Sorry this is a basic question, the last battery I bought for my Focus was Bosch S5 007 https://www.eurocarparts.com/p/bosch-car-battery-100-74ah-5-year-guarantee-444771008 and this lasted 6.5 years which is fine.

I recently bought a Bosch S4 007 https://www.eurocarparts.com/p/bosch-car-battery-100-72ah-4-year-guarantee-444771007 this doesn't say anything about being silver calcium, although neither does the other one, the price difference with almost same capacity has made me wonder, is it compatible with Ford smart charge, can anyone confirm this battery is ok?

Hi Jim, I just installed the same S5 model battery you had for 6.5 years. I asked the same question on the forum then as it was more powerful than my old one. A member (Tom?) explained one benefit of the old 1.8 TDCI (mines 2008) is that it doesn't have so-called Smart charge, so just put the S4 in. The S4 battery is probably contemporary technology to the car anyway. Aside from the non-existent Smart charge issue, you can check battery details on the Tanya Battery site. Good prices and service too.

46 minutes ago, Jim_Cambridge said:

this doesn't say anything about being silver calcium

......because it's not.

Silver Calcium battery technology while being excellent, has been resigned to history in favour of new technology which is less good, lasts a shorter time but somehow will save the planet !!

 

12 minutes ago, TDCI man said:

A member (Tom?) explained one benefit of the old 1.8 TDCI (mines 2008) is that it doesn't have so-called Smart charge, so just put the S4 in. 

That wouldn't have been me.  All Mk2 Focus's have SmartCharge.  They should use a Silver Calcium battery.  But the manufacturers don't make them any more.  Just have to accept a shorter battery life and potential alternator damage with a standard battery on these now.

Mk3 Focus moved on to variable charging in addition to to original SmartCharge so they require an EFB battery.

Mk4 Focus has SmartCharge plus variable charging and also limited maximum charging for reduced emissions.  These also use an EFB battery.

Well if it wasn't you Tom, I certainly remember being told by someone helpful on this forum the 1.8 TDCI was too old a set up to have Smart charge. So I just chucked in the S5 battery which quite a bit more powerful than the one it replaced and no problem. 

Will try to find that post.

Here we go ... It was @unofix who I should have credited and the matter was resetting of the BMS (getting my wires crossed). Anyway hopefully the below quoted is helpful to Jim:

  On 9/19/2024 at 9:56 PM, TDCI man said:

can I put a larger capacity battery in?

Yes, so long as it will physically fit the battery tray you can install the largest capacity battery you can find.

  On 9/19/2024 at 9:56 PM, TDCI man said:

what steps do I need to take to reset the ECU, BMS, or whatever,

On a 2008 model there is nothing to do. The vehicle is not equipped with a Battery Monitoring System (BMS) so there is nothing to reset.

The charging system on your car uses a simple smart charge control and the alternator maximum voltage is about 14.9V so your battery will be conventionally charged and the SOC will sit around the 85 to 95% depending on the equipment being used in the car at any given time.

Personally if / when I replace the Bosch S5007 (100 size), I may go for a 110 size like S5010 as the battery tray is big enough... Only thing is to work out a cheap and easy way to quickly access the negative terminal which will be even deeper under the scuttle with a 110.