Novice question: How much power does a 2020 Ducato alternator deliver to a B2B

[slowdriver]

I have a 2020 Ducato (heavy chassis 180hp motor). I understand that different spec Ducato vans can have different alternator amp outputs. I hope to replace my 150ah AGM battery which comes with a 30amp Votronic B2B with 300ah of Lithium (battery yet to be specified). A couple of suppliers have suggested that it would be a good idea to increase the size of the B2B either by:
1) The first supplier proposed to add another 50amp Votronic thus increasing the theoretical maximum B2B charge to the battery to 80amps - but to get to 300ah requires 2 x 150ah batteries.

2) The second proposes single 300ah battery and scrapping the Votronic kit and replacing it with either a Sterling 70A Battery to Battery charger or a Victron Orion 50A DC/DC charger

My first and most basic question that applies to both solutions is:
Is the continuous (rather than the peak) output of the Fiat alternator capable of meeting that draw?
- I cannot find the specifications for the 2020 Ducato alternator alternator output.

Does running an additional Votoronic 50a B2B alongside the existing 30a one present any balancing issues on a single 300-ah battery? or on 2 x 150ah batteries.

I am assuming that since these are both reputable suppliers they would not propose either of these solutions if they didn't work - because then they would just have a bunch of aggrieved customers. I am a mechanical and electrical clutz looking for some reassurance that either approach works equally well.

 

[Mike800966]

It firstly depends on hpw ypu want to use your van.
Seems to me a vast overkill unless you intend to be static for days then only drive short distances in winter. If its summer time use why not look at solar?
Mike

 

[AdrianChen]

I think your alternator will be 150amp, but I'm not sure - someone on here will know, and many motorhomes are specced by the converter for the higher output option so 180+

If 150, then with 300AH of lithium, it will be pushing the alternator at times using an 80amp B2B (especially when idling or engine running slow in traffic etc which is when the internal cooling fan is less effective). Overall it will work, assuming a suitable cable and fuse is put in to the supply the B2B but I think a better percentage is 40% of the alternator output for long life - that is all based on heresay though! Might go for years.

As for the batteries one 300 or two 150's - The difference may be the maximum output limits, depending on the manufacturer the BMS will give perhaps 100A for each 150amp battery, and possibly the same for the 300, so check the output, and that the 150's manual specifically states they are suitable to be paralleled.

I think according to Votronic, paralleling two will work only if they are the same type ie two 30amp or two 50amp (easy enough to check the Votronic instructions), and wiring must be done carefully to ensure same length output cables etc. Personally I would not mix and match 30 and 50.

I agree a 30amp unit is small for a 300ah battery, so would upgrade it (and cables/fuses etc).

The choice between Votronic 50 and Victron:- Personaly I would go with Victron since the XS unit is fanless, very efficient and via the connect app gives good reporting on the chargers performance, but it will need a Victron Smartsense, smartshunt or other means of monitoring the battery voltage and temp for it to give the best results. Since you are fitting a big Lithium, depending on the make you select it is tempting to pop in a smart shunt or BMV at the same time to keep a more accurate eye on the SOC than with the batteries internal bms. If all Victron this can all integrate through bluetooth and report through the connect app.

I think but am not certain that a suitable temp sense/voltage sense cable comes included with the Votronic.

Doubtless others will attest that the Votronic has been totally reliable in their experience, so either will do the job of a B2B. I use Victron because my MPPT controller, inverter charger, and shunt are all victron making a nice integrated system with simple controls through one single app.

Good luck!

 

[TheCaller]

I think I'm right in saying that the X250 had a 150A alternator as standard, with 180A as an option. The 180A model then became the standard on the X290.

Unfortunately, the only way to be certain as to what an individual vehicle has got is to look at the label on the alternator itself. That requires crawling underneath with a torch, a mirror or an endoscope and a fair degree of personal flexibility!

If it was me, I'd go for the single 300ah battery with the new Victron Orion XS 50A DC-DC charger & sell the Votronic 30A unit. You don't mention whether you also have solar, which is where I'd be looking for anything additional. So much depends on how you use the van as to what is the right balance of power sources.

 

[Guigsy]

Is it a good idea to have mixed brand B2Bs in parallel? Won't they have different charge profiles, so potentially confuse one another?

If you do a lot of UK trips off-grid between late October and early March, and you drive around a bit, then you'll be leaning on the B2B quite a bit because solar isn't going to be providing much. It's really dependent on your battery consumption.

Personally, I generally off-grid for only a few days at a time during the winter. But my battery lasts for several days. So I don't have an issue with my battery slowly depleting. It'll get topped up overnight when I get to a hook up.

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[Jev88]

I thought?? it was limited by the B2B and so protects the alternator from too high a draw?

 

[eddie]

On my Mercedes I have a 220 amp alternator and a 120 amp B2B which works very well for us

 

[tacr2man]

If going with two B2B it might be a good idea to have at least 1 switchable so you don't load the alternator heavily when at low charge state , and with engine idling or at low rpm for extended period, as this is when the alternator can be damaged.

 

[slowdriver]

I think I may have found more, useful, information here. Others may find this helpful

https://diysolarforum.com/threads/big-dc-dc-b2b-charger-harms-alternator-and-battery.19925/

 

[AdrianChen]

I thought?? it was limited by the B2B and so protects the alternator from too high a draw?

A lithium battery working over an SCR will run the alternator to max output (150amps easily on a 300ah empty lithium), which will probably blow fuses and cables, unless they're also upgraded., so a b2b limits this to the output of the b2b, plus the cable losses and ineficiency within the B2B, so a 30amp b2b might draw 35-40 amps from the alternator, but not 150! So yes it protects the alternator, but not if you were to put too big a B2B on..

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