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Author Topic: Observation about SLA non-spillable batteries  (Read 4741 times)

Offline Brian516

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Observation about SLA non-spillable batteries
« on: February 12, 2015, 04:55:19 PM »
I know this isn't about any new kind of battery, and for that I apologize, but I found nowhere else to post this information.

I have observed that by opening up non-spillable SLA batteries and adding some H2SO4 solution to them, they will charge up a WHOLE lot faster, take a whole lot longer to discharge, and increase in capacity.

It seems that the manufacturers of such batteries do not add enough H2SO4 solution to their batteries, resulting in there not being enough solution in them to allow them to go thru the full charge/discharge cycles.  By adding even just 2 or 3 CC's to each cell, I have given the cells more solution to work with in order to re-form the Lead Peroxide layers on the plates, resulting in thicker layers of it and faster charge times.

Example:  I stuck a 12V 5Ah battery on my SG charger before adding any solution.  It was on it for 2 1/2 days (it's a small machine) and wouldn't go above 13.52V at all. It topped out and then stopped, for almost a whole day it stayed at 13.52V.
I left it running with same battery, put my meter on it, popped the caps off, and added 3CC's to each cell.  It almost immediately dropped a few millivolts since I gave it more solution to electrolyze.  I left it overnight.  10 hours later, it was at 15.86V.

Since I am not a chemist, and not an expert with batteries, does anyone have any input on this?  Can you find any cons to doing this?

I did it with 2 4.5Ah 6V batteries, got them to 14V in series (they are fairly new still) and have been running a 12V 1Watt LED bulb off the two of them together for the last 3 days, and they still haven't made it to 12.5V yet.

If anyone plans on doing this, make sure you either leave the rubber caps off the first time you charge/discharge, or put the plastic back over top of the caps.  If you don't, when they pop off from the pressure you might lose them!!

Oh, also, I am going to be making my own lead based battery soon, plates and all, and would like some input from some people about various experiments I should do with the cells.  I am going to try various different sulfates for electrolyte, both the Plante process and the Faure process for forming, and different ways of configuring the positive plates (laminations, thick plate with cuts thru it and red lead dried inside, heavy grit sanding, razor blade scratches, pretty much anything I can think of to increase the surface area).   Does anyone want to toss some ideas my way, and that may be interested in hearing the results of these tests?  I may also try one as a hydrate crystal cell.  (before anyone chimes in and says "you should do the Alum electrolyte instead of sulfates! -  Alum (aluminum sulfate) is a sulfate.  It still turns into a form of sulfuric acid electrolyte, just not as caustic of an electrolyte.


Offline MarkE

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Re: Observation about SLA non-spillable batteries
« Reply #1 on: February 12, 2015, 05:09:09 PM »
A couple of comments:  15.9V is severe overcharge for 6 2.1V lead acid cells in series.  Lead acid batteries are far more forgiving of overcharge than other chemistries, but even they have their limits.  13.2V is a good place to keep the battery.

Working with lead at home could cause you all kinds of EPA grief.  I would look into some of the regulations before potentially finding my home classified as a Superfund site.

There are advanced lead acid batteries out there.  Some use carbon sponge like Axion to get much greater cycle life.

The biggest problems with lead acid:

Round-trip efficiency of about 60%.