12 Volt Battery Specifications

The 12V Smart Battery

Petrol 450 Fortwo

Euro:
Type 012
Tech SLA
12 Volts
50 Amp/h

USA:
No direct match but Group Size 90 fits

Diesel 450 Fortwo

Euro:
Type 065
Tech SLA
12 Volts
61 Amp/h

USA:
Group Size 90
Tech SLA
12 Volts
61 Amp/h

452 Roadster

Type 063
Tech SLA
12 Volts
42 Amp/h
B13 style base

Petrol 451 Fortwo

Euro:
Type 012
Tech: SLA
12 Volts
50 Amp/h

USA:
Group Size 47
Group Size H5
Group Size L2
Tech: SLA
12 Volts
50 Amp/h

MHD 451 Fortwo

Type 027
Tech: EFB
12 Volts
60 Amp/h

For stop/start cars, it’s important to get AFB/EFB or AGM type batteries. Would you like to know more. Click.

Diesel 451 Fortwo

Type 027
Tech: SLA
12 Volts
60 Amp/h

Petrol 454 ForFour

Type 012
Tech: SLA
12 Volts
42 Amp/h

Diesel 454 ForFour

Type 027
Tech: SLA
12 Volts
60 Amp/h

453 Fortwo & Forfour

Type 027
Tech: EFB
12 Volts
60 Amp/h

Hashtag 1

Type 012
Tech AGM
12 Volts
50Ah

For stop/start and EV cars, it’s important to get AFB/EFB or ideally AGM type batteries.
Would you like to know more. Click.

American Battery Sizes

Obviously America has to be different to everyone else just to be irritating. The 063 battery is used in about 60% of all European cars but it’s not easily available in the US. Because they don’t have as many cars with sensible sized engines, manufacturers don’t make them and sellers don’t import them due to the weight/cost.

The slightly larger 065 battery used in the 450 diesel does have an American version.
Group Size 90

This will fit and work in the petrol (gas) version of the 450 fortwo as well.

On the 453, the battery is:
Group Size H5 also known as Group 47.

However, make sure it looks right because H5 is also used for totally different batteries meant for trucks. Also, make sure it’s the AFB/EFB or AGM type battery or it simply won’t last.

Standard Vs Made Up Battery Codes

It goes without saying that having battery size standards is a good idea and that having preset codes makes buying a new battery a lot easier. Unfortunately, like America who just made it all up as they went along, there are some battery companies who create their own codes despite the batteries being standard sizes and outputs.

Why?

Because they are scumbags who are trying to make it as tricky as they can for you to go and get a replacement.

Normally, you’d look at a battery, see the code like 063, go on the internet and type in 063 battery and you’d be inundated with sellers and options. However, if the battery had a manufacturer’s specific code on there, you’d search for that code and you would only find that particular battery from that manufacturer.

Most people wouldn’t do any further research and would just buy that battery. The scumbag company has screwed you over and you probably had to pay a lot more than you would have if you bought a battery from a company that uses the correct battery codes.

I recommend that you do a search for the battery’s size. For example. Fulmen don’t sell an 063 battery. However, they do sell a 207mm x 175mm x 175mm battery called a FB442 (Fulmen part number).

Battery Specifications

These are the typical outputs and sizes of each battery code.

Battery Code	Voltage	Amp Hours	Cold Crank Amps	Length	Width	Height
012	12	45	360	207mm	175mm	190mm
027	12	60	540	243mm	175mm	190mm
063	12	45	380	207mm	175mm	175mm
065	12	54	470	243mm	175mm	175mm

Buying A Battery

Most people who need a new battery will automatically think “I know, I’ll go to Halfords”. For your sake, don’t. Batteries from Halfords are double the price of the same battery that can be bought at a local motor factors. Either look in the Yellow pages (if that even still exists) or search for a motor factors in your area on Google.

The Right Battery

Fortwo

Finding the right battery for a Fortwo 450 or 451 isn’t as easy as getting one that will fit that matches the specifications above. There is one very important factor to take into account.

Battery Gas Venting

When a standard car battery is charged via the alternator, it creates hydrogen gas. In standard cars, that battery is under the bonnet so the gas drifts away. In the Fortwo, the gas could accumulate in the cabin causing an explosion hazard.

The standard Fortwo battery comes with a venting tube that exits the bottom of the battery tray, your replacement should have this connection unless using a sealed Optima battery.

Roadster

Any 063 type battery will be fine, the battery doesn’t need the vent pipe like the fortwo.

Forfour

Any 063 (petrol engine) or 027 (diesel engine) battery will be OK for the Forfour.

Larger Battery?

When it comes to batteries, biggest isn’t best. It’s always a good move to stick to the manufacturer’s recommended size. The car only uses a set range of voltage and amperage so a larger battery won’t benefit the car at all. However, the car’s alternator is designed to charge a certain size battery so an oversized battery could either not get charged fully which would affect the battery or the car could try its best to charge it and damage/stress the alternator.

Where Is The Battery?

Fortwo
Roadster
Forfour

Right Hand Drive (RHD)

Open the passenger’s door and slide the seat all the back (well, as far as it will go with all that junk behind it). Pull the carpet back to reveal the polystyrene foot rest block. There are 2 big plastic retaining nuts that twist off by hand at the top and bottom.

Remove the foot rest by taking it sideways out of the car, it can be awkward.

Left Hand Drive (LHD)

Open the passenger’s door and slide the seat all the back (well, as far as it will go with all that junk behind it). Pull the carpet back to reveal the polystyrene foot rest block. There are 2 big plastic retaining nuts that twist off by hand at the top and bottom.

Remove the foot rest by taking it sideways out of the car, it can be awkward.

Roadster

Open the bonnet and remove the boot liner tray, the battery is then visible.

Forfour

Open the bonnet and the battery will be obvious.

Fortwo & Forfour 453

Remove the front bonnet (hood) panel and you will see it over to the left.

Removing The Battery

The removal procedure can be found here.

SLA, AFB, EFB, AGM Battery Types

Lead acid batteries have been around for longer than the cars that they are fitted into. As with all technology, it is refined and improved over time.

SLA – Sealed Lead Acid

This was the 1st improvement on the design. Sealing the standard battery made it safer. However, it did mean you couldn’t maintain the battery so they don’t last as long. The lead plates also degraded making them less effective. This type of battery will normally start a car 30,000 times.

AFB – Advanced Flooded Battery & EFB – Enhanced Flooded Battery

2 different names for the same thing. It’s basically an SLA battery with a fleece material against the lead plates. This holds newly converted electrons closer to the plates and also prolongs the quality of the lead plates.

AFB/EFB Batteries are a minimum requirement on stop/start cars like the MHD and 453. They do cost more than standard SLA batteries. This type of battery will normally start a car 85,000 times.

AGM – Absorbent Glass Mat

These have glass matting between the lead plates which holds the acid. They contain just enough fluid to keep the mat wet and because they don’t lose fluid like standard batteries, they do not require reservoirs of fluid like a standard battery. If you split an AGM battery open, almost no acid would run out. Due to the construction, there are more plates and less open spaces for fluid, this means that AGM batteries can create more power for the equivalent size SLA battery.

AGM batteries are ideal in stop/start cars like the MHD and 453. They do cost a lot more than AFB batteries. This type of battery will normally start a car 120,000 times.

Which Type Should I Get?

If you have a stop/start car or an EV, just get an AGM battery. For everything else, just get an SLA.