Jeep / Die Hard Battery question

2000 JGC, V8. Die Hard 60 month battery installed, May/ 2007, just over 24 months ago.

For security reasons, I had to leave my flashing security lights on for five hours. This flashes all of the parking lights on and off. It killed my battery. I got a jump start, and the battery recharged about running it about 15 minutes at high rpm. (I still had that problem these Jeeps have about having to keep it running at a speed higher than idle, as it would cut off. I am told the computer module has to reset or something like that. This is tricky when you have to get a jump start in this jeep, as you really have a double problem.)

My main question......... is it normal that using the flashing lights for five hours straight would run this battery down ?

Thanks for any comments.

James

Reply to
James
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Absolutely.

15 minutes of charging at any RPM is insufficient. You need hours to fully recharge the battery.

But... If the battery was totally discharged, it probably has been damaged.

The shutting down is sometimes caused by the computer turning off the alternator because it is overly hot. The battery however, still doesn't have enough charge. I'm not sure this applies to your case however.

Reply to
PeterD

I have found that most DieHard batteries require a very slow and very long charge to replenish its juice. I charge them overnight or for 6-8 hours and then install them back into the vehicle. I believe that the alternator won't do a sufficient job of recharging it unless you are taking a long trip.

JMHO

Reply to
dave AKA vwdoc1

I drove the Jeep 90 miles right after this happened, and the battery seems to be fully charged.

My main question was whether the flashing lights for five hours would run down this two year old battery. One reader has said yes.

Thanks

James

Reply to
James

To be succinct:

Yes.

If you wish to test the battery further, grab your digital voltmeter. After sitting ( say overnight ), your battery will read somewhere in the vicinity of 12.56 volts. Much lower than that could be a problem. Higher is good. ( I have four deep cycle bats on my home back-up system that hover in the

12.8 range ! )

12V car batteries are really 6 - 2.2 volt cells tied together. Your vehicle will usually read around 13.8 volts when running.

Most auto parts stores ( like mine ) have a "battery tester", which is next to useless, but it will read out the present charge, and most will perform a load test, which is a better indication of the battery's condition.

Like the first poster mentioned however, when a battery is severely discharged ( unless it's a deep cycle battery ) they are *damaged* to a degree.

Common sense rules supreme here. If the battery seems to be cranking the engine normally, you're good to go. ( for a while :-)

However, I have seen lots of batteries fail catastrophically. Gitcha somewhere, and never work again. Matter of fact, this seems to be typical with today's batteries. "Back in the day" it seems that batteries would give you some warning by cranking engines slow. Not anymore.

Reply to
Robert E. Watts

My main question was whether the flashing lights for five hours would run down this two year old battery. One reader has said yes.

Thanks

James

Are you thinking that there may be an issue with the battery and you want to have it replaced on warranty, quick before the warranty runs out?

At the risk of soundling like a smart azz.... (and not really meaning to)

You have this battery in your Jeep You left the flashers on for FIVE hours (that's a long darn time to be blinking that many bulbs) Your battery went dead.

End of test.

Fom your experience my guess would be: YES running your flashers for five blinking hours will kill a 2 year old die hard.

Darned if I'm going to test that theory to see if it works on my rig just to see if it will kill mine too.

Now, why were your flashers on for five hours? inquiring minds want to know ;-)

Reply to
Kate

Take it down to Autozone or wherever and have them test it.

Reply to
J. Clarke

You can do the math. What is the wattage of each bulb, times the number of bulbs, divided by (approximately) twelve volts, times five hours? This will give the number of amp-hours James used up by leaving the flashers on for five hours. If that answer is not roughly equal to the number of amp-hours advertised on the battery, well then there might be a problem.

To your question Kate, there's always a reason to do dumb things. ;^)

WTF are alt.jeep-l and rec.autos.jeep? My news server can't resolve them.

Earle

Reply to
Earle Horton

r.a.j is on the servers at cox. not often used. a.j-l Looks like a fairly active group. -l ususally means listserv or mailing list redirect.

Ask your news admin to carry them. At least a.j-l

Reply to
DougW

yes and you have proved it!

Reply to
dave AKA vwdoc1

The more accurate answer is possibly, depending on the general charge and health of your battery and whether there is any extra drain in your flasher system. I've left the lights on a Die Hard Platinum for about

4 hours, and by just turning them off and letting it set for an hour, managed to get enough recovery charge to start.

If you regularly need to leave your flashers on for that long, you really need to buy a battery system designed for such abuse.

The battery may seem charged, but it may not be. Park where you can get to a charger. Then turn off your ignition. Turn your headlights on bright and leave them on fifteen minutes. Then measure the battery, or just turn the key and see if it will start. If it won't, it either needs a deep charge or replacement.

Reply to
Lon

James....Bottom line is that the condition that you are describing will greatly shorten your battery life. Having worked with solar panels and deep cycle batteries I can tell you that in the winter batteries are about 50% less efficient than in warmer weather. So in the winter the thing you describe would discharge your battery much quicker, because as the temperature gets lower the battery is less efficient. (The battery chemistry of batteries used in a solar array (deep cycle batteries) and an auto is very similar, except for the physical design of the internal charging plates.)

In the warmer weather, all would depend upon the age and condition of your battery as to whether or not it would survive the activity you describe even one time.

There are three things that do the most damage to your auto battery (and to deep cycle batteries as well). The first is regularly draining a battery below 50% charge will, over time, reduce battery effectiveness. Second, draining a battery to zero charge will damage it. And third, and more often, recharging a battery quickly, like your auto alternator does, will damage it. In fact your auto alternator actually brutalizes your auto battery because it charges the battery too far too quickly and it is also not temperature sensitive. In colder weather, the battery should be charged at a slower rate. That is why batteries in a solar arrays have a temperature sensitive charge controller. And that is why deep cycle batteries in a solar array last upto 6- 8 and maybe more years.

I think the most I have gotten out of a car battery is 3 years (one time maybe four years), mostly because I have lived in colder climates.

Larry

Reply to
Larry

Thanks Lon, and your response answers the question.

James

Reply to
James

Thanks Larry, that all makes sense !!

James

Reply to
James

Not to be contrary, Larry, but it's unusual for any automotive batteries I've had to start showing signs of age in less than 5-6 years in automotive use (typically full charged and seldom under 80% charged). Back when lead-acid batteries were the norm, aircraft batteries used to start jet aircraft I flew would typically discharge at max discharge rate (800 amps @

24 volts) to about 60% just starting the first engine and the second engine start was touchy unless the first one started and the starter/generator came on line. Our charge limit was 800 amps for 5 minutes with full charge in 30 minutes at a lower rate just because of heat. Then I designed backup power supplies using lead-acid or sealed gell cells for about 15 years. The chargers that worked best for us were designed to monitor both temperature and voltage and to charge at max discharge rate until the cell temperature reached 40 C (about 105 F) or 75% as measured by the voltage. That's one nice thing about lead-acid - the voltage is a good measure of charge level. We typically programmed the units to switch to battery operation and discharge the batteries to about 20% before starting a charge cycle on a regular basis.

You are correct about one thing: temperature is the main enemy. But discharge levels and everything else takes a back seat to plain old gravity and chemistry when it comes to battery life in lead-acid. Letting the battery sit for ANY length of time fully discharged is plain old murder on them. They sulphate will start to settle out as soon as the current flow drops enough to let them start cooling and overnight will generally kill them dead after a full discharge. That's one reason for the high initial charge rate - to get the temp up and to create turbulence in the electrolyte to keep the sulphates suspended until re-absorbed.

As I sit here, I keep thinking about the battery in my 88 MJ. It is the cheapest one the dealer could find when I made that a condition of the sale when I bought the truck in July 2000. It has been discharged to the point that the engine quit at least 5 times since I've owned it (don't try and make it from Tulsa, OK to Colorado Springs with a blown alternator - there are stretches where you can't find a station to recharge it! Honest, I know that for a fact). Since I'm heading down to the Rio Grande Valley in a couple of weeks, I just had it load tested and it's still well within the rated capacity so I'm 9 years into a 60 month battery.

Reply to
Will Honea

I've seen LED replacement bulbs in some automotive sizes like 1157. If you need to do this, replacing all the bulbs in question with LEDs should lower the current draw significantly.

If you can find an appropriate size, there are Marine/RV dual-purpose lead/acid batteries available that can deep-cycle and start. They take just as long to re-charge. Some of the newer spiral-cell dual-purpose AGM batteries can also take deep discharges and charge faster, but are hard on alternators. Expensive, but the one in my boat is going on 8+ years.

Reply to
AJ

Interesting...about aircraft batteries and your experience with a cheap battery. If you are getting 9 years out of an auto battery, I would certainly stick with that brand... Living in North Dakota for 21 years, about 3 years max is all I could get out of an auto battery in my three jeeps. I always had purchased and had them installed by the dealer as I am not handy at that and I don't trust anyone else to mess with the electrical system in my cars (just my phobia). So the batteries were not cheap ones. The longest time I got was on the original battery in my 01 grand and that was 4 years. It failed in the winter when I attempted to remote start the car. I got the car started eventually, but replaced the battery immediately. When I got interested in solar power, I started following the group: sci.chem.electrochem.battery. And from postings in that group, I began to appreciate how really complicated battery chemistry is. They have a great faq on batteries, their care and maintenance. And one really interesting thing about batteries, as you mention, is their voltage is a pretty accurate measure of their remaining capacity.

Larry

Reply to
Larry

There are a lot of advantages in lead-acid technology - and not a few disadvantages. For what you are doing it's probably by far the best choice because of the simplicity. You have no driving need for energy density - the major advantage of NiCd and Lithium cells - since you don't have to lug them around (much).

From you comments, I'm guessing that your vehicles are out in the cold overnight. One tip I got from an old-timer when I spent 2 years in the icebox up in Wisconsin was to run a trickle charger as well as a block heater overnight - and you're even colder than that was. Hmmm... maybe a move South would help?

This could go on forever - I taught a few courses on batteries and charger design - but we're wandering off topic. The email address in the header is good if you have any questions I might be able to answer about batteries in general.

Reply to
Will Honea

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