What size alternator?

I

IanRJ

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Tyneside-Cadiz: All points between!
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60,781
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Autotrail Delaware
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Years Tugging - Newbie MHing
Hi folks. I have an Autotrail Delaware HB, on Ducato 2.3 multi jet 150, 2019. I have been trying to determine the output of the alternator in order that I might consider a B2B addition.

However non of the tech books that came with the van state the output capacity of the alternator and I cant see the markings on the body in the engine bay!

Looking at replacement units they seem to be available in anything from 80amp to 180amp, and couldn’t find a factory replacement to check its capacity.

Anyone got an idea of what is fitted to this model year, it’s not a smart btw.

Suggestions welcomed.
 
Turn the lights on for 20 mins, start it up, put heater blower, wipers, full beam, demist, radio etc on and then clamp an ammeter round the fat red cable that comes off the back of the alternator..
 
When our alternator failed some years ago the mechanic RAC took us to wouldn't order a replacement until he had inspected the original; apparently there are several different types even on the same engine!
But I wouldn't worry too much - I believe the alternator can put out as much as any of the B2B chargers can handle. Certainly we've had no problems with our Sterling, a 50 amp model, over a number of years.They're easy to fit, just need to make sure you use the correct cable obviously.
 
Sterling need to know the output before they will recommend which b2b should be used. Replacements for this van (non fiat) range from 80amp to 180amps. If the alternator will take it I’d go for a 120amp b2b, but need the actual output to be sure. Crazy it isn’t even in the specs in the handbook.

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My 2012 2.3 is a 140 Amp cant you see the plate with a mirror. Any b2b should OK. My mate has a 60A but I thought I only needed a 30A, as I have more solar power
 
Surely 60amp is a maximum current but if the alternator is 50amp then only 50amps will be transfered through the 60amp B2B..
If its a 140amp alternator then 60amps will be transfered through the 60amp B2B.
A B2B can't produce amps that aren't there to start with.
 
Last edited:
pappajohn said:
Surely 60amp is a maximum current but if the alternator is 50amp then only 50amps will be transfered through the 60amp B2B..
If its a 140amp alternator then 60amps will be transfered through the 60amp B2B.
A B2B can't produce amps that aren't there to start with.
Click to expand...
You are right it will take what it can, however I would like the max available charge to the battery. If it can offer 120amp then why not use it? The B2B will handle any over charge, but as mentioned it can’t make up what isn’t there!
Thanks for the feedback all.

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Given that any particular B2B chosen cannot supply more amps than it has has input and that
Any given alternator cannot "over current" any particular b2b chosen.
The outcome is thus.
Buy the biggest one you can afford.
Fit that.
Test it works as required.
Forget about it.
??
 
HandyAndy said:
Given that any particular B2B chosen cannot supply more amps than it has has input and that
Any given alternator cannot "over current" any particular b2b chosen.
The outcome is thus.
Buy the biggest one you can afford.
Fit that.
Test it works as required.
Forget about it.
??
Click to expand...
You are correct. However the necessity for understanding the alternator output is to gain advise from Charles Sterling with regard to our setup (EC700 b PCX 300 charger) including cable requirements etc.

So still looking for the size of the output, but thanks all for support.
 
Then play safe and say the alternator is 180amp.
Heavy wiring won't be detrimental if it is only 100amp alternator and at least you're covered for any size.
 
pappajohn said:
Surely 60amp is a maximum current but if the alternator is 50amp then only 50amps will be transfered through the 60amp B2B..
If its a 140amp alternator then 60amps will be transfered through the 60amp B2B.
A B2B can't produce amps that aren't there to start with.
Click to expand...
I would be concerned about running a 60AMP Alterntor at full peg for hours on end. I would rather upgrade alternator and ensure it was over specced for the job?

Just my thought.

IanRJ Alternators aren't that expensive these days, might be worth upgrading at the same time as installing the B2B. Maximise the benefit?
 
Can you just put on a bigger alternator or do they chip them or something

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Gromett said:
I would be concerned about running a 60AMP Alterntor at full peg for hours on end. I would rather upgrade alternator and ensure it was over specced for the job?

Just my thought.

IanRJ Alternators aren't that expensive these days, might be worth upgrading at the same time as installing the B2B. Maximise the benefit?
Click to expand...

Thing is, unless you've a large battery bank that's almost flat it won't be running at max output for long. However there is (should be) a temperature sensor which attaches to the alternator and watches for overheating then the B2B automatically reduces it's "draw" until things get back to normal. The B2B is an intelligent charger so it will charge in stages until the batteries are fully recharged.

Interestingly our alternator failed BEFORE I had the B2B nstalled.
 
Gromett said:
I would be concerned about running a 60AMP Alterntor at full peg for hours on end. I would rather upgrade alternator and ensure it was over specced for the job?

Just my thought.

IanRJ Alternators aren't that expensive these days, might be worth upgrading at the same time as installing the B2B. Maximise the benefit?
Click to expand...
It was just an example, and it was a 60amp B2B.... The alternator size was 50amps.
Can't remember seeing a 50amp alternator on anything in the last 20 years at least.

Oh, my last alternator, a 180amp jobby, cost me just over £200 (exchange) trade..... I wouldn't call that 'not that expensive'
 
When I was considering a B2B for my Boxer based MH I was told they all had a 150A alternators up to Euro5. When stop/start Euro6 came in they were upped to 180A.
Regarding the B2B I was told its basically the number of Amp Hours required over what time (of journey). I when for the best quality B2B I could find, a Votronic, 45A model. It had an input spec of max 700W and max input of 63A at between 10.5 to 16.5V. I have the "limit switch" applied which limits the input current to 48A. I can't measure the input current but typically I see an input voltage of 13.5V and get 41.5A output. It can be configured to charge four types of lead acid batteries and four types of lithium batteries. Good luck with whatever you choose.
 
IanRJ said:
Sterling need to know the output before they will recommend which b2b should be used. Replacements for this van (non fiat) range from 80amp to 180amps. If the alternator will take it I’d go for a 120amp b2b, but need the actual output to be sure. Crazy it isn’t even in the specs in the handbook.
Click to expand...
Wondering what size battery bank you have as you are looking at getting the 120A B2B. I assume you have at least 400 a/h if not you will be in danger of frying the batteries.

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It does't work like that, lead acid will essentially take whatever amps you throw at it, they are self regulating in a way as the harder you try to shove amps into it, resistance in the battery increases basically pushing back, limiting what it will take.
 

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