Charging Large Jell Cell Batteries

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.

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

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.

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

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

electrolyte

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

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 :-)

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

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.

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

Thanks