Nearly new car battery flat

Jim79

08 toyota verso petrol; over a few months the old battery was becoming a problem if car not driven everyday the battery would most likely need a jump start. so a couple of weeks back i got a new battery fitted.

It was fine for awhile obviously now i am not travelling far but even if i have a short drive yesterday the battery can be 2.3V in the morning. with engine running the battery is reading 14.6V (so i am thinking there is no alternator problem). Yesterday i disconnected the battery and this morning its voltage remains 12.4V.

Could i have a bad battery/ wrong battery/ parasitic draw?
Any suggestions on getting to the bottom of this.

CalamariFritti

Could be that (bad battery/ wrong battery/ parasitic draw) or more likely the alternator could be the problem. If its not charging right it doesn't matter how new the battery.

Bikerman2019

My friend had similar symptoms to you and I went down to take a look. She had a little micra but knew ZERO about cars.


I got into the car and turned the key. She had everything on and I mean everything. Demist, lights, heater on maximum, radio, you name it she had it. Add to the fact she only did the school run twice a day, the car never got a chance to recharge the battery. Any possibility this could be it?


Or maybe a circuit staying live and its draining 24 hours a day.

Bikerman2019

CalamariFritti wrote: »

Could be that (bad battery/ wrong battery/ parasitic draw) or more likely the alternator could be the problem. If its not charging right it doesn't matter how new the battery.

If the battery is running at 14.6 with the engine running, that suggests the alternator is charging.

zg3409

It is unlikely a new battery has become faulty unless the car caused it to be drained flat and it was left flat for a few days.

In the current climate all cars are at risk if batteries going flat if they are only doing 2 local trips a week.

When you say 2.3v how are you measuring this?

Parasitic draw can be common enough with most cars computers not going to sleep unless all conditions are net such as doors locked, bonnet switch closed etc. Best way is to put a multimeter in line with battery (set to current in amps) and check draw after say 45 minutes with car closed and locked including bonnet)

It could be as simple as headlight or courtesy light left switched on near rear view mirror, dash cam or something in cigarette lighter outlet such as a phone charger. Some cars don't turn off this outlet when car locked.

Ideally for any car these days leave battery disconnected or charge using a car battery for 5+ hours a week. Short trips don't charge battery enough.

If your battery is really 2.5v each morning then it is likely damaged at this stage and won't recover even if charged back up. Unlikely supplier will agree that battery was faulty, more likely alternator dodgy, something left on, etc.

FDave

If your battery is 12.4v after you drive it and is dropping down to 2 volts over night there is definitely a parasitic draw somewhere. There are videos on youtube showing how to test for millivolt drop across fuses to find the source of draw.
Also measuring the altenator voltage with a multimeter doesnt tell the full story of how clean the waveform is. Any good battery tester wil pick up on the problems.

John.G

Dropping down to 2V!!!!!, somebody is obviously joking as no battery will recover from that, maybe dropping down by 2V which is say 10.5V, still fully discharged state.
Its very easy to check for parasitic loss. Disconnect the negative lead from the battery, put a multi meter to the 10A scale, put the positive lead on earth strap and the negative lead to the negative battery post and read off. I don't know what a modern cars parasitic loss is but all the VWs I had varied between a lowest of 0.04A, 40ma, to a highest of 0.095A, 95ma.

Waterson

As above check for a parasitic drain. Better to use an inductive ammeter, rather than placing ammeter in series between chassis and earth terminal, as its totally uninvasive, i.e. disconnecting then reconnecting battery occasionally 'fixes' sleep problems in modules. However as its a 2008 Toyota, its unlikely to be a module issue. OP have you got any aftermarket equipment fitted? Radio / Parrot Bluetooth set etc.?