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Topic re flat batteries

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  • Topic re flat batteries

    Ladies and gents i'm starting this topic to try and keep all information together.

    It seems now that a few members here and on the Hilux forum are experiencing issues with random flat batteries. My GX has been experiencing the odd unexplained flat battery since new . I dont drive it daily , and since i'm retired the car may sit there for anything from a couple of days to a week before it gets used. When i do use it i go across town and back and its about 20klm or so , regional area not the big smoke.
    Im fairly good with electrical stuff so have been monitoring the battery voltage since new. When it was new the battery would charge at 13.6v and never higher. this is most likely due to the variable voltage alternators we have. All was fine over the last 9 months with only one or two unexplained flat battery events but now in the last month its been flat twice. Ive had to charge it with a house charger overnight to bring up the float voltage. Now the car is charging at 13.9v and never lower. I suspect the battery itself is at fault though it will pass a load test OK.
    I do have numerous electrical accessories fitted , everything from a DCDC to brake controller and numerous lights , dash cameras , etc. All these items run off the aux battery so the main remains unaffected. I can also remote jump start from the aux battery if required.
    Today i inserted a current meter into the negative lead ,and there is a draw of 120milliamps when you first lock the door but this drops off to zero after 20 mins , so i dont think its the car drawing any stray current.
    Its going in for the ECU recall next week and ive asked them to check the battery while there.
    2019 GX , in White

  • #2
    Maybe some batteries don't like cold weather, crystallize / lose charge quickly. I've seen some batteries work better in warmer climate, and then require some trickle charge during winter.

    Other possibilities could be battery does not handle high dcdc amperage very well, or some positive grounding issues somewhere either in wiring or electrical devices, or if you can confirm wiring is ok, then it's almost the battery itself.
    Last edited by Kiat; 26-06-2017, 06:14 PM.


    • #3
      i'm thinking its the battery itself , combined with a silly Euro 5 charging system which doesnt allow the battery to fully charge properly between runs.
      2019 GX , in White


      • #4
        No probs with my 2015 GX which still has the original battery in it. That said when time to replace it, I'd like to get a slightly larger battery for it. My start battery only runs the usual Tuner electricals & is wired up to the Warn winch. Everything else is wired up to the deep cycle battery. I've also got a Redarc for managing the dual battery system.

        Like White One I'm also retired, but my Tuner's my daily drive with short trips a couple of times a day, of no more than about a 7 km round trip from home to shops for a coffee, groceries etc etc.

        Not that I know about cars by any stretch, but any chance the battery was partially rat$hit from new & got worse over time? Only saying this because my dual batt/system optima deep cycle had 1 dead cell "off the shelf" when fitted. So regardless of driving 8+ hrs a day driving to Darwin, the yellow top would drain overnight, leaving my fridge off with barely cool food & drink in the mornings.

        Regardless of the cause, I hope you find out what the issue is. Most of us would like to know....


        • #5
          I'm having issues with my battery also, after short trips under 5 or so ks the car barely starts. It's only 18 months old and I would have thought a new battery should last longer than this.


          • #6
            update - a couple of months back i added a 5w solar panel to the dashboard and kept the factory battery trickle charged while the car was at home. this worked for a while the car started normally after not being used for a week. So anyway i drove to Sydney to see the kids and the car wouldnt start. Took it to the closest Toyota dealer who said the battery tested fine!! they said it needs a long drive periodically. I pointed out my QLD plates and said it has just done 1300klm to get here. no technical advice whatsoever.
            went to Battery World who tested the battery again but this time with the DCDC unit disconnected , and it failed the test , was down to 360CCA. Toyota tested the battery without dsconnecting the DCDC which is why it passed , i 'd say the components in the DCDC will give a false reading to the battery tester. Battery World bloke was awesome and had seen the issue before. They didnt have a new batt in stock so i went to Repco , who tested again and said its buggered the CCA reading was dropping on each test.

            so i now have a new 590CCA battery to replace the factory 490CCA at a cost of $260. I could have gone back and argued the point with Toyota and even tried a warranty repair but didnt bother. The factory battery was dated 08/2015 and i bought the car 10/2016 do who knows how long it had been sitting around for .
            2019 GX , in White


            • #7
              Interesting about the DCDC unit.

              Can only speak of optima deep cycle yellow top per my issue as stated above, but a mate also had a yellow top, & he also suffered the same fate as me. Dead deep cycle battery after driving 7-8 hrs p/day around the Googs Track & the Eyre Peninsula. He also went to battery world, & he was told that at one point Optima were apparently making their batteries in Spain where quality control was shot to bits.

              Think I'll do as White One did & visit Battery World when next I need either a start or deep cycle battery.


              • #8
                the Battery World bloke said a low charge voltage is a significant contributor to battery sulphation , I'm still considering a way of increasing the 13.6v , whether it be retrofitting an independant internal regulator or making Canbus changes or some other hack
                2019 GX , in White


                • #9
                  My Tuner is an Oct 2015 GX model which I bought when it was a 6 month old demmo model. I've got a 490CCA start battery, which might? still be the first start battery in it since it came off the production line.

                  So after 2 yrs, it may not have much life left in it. It'd be interesting to see how much longer I get out of it.


                  • #10
                    the factory batteries are branded Yuasa Thailand , which are a good battery , and come with a 3 year pro rata warranty. Trouble is if the battery is weak to begin with or has run flat a couple of times the lifespan is reduced. If i was using the car every day it may have lasted longer , not sure.
                    I didnt ask Toyota how much they charge for a new battery but it would have been a fair bit , being an oddball size with recessed terminals. Repco''s price was reasonable and they use Century Yuasa with a nationwide warranty.
                    I''m fairly good with battery maintenance - my bike , boat , jetski and shed batteries are all kept topped up by solar panels.
                    2019 GX , in White