I have always liked appropriate technologies that are accessible to everyday people (eg ram pump) so when i found this resource i knew i had to try it for myself.
I will not be able to start testing for a few months but I will add links as i find them and give time for people to find the thread and comment.
If anyone has a good source of batteries please share and eventually we may get a small group reviewing together.
The general concept/theory is that sulfuric acid is NOT the only electrolyte you can use with lead.......yes there are trade offs and attention to detail is required but battery life span and dollar benefits are potentially huge.
JUMP TO ABOUT 25 MINUTES INTO VIDEO TO GET TO RELEVANT PART
Virtually the only guy that has done his own testing
Don't worry that it says v1.1 in the link, it's a PDF with a link out to the latest version.
Re: my work.
There are so many arms of Lead-Acid chemistry and utilising alternative electrolytes is just one area.
Desulphating and rejuvenating old FLA cells is another huge and exciting area.
10 years ago I couldn't join the dots either when it came to the science behind "how and why", but now I have a firm grasp on the processes involved, and years of tests to demonstrate it.
I am finishing off my latest version of another paper title "Desulphating Lead Acid Batteries", and there will be a link to it also from the same PDF file above on my website.
Don't expect it until end of 2018 though :)
The latest version of my "Alternative Electrolytes for Lead Acid Batteries" paper is up to v.1.5, and I went back and basically re-wrote 20 pages of the previous paper, so keep up to date with the revisions. :)
At this stage, in terms of a good all-rounder electrolyte for a simple liquid replacement, the winner has to be one of the "double metal sulphates" or "alums".
It doesn't only refer to Potassium-Aluminium-Sulphate (which is commonly also called "Alum"), but can work with various double metal bound sulphate compounds.
I have had good successes using Sodium-Aluminium-Sulphate as it has a higher solubility than the Potassium counterpart, and I can get higher molar concentrations per Litre, which acts more on plate surface area to provide a larger overall Ah/capacity.
Note though, the working characterises of the lead-acid cell are changed substantially!. I have found that a large difference occurs even depending on "how" one prepares the double metal sulphate compound. For example, taking a working pre-charged lead-acid cell (meaning that the positrode is a mixture of PbO and PbO2 and the negatrode is a spongy lead mass) and filling it with Aluminium sulphate, charging it at a 1C rate at 4v, (it plates the Aluminium onto the negative electrode fully) then adding Sodium sulphate and discharging provides very different results and discharge curves than pre-preparing the Sodium-Aluminium-Sulphate (NaAl(SO4)2) first and then filling the cell. See the discharge graph below for a "plated aluminium" lead acid battery. Performance gives around 1/5 of rated Ah capacity of normal Lead-Acid using Sulphuric acid at a 5M ratio, but I found no lead-sulphate formation upon 100% discharges. See the attached various discharge charts for different electrolyte compounds compared to the same 100Ah rated Lead-Acid cell.
I have come to have the opinion that, in regards to the current standard Lead-Acid chemistry, A low pH is definitely required to ensure the formation of PbO/PbO2 oxide layers on the positrode plates, and that a range of alternative electrolytes will work if they also have low pH values. Once you start to cut down the list of compounds and options though, because you don't want to produce any soluble lead-compounds, the list narrows down very quickly. ^_^
I think that Ah capacity rates of 25%> certainly do make the cells a possible player on large scale, no weight issue installs such as off-grid buildings, who cares if there's 2Ton of batteries sitting on slabs on the ground if the cells will outlive the owners of the house a few times over, :p.
I have not done any energy efficiency testing, though using the Ah % comparisons that I give in the paper, we could estimate energy density (e.g., using Lead-Acid H2SO4 5M as the standard for our usual 40Wh per Kg measure for Lead-Acid, we could estimate that Boric Acid electrolyte cell would provide 10Wh per Kg, etc..)
I don't have any data for overall coloumbic efficiencies though regarding charge input/output, etc..
I feel that, in the case of the modified electrolyte lead-acid cells, this will be more to do with changes to the Hydrogen and Oxygen over-potentials (electrolysis and gassing voltages).
My initial work the last decade has been compiling a "trial and error" list of compounds and data, since my research is entirely self funded and has to work around my family and my other businesses.
Regarding cycle life, the only 2 factors that I've been noting in my experiments thus far have been observing the sulphation of the negative electrodes (or any other deterioration of the negative electrode surface area) and the pitting / shedding of the active material (PbO/PbO2) from the positive electrodes during charge.
The research is still too much in it's basic stages to have this data yet though. Setup with a charger that records CHG/DSHG and will graph Ah capacities v's cycle count, this could be easily obtained.
very interesting. I'll have to take the time and dive in more deeply later. I'm playing devils advocate here. What is the advantage of using sulphuric acid alternatives? I understand that current lead acids wear out but that always seems like a matter of economics to me not failings on their parts. The batteries could be built for refurbishment and reconditioned as they once were instead of as a throw away product. If the best alternative electrolyte is 25 percent the effectiveness that means 4 times the resources for the same capacity. Would the energy invested in refurbishment not be less then all the additional resources devoted to the larger bank?
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