How and when to refill battery water (acid)

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  • OVERALL DIFFICULTY INDEX: 1/10
  • NO TOOLS REQUIRED FOR THIS JOB
  • IF YOU HAVE NO EXPERIENCE YOU SPEND 5 MINUTES TO CARRY OUT THIS JOB.
  • RISK OF FIRE OR EXPLOSION, SEE BELOW.
BEFORE YOU START
  • You need at least one US Gallon (some 4 liters) of distilled or deionized water at hand and sometimes more.
  • DO NOT GET CLOSE TO BATTERIES WITH AN OPEN FLAME OR A CIGARETTE. 
  • Hydrogen is produced by batteries when charging. Concentrations could turn explosive under some circumstances. 
DISCLAIMER:
Our pictorials are of informative nature and do illustrate works carried out by ourselves at our own premises for our own use and satisfaction.
Readers who envisage to carry out similar works inspired by the below method shall do this at their own risks and liability.
 

How to check solar system and UPS lead acid battery water level

Checking the electrolyte level on batteries with normal plugs, not float indicators:
  • Remove the plugs of all six compartments of your lead-acid battery at a time by turning them slightly to the left and pulling them up.
  • The liquid level should be covering those vertical plates you see within each compartment, the ones of a grey color beneath the liquid.
  • If this is the case, all is fine and it is great time to top up the level, proceed further below to see how.
  • The purpose is therefore to continuously keep those plates covered with electrolyte; in case the liquid level of your battery is lower, you can still top it up, but this means that you're not doing your batteries maintenance on time and that you're taking serious risks for reducing their life.
Checking the electrolyte level on batteries with float indicators:
Solar systems batteries are systematically supplied with float indicator plugs, which you should use to replace the normal plugs fitted during shipment.
Once done, the red indicator will immediately come up to the maximum level.
When the solar batteries need to be refilled with water, such indicator will be close to its lower position marked with the red circle at the bottom of the transparent cylinder of the plug.
In case your float indicators are damaged or broken, you may check the level like for regular batteries as explained above.
This picture shows how the electrolyte level of the solar battery is correct since all float indicators are up to the max:

Refilling the solar and UPS batteries with water

  • Use only distilled water to refill batteries. Do not be tempted to use tap water, this will destroy your battery!
  • Simply pour water into the concerned compartment of your battery. Use a small funnel if needed. Do so by adding a small quantity each time and checking that the liquid has touched the bottom of the plastic walls which indicates the right level.
  • Refit the plugs or the float indicators, that's it!
  • A specific tool exists and will make your work even easier especially if you have several batteries, you may buy it here from our partners' stores:

See also our other tutorials in relation with batteries...

...and buy more tools for your batteries from our partners' stores: