Flat/dead battery

Technical Area Electrics & ICE
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  1. My model of MX-5 is: NB__
  2. I’m based near: Hatfield__
  3. I’m looking for technical help or recommendations on: Flat battery
    New panasonic battery sept 2020. Run car in 2020 and 2021. Been laid up in garage since Oct 2021. Went to start on Monday, battery dead. Purchased a trickle charger and connected battery which I had removed. The charger lights showed battery fully charged but still no power output. Is there a problem trickle charging a Panasonic battery?_
2

I’ve trickle charged Panasonic batteries, but not from fully flat. I think when they are full discharged, thats it. COVID wrecked a brand new Panasonic for me, due to lack of use.

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I have trickle charged one from 2.5v and it’s working fine in my NB. It was a new one, purchased from my Mazda main dealer last November. It subsequently checked out 100% on a battery tester.

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4

I’ve taken, against all the odds and likely technical outcomes, a dead Panasonic in my Mk1 on more than one occasion back to useful life.
Same battery. It ought not to happen, but there is nowt to lose by sticking it on ICU foe a few days on a proper gel battery trickler.
Does not make sense…but there we go.

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If you have a totally flat battery some chargers can’t see it connected. Solution is connect another battery (that does have some voltage in it) in parallel with jump leads, then connect your charger to either battery.
Eventually voltage will build up in the flat battery and you can disconnect the slave battery and carry on charging. I use a CTek conditioner for sthe times s car is laid up more than a couple of weeks. It cycles between charging and discharging constantly and will desulphurise the battery.

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