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RE: Battery Question

Started by MrBuneez, Mar 25, 2003, 09:43 PM

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MrBuneez

 Thought I would ask this SIMPLE battery question. After sitting all winter, can I recharge the battery as I would a regular car battery with a trickle charger?

MrBuneez

 MrBuneezI just read the post that WhiteStar posted a short time ago and got a lot of info from the replies from that post........sorry for duplicate posting. Should have looked before I leaped!

AustinBoston

 MrBuneez
QuoteORIGINAL:  MrBuneez
 Should have looked before I leaped!
 

 We ve all leapt before looking before.  Sometimes, repeating a discussion brings up info that wasn t covered before, or hasn t been covered in a long time.
 _________
 
 In very general terms, a trickle charger is best for maintaining a battery that is not deep-discharged.  Even so, car batteries (which shouldn t be deep-discharged) get a surge of charging current when you start the car, followed by a trickle while running.  With a discharged deep cycle battery, it is best to hit it with at least 6-10 amps of charging current just until it reaches full charge.
 
 How to determine what full charge really is could be the topic of a whole other discussion.
 
 Austin

garym053

 MrBuneezI ve recently learned the expensive way to check the battery water level OFTEN!!! Two of my deep cycle batteries were almost dry when I checked them this Spring!! Added Distilled Water and one has come up to full charge (according to Deep Cycle Charger) but the other one is staying at a charge rate of about 6 amps, and I m thinking maybe it s toast!

MtnCamper

 MrBuneezGary, In the past couple days I have learned, your battery may not be 100% charge, even if the charger says so. Mine says 100% and checks 12.42V, which is actually 80% of the useful charge.
 
 Also if you replace the bad one, and have a not so good one, wired parrellel, the new one will soon be consumed trying to equal out the not so good one. So in effect you have 2 not so good batteries. Better to buy them in pairs.

wynot

 garym053A thought on the battery staying at 6 Amps.  What does the battery test out at voltage-wise?
 
 I ve had some luck on a battery recovering with a charge-discharge-charge sequence.  No promises, but it might be worth a shot.  Probably best if you can use it in a car.  Won t help if you have a short or dead cell either.
 
 If you have 12.6 V, and the battery can actually start a vehicle, and you can put it in your auto battery tray, use the discharge of starting, coupled with the charge circuit to  exercise  your battery.  Don t leave home without your good battery and jumper cables.

AustinBoston

 wynot
QuoteORIGINAL:  wynot
 If you have 12.6 V, and the battery can actually start a vehicle, and you can put it in your auto battery tray, use the discharge of starting, coupled with the charge circuit to  exercise  your battery.  Don t leave home without your good battery and jumper cables.

 I would think the huge currents needed to start a vehicle could damage a deep cycle battery, just as deep cycling could damage a starting battery.
 
 A better approach would be to hook a 12 volt load to the battery (such as a 12 volt lamp) and let it run down to the 12.0-12.2V range, then charge it.
 
 The charge-discharge-charge cycle does work, though.  I had trouble getting my battery to take and hold a full charge.  After double checking the fluid levels, I used it to run a 12V spotlight for about 12 hours.  Then I did a standard charge cycle, and it charged faster and held the 12.6V nicely.
 
 Austin

wynot

 MrBuneezAB,
 
 I ve not had anything evil happen to a Deep Cycle battery from starting a car, I used my second battery off the camper when my car battery decided to lose a cell, and I needed to get back and forth a few times before the battery was available at Sears.  Wouldn t be my choice as a routine though, it doesn t provide a lot of cranking amps.  But the battery still works as well as ever for a house battery.
 
 In this case, what I was looking at was to provide a hard discharge to it, followed by a charge cycle, actually a few of them to see if there was a way to get it back to  normal .

mike4947

 MrBuneezWynot, take a look on those battery pages of Bart s I posted the link to. Look under sulphation. That s what cause about 80% of the problems with our deep cycle battery (other than outright abuse or neglect)

TheWallRocks

 MrBuneezI purchased one of those " Battery Minders"  that are supposed to charge, condition and de-sulfate a battery.  It comes with a handy pigtail that can be permanently attached to the battery terminals, so all you have to do when you get home is plug it in.  It is designed to be used at all times the battery is not in actual use.  I figured $50 was cheap insurance to keep a pricey deep cycle battery in tip top shape.
 
 

garym053

 MrBuneezJust so happens I have a 12v spotlight that I was going to use as a back-up light for the trailer! I think I will connect it and drain the battery and see what happens! It s kind of weird- I never paid this much attention to the batteries until this year when I have to run a medical device off of one with an inverter!
 I ll have to recheck some of those battery pages as I forgot what the voltmeter should read when fully charged!
 Thanks!

mike4947

 MrBuneezGary, trust me you don t want to " drain"  the battery. Anytime you take the charge below 50% you lose life. Most true deep cycle battery have a range of around 50 or more discharges. The trick is it s not 100% discharge. That can reduce the life by 20% the first time it happens. Do it  2 -3 times and you ll be buying a new battery.

AustinBoston

 mike4947
QuoteORIGINAL:  mike4947
 
 Gary, trust me you don t want to " drain"  the battery. Anytime you take the charge below 50% you lose life. Most true deep cycle battery have a range of around 50 or more discharges. The trick is it s not 100% discharge. That can reduce the life by 20% the first time it happens. Do it  2 -3 times and you ll be buying a new battery.
 

 I think the typical performance of a deep cycle battery is better than this.  Even a starting battery can take 5-6 100% discharges before making the recycle bin.
 But in general you don t want to deliberately 100% discharge any lead-acid battery.  Every time you do, you loose some life and have one less opportunity for a mistake.
 
 I don t know where I picked this number up from, but I ve always aimed at 12.2 volts while resting (resting means with nothing connected to the battery for at least two hours).  That might be more discharged than the ideal, but I have only " needed"  to do so twice.
 
 The best way to check the state of charge is with a specific gravity dohickey (uh, ok...) not a voltage meter.  But even these are not 100% reliable.  I saw an emergency light that showed 100% full charge (both the voltage and the specific gravity), that would run the emergency light for about 15 seconds.
 
 15 seconds was enough for the maint. people, because that s all the fire inspectors ever held the test button down for.[:@]
 
 Austin (who tried to fumble his way out of the dorm at 2am in a fire drill)

wynot

 mike4947
QuoteWynot, take a look on those battery pages of Bart s I posted the link to. Look under sulphation. That s what cause about 80% of the problems with our deep cycle battery (other than outright abuse or neglect)

 Mike,
 
 ?? Don t know where this link is.  thanks.