Technical Alternator Capacity Amps

[Malibu9speed]

My 2020 Ducato 2,3 liter 160Hp Euro6L
How to find the alternator capacity?

Any system?
Some say 110-150 Amps
Some say this never models got 180-200 A alternators.

I was hoping for hints and tips from the dealer.
No luck other than «pull the unit out of the engine and have a look».

My question; Whats fitted in my van?

 

[portland_bill]

No luck other than «pull the unit out of the engine and have a look.

Sadly, unless you can read its label with a torch and mirror, that advice is about as good as it gets.

Has always been so. Since alternators were first fitted, (late '60s?) every manufacturer has seemed to fit occasionally at random, and what is listed may not be what you find.

With a van, the choice may be even more difficult to predict.
Many cars will these days have two choices, with/without aircon, but vans could be specified with higher outputs depending on use, as the first owner can customise for their business, adding electrical equipment. Motorhome manufacturers may well specify bigger outputs.

Mirror on a stick, like a dentist, bright torch, and a helper to write down whatever you read out while standing on your head. Or if it is not working properly, take it off.

 

[Malibu9speed]

Writing 2021
People already walked the moon...
And the dealer cant tell me whats fitted in my Ducato

I was hoping that would be easy with a VIN / chassis number
Not so much

And yes;
I will stick a mirror or a camera in by the alternator
It is not a year old... still pretty clean
Just need some sun and higher temperatures

 

[Malibu9speed]

I would like to fit a 60A battery to battery charger
Nice to know the alternator limits

 

[jackwhoo]

You can fit whatever capacity battery you like the alternator output has no bearing on battery capacity.
As long as the alternator voltage and battery voltage match.

What type of battery is currently fitted?
60ah capacity sounds rather small to me.

 

[portland_bill]

You can fit whatever capacity battery you like the alternator output has no bearing on battery capacity.
As long as the alternator voltage and battery voltage match.

What type of battery is currently fitted?
60ah capacity sounds rather small to me.

I'm guessing this is an additional battery, perhaps for accessories, or a motorhome conversion. If it is, I've no idea what size battery would be needed, but it is likely it needs to be a leisure battery, not a normal automotive one.

 

[Anthony489]

Hi

I think malibu is talking about the current rating of the Battery to Battery charger (inverter), not the Ah capacity of the second battery.

Having said that, 60A will probably be the maximun current. I would expect a modern Ducato alternator to cope with that.

 

[wavehead]

I think it may not matter, as the alternator will work up to maximum when the B2B starts to drag down the engine battery (just like it would with all the car lights and heater fans, fridge on etc) and the B2B only transfers power when the engine battery has adequate charge.
Cable/connection size is very important at 60A, as well as temp sensors at alternator and battery.

 

[Malibu9speed]

Its a 2020 motorhome based on a Euro6L Ducato Van

From factory it came with a single 100A AGM leisure battery,
and a 30A B2B charger (between the start and leisure batteries)

I have replaced the AGM with 2x100Ah lithium leisure batteries.
Until now I guess this will be a walk in the park for the alternator.

My plan is to install an additional 60A B2B charger.
Manually I will select max 30, 60 or 90A charging current.
Pulling 90A from a 110A alternator would be hard on the alternator
Pulling 90A from a 180-200A alternator would most probably be another walk in that park.

And thats why I would like to identify the alternator capacity.
Is it a 110A? 150A? Or 180-200A like some told me.

My best idea was to bring my Vin / chassis number to the dealer and ask.
No luck; «you need to look at the fitted alternator»
And that will not happen before we got some higher outdoor temperatures.

 

[jackwhoo]

Please check the maximum charge rate your leisure batteries can safely tolerate and don't exceed the safe rate.

Please be careful.

 

[Malibu9speed]

my batteries 2 x 100 Ah
Nominal 60A ...each... 100 A max
In other words a total of 120A and 200 A max

My 90 A max would be ok
That would be 45 A for each battery

 

[RS3100]

my batteries 2 x 100 Ah
Nominal 60A ...each... 100 A max
In other words a total of 120A and 200 A max

My 90 A max would be ok
That would be 45 A for each battery

That's not how it works. Connecting two batteries in parallel effectively turns them into a single battery, so you will have a 200Ah battery (2 x 100Ah).

A 90A current isn't halved on receipt by each battery. 90A is 90A.

The absolute maximum safe charging rate is generally C/40, which is 80A for a 200Ah capacity battery, but that can lead to a lot of gassing which may not be safe in a motorhome.

C/20 is the recommended maximum for good battery life. C/40 will likely shorten the battery life considerably. So 40A would be a safer maximum charge rate.

Don't forget the alternator isn't actually charging the vehicle battery at its full output. Much of its current is used to support the load of running consumers on the vehicle, whilst maintaining the battery state, not fast charging it.

All a B2B charge does is to falsify an additional load on the vehicle alternator to force it to increase its output.

I have 200Ah habitation battery capacity on my motorhome, and find a Votronic 30Ah B2B charger perfectly adequate and about 5 - 6 times faster than the original split-charge relay at charging the batteries.

 

[Malibu9speed]

That's not how it works.

And I would say "thats how it works"

In my case 90 Amp charge would split into 45 A for each battery connected in parallel.
Thats how it works... and also easy to measure,
(since I do have a internal battery monitor on each battery,
and also a common shunt "in front" of the battery bank.)

My batteries do come with a datasheet.
In the sheet I can read "max charge current 100 A".
Also I can read that cont. charge should be limited to 60A.

My initial question was "what is the capacity on my alternator"
Not even the Fiat dealer can (or will) tell me.

If the rumors are true,
that the newer Euro6L engines with smart alternators would be 180-200A,
I would be comfortable looking at 90 A charge current.
It would not fry the alternator.

 

[PuntoHowTo]

Have you checked the specs of the batteries? A quick search suggests they may (obviously depending on who made them) only be able to charge at a maximum of 20A. (What brand are they)

As you say they are lithium batteries, pushing high rates of current into them could result in a very Big Bang, but to be honest the without the use of a shunt the battery will decide how much current it draws from the alternator to charge, most dedicated battery chargers would not be pushing 30A, maybe 10A at most for a lithium charger that’s going to protect the battery, and given that these batteries cost hundreds compared to fairly cheap lead acid batteries you’d be a fool not to use a specialised lithium battery charger?

 

[Malibu9speed]

Have you checked the specs of the batteries?

Yes I have checked the numbers for my batteries;

Since we never visit hookups,
the time (distance driving) to top up our batteries are essential.
As I wrote above; under normal condition I do charge with 30A B2B
Every now and then I would like to speed up the charge.
I live in a country without that much sun...
And for that reason.......

Most lithium batteries come from the same few sources...
Then they are all branded depending who are selling them.

My batteries are from Skanbatt,
one of the top brands sold in Scandinavian countries.
Considered top brand for their reputation, quality.... and price.

The batteries have internal BMS with Bluetooth connection and HEAT.
The Bt makes it easy to read all kind of internal data, and also the current (in or out). The APP (on the phone) present the data in a "analog multimeter", with green colour for safe values, and red colour for values way up there.

The internal heat function (heat element) will keep the internal temperature above the scary limits for use or charge during winter.

When the company behind the batteries provide a datasheet telling the values,
I do use those numbers. In this case Normal Charge current
≤60A And max charge current 100A


A copy paste from the datasheet;
(And my translation )

Standard charge

1
Temp. range
0~45℃ (* remarks)

2
Charge voltage
14.4±0.2V

3
Float voltage
Under 13,9V (from 13,3 - 13,8V)

4
Max charge current
100A temperatur 25±5℃

5
Normal Charge current
≤60A


Standard use

1
Temperature range
-20~60℃

2
Voltage range
Ca 10 - 13,2V

3
Max cont. use
100A

4
Max short use
130A <5 min @25℃

5
Max peak use
350A <3 sek

NB! Not to be used as start battery

6
Lowest voltage for BMS to shut down battery
8-9V

 

[PuntoHowTo]

Well in answer to your original question it’s likely you’ll have to pull the current alternator out and see which model it is, obviously you can replace it with something updated and you can in many vans usually find somewhere to fit a second alternator

 

[Malibu9speed]

Well in answer to your original question it’s likely you’ll have to pull the current alternator out and see which model it is, obviously you can replace it with something updated and you can in many vans usually find somewhere to fit a second alternator

Yes, thats probably the way to go.

 

[Fionn]

Has anyone any details on how someone has managed to shoehorn a second alternator in? Accessing the original one seems tight enough as is!

 

[jackwhoo]

How much electrical power do you need?

You could spend a great deal of money and then find out what you had to start with was sufficient.

 

[Malibu9speed]

A second alternator would be nice entertainment.
Never get enough Ah’s these days. Grey rainy no sun climate combined with all kinds of electrical apliances and gadgets; Bring all the small currents to me

But if my alternator aleady is labeled for max 180-200 A I am happy
A B2B charger at 60A on top of my existing 30A and I am getting what I want

Nobody going to tell me whats enough current for me or not

My question was;
how to indentify the capacity of my 2020 Ducato regen alternator?