Renew Your Sealed Lead Acid (SLA) Battery With Distilled Water!

Introduction: Renew Your Sealed Lead Acid (SLA) Battery With Distilled Water!

SLA stands for Sealed Lead Acid. It is a type of lead acid battery that more secure and can be found in anything from Home Security systems to electric bike batteries and just like Car Batteries which are standard Lead acid batteries, SLA batteries can dry up too!

This instructable was inspired by


  • The following instructable contains Voltage and Acid Proceed with caution!

Step 1: Materials/Tools


  • Multimeter
  • Eye Protection
  • Distilled Water (Steps included on making your own!)
  • Battery Charger
  • Tiny Screw Driver
  • And of course a lifeless SLA Battery
    • I got mine from a old backup power supply system for a server at my work and was hovering around 8 volts when I got it. I tried charging it for 12 hours and it would not exceed 10volt

Step 2: Step 1: Preparing the Batteries.

My batteries had plastic caps on each cell as oppose to one large cap covering them all. Please be carefull when removing the caps for they will need to go back on. (I already did these steps for the battery on the right)

  • Grab your tiny screwdriver and Pry off the plastic tops.
  • Remove the rubber caps.
    • Warning: Use your eye protection pressure may have built up in the cells. Also! At this point do not tip the batteries unless you are looking for a floor filled with battery acid (I would not recommend this)

Step 3: Step 2: Distilled Water

De-ionized water is best but another option is to use Distilled Water! Tap water is not recommend.

Option 1: Make your own using evaporation!

  1. Fill your largest pot 1/4 full with tap water
  2. Put a object like a brick or something in the bottom of the pot
  3. Put a bowl on top of it (this will collect the distilled water)
  4. Flip over the pots lid and begin boiling water

As the water evaporates and hits the lid it will condense and drip into the bowl.

Option 2: Let your air conditioner do the work

  1. Turn on your air conditioner and let it run
  2. Remove Distilled water!

Option 3: Let Nature do the work for you

  1. You can also collect rainwater in a clean container and use it!

Note: not all air conditioners have a valve like mine you may need to rig something to collect the water from yours.

Step 4: Step 3: Add Your Distilled Water!

Move your distilled water into ideally a syringe so you can carefully add the water to the cells. Or you can make a mess like I did.

Step 5: Step 4: Start Charging!

  • Leave the caps off and start charging.
    • Note: The water will begin to bubble this is ok. Be Sure you charge in a well ventilated space! the gases coming from the batteries is flammable.
  • Once we confirmed the battery is working again re-add all the rubber caps and the plastic caps. Some sort of mild adhesive or tape works best for the caps.

Step 6: Step 5: Enjoy Your SLA Batteries

Whatever your use is be sure to enjoy them! I will be taking my electric bike farther and faster with these 24ah batteries (upgrading from 10ah!)

And if you like please don't forget to Vote! :)

Teach It! Contest Sponsored by Dremel

Participated in the
Teach It! Contest Sponsored by Dremel

Fix & Repair Contest

Participated in the
Fix & Repair Contest

Remix Contest

Participated in the
Remix Contest

Be the First to Share


    • Puzzles Speed Challenge

      Puzzles Speed Challenge
    • "Can't Touch This" Family Contest

      "Can't Touch This" Family Contest
    • CNC Contest 2020

      CNC Contest 2020

    6 Discussions


    Reply 2 years ago

    My batteries are still flat after this despite being recharged for two days - what do you suggest I try next?

    1024 Web Solutions
    1024 Web Solutions

    5 years ago

    if it is SLA where did the water go, in order to add more?


    5 years ago

    Nice instructables and please add that the open battery should be charged in a ventilated area. The charging process will release hydrogen, which is quite flammable.


    Reply 5 years ago on Introduction

    Ah yes, Thank you I have added it to the instructable!