I think the battery on my Punto is on the way out.

The car hasn't started first time about 4 times and today was the worst where i had to crank it over for ages.

The current battery is a
Varta 12V 50Ah 360A

It's a 2007 Grande Punto 1.2

I've checked in the manual and google but can't find which battery it needs, is there any specifically recommended?

I've just bought an Exide 012 for mine, works great.

Eurocarparts have a sale at the mo. Just give them your reg they'll find it all and give you a choice of brands just see which you want I just went for the cheapest one which still has 2yr guarantee

The Black Box said:

Eurocarparts have a sale at the mo. Just give them your reg they'll find it all and give you a choice of brands just see which you want I just went for the cheapest one which still has 2yr guarantee

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As black box says!

Buy it online for a couple of quid off RRP compared to Halfrauds.

Mega easy to sit as well, so give us a shout if you struggle with it.

I took mine to 'halfrauds' and got a new one, they did a free battery check, refunded me saying I didn't need one
They don't seem all that bad haha

Just a follow up, it stopped last year but has started again in the cold weather so I've just ordered an Excell 012.

I checked Eurocarparts and it was on there as well as the recommendation above plus it's got a better CCA than the current Varta. Found it £5 cheaper elsewhere as well at £46.

Exide Excell 012
Amp Hours: (Ah): 50Ah
Cold Cranking Amp: (CCA): 450CCA
Length: 212mm Width: 175mm Height: 190mm
Type: 012 / 079
Model: EB500
Desc: 50Ah 450cca Sealed

Should do the job

MarkW7 said:

today was the worst where i had to crank it over for ages.

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Does it crank over normally or is it very slow, if the battery is to blame then you would expect to see it not cranking or being very very slow turning over

It might just need topping up and a good charge, worth a go if you can rather than spending £50 on a battery you don't need

It normally starts straight away, cranking over maybe 1 time first.

I actually wanted to go out before and it wouldn't start at all this time after three attempts! Check the voltage and it was at 10.9volts, it's been on charge for a few hours just re-checked and it's now 12.9volts and it started first time like normal.

I've already ordered the battery anyway and It was almost a year ago I posted this so I think it's time for it to get swapped out then I know it's alright.

Whilst your there have a close look at the negative battery cable for green fur round the chassis leg crimp and the one on the gear box this can also cause bad starting and poor battery charging

Well, mine is a bit funky, but it's probably due to age. To my knowledge, the battery has never been changed, or at best once before, which would make it around 10 years old(!). I measured the voltage across the terminals after running the car for 2 minutes and turning it off. The charge was about 12,85 V, which is right around the correct voltage. However, as the car has shown trouble when cold-starting (cranks slowly and a few seconds longer than usual), and sometimes the dashboard lights go black for a second when cranking!


So I also measured the voltage drop when starting the car. That's where it shows the problem: When cranking, the voltage drops all the way down to about 6,8 V before rising back to about 12,5 V. Once it has started, there are no issues with electricity. But anyway, 6,8 V is way too low Just for S'n'G, I also checked the idle running voltage with the front and rear fog lights turned on. Well well, it drops to 11,8 V stable!

I guess around 10 years is a ripe age for a battery, especially in the Nordic climate

Ok, let's go for a bit of theory ...

A car battery, actually a battery cells accumulator, has 3 main characteristics:

- voltage: given by the number of cells in serie, with 2,1 volt per cell (charged)
- Capacity: the amount of "energy" contained within the battery, i.e 50Ah which means it can deliver 50 Amps of current over one hour,
or 25 Amps ver two hours, etc.
- Discharge capacity: the maximum current that can be delivered at a given moment, i.e 360 A

The fourth one, which is never used, is its internal resistance.

Very roughtly the capacity is related to the amount of active components, electrolyth and electrodes, while the discharge capacity is
a function of the electrode to electrolyth contact surface (and external factors like temperature).
The internal resistance will vary with the charge level and also the electrolyth composition: when new the battery will have a small
internal resistance, which means the current can flow thru easily.

When current circulates in a circuit it creates a voltage drop when it encounters resistance: the higher the resistance, the higher
the drop (ohm's law U=R*I) when NO current circulates there is NO voltage drop. That's why you can read 12,6 volts on your charged battery.
But as soon as you drain current from it (which circulates also IN the battery), a voltage drop occurs in the device being connected AND in
the battery itself.
With a new battery (and a low internal resistance) the drop will be minimal, but with a "worn" battery with a much higher internal resistance,
the drop will be significant and can cause the engine not to start (too low voltage for the pumps, ECU, etc.).
This phenomenon, combined with cold temperature explains why bateries generaly die in winter (well, actually are detected as dying...).

Similarly, during charge the same thing happens and the voltage drop in the battery limits the energy that can be transfered to the active components.
This is why you read 11,8V only with engine iddling and "just" the fogs ON.

The only way to ease-up (a bit) hard cold start is to "pre-heat" the battery so it can deliver (a little) more "instant power".
To do so turn the ligths ON for 10-20 sec, the OFF before cranking the engine, this will "wake-up" the chemicals inside the battery.
If the car is a diesel, pre-heat plugs will already wake-up the battery so that trick is useless !

BRs, Bernie

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