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Swollen 2v Gel Batteries
Tom C
Posted: Wednesday, August 17, 2011 10:48 AM
Joined: 01/03/2011
Posts: 19

The gel batteries for the services,25 x 600aH have overheated and swelled. They are still holding some charge and of course need replacement. Battery explosions and fire are of course a big worry but how dangerous can swollen gel batteries actually be? And is it dangerous enough to cancel a trip with the guests before replacing the batteries?
Posted: Wednesday, August 17, 2011 11:48 AM
Joined: 14/01/2009
Posts: 1024

Dont know. There is a test routien to verify battery a pro. Overcharging on shorepower is a problem that ruins batteries and burns up boats. Ive had to block and tackle overcharged, Swollen, Absolite batteries out of their cartridges with a block and tackle. At battery bank replacement insist that the battery chargers are correctly installed, calibrated and that the heat sensor on the battery bank is effective. Always monitor battery bank temperture.
Posted: Friday, August 19, 2011 7:57 PM
Joined: 13/03/2009
Posts: 1

Usually swelling indicates gassing/overcharging... gels can gas if put into a thermal overcharge for a period of time.. or a bad plate/cell

what make and models are the batteries?  What battery charger do you have connected to the battery bank and what setting is the unit set to?  Is the charger putting out the correct current? (charger could be out of spec?)

Are all the batteries the same age and type...(example//had one battery in the bank go bad .. so you replaced just that battery?_)
Posted: Friday, August 19, 2011 7:59 PM
Joined: 01/08/2008
Posts: 14

Over charging or exposing batteries to high temperatures can lead to thermal runaway. The batteries life is drastically reduced and it may swell up before it fails. The danger is if the battery splits you then have a possible chemical spill. This is less likely with gel batteries but if it is a lead acid battery and the contents spill out and come into contact with sea water, chlorine gas will be given off. This is also a concern. The batteries should be disconnected and replaced as soon as possible. They may last you until the end of the season but if there is an accident before then and you knew about their condition...well..... oh and junior what else would you block and tackle with?
Posted: Friday, August 19, 2011 9:18 PM
Joined: 14/01/2009
Posts: 1024

What else would I block and tackle with ? Dont know...somehow you need to pull the swollen cells from their steel cage. We fabricated a webbing strap with eyes on each end...bolted the eyes to the terminals...then sucked the cells out with a block and tackle. This was a 1800 amp hour, horizontal stack bank. If you could access the bottom end of the bank I suppose you could push them out with a jack. And a word of wisdom. Battery bank work is a dangerous task. Dont work alone, Rubberize all tools, wear eye protection, fire extinguisher handy, illuminate the work area and be carefull. you are handling a huge stored energy source. Ive witnessed a terrible battery handling accident.
Posted: Friday, August 19, 2011 10:10 PM
Joined: 03/03/2011
Posts: 100

Personally, I wouldn't take it off the dock until they were replaced but that is for you to decide. Consider what services use them and how could you run without those services - knowing what you might loose may well make up your mind for you. Change ALL of them out and then also check the charge output from your charger(s) once the new bank(s) are installed. Likelyhood is a couple of poor cells are making the charger pump out more power and in turn overcharging what is left.
Posted: Saturday, August 20, 2011 5:23 AM
Over charged Throw them and get new ones!!!