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Alum Battery Conversion

PRELIMINARY SPECIFICATIONS - WORK IN PROGRESS

Desired Outcomes of this Project

Convert a lead-acid battery to a lead-alkaline battery using Alum (Potassium Aluminum Sulphate) and Epsom salt (Magnesium Sulphate).

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Description

Most batteries have a lifespan of anywhere between 5 and 10 years, depending on the manufacturer. These batteries, called SLI (Starting, Lighting, Ignition) batteries, are commonly used in cars, UPS systems, etc. for lighting and using other electrical appliances. These batteries, also popularly known as lead-acid batteries have been popular and find their place in a lot of applications in every day life.

 

Why this is important

Following are the advantages of using Alum (lead-alkaline) batteries compared to lead acid batteries.

  • Higher Energy Density - Alum batteries have a higher energy density. This allows the battery to produce the same energy while lasting longer than other batteries. 
  • Battery Life - Longevity is another advantage of alkaline battery. It has longer shelf life than lead-acid batteries.
  • Lower discharge rate - When not in use, these batteries tend to discharge energy slower than lead-acid batteries. These batteries store charge up to 4 months when not in use.
  • Environmentally safe - Alum batteries are safer compared to lead-acid batteries when it comes to recycling, or disposal.

 

What this project needs to move forward

We need these skills to move this project forward:

Hands on Builder - someone that can build this project, do side by side comparisons on a converted and standard batteries, take measurements, run load tests, and record results.

Apply now if you are interested in participating in this project or visit the Project Management board (here) and jump right in.

 

Preliminary Research and Documentation

The following research and documentation is meant to get this project started. Please consider this a work in progress. Significant work is needed to move this project forward.

 

Components

The following components and chemicals are required to convert a lead-acid battery to a alkaline battery:

  • Used lead-acid battery
  • Baking soda (Sodium Bicarbonate - NaHCO₃)
  • Epsom salt (Magnesium Sulphate - MgSO4·7H2O)
  • Alum (Potassium Aluminum Sulphate - KAl(SO4)2·12H2O))
  • Distilled water
  • Funnel
  • Multimeter
  • Filter paper
  • Battery charging station
  • Lighting circuit (optional)
  • Gloves and protective eyewear (required)

 

Method

The process of converting a lead-acid battery to a lead-alkaline battery involves the following steps:

  1. Neutralize the existing acidic electrolyte in the lead-acid battery. 
    1. Place the battery on a flat surface and carefully unscrew the cell covers.
    2. Add 3-4 tablespoons of baking soda (sodium bicarbonate) into each cell. This neutralizes the acid (sulphuric acid) solution in the battery. Let the battery rest for 30 minutes so that the sodium bicarbonate completely neutralizes the acid
  2. Empty the battery electrolyte of the lead-acid battery into a bucket. This needs to be disposed off safely. 
  3. Wash the empty battery with distilled water and let it dry.
  4. To 4 liters of distilled water, mix 500 grams of potassium aluminum sulphate and 150 grams of magnesium sulphate. Ensure that the salts are completely dissolved. 
  5. Filter this solution through the filter paper to ensure that there are no solid particles in the homogeneous solution.
  6.  Carefully pour the alkaline electrolyte into the battery cells using a funnel till each cell is full.
  7. Screw the cell covers back and clean up any spillage of the electrolyte on the surface of the battery.

 

Testing the Converted Battery

Charge the battery using the battery charger and record the charging at regular intervals of time using a multimeter. When fully charged, use a lighting circuit and/or motor circuit to test the discharging of the battery at regular intervals of time.

 

Documenting Results and Recommendations

Documenting Results 

The outcomes of this project must give a recommendation of percentage of alum and magnesium sulphate that must be mixed with distilled water to get maximum performance of the battery based on these parameters:

  • Amount of alum added in distilled water
  • Amount of magnesium sulphate added in distilled water
  • Time taken to completely charge the battery. The results must be documented in intervals of 10 minutes and percentage of battery charge. 
  • Time taken to discharge the battery. The results must be documented in intervals of 10 minutes and percentage of battery charge.

 

Sample report (not accurate)

Electrolyte 1 [150 grams MGSO4 + 500 grams Alum + 1 liter of distilled water] - CHARGING/DISCHARGING

Percentage Time Time Percentage
10% 00:10 hrs 1:00 hr 18%
20% 01:15 hrs 2:00 hr 28%
30% ---- 02: 22 hrs 3:00 hr ---- 34%
----- 100% 11:45 hrs --- 12:00 hrs 100%

Notes:

  • When starting the project, start with a fully saturated electrolyte in 1 liter of distilled water (max saturation electrolyte).  
  • Reduce the saturation in subsequent trials by adding different quantities of distilled water to each trial. 

 

Publishing Recommendations

A detailed report of the recommendation must accompany the results. The recommendation must specify the following:

  • Quantity of chemicals per liter of distilled water
  • Fastest and slowest charging time
  • Fastest and lowest discharging time
  • Energy density of the resultant battery
  • Precautions on handling components, battery, chemicals, charging stations and testing and measuring equipment

 

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