MK2.5 1.8 Duratec: Battery options

[rhyds]

My 2010 MK2.5 Duratec 1.8's battery may be getting towards the end of its useful life. its an AA one fitted by a previous owner and so doesn't have much in the way of labelling.

My question is: What's the correct battery size for a 1.8 Petrol 2010 Focus? Also, will a larger battery fit the standard battery box?

[wilto]

this this is the one I bought for my 2010 1.8 focus, it has a better cold cranking amp than the Bosch one it replaced. It was a toss up between this one and a yuassa one

[Matt92]

Go to the Yuasa site here Link put your reg in and see what it comes up with. If it comes up with the YBX5075 that’s what I fitted when I had mine, pretty sure the first number is the number of years warranty, so 5 years. Then just see what’s the cheapest you can get it for.

[Westville]

What a useful link - lots of info about my car

Bit of a shock though when I saw what battery I needed and how much it would be!

[YOG]

https://www.tayna.co.uk/car-batteries/yuasa/ybx9115/

[rhyds]

Thanks for confirming the standard size. Can anyone confirm if a larger battery than an 075 type will fit in the standard battery box?

[isetta]

take the lid off the battery box and see if any spare space. you can measure the max dimensions you have in there. you can find the dimensions of different battery models on the internet. But don't forget if you buy a different model make sure it has the battery terminals orientated the same as what you have otherwise you might find leads don't reach.

I recently had to remove a battery on a mk2.5. The front end of battery box is removed (it kind of slides in) but even then it was quite difficult to get the battery out and back in. I don't know what model battery it was, it was big and filled the box.

[isetta]

https://www.tayna.co.uk/tools/battery-wizard

find battery by size and terminal configuration

[isetta]

https://www.puretyre.co.uk/car-battery-specification-chart/

[rhyds]

Thanks for that Isetta. While I could measure it up I don't want to be waving a steel tape measure around a very pokey battery box, also its not clear what the mounting bracket positions are like for a larger battery. All I really need to know is if the larger 100-series Diesel battery fits in to the standard 1.8 battery box or not...

[wilto]

I'm sure someone will correct me if I'm wrong, but when I was researching a new battery for mine, I too wanted the biggest battery I could get away with, but I'm sure I read that if it's to big the alternator has to work extra hard to get it fully charged or something like that.

[wilto]

8 hours ago, Matt92 said:

Go to the Yuasa site here Link put your reg in and see what it comes up with. If it comes up with the YBX5075 that’s what I fitted when I had mine, pretty sure the first number is the number of years warranty, so 5 years. Then just see what’s the cheapest you can get it for.

That's the battery I WAS going to buy but decided on the advanced one only cos it was cheaper and 2ah bigger

[Matt92]

@Westville take the prices with a pinch of salt, my current car battery comes up as 180 on that site, but I got it for around 120 locally, that’s for an EFB stop/start fancy thingy.

@wilto I can see why you went for the Advanced, if the 5 year warranty stands up then it’s a good deal. I get mine locally through work, so have what ever they have in stock, which is usually either really cheap for if you’re just selling the car, or rather more expensive if you’re keeping it for a while.

[rhyds]

15 hours ago, wilto said:

I'm sure someone will correct me if I'm wrong, but when I was researching a new battery for mine, I too wanted the biggest battery I could get away with, but I'm sure I read that if it's to big the alternator has to work extra hard to get it fully charged or something like that.

That's not how it works. A battery is effectively a bucket with water streaming in to the top (charging current) and a hole in the bottom letting water out (the car's electrical load).

If you fit a bigger bucket (battery), then the hole in the bottom is still  the same size and water (power) flows out at the same rate, while the incoming stream (alternator) is also at the same rate as before. The difference is that the bigger bucket has more reserve for dealing with a higher water flow (cold weather, kit used while the ignition is off etc). Unless there's a drastic change in the size of the hole then the alternator doesn't need to work any harder, as the battery's water/charge level doesn't drop any more than with a small battery. 

[rhyds]

Well I went out and measured the battery box, and it looks like a type 100 battery should fit, and there seems to be enough slack in the negative terminal wiring to reach the terminal. That's a nice option to consider when buying a replacement battery...

[rhyds]

Just to confirm, the 100 size battery I bought has fitted fine in the 1.8's battery box. All it needed was a small spacer removing from the back of the battery box and a small bit of packing put under the upper battery clamp. It should last a bit better than the battery that came out!