kanicbird sorry I started writting that last post at about 1AM and got so punchy I saved it for this AM.
Let me address your questions now.
If I had an 8 hour drive and a dead battery I would either buy a new battery if mine was well and truely D-E-A-D, or maybe buy a small battery charger. At the end of the day I would test the voltage on the battery and see where it was. If the battery tested good on open circuit voltage, I would return the battery charger to the next Wally World I came across. If it still showed low, I would take it inside and charge it.
About your further question. If this were true, we could tell all the oil producing countries to fuck off and kiss our ass. We could solve the world’s energy problems with a bunch of dead batteries, and some inverters, and chargers.
What you are describing is perpetual motion. The inverter is not a 100% efficent process, and neither is the charger, nor are the connections. for this to work at least one of these would have to be >100% efficent.
Where did you get this idea from. The car is still burning gas.
You point is that a altenator is a ineffective trickle charger, due to how it was desgined (along with the voltage regulator). OK I can accept that, but you know that a altenator can usually provide more power at the expense of more fuel - OK did we now get that perpetual motion idea out of here - good.
Since that altenator can produce more power, it just won’t do it to directly recharge the battery, I would think the altenator would be more then happy to dump some extra power into a inverter. The altenator not really caring what happens to that power once it is handed off into the inverter. The invertor then gives it to a battery charger, which is used to recharge the battery (again, don’t get worried here Big Oil at the cost of more gas).
Again I ask would this recharge the battery better/faster then just using the altenator?
Funny, I just got back from the auto parts store with my new battery, cause I left my lights on last night, and my old factoryy installed battery would no longer hold a charge. This is the second time in as many months that I have done this. Could this be the reason my battery would no longer hold a charge?
I am running into a problem in this thread. I accept that somebody like Rick probably knows way more about cars than I do. OTOH, I have these unique things called “jumper cables” that I have used at least 3 dozen times over the years for myself and others to get a dead car started in 5 minutes or less. Most of the cars including mine seemed to be fine after a half hour drive or less and continued to be that way for years afterwards. The power was coming from somewhere yet we are only looking at a battery to battery short-term boost here.
When a wet cell battery is fully discharged it has to be “Jump Started” charged.
The batter will have a greater than normal resistance so when recharging a fully discharged wet cell battery start with the “High Amps” setting of a commercial battery charger.
So, to answer the OP. Never. Unless you ‘zapped’ the battery with high amperage the battery will never become fully charged to its full capability.
Okay, I get what you are saying and I have been taught various reasons why that might happen. (High voltage and current on a really D.E.A.D. battery, not doing the job. )
But…
Battery discharged quickly with headlights and stuff and such until it is at a , say, 4 volt condition after only 1-2 hours, and an alternator charge works just fine.
Battery discharged S.L.O.W.L.Y. over the course of months, as you have described, and is now at a 4 volt condition.
:: One idea I was taught was ‘sulfation’ (sp) — having to do with what happens to the plates …
So, little normal battery chargers would not work and we would have to use the big honkin “Constant Current” charger to ‘blast’ the sulfation off the plates ( being very careful about rates, heat, gas production, etc. ) until a more normal method would then work to finish the process.
What is up with that?
( Yeah, the batteries were never quite as good as a new one but they would work for a long time after doing that. ) (( Admittedly, this did not work every time. ))
What is the current thoughts on cell - plate condition due to various discharge methods?
OK, more have jumped in and I did not preview so I will look to answers to them for some of my answers also. Sorry…
*::: So, what do you personally recomend? Buy a top quality battery and hope your wife ( gonna get slammed for that one ) does not leave the lights on a often or buy a Wall-Mart special and just replace every year? What about the new super batteries that have a sort of round cell shape that they are pushing now and cost $$$$$ ?? ::: In normal / average car application? ::: *
And this is where you lose me. If you take a dead, dead battery, that requires a long, low current trickle-charging to take a charge, and put it in a jump-started car, what is actually happening? Is the alternator holding the terminals at 14V and the battery simply isn’t accepting a current? (I have no idea by what mechanism such a thing could occur, and I’m somewhat sceptical that it does.) Does the voltage regulator sense the state of the battery somehow and isolate it from the charging circuit?
My best guess is, with a deeply discharged battery in the car, you get a momentary very high charging current as you would expect. This trips the overcurrent cut-out, that isn’t reset until the engine is turned off. That would at least make sense to me and explain the symptoms as described!
I’m still not getting it, Rick. Upthread, persons were talking about batteries that had died, been jumped, driven around for 30 minutes or whatever, and then continued to work for years. Everyone agrees that is a regular occurence. But you and **QED ** and others suggested that if you do this without using a proper off-car charger to bring the battery up to full strength it will never get properly charged. Others subsequently suggested that they couldn’t understand why not.
Your long latest post deals with the question of why an apparently dead battery might be revived by a proper trickle charger, when it won’t be revived by the alternator. But that is not dealing with the question at hand, which is why a battery “charged to say 50-60% which is plenty to crank the car” (to quote you from post #8) won’t come up to full charge just by driving around for a long while.
As has been noted above, alternators/generators and in general the entire electrical system is designed to maintain a fully charged battery - not recharge deeply discharged batteries. Typical lead-acid batteries do not benefit from “running down” at all, even one complete discharge will degrade that particular battery permanently. Yes, it will charge up but never quite be what it was. A “trickle” charger providing 1 or 2 amperes is perfect for semi-permanent use as are products like the “Battery Tender”. Interestingly, though cold weather reduces battery performance, it is hot weather that tends to discharge batteries and promote sulfation, the real culprit of premature battery death. So charging in warm weather is probably more important. I’ve read that typical units sold for use in say, Michigan, are constructed differently than Arizona - the scorching underhood temps. require a different approach. YMMV.
A “smart” charger has advantages - the larger “dumb” units can boil a battery dry if left unattended. See http://www.batterytender.com A continuous float charge simply maintains the battery at the optimum charge and can be used indefinitely as they are current limited. Some after-market solar powered units look promising - modern cars and trucks have a fairly high parasitic drain with all the sound-systems, gps, security controls and golly knows what…
That’s my understanding as well. The best battery charger goes on and off as needed as opposed to CCCCHHHHARRRRRGGGGEEEE all the time. We have some batteries on charge for months at a time so they’re ready to go when motorcycle season or what have you kicks in.
