Car battery

johng19

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Hi all, I have a toyota avnsis 2007 2 letire tdi, think I might need a new battery but the ones I seem to be looking at seem to be less than 90 ah. And when I find one, it don't say it's for my car, they all seem to look like a smaller battery. How inportant is the ah and size of the battery.
 

david white

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The physical size of the battery will have implications as to whether it can be safely be secured in your car the AH rating needs to be or exceed your cars requirements to facilitate the starting cranking power demand ( also iirc the output of the alternator has some relevance to the AH rating on the battery )
 

biggsy

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Have a look on Eurocarparts, enter the vehicle reg no and see what it suggests. If you time it right they sometimes have 50% discount.
 

ae111sr

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A few months ago I was looking for a new battery for my 20 year old Corolla and was having trouble finding exactly what I wanted. Called local Toyota dealer and they were able to offer me exactly the right battery at a discounted price, with 3 year warranty and they had one available from stock. You might have the same result.
 

Neil ofthe nene

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The 90 ah merely refers to the amount of power available over time. So a 90 ah battery could provide 10 amps for 9 hours. As you rarely use car electrics without the engine running and providing the power, charging rather than taking from the battery the ah rating is largely irrelevant.

The main use of the battery is to start the car and for this you need a certain level of Cold Cranking Amps (CCA). That is the amount of power that can be delivered for a short length of time in order to turn the engine over

"CCA is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. The rating refers to the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts."

I am sure all car batteries sold today can deliver a high enough CCA to start the engine.

Car batteries should all be one size unless you are driving a huge 4x4 or similar.

I have used The Battery Guys in the past and had good service and a good battery. Next day free delivery.

 

Chervil

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Put your reg or car details in and Halfords will sort out a battery for you. Then buy it somewhere else!

 

johng19

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The 90 ah merely refers to the amount of power available over time. So a 90 ah battery could provide 10 amps for 9 hours. As you rarely use car electrics without the engine running and providing the power, charging rather than taking from the battery the ah rating is largely irrelevant.

The main use of the battery is to start the car and for this you need a certain level of Cold Cranking Amps (CCA). That is the amount of power that can be delivered for a short length of time in order to turn the engine over

"CCA is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. The rating refers to the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts."

I am sure all car batteries sold today can deliver a high enough CCA to start the engine.

Car batteries should all be one size unless you are driving a huge 4x4 or similar.

I have used The Battery Guys in the past and had good service and a good battery. Next day free delivery.

I did see this site on my search, but no 90 ah, and in my car is from new, this is the first time it been flat. So I think I would be wise to get the same. Might nip into toyota see what they say.
 

pauln

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I put a larger AH battery in my Audi and my MR2 the Audi needed coding so it could use a different charging profile.
The MR2 needed the holding down bracket modifying before it could be secured as the battery was slightly larger ( but europarts said it fitted ! )
I would suggest you measure the existing battery before purchasing a new one.
 

Pompous git

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In 1988 I bought a new escort and not long after the guarantee ran out it started to misfire and crank slowly. I bought a new set of
lifetime HT leads and distributer cap along with a lifetime battery from Halfords. I owned the car a further nine years and ran up a
huge mileage with no further trouble from the ignition or battery. Do not discount Halfords they sell some decent stuff, just look at
their professional range of spanners.

When my C class Mercedes was twelve years old the engine started to crank slowly and I asked my local garage to check the battery
when it was serviced. They told me the battery was only 40% of its original capacity but being a big battery I was getting away with
it even in the cold weather. I bought a Bosch platinum replacement and after nine years it is still chucking the engine over at a rate
of knots, cheap stuff is cheap for a reason, I would stick to Toyota.
 

Maesknoll

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Car batteries should all be one size unless you are driving a huge 4x4 or similar.

The effort to spin over a short stroke 1000cc petrol engine will be considerably less than a 2.0 long stroke diesel, so if all batteries were the same size, either the 1000cc town run around would be massively over engineered, or the 2.0 saloon would be under engineered and likely to suffer battery and starter motor failures - the lower the voltage of a battery, the higher the amperage.
 

62tucker

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Defo check euro car parts out. I got 50% off last week on at set of wipers. Code was actually on the website
 

lp1886

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I recently bought a Bosch S5 from Batterymegastore.co.uk, it was far cheaper than anywhere else online.
 

Trogg

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Just had a look and according the RAC etc your battery should be the same as the one on my 4x4 apparently!

I bought this one from Autocarparts, but i got it through their Ebay shop because it was a tenner cheaper that way.

 

Northantslad

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Battery largely needed for situations when the engine is off:
Starting (cranking)
Lighting (dash and courtesy lights)
Ignition coil charge (Petrol Engine)
Fuel system priming (Petrol Engine)

Once the engine is running, the alternator will take over supplying the current for the vehicles electrics; should it struggle, the battery will be called upon also.

In terms of sizes, Output (measured in Cold Cranking Amps) and physical size Volume (space occupied by the battery) will be proportional. Bigger casing to accommodate larger plates internally. Bigger the surface area of the plates- bigger the output- bigger the casing.

Ampere hour (Ah) is also a rating used as suggested, as a measure of output over time, for situations where the battery may not be receiving a charge but being called upon.

A battery on any engine and regarding starting, its primary role, is essentially pushing the piston up the cylinder:

Battery supplies starter motor- starter motor turns flywheel- flywheel turns crankshaft- crankshaft pushes pistons up the cylinder.

Any battery is therefore needing to be 'big' enough to overcome what the piston is having to overcome- friction and compression.

A diesel engine has, as a rough rule of thumb, twice the compression of a petrol engine (the air above the piston is needing to be squeezed by the piston more than a petrol engine), hence diesel engined vehicle batteries are 'larger', both in size, but also output capability.

Put that together if it helps, although as a motorist/garage customer you should be pointed in the right direction by a garage and be able to have like for like replacement. Battery types have a generic code such as 063 (that is one of the smallest), i think 081 was another. Find that and that is what you need to replace the old one.
 
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TrickyD

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Make sure you have the code for your radio, will need re setting after a new battery.
 

johng19

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Still not got one yet still checking things. Charged the battery yesterday put back on worked fine, went out today about dinner time started fine. Not used the car just started it up. Went out to night to go to work, not enough power car did not start. All the lights would go on, when you try to turn the car over lights went really dim to being off tryed to turn but just seemed like there was not enough power to start.
Iv had a good look at the car nothing left on, other than the alarm.
When I charged the battery I left till it says it fully charged. The charger only has a power light and a fully charged light. Question can the battery just not holed the the charge or does something need to run it down. If had no trouble with the car till this. It just would not start Thursday. One other thing it was fully charged within two hours which I thought was very quick.
 

Northantslad

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A quick check (by someone in the know) with an ammeter will detect a parasitic drain on the battery.
Same person would also be able to a basic check to see if the alternator is charging the battery 13.8v -14.2 v engine running.
Based on just what you have written so far and it getting to a cooler time of year, it does sound like the battery is on its way out, but checks above need doing first. Does sound like battery to me though.
 
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