Car battery - stuffed?

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linw

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#288498 4-Jul-2021 08:08

Haven't used this car for a couple of weeks and now found its 4 year old battery is reading 1.77V!!

Am I right in thinking this is stuffed and recharging is pointless? Certainly seems so to me.

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#2738598 4-Jul-2021 08:16

Something must be draining it to get that low. Check the car for parasitic loads, lights on, glovebox light etc.

linw

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#2738600 4-Jul-2021 08:25

Yea, that is what went through my head as well.

But, does this VERY low voltage damage the bty so it needs replacing rather than recharging?

RunningMan

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#2738602 4-Jul-2021 08:31

Yes, discharge to that level will probably have caused some damage, however it may not need immediate replacement - might still have some life left.

I'd establish why it went flat, make sure the car is charging OK when running, then recharge the battery and see if it is OK.

snnet

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#2738604 4-Jul-2021 08:40

Four years is pretty good lifespan of a battery - my ns70s used to get about 3 years - it was likely on its way out anyway to be honest (and if the vehicle is outside, the cold likely didn't help)

Even if you do manage to get it charged (there are a few methods) it probably won't be very reliable

what kind of vehicle is it? there are some ford rangers that you can't leave parked without use longer than 2.5 days before the engine won't turn over

mudguard

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#2738606 4-Jul-2021 08:48

If it gets very little use you could leave it attached to a trickle charger. I've got an old school immobiliser on a Civic and it drains the battery pretty quickly.

jpoc

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#2738612 4-Jul-2021 09:18

How did you measure the battery voltage?

Still in the car and still hooked up?

Try to disconnect both of the terminals and then measure the voltage again.

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Batman

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#2738614 4-Jul-2021 09:28

RunningMan:
Yes, discharge to that level will probably have caused some damage, however it may not need immediate replacement - might still have some life left.

I'd establish why it went flat, make sure the car is charging OK when running, then recharge the battery and see if it is OK.

My cars to that a lot. Sometimes the battery is gone and sometimes it revives just fine. But me no autosparky.

xpd

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#2738618 4-Jul-2021 10:10

Nissan by any chance.........

XPD / Gavin

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k1w1k1d

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#2738623 4-Jul-2021 10:24

I will assume your voltmeter is reading correctly.

As previously advised, a voltage reading that low is a good indication of a parasitic current leak, but not always. A faulty battery usually retains a reasonable voltage until a load is applied, eg tuning the ignition and trying to start the engine.

Remove, charge, and test the battery. There is a reasonable chance that your four year old battery may not recover from this.

Check the charge rate after refitting the charged battery, or fitting a new one.

Shut the engine off and try to connect an ammeter between the battery negative post and negative battery lead without actually disconnecting the circuit. Can be a bit fiddly to do.

The ammeter will now read any current drain present with the vehicle turned off. Many modern vehicles will show a flow for some time until all the ECU's go to "sleep". Some can take a while, but eventually the current drain should diminish to a few mA. There will usually always be some drain in modern vehicles due to keep alive memories in ECU's, immobilizers, and radios etc. Older vehicles will drop to zero.

It doesn't take much current drain to cause starting issues in a vehicle left for two weeks. 100mA x 24hrs x 14 days / 1000 = 33.6amp hours. That's a fair chunk out of a 50amp hour car battery.

linw

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#2738632 4-Jul-2021 11:29

Thanks for the input, all. I borrowed a bty charger and will leave it for a good while to see what happens.

If it won't take and hold a charge so be it and I'll buy a new one. Pity we can't buy Japanese btys. The original bty lasted 8 years!

Car is a 2009 Mitsi Lancer hatch. The one that blew the ecu a while back!! Hope it is still OK!!!!!

I have measured the voltage with the bty disconnected.

Goosey

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#2738648 4-Jul-2021 13:47

Just low and slow trickle charge it, most workshops will do this for you…

then go for a good long drive….not start stop…

should be good as new unless battery is more than 5 years old…

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allio

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#2739032 5-Jul-2021 10:46

I've killed a battery to about that level before. Restored to usability with a controlled overcharge (recondition mode) with a CTek charger, but it was certainly never the same. Would noticeably struggle to turn the engine over after sitting for about a week, and would need a recharge if not driven for two weeks.

Doing a regular charge (no overcharge) wasn't enough - battery health indicator stayed red and performance was terrible.

richms

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#2739040 5-Jul-2021 11:09

Its also the cold that will push things over the edge with batteries. Mine was slow to crank this morning after not being used all weekend. Not looking forward to that unexpected cost if its actually failing. I find that in Auckland traffic with the blower, lights, power steering and other stuff on it barely charges unless its at decent revs.

Richard rich.ms

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#2739049 5-Jul-2021 11:19

richms:
..... I find that in Auckland traffic with the blower, lights, power steering and other stuff on it barely charges unless its at decent revs.

The blower?

People often mistake me for an adult because of my age.

Keep calm, and carry on posting.

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timmmay

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#2739193 5-Jul-2021 13:38

Endurant / Battery Town are decent. My Corolla has one that's 5 years old, used one a week to once a month, going ok. I put it on the charger every month or so to give it a boost.

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