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MG MGF Technical - How long should a battery last?


I have the feeling mine is coming near to its end of life as in the cold it is showing signs of hestiting on turning the key. It is the car original battery so is nearly 6 years old.
Is there a way to check the battery apart from measure its voltage?

Tom
Tom Randell

Tom

Six years is bloody good - get yourself a new one before you get agro!

Make sure that you get the heavy duty battery - some of the shops want to sell you the non PAS car battery which is (or was) smaller.

Ted
Ted Newman

Mine's recently experied at 6.5 years - so yes, I reckon yours'll require replacing too Tom.
Rob Bell

Mine's on its way out as well after 5 years.

Still holds charge ok, just not not for very long.

(15 mins with lights left on and the battery is flat.)

So Makes/Models any BBS recommendations?

paul weatherill

Check the elecrolite (water) level. Daughter's battery (also about 5 years old) gave trouble recently and kwikfit wanted £50 for new one. Covered plates with water (took about a pint so it must have been almost empty) and its been fine ever since. Started this morning at -5 degrees celcius without any bother.
David Clelland

Good point David!

I purchased a Varter unit from a local motorfactor. It wasn't exactly the cheapest (75 quid, plus VAT! Ouch!) But high performance with a high current rating - so should perform reliably for many more years to come, I hope!
Rob Bell

I will have a look at the battery level this afternoon, but the last thing I want is a car which lets me down as I had enough of that during the summer.

Looks like a new battery then as at least that will give me piece of mind.

Thanks for the advice.

Tom
Tom Randell

>>Is there a way to check the battery apart from measure its voltage?<<
Look at the voltage drop while cranking.
It's easier to do this with an analogue meter (or a 'scope). You could also take off the cell caps and look for any 'fizzing' in one or more cells during cranking; All cells should have equal activity.
Then take a look at the voltage after the engine starts - just to make sure that it's being charged.

I would guess that your battery is nearing the end of its life (like mine), but with your car's recent history you need to be careful that no electronic components have been damaged in the charging circuits.

Steve
Steve

Why mess about. £35 buys a decent battery with a 2 year guarantee. Take it out of the Christmas beer money for the sake of peace of mind.

When it fails it will surely be 3:00 am in the pouring rain

Brian

I may be wrong here guys but...

there is no point in buying an "uprated" battery for the car. This is because the alternator wont charge it to the uprated level. So buy the battery crank setting for the car.
Any good motor factors will have a battery book and will be able to sell the correct battery.

As for which to get, the easiest way to tell if its a cheapo battery is if the case is non see through. This characterises the cheapo rubbish, since you cant see the water level in the battery to top it up.

Six year battery life is supurb, the one on my F was replaced after 36 months.
Ian

Hmmm, IMO charging the availiable mechanical fitting uprated should work if not to much oversized ?

Can anyone sweep the daubts or confirm ? Any calculation possible due to the alternator power ?

6 years for a factory installed battery sound superb 4me. Years ago you'd be happy getting out 4 years from batteries.

Regards
Dieter
Dieter K.

I think there is value in buying an uprated battery.
The charging circuit can charge a higher capacity battery - it may be able to supply more current on these cold mornings (and less voltage drop, which helps ignition)
It also a good idea to buy a more robust battery.

The battery on my Ibiza is 8.5 years old - and isn't giving any problems. It's generally misuse rather than age which kills batteries.

Of course, if you're not planning on keeping the car long, it's pointless spending money on long-term requirements.

Steve
Steve

All car batteries, are nominally 12V and run at around 14V when being charged. The "rating" of a battery is in ampere hours. In other words the current it can provide x the time it can supply this current. A high ampere hour battery will still be charged properly by the car's alternator but will last longer both when cranking the engine and when the car it standing idle for weeks.

Another rating is the ability to supply a high current for starting the car, some batteries are designed for storage as in emergency lighting units, others for high current as in car batteries.

A third factor is battery quality, the more you pay the better you get. Incidentally, within a battery's 3-4 year life there should be no need to top up the electrolyte unless the battery has been overcharged. The alternator control system keeps the charging voltage below that at which gassing occurs. If the battery is sealed there should be no loss due to evaporation.

So, you pay as much as you can afford, assuming you want to keep the car and your selection will fit into the space available. Then you maintain the battery by charging occasionally if the car is not being used.

And watch out for the coming 48V car electrical systems.
Brian

The only reason I mentioned getting the heavy duty is because 'the books' that some of the shops use show a very small battery as standard - which it is if you do not have the EPAS.

The guy in the shop that I went to insisted in looking at the car to make sure that the heavy duty would fit in!

Ted
Ted

You're right Ted - the standard listing for the 1.8i model is a poxy small battery that is smaller than the original one fitted to all cars equipped with EPAS. This is, I am sure, an error.

I purchased the same battery that's specified for the VVC model.

It has a higher than average rating, primarily because I'm thinking about installing an amp for the stereo! ;o)
Rob Bell

What "kills" batteries is sulphation on the plates. There are 2 sorts (and I can't remember the chemical difference!). "Soft" sulphation forms and disappears as the battery discharged and charged. "Hard" sulphation forms when the battery is over discharged and doesn't dissapear when the battery is recharged.

Hard sulphation is reduced by keeping them charged: i.e. used regularly.

I think that's why we see a range of lifes being reported here. It depends on how often the cars are used.

Charging a lead acid battery gives off hydrogen and oxygen - decomposing water - which is why I always thought that "sealed" batteries were a bad idea - you can't top them up!

Any 12V battery that will physically fit will be fully charged by the alternator. I can't see that the presence of power steering would make any difference in the battery capacity required: it only works when the engine is running, and the alternator will be supplying its power (an alternator can supply 50+ amps - often a lot more).

About the only time that "heavy duty" batteries are a good idea are in automatic/steptronic varients where you don't have any option of a bump start if the battery goes flat.

There's lots about lead acid technology on the web for the reading!

Neil
NNW49 - battery nearly 6 years old
Neil

Neil

I hate to argue with a neighbour but overcharging gives out hydrogen and oxygen. Controlled charging up to the correct float charge voltage does not.

In fact, gassing is a sign of a fully charged battery and an indication that the charger should be switched off.
Brian

Neil

Whilst you appear to have vast knowledge of batteries I am sure that MGR would not put in a heavy duty battery if they thought they could get away with a smaller and cheaper one AND I can assure you that they supply a smaller battery with the the non EPAS cars.

Ted
Ted Newman

All

Ok its not an MG but I have a Landrover running on its ORIGINAL batt and its over 12 years old.
Now when I park it way from home for some time, say a two week at the airport using airport transfers tunbridge wells, then a solar powered charger sits on the dash. This vehicle has two alarms on it so doing nothing will kill the battery in about a week. Disconenct the battery and it is good for three months before I have to think about charging it.

And if you do need to charge a battery do it slowly nothing kills a battery faster than cooking the plates by a rapid charge.


Tony
j langford

At the weekend I went to get the battery tested and yep under load it is a bit low, so thought might aswell get it changed there and then but after looking in the book for the correct battery for an MGF it was only coming up with a low power one which did not match the current battery so hopefully today will go else where to find the correct powered battery.

Tom
Tom Randell

My one lasted less than three years, replaced it with a very high quality one.
T.E.D.

I replaced the battery on my VVC in November last year. Just recently, after reading the threads on brightness of headlights, I began to notice that my lights were no longer very bright. I put this down to the dismal weather and disclouring of the reflectors. However, today my car refused to start because the battery was flat. The voltage was way down so I removed the battery to recharge it indoors. One of the cells was short circuit so in effect I had a 10 volt battery! No amount of charging would make it rise to 12. The shop where I bought the battery replaced it under warranty with no quibble. My lights are now a lot brighter.

My point is, perhaps some of the headlight problems we have are to do with the voltage of the battery being down, so check this before buying new bulbs.

Bruce
Bruce Caldwell

This thread was discussed between 19/12/2002 and 23/12/2002

MG MGF Technical index

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