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GS Yuasa "OEM" Battery - Gel or AGM?

Discussion in 'Gen 2 Prius Main Forum' started by dorunron, Aug 21, 2012.

  1. dorunron

    dorunron Senior Member

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    Subject line of the thread says it all.

    Here is the question. Is the original 12V factory installed battery that comes with the second generation Prius a Gel or a AGM type battery?

    There are three types of batteries that I am aware of for use in the automotive industry. "Flood, Gel, and AGM". Since it is a sealed type battery, the "Flood" can be ruled out immediately as flood type batteries have caps or covers on the cells that can be removed to add distilled water to.

    There are various chargers available to charge and maintain these batteries. Some of the chargers have switches on them for the type of battery. The charging algorithm varies depending on the type of battery.

    Contacting Toyota both at the dealer level, and the 800# was of no help. To quote the 800#, "Toyota does not publish this information, therefore we suggest you contact the dealer for more help". When you call the dealer, they say "We don't know what type it is, and to contact Toyota at the 800#.

    With all of that said, I am looking for input from the experts out there. I intend to charge and maintain the OEM battery until it is no more or until I feel that it is time to retire it. Then I will change it out to the Optima Yellow Top which is known to be a AGM type. I understand that the "gel" setting will work if worse comes to worse, however if the Yuasa brand battery is found to be a true "AGM" type battery, the AGM setting would be better due to slightly higher voltages used in the algorithm which will definitely affect the overall lifetime and charge percentage of the battery being maintained.

    Thanks everyone!

    Ron
     
    #1 dorunron, Aug 21, 2012
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It is supposed to be AGM. See p. 11 of this catalog:
    http://www.batterymasters.co.uk/ProductDocs/CARYUAF46RPW654-TECH.pdf

    Some Prius owners have found that their original equipment battery is flooded lead acid. I looked into two of my original equipment Prius batteries (from the 2001 and 2004) and both were AGM with fuzzy white mats separating the lead plates.

    All of these batteries were marked GS, no obvious differences in the case design. So unless you remove the top sticker (which has a warning statement not to remove it) as well as the translucent plastic cover over the six cells and look inside, who knows what you will find.
     
    #2 Patrick Wong, Aug 21, 2012
  3. dorunron

    dorunron Senior Member

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    Thank you Patrick. This is good info to know as the charger I am using set at Gel will run a slightly lower voltage cut off before it jumps into maintenance versus running it at AGM. It is only .5 (1/2) volt of difference in the algorithm, but is still a difference imo. I really do appreciate the tech help as Toyota would not answer the question. I even mentioned that I am a proud Prius owner and was very disappointed that Toyota would not answer a simple technical question. Alas, they act like everything is a trade secret today :rolleyes:

    Anyway, I really do appreciate the reply and the info. Charging now with the new battery mender.

    Ron
     
    #3 dorunron, Aug 21, 2012
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