Seicento battery replacement

Seicento battery replacement guide.

Remember:
Always disconnect the earth connector (negative) first and re-connect it last.
Make sure not to short anything. This can cause extensive damage.

My Seicento had trouble starting after it was not used for some days.
The battery has never been replaced, so it's almost 9 years old.
Time for a new battery.

Requirements:
- new battery
- optionally: battery charger
- 10mm spanner
- Vaseline
- 20 minutes (In my case)

The original battery is 12 Volt / 40 Amps (Magneti Marelli).

At the local shop I bought the following battery:
- Exide Excell 44Ah 12V (80 euro)



According to the indicator on the battery it was fully charged.
To be sure I fully charged the battery. It still needed more then one hour.
So the indicator is not reliable (see troubleshoot below) at all.



Open the engine compartment.
Locate the battery and remove the bracket.
It's secured with one bold on each side.
Loose the bolds almost entirely.
Now rotate the rods a little and remove the braced.





Now disconnect all electrics.
First remove the negative one. Then the positive.
Please make sure you do not short anything!
The positive connector has three wires connected to it.
I had to disconnect both separate wires to fit the new battery.
Otherwise it was not possible to slide the new battery underneath it.
(And yes, i noticed i did not remove the negative first in this picture )





Pull out the battery. The original one comes out easy.



This red bracket was clearly in the way.
I bended it a little backwards (1 inch / 2.5 cm).
Now there is 'plenty' of space for the new battery.



Comparison of both batteries. Original at the right.



In my case the new battery was a little bigger.
Now the struggle begins. Flip the battery inside.
The new battery fits quite tight in the Seicento.
Make sure you don't damage any parts.
Especially the wires and tubes around are quite vulnerable .



Put the bracket back and tighten the bolds.
In my case the new battery was a little lower.
So i added a few extra rings to the threaded rods.
Make sure everything is secured tightly!



Put some vaseline on both terminals and connectors.
This prevents corrosion.
Reconnect all wires properly.
First connect the negative and then the positve.
Again, make sure not to short anything.





Now put back the little red cab and enjoy the result!



Close the engine compartment and make sure nothing is left inside.
Now my Seicento starts perfect again. Even better then in 2001

Troubleshooting:

Make sure the battery is fully charged.
First time I did not charge the battery at al.
The battery indicator was green, so I assumed it was fully charged.
When I tried to start the Seicento it started revving the engine like crazy.
The ECU triggered this probably in order to charge the empty battery.
After charging the battery the revving did not happen.
So, despite of the green indicator, the battery was almost empty.
Conclusion: Just charge the battery before inserting it.

This guide is quite simple and probably too comprehensive.
But hopefully it can help someone else struggling with the sample problems.

Help page brought to you from a member of the Fiat Forum.

you mention the car was revving itself the problem was simply that the ecu has a ten min power down so when the battery has been off for longer than that time the ecu self learns all its parameters again and will rev through the ranges to test its basic functions they were designed to do this for a process called throttle learn a diagnostic process , also if you remove the bolts from the header tank the batt goes in a lot easier even though not actually required hope this helped , tim