'Hacking' sealed VRLA batteries for maintenance??

[IC_theSun]

Hello all, new to this forum.

I've just bought some replacement VRLA sealed batteries for my small off-grid setup. They're fairly cheapo 'maintenance free' batteries.

The ones I'm replacing are pretty much the same, which are now entirely dead after about 3 years constant use.

So... I'm no expert but am thinking the main cause of the demise of the previous set of batteries would be plate sulfation and at this point they probably don't have much electrolyte left in them? Could that be right? I imagine, despite being 'sealed' they do in fact vent a certain amount of gas which eventually after many many cycles over years will mean that the electrolyte will reduce to low levels.

So... am thinking wouldn't it just make sense to drill these new batteries and put some bungs in them, so can 1. do regular equalization charge to break off sulfation, and 2. inspect/top up electrolyte when needed.... and maybe even 3. add some kind of chemical to recondition them, something I've seen mentioned on youtube, but am a bit wary about stuff promoted there!

I reckon the old batteries are probably beyond repair, being completely dead.... but i wonder if I modify the new batteries to be 'maintainable' might get a few more years good use out of them than just 2-3 years. I have a pair of 6v flooded Trojans with vent caps that are about 9 or 10 years old and have seen much abuse, but I'm still able to top them up and they still hold a reasonable amount of charge.

Be interested to hear some reactions to the above Has anyone tried this sort of thing?

 

[sunshine_eggo]

You can do it.

The result will never be as good as it was or even as good a regular lead acid battery.

You will only recover a certain percentage of its original capacity - usually a disappointingly small %.

Once done, it must be maintained as a flooded battery.

Well maintained FLA ALWAYS lasts longer then AGM/SLA.

 

[OzSolar]

Be interested to hear some reactions to the above Has anyone tried this sort of thing? I drilled off the caps with a hole saw and covered the cells and charged

I have but wasn't very scientific about it, batteries we're already challenged. I used a hole saw saw to remove the caps from each cell on some 12v Concorde batteries added distilled water to and then charged them at 2.7 VPC per Concorde's advice. Maybe I helped them recover a little bit but in the end it was a fool's errand.

 

[Hedges]

I don't think they're supposed to lose H2O, unless charged wrong (which could happen if some cells go bad and are low voltage so others overcharge.)

They can be gently equalized, I guess slow enough to recombine and cool enough.

I did try drilling and tapping into middle busbar, trying to get 3 good cells of an Optima for a 6V car (hate paying the price they charge for half a battery), but it was too far gone.

I do have 105 Ah 48V SunXtender that is about 15 years old. I think a cycle test couple years ago indicated 40% capacity remaining. I haven't tested cranking amps, don't know if it can deliver much surge. But I'm using them for a test setup, to light up 3-phase island grid.

 

[IC_theSun]

Thanks for answers folks. The new batteries are on order and as soon as they arrive I'll be pulling out the old ones. Will probably have a bit of a muck-around seeing what I can do with them in terms of getting the top cover off to expose the cells, just for practice... and also to see what things are like inside.

Whether or not i'll attempt to modify the new batteries... probably not. I doubt if it's worth the hassle. It would be difficult, if not impossible, to fit proper twist caps anyway, so I'd probably have to use bungs... which bothers me in terms of the risk that they would pop off under charging, and I'm not willing to remove them every time I charge.

They were relatively cheap so i'll probably just see how long they last and in the meantime save up for some Trojans!