Engine battery State of Charge after driving with the not-so-smart alternator. (5 Viewers)

[LithiumConvert]

After driving for a couple of hours in our nice new Fiat based motorhome, the starter battery is in a state of discharge. This is by design as the regenerative braking does not work if the battery is charged.

The B2B has ensured that the leisure battery is fully charged, but the engine battery is well down, needing about 30Ah to bring it up to full charge.

So the question is:- Should I be charging it properly after every trip, if not going to used for a while and not on EHU.

Surely, lead acid batteries like to be fully charged? (even AGM starter batteries)

 

[Richard n Ann]

Sounds like you need a B2B for the engine battery. Definitely needs charging then maintaining.

 

[DBK]

If you had to put 30Ah in to fully charge it then this means it had probably "used" about 25Ah. Depending on the size of the battery this means it was at about 75% charged at the end of the journey. This is perhaps a bit low but I'm not sure this means it needs charging every time you stop.

However, my suggestion would be to fit a Battery Master and assuming you have solar this will keep the cab battery topped up.

 

[AdrianChen]

I always thought the idea of a smart alternator was to reduce the amount of energy used running the alternator at full chat by using "wasted" energy when the car is on the overrun to re-charge the battery. To allow this the ECU monitors the battery and only turns the alternator output up to a charging voltage when the battery is below around 60-70% or so. The voltage output thus idles at low levels, pretty sure my merc went down to 12.?v, so the alt uses little power from the engine, then when needed the ECU increases the voltage again on my merc I'm sure it went over 15v.

The B2B will boost this output back up to a useful charge and maintain the leisure battery, but the starter battery will remain as designed at a lower state of charge. I guess this level is chosen to be sufficient to maintain the battery from sulphation, and restart the engine when required. Personally I think it is a horrible system! AGM's do need to get a full charge regularly from my experience, and Lead Carbon seems to have replaced them in a lot of manufacturers vehicles. Our Mercs lasted 1 year, but I don't know how it was maintained during the build/shipping showroom time, so may have been left flat etc.

When we used that van, the CBE system linked the Hab and Cab batteries whenever there was a charge source so up to 6amps could flow into the start battery, and when in storage we had a BM type device to maintain the Cab battery. So for the majority of the time the battery was kept pretty full, and perhaps it was only on longer journeys it dropped to the "working charge level" when the BM thingy wouldn't keep up.

But in theory your battery is operating as designed by the manufacturer, so should be fine in regular use. Personally though I would use something to keep it topped up while there is Solar/EHU available, but then I'm no expert and it's OCD that drives that decision!

Our 2022 Iveco happily doesn't have a smart alternator.......

 

[andyman]

After driving for a couple of hours in our nice new Fiat based motorhome, the starter battery is in a state of discharge. This is by design as the regenerative braking does not work if the battery is charged.

The B2B has ensured that the leisure battery is fully charged, but the engine battery is well down, needing about 30Ah to bring it up to full charge.

So the question is:- Should I be charging it properly after every trip, if not going to used for a while and not on EHU.

Surely, lead acid batteries like to be fully charged? (even AGM starter batteries)

What voltage is the engine battery showing on the dash display.

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[funflair]

I always thought the idea of a smart alternator was to reduce the amount of energy used running the alternator at full chat by using "wasted" energy when the car is on the overrun to re-charge the battery. To allow this the ECU monitors the battery and only turns the alternator output up to a charging voltage when the battery is below around 60-70% or so. The voltage output thus idles at low levels, pretty sure my merc went down to 12.?v, so the alt uses little power from the engine, then when needed the ECU increases the voltage again on my merc I'm sure it went over 15v.

The B2B will boost this output back up to a useful charge and maintain the leisure battery, but the starter battery will remain as designed at a lower state of charge. I guess this level is chosen to be sufficient to maintain the battery from sulphation, and restart the engine when required. Personally I think it is a horrible system! AGM's do need to get a full charge regularly from my experience, and Lead Carbon seems to have replaced them in a lot of manufacturers vehicles. Our Mercs lasted 1 year, but I don't know how it was maintained during the build/shipping showroom time, so may have been left flat etc.

When we used that van, the CBE system linked the Hab and Cab batteries whenever there was a charge source so up to 6amps could flow into the start battery, and when in storage we had a BM type device to maintain the Cab battery. So for the majority of the time the battery was kept pretty full, and perhaps it was only on longer journeys it dropped to the "working charge level" when the BM thingy wouldn't keep up.

But in theory your battery is operating as designed by the manufacturer, so should be fine in regular use. Personally though I would use something to keep it topped up while there is Solar/EHU available, but then I'm no expert and it's OCD that drives that decision!

Our 2022 Iveco happily doesn't have a smart alternator.......

Thought a 2022 IVECO would be "smart" I am pretty sure ours is.

 

[Tigger-Tim]

In the summer months, when my solar panel keeps the starter battery well charged, the alternator runs at 12.2v unless I'm braking (when it goes to 14.9v)

In the winter months, the alternator runs at 14.9v until it thinks the starter battery is reasonably charged. For at least the first 2-3 hours of the journey.

Both seem to be normal behaviour for my van. It prefers to leave the starter battery at about 75% charged. Doesn't seem to cause any issues.

 

[Richard n Ann]

Great for the environment, 10 million AGM batteries in a skip somewhere

 

[AdrianChen]

Thought a 2022 IVECO would be "smart" I am pretty sure ours is.

Yes I was surprised! Especialy after spending half a day looking for a non existent B2B!

 

[Russell's Dad]

I was worried about my starter battery being undercharged until those with superior knowledge on this forum explained that it was normal for a smart alternator.

At that point my solar controller charged both my starter battery and leisure battery alternately. I replaced that solar controller with a Victron, which only charges the leisure batteries. I also fitted an Ablemail to keep the starter battery topped up by the solar.
My van has a significant power draw from the starter battery when the TV is on ( the radio head unit is used) and an alarm and tracker, and the Ablemail's default "smart alternator" setting only charges the starter battery to 12.4 v to allow regenerative braking etc. to work. This worried me, given the draw from the head unit in the evening, so I've set the Ablemail to "non-smart alternator" and it now charges the starter to 12.7v (when the leisure batteries are over 13v).
I figure this happens anyway when on EHU as my CBE charger charges the starter battery as well, and it also happened with my old solar controller. It doesn't seem to do any harm, and I'm happy that my starter battery will do it's job. I guess the only thing that would happen would be the smart alternator perhaps not utilising regenerative braking etc.so quickly.

If the leccy gurus on here concur that my set up will do no harm, then an Ablemail or Battery Master might be your answer.

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[funflair]

Yes I was surprised! Especialy after spending half a day looking for a non existent B2B!

When N+B Flair came out on the new Daily chassis about 2017 I guess, it was the start of Smart alternators on the Daily chassis but N+B didn't make any allowance for this so consequently no charge went to the habitation batteries, a couple of guys on our owners forum were affected and contacted N+B who directed them to IVECO who reprogrammed the ECU and all was good

 

[LithiumConvert]

Sounds like you need a B2B for the engine battery. Definitely needs charging then maintaining.

The second B2B is already there. That is what I used to determine that the starter battery needed 30Ah to fully charge it.

then an Ablemail or Battery Master might be your answer.

Not needed in my case as I already have the second B2B which does the same job.

Both of these should keep the starter battery topped up, but I was intested in seeing how other people got the missing 30Ah replaced before relying on a Battery Master to keep it topped up after fully charging.

My van has a significant power draw from the starter battery when the TV is on ( the radio head unit is used) and an alarm and tracker, and the Ablemail's default "smart alternator" setting only charges the starter battery to 12.4 v to allow regenerative braking etc. to work. This worried me, given the draw from the head unit in the evening, so I've set the Ablemail to "non-smart alternator" and it now charges the starter to 12.7v (when the leisure batteries are over 13v).
I figure this happens anyway when on EHU as my CBE charger charges the starter battery as well

I did not know that the Ablemail could do that. Your post is the sort of information I was looking for. Thank You.

 

[Odd job]

After finding food starting to defrost, I now drive with the headlights on when I'm using the fridge, that keeps the "smart" alternator working

 

[Pausim]

So the question is:- Should I be charging it properly after every trip, if not going to used for a while and not on EHUEHU.

The smart alternator is doing what it is designed to do and the AGM engine battery will have been selected to cope with this behaviour. The designers don’t want it to be 100% charged.

During a long lay up I might add a solar panel to keep the engine battery topped up. With or without a smart alternator there are permanently live systems that put a small drain on the battery. Adding a tracker and alarm adds to this small load. None of which has anything to do with the smart alternator.

 

[Russell's Dad]

did not know that the Ablemail could do that. Your post is the sort of information I was looking for. Thank You.

settings for lead acid, lithium, smart and non-smart alternator and for high parasitic load

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