When to use external battery charger

[y_p_w]

My wife drives almost exclusively short trips and likes to leave the map lights on in the garage because she wants to read something. Of course she forgets to turn it off and occasionally we end up with a battery that won't start the car. Whenever possible I'll charge it up with one of several chargers (3/12 amp selectable with auto-maintain when done, 1 amp manual, or 1.5 amp maintainer). I'll use the jump starter if I have to, but then charge it fully when it's back in the garage.

However, often it's already low or drained with the map lights on (and I find it an turn it off) but where it can still start. I'm thinking it's helpful to charge up the battery as an occasional maintenance item. Any thoughts on this - if this is useful or I'm just wasting my time.

I also remember a coworker who asked to borrow my jump starter. I've used it several times in the company parking lot, so several people know I have one. She just wanted to bring it home and start her car. However, I was told that it was driven a short distance and then wouldn't start because the battery wasn't fully charged. She really only needed it the next morning and it was in a garage with access to a power outlet. I probably would have been better off lending my 1.5 amp maintainer, which I had in my trunk at that time. I think overnight it would have charged up the battery enough for several starts such that it could still restart with several short trips.

 

[2009Edge]

1. Drive it on a weekend for at least a ½ tank of fuel on an interstate or other highway where you can maintain a speed of +50 mph. That should take care of it for a couple weeks or so.

2. Educate the wife on the consequences of leaving the map lights on.

 

[mattwithcats]

Better, change the map light to an LED...

Look at www.superbrightleds.com for bulbs.

I replaced my dome, stayed on for 36 hours, car started fine...

 

[bepperb]

Have similar problem with wife and kids. Change over to led bulbs. Haven't used the above url, can't remember where I bought mine but it was about 10 bucks a vehicle (a lot cheaper than superbright) and it's been a few years with no issues.

 

[The_Jeff]

You bet it's useful, will help with battery sulfation. I'd give it 12 amps and watch the meter until it shows it's only taking a ocuple amps.

It's funny though, 12 might be a bit much, I like 6, but then maybe just for a bulk charge/ hour or two it won't overdo it.

The thing I like about dumb manual chargers is you can watch them work.

Does your car have a sunroof? Can you hang a bulb over it that runs off house current?

 

[901Memphis]

Always best to keep the topped up if possible. They last longer when you keep them full.

 

[razel]

Agree with the LEDs. Replace the map lights she uses. They're wonderful. Just a warning... they are directional so buy wide dispersion (180+ degree) versions on superbrightleds. Also if you car is fancy and does a subtle dimming to off with some of the interior lights when you close the door, you may notice that the LEDs may still be dimly lit... even after 2-3 hours. They are that power efficient.

From the sound of things, your battery could be hopeless. I'd buy a new one next time it dies then use the charge maintainer. On my weekend ride I attached the charge wires directly to the battery terminals and just run the wire to the quick-disconnect plugs tucked hidden in the bumper so that I don't have open the hood.

 

[440Magnum]

Might be time to buy a set of LED bulbs for the map lights...

 

[gathermewool]

To clarify, does your wife park in your garage at home and then pick something up to read, or is she reading to kill time before work in a parking garage?

Have you considered a deep-cycle battery? Also, with her bad habit of leaving the light on I'd hook up a trickle-charger once/week to keep her topped off. Even if she only kills the battery infrequently, it's cheap insurance that the battery will be maintained in better health for longer.

 

[y_p_w]

Originally Posted By: gathermewool
To clarify, does your wife park in your garage at home and then pick something up to read, or is she reading to kill time before work in a parking garage?

Have you considered a deep-cycle battery? Also, with her bad habit of leaving the light on I'd hook up a trickle-charger once/week to keep her topped off. Even if she only kills the battery infrequently, it's cheap insurance that the battery will be maintained in better health for longer.

Only once she gets home. She's done that to my car too. She'll typically be looking at stuff on her phone or just reading something in print. Even with a phone she prefers that the light be on. Then she forgets to turn it off and then gets back in the house. Even when she does remember to turn it off, it could be a half hour to an hour.

I don't worry about my car since I have a one-way commute of about 50 miles. If that doesn't fully charge the battery, then I have some serious issues with my car beyond how I drive it.

Like I said, I have a choice of chargers. I actually have two different versions of the Schumacher 1.5A maintainer. One is an older version with a coil transformer. The box didn't say it had any auto shutoff if connected improperly (or shorted). The newer version is microprocessor controlled and has a connection shutoff and uses a switching power supply. It's much lighter. However, last night I hooked up the 3/12 amp charger and selected STD battery type and 3 amp charging rate. It has a crude percentage indicator, which said it was at 52%; it switches between sampled voltage and percentage. I don't think it's that accurate, but better than nothing. In the morning it had already gone into maintain mode where it's usually off and has a timer before it samples voltage again.

 

[Eddie]

Train id10t wife to hook up charger or learn to read in the house. )

 

[Kestas]

Originally Posted By: 2009Edge
1. Drive it on a weekend for at least a ½ tank of fuel on an interstate or other highway where you can maintain a speed of +50 mph. That should take care of it for a couple weeks or so.

I wouldn't suggest burning $25 worth of fuel every so often just to maintain the battery. Buying a charger to trickle charge when needed is considerably cheaper, less wasteful, and more convenient. I understand using the alternator in the car to substantially charge the battery is hard on the alternator.

 

[Garak]

This is what I use on my F-150. It gets mounted in a semi-permanent fashion and can be left plugged in all the time, and is mighty handy in the winter. The above link is for reference only - do not look at the price, fall off the chair, and hurt yourself. Napa can get you it for $35, as can many, many other places.