing in the aqueous electrolyte as opposed to actually reversing chemistry. After a few minutes rest perhaps with even a slight amount of load on it, then try again.

At the point where you just can't put the fast charger on the 12 A without the voltage peaking out, it's not a problem. that's the point to put the slow charger on let it sit overnight and not worry about it. or getting slightly fast charger. It's amazing the difference 1.25 or 1.5 A makes versus something that's below 1 A for a slow charger.

 

[The_Jeff]

Don't you have an appliance timer? Stick it on the heavy charger as a fail-safe to click off after a couple hours.

If the battery has enough umph to start the car, it has enough to soak up the peaks and valleys of "buzz box" current while still connected to the car mains. If you want to check on this, turn on your AM radio and see if the 60Hz buzz overpowers the stations or not.

 

[HTSS_TR]

I would use slow charger/maintenancer overnight.

 

[raytseng]

Are you in a rush?
Did you drain the battery down to can't start the car anymore?

If the smart charger is already connected, just leave it there until tmrw.

 

[901Memphis]

Or you could get yourself a higher amp smart charger, i found an awesome one myself and there are a few other ones similar if you need recommendation other than that let me know.

https://bobistheoilguy.com/forums/ubbthreads.php/topics/3810865/Finally_found_a_good_automatic

Slower charging is good, but 1 amp isn't enough to do much if the battery is low.

Noco also makes some darn fine chargers in addition to the Pro Logix i linked. My Pro Logix is temperature compensated and charges perfectly not going over about 14.6v-14.7v so you never have to worry about damaging the battery like the cheap smart chargers that go above 16v, which is very bad!

my video too if you're interested.

https://www.youtube.com/watch?v=3zHFN0KrVwc&feature=youtu.be

 

[Wolf359]

Why not just get a cheap smart charger? In the past Sears has sold one for $20 on sale, normally around $30 for a 2amp smart charger. If the battery is a 60 amp hour battery, if it were totally dead it'd take 30 hours to recharge, but it's probably only 1/2 dead which means about 15 hours on a 2 amp charger so just basically overnight.

 

[bvance554]

Did you drain it till it won't start and you need to charge it? You don't say. I can't tell if you have a dead battery or if you're just looking for a use for your chargers.

 

[Dave Sherman]

Thanks. Lots of answers, but nobody answered my only question.

 

[Ducked]

I don't know, because I have no experience with recent model cars, and don't want any.

Therefore, I wouldn't, personally, risk leaving it connected while big-dumb-charging it.

If they've managed to design it so that disconnecting the battery is a significant hassle, seems likely they've built-in some other gotcha's.

 

[cjcride]

Disconnect the battery and put the big one on it then you have no worries. Keep an eye on it.
OR
Leave the trickle one on nightly for a few days.
It's your choice.