Is the Fiat Gear Box ECU the new air bag problem.

LithiumConvert

LithiumConvert

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Half a dozen years ago, the common problem with Fiat Ducatos was that the airbag ECU failed if you had a poor starter battery.

Is the new problem that the gearbox ECU fails if you have a poor battery?

and some motor homes are delivered with a poor battery and a not-so-smart alternator which does not fully charge it anyway
 
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LithiumConvert said:
Half a dozen years ago, the common problem with Fiat Ducatos was that the airbag ECU failed if you had a poor starter battery.

Is the new problem that the gearbox ECU fails if you have a poor battery?

and some motor homes are delivered with a poor battery and a not-so-smart alternator which does not fully charge it anyway
Click to expand...
Is this on the new 9 speed box?
 
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Total topic timing irony; our airbag ECU has just failed 😨
6 year old Fiat Ducato. And the mechanic found a loose connection on the alternator and consequently low starter battery voltage….(and we’ve had long running issues with charging)
New ECU in tomorrow, then MoT. 🤞
 
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LithiumConvert said:
Half a dozen years ago, the common problem with Fiat Ducatos was that the airbag ECU failed if you had a poor starter battery.

Is the new problem that the gearbox ECU fails if you have a poor battery?

and some motor homes are delivered with a poor battery and a not-so-smart alternator which does not fully charge it anyway
Click to expand...
Cheery soul aren't you!:rolleyes:

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LithiumConvert said:
Half a dozen years ago, the common problem with Fiat Ducatos was that the airbag ECU failed if you had a poor starter battery.

Is the new problem that the gearbox ECU fails if you have a poor battery?

and some motor homes are delivered with a poor battery and a not-so-smart alternator which does not fully charge it anyway
Click to expand...
Have you had a failure?
 
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Petroleumblownapart said:
Why do you say that please?
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The vehicle has regenerative breaking. (The alternator only charges the battery when the breaks are on). That would not work if the battery was already fully charged.

Yes, I know there is also some charging, at a lower voltage, when the vehicle is using engine breaking. i.e. foot off the accelerator.

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LithiumConvert said:
The vehicle has regenerative breaking. (The alternator only charges the battery when the breaks are on). That would not work if the battery was already fully charged.

Yes, I know there is also some charging, at a lower voltage, when the vehicle is using engine breaking. i.e. foot off the accelerator.
Click to expand...
My vehicle does not have regenerative braking and is Ike most.
A smart alternator can charge higher than your quoted voltage. The voltage you quote is the usual minimum voltage not the average. In addition most smart alternators use B2B to charge the hab battery which sucks juice from the engine battery triggering the charge rate to be increased as the voltage drops. A smart alternator is a misnomer as it is actually an alternator without a built in voltage regulator but is tightly controlled externally by the vehicle's ECU.
Most correctly designed mohos have a B2B to charge the hab battery at the higher voltage accepted by lithium etc. which is pulled out of the engine battery.
 
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I thought regenerative breaking was for EV’s, my last company car had it. But never heard of it fitted to a diesel van. The alternator charges the battery surely?
 
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TheMachMan said:
I thought regenerative breaking was for EV’s, my last company car had it. But never heard of it fitted to a diesel van. The alternator charges the battery surely?
Click to expand...
The term regenerative is referring to the alternator nothing to do with the brakes.
See Gus's link above.
 
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Lenny HB said:
The term regenerative is referring to the alternator nothing to do with the brakes.
See Gus's link above.
Click to expand...
Seems there is a confusion here between spelling 'breaking' and 'braking' added to by confusion caused by the use of the word 'most' when 'some' is more accurate.
 
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I did not invent the terminology and as has been pointed out above the altermators are not really smart at all. It is the engine ECU which has all of the smart stuff.

The alternators just do what they are told to do by the ECU.

When the vehcle is being driven (foot on accelator), the ECU tells the alternator to turn down the voltage thus saving fuel and emissions.

When the ECU detects that the driver wants to slow down (foot off accelerator), the ECU tells the aternator to output a higher voltage, thus letting the energy of the moving vehicle turn the alternator and put some of that energy (charging current) into the battery.

If the ECU detects that the driver touched the break pedal (and not necessarily hard enough to apply the break pads), the ECU tells the alternator to output its maximum voltage, thus charging the battery even more by using even more of the energy of the moving vehicle.

It is called regenerative braking and it works in all moderrn cars and vans (electric, petrol, diesel - even my mobility scooter has it.)
 
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