I saw some Youtube videos that recommends adding water to AGM battery to extend its life time.

However, some do not recommend it.

Which is correct?

I have a 6 years old car with its original AGM battery installed. The battery just works fine. I am not so sure if I should replace the battery as a precautionary measure or just wait for its death.

  • Why do you think you need to rejuvenate a battery that is working well, when advised not to? The videos are adding water to a battery that is dead, in an attempt to restore it. If the battery then works, then yes. If it doesn't work there is nothing lost (it was dead). If it isn't broken, don't fix it. When a battery does wear out, it is not usual to break down, it is more usual that the engine will not start. If someone is trying to sell you a new battery "in case yours fails" walk away. There is usually some warning of failure, as the car becomes hard to start, or it needs frequent charging. Jun 19, 2021 at 19:03
  • I see some videos talking about recovering AGM batteries that have lost capacity, and some other videos talking about adding water to wet cell batteries as a maintenance task. I don't see anyone recommending adding water to an AGM battery that is working normally.
    – barbecue
    Jun 20, 2021 at 18:57
  • Please check this video. This person recommends adding water to the dried cells in AGM battery. youtu.be/ZI648J9KBVM
    – notilas
    Jun 20, 2021 at 20:19

2 Answers 2


If you are lucky to have a battery with plugs, it means that you can and should top up distilled water. The sealed batteries are supposed to be unservicable, thus an classic replacement item..


As always, the devil is in the details. It depends why your battery is low. If it is not sealed, and there is evaporation or heat, it may lose some water. In that case, adding back can help.

But AGM shouldn't have this problem, and it should be sealed well enough to avoid evaporation.

Also it depends how badly gone the acid is, and how much exposure to the air there has been. If the acid has eaten away the inside of the battery, adding water will not help and may make it worse.

Generally speaking - don't fix what isn't broken. Always consult the manufacturer for specifics like this and follow their recommendation. YouTube can be a dangerous place to be if you don't know what you're doing.

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