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Charging Large Jell Cell Batteries

I have a question about charging large Jell-Cell batteries. I have a large 12 volt Jell-Cell battery from SBS that I use the back of my truck for fast charging some of my planes. The battery is a 70 amp hour batter. Currently I use an automatic 12volt car battery charger set to

2 amps. The question that I have is that when I charge the battery after it is on for a little while and before it registers a 100% charge the batter sounds like it is boiling just slightly and making slight popping noise. I know on a standard lead-acid batter this would be normal but I'm not sure about a Jell-cell. Do any of you know if this is normal? I am also a little currious about another function on my automatic charger. It has a switch to change between whether or not the batter is a standard low maintance battery or a maintance free deep cycle battery. I am curious as to exactly how the charger physically functions differerently between those to charge functions. Is the charge cut off point slightly different, or how the charger ramps down the current? Any information would be greatly appreciated. Thanks.

Scott Heling

Reply to
Scott
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I would check the actual output of the charger! The gel battery should NOT make noises when charging and 2A is well below the charging limits for that size battery.

Reply to
Paul McIntosh

What you are hearing is not normal for a 2 amp charge rate into a 70 AH battery. Sounds like it is venting.

The end of charge voltage limit is probably set a bit lower by the switch on your charger for the maintenance free battery (to avoid loss of electrolyte in overcharge).

Your battery could also have dried out (loss of electrolyte) somewhere along the way.

-- Red S. Red's R/C Battery Clinic

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us out for "revolting" information.

Reply to
Red Scholefield

The jell cell I have requires a special charger. You cannot charge the jell cell I have with anything else. So the fact that you are getting noises while using an automatic 12volt car battery charger is not surprising.

Reply to
Greg Cisko

I checked the output of the charger and when the battery was registering approximately 90% charged it was putting out approximately 5 amps. As it neared

100% it dropped down to approximately 3 amps. I hooked my charger up to a friends battery who has the same battery as mine and his registered approximately 3.3 amps, though that battery was already near full charge. I'm not quite sure what I should do about this battery. It seems to still hold a charge, or atleast it has for the past week of fast charging, though lately I've only been charging smaller cells, 1000 mAh and such so nothing really taxing. Is there any way to determine if I have lost electrolyte?

Scott Hel> What you are hearing is not normal for a 2 amp charge rate into a 70 AH

Reply to
Scott

electrolyte

Bottom line, is using a maintenance free setting OK, or not? If not, what?

Reply to
Morgans

See, now ya did it. There is a simple answer. If he's using a Sears automatic charger then throw it in the trash! They overcharge regular and deep cycle batteries so i would think it's doing the same thing to his gell-cell. Build yourself a constant voltage charger. There are many to be found online via Google. P.S. I'm not an expert but the 4 Sears automatic chargers i've tested all did the same thing. Turn off about 15.5 volts if i remember correctly!

remove my-wife to reply :-)

Reply to
Icrashrc

Thank You Red and all the others who have posted! Actually all of your advise has helped. The next time I need to recharge I'm going to use my 1.5 amp automatic trickle charger that I have been using on some of my smaller, 7 to 15 amp hour, jellcells for years now without any issues. If I still hear bubbling and popping then I would probably suspect that something is wrong with the battery. If not then something is not quite right with the charger. What I have learned form this that is very valuable is that it is not normal for a jell cell to make popping and bubbling noises as its being charged at 2 amps and that there is a fair probability that my charger should be putting out less current when the battery is nearing 100% capacity than it does so it is suspect. So now I have a direction to go in and things to check out.

Scott Hel> See, now ya did it. There is a simple answer. If he's using a Sears automatic

Reply to
Scott

What should the voltage of a gel cell be, when the automatic charger cuts off? It is a 7 Ahr, useing a 1.5 A automatic cutoff charger.

Reply to
Morgans

Figure something between 2.45 and 2.5 volts per cell, for a 12 volt battery (6 cells) this would be 14.7 to 15.0 volts. These are voltages when it is still on charge.

-- Red S. Red's R/C Battery Clinic

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us out for "revolting" information.

Reply to
Red Scholefield

Thanks

Reply to
Morgans

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