Buck-boost vs Orion DC-DC

[CaptainRivet]

Originally Posted by Meaban

I tried. Boat builder says it's not possible to get a D2 with only one 24V alternator, the 12v one is always supplied (warning to waranty issues).



600W rigid sunpower on the arch



W&S = 2 years European warranty, a spare prop is a good option. I should go for the short model with 2 supports port / starbord. There have been issues with these hydrogenerators, seems better now. Several boats I know have done 20000+ miles with no issue. Anyhow I'll have a look to the German offer.

Talk to Volvo directly, you wanna have 24V starter and control panel and well they deliver the 12V alternator too but 24V is mounted.

But why 24V, what big loads do you have or will have?
24V bowtruster is seperate and a 12 to 24V DC2DC charger 15A for it will work.
w&s: look at the terms so you keep the warranty…that turned me off.

Fixed solar is good, use bifacials to squeeze every watt out of the given surface.

[s/v Jedi]

The disbelief of the new Victron dc-dc converter/charger efficiency is hilarious

This is a real product and it’s out there doing everything it’s spec sheet says. The only problem is that we only have a 12/12V version until later this year.

[Statistical]

Originally Posted by s/v Jedi

The disbelief of the new Victron dc-dc converter/charger efficiency is hilarious

This is a real product and it’s out there doing everything it’s spec sheet says. The only problem is that we only have a 12/12V version until later this year.

There was no disbelief of XS series chargers in the thread by anyone. The OP didn't even ask about them. The OP found a non-marine non-orion "buck-boost" converter (yes that is the actual brand name) intended for OEM integration into hybrid autos.

https://www.victronenergy.com/dc-dc-...verter-25a-50a

[s/v Jedi]

Originally Posted by Statistical

There was no disbelief of XS series chargers in the thread by anyone. The OP didn't even ask about them. The OP found a non-marine non-orion "buck-boost" converter (yes that is the actual brand name) intended for OEM integration into hybrid autos.

https://www.victronenergy.com/dc-dc-...verter-25a-50a

I don’t think this model claims a 97% or higher efficiency? I don’t think I’m the only one messing this up I just checked the spec sheet and it doesn’t mention the efficiency?

It is a Victron brand converter for general car applications. Buck-boost is the model name.

[CaptainRivet]

Originally Posted by Statistical

There was no disbelief of XS series chargers in the thread by anyone. The OP didn't even ask about them. The OP found a non-marine non-orion "buck-boost" converter (yes that is the actual brand name) intended for OEM integration into hybrid autos.

https://www.victronenergy.com/dc-dc-...verter-25a-50a

The question with the expensive XS is why spending 450Euro, don't have a real protection of the alternator as you just limit current but the real danger is heat and you castrate an alternator thats capable of 85A constant to 50A

When you get a nordkyn VSR200 for 100Euro less that without mods to the alternator turns it into an regulated alternator that puts 85amps out, has charge profiles for the different chemistries and really protects the alternator.
In case of the Mitzi 115A it really protects itself already in stock config as it has a well working internal temp protection.
There is tons of disadvantages using the XS here incl. Its more expensive.

[Meaban]

Originally Posted by CaptainRivet

Talk to Volvo directly, you wanna have 24V starter and control panel and well they deliver the 12V alternator too but 24V is mounted.

But why 24V, what big loads do you have or will have?
24V bowtruster is seperate and a 12 to 24V DC2DC charger 15A for it will work.
w&s: look at the terms so you keep the warranty…that turned me off.

Fixed solar is good, use bifacials to squeeze every watt out of the given surface.

Tks, will contact Volvo, maybe a misunderstanding from my side if they supply the 12V alternator but in fact don't mount it (very strange way of doing...)
A full 24V system including starter and so engine battery would obviously be perfect.

Bifacial is unfortunately useless as this is a composite sandwich arch with full top part under the solar panels. Nothing is perfect. But I will add later some other panels, either fixed on lifelines (but removable for heavy passage trips), either with a double cassette system on the arch. I guess we would be comfortable with 800W.

Consumers : electrical winch, 3000W inverter that would supply a portable induction plate (complementary to gaz cooking), freezer, and later a watermaker. I'm sensible to efficiency that's why right or wrong I wish to go with 24V.
I'm not an electrical specialist but try to educate myself with skilled CF members like you, Jedi, and some other ones (even though specialists seem not so often to agree together).
One comment regarding the shipyard : They agree for me to supply a home made winston battery + BMS (they want me to add a BMS, so no question about if it's a good option or not). So they are quite open minded, but on the other hand they have their own responsibility and wish to keep control on the electrical system. And while they are very skilled regarding composite construction, deck plan, rig, and so on, I feel that the electrical system is not their best know how.

[CaptainRivet]

Originally Posted by s/v Jedi

The disbelief of the new Victron dc-dc converter/charger efficiency is hilarious

This is a real product and it’s out there doing everything it’s spec sheet says. The only problem is that we only have a 12/12V version until later this year.

Originally Posted by Statistical

There was no disbelief of XS series chargers in the thread by anyone. The OP didn't even ask about them. The OP found a non-marine non-orion "buck-boost" converter (yes that is the actual brand name) intended for OEM integration into hybrid autos.

https://www.victronenergy.com/dc-dc-...verter-25a-50a

The question with the expensive XS is why spending 450Euro, don't have a real protection of the alternator as you just limit current but the real danger is heat and you castrate an alternator thats capable of 85A constant to 50A output plus forcing to have a lead starter battery

When you get a nordkyn VSR200 for 100Euro less that without mods to the alternator turns it into a full regulated alternator that puts 85amps out, has charge profiles for the different chemistries and really protects the alternator plus can charge directly lithum so you can use a lithium starter or directly charge the LFP house.

In case of the Mitzi 115A it really protects itself already in stock config as it has a well working internal temp protection and its AGM regulator doesn't go over 14.4V, normally hardly 14V so with a simple argofet charge diode can charge AGM starter and lithium in parallel.
After the argofet use a simple step up converter from 12V to 28.0V, i often used the 60A daygreen https://daygreen.com/collections/12v...-year-warranty. The BMS simply switches off via remote the step up converter when at 95% and leave solar to do the rest. The lead is always their as surge protection
Know several boats that also have the daygreen 120A step down converter from 24v to 13.8V https://daygreen.com/collections/24v...tage-regulator
and use it to run a 12V 1000W lofrans caymann 88 windlass via this converter since years without any issue. This is cheaper then a new windlass 24V motor when going to 24V and eg your windlass is newish. It can handle the surges of the windlass which means it must be a good one doing that over years.

There is tons of disadvantages using the XS here incl. Its more expensive.
That whole DC2DC charger stuff makes sense for old small alternator till around 70A where its just more economic to use a 30A DC2DC and charge the lithium beside lead starter which also goes to the limit of the existing alternator.
And for the ones where they just make sure the alternator is working properly when converting to lithium...but >80% then realize why throwing charge current away when engine is running and install more Dc2Dc (and be more expensive) or install a big alternator.

But already with eg the widely used old 85A Hitachi it makes economically sense to just modify the alternator (and overhaul it at the same time) to external regulation for 100-150 bucks and use a Balmar or the Ars5 from mastervolt which is 350Euro+100Euro= whst the XS cost.
Like this you get regulated 60A =10A more then XS out and really protect the alternator plus need no anchient lead anymore thats cronically unreliable and needs frequent replacement.
Well you can ask several sailors that just smoked their DC2Dc charger "prorected" alternators in greece with 45 degrees ambient and motorssailing with 1400RPM...the XS would be a really good DC2DC if it had an external temp sensor you csn put on the alternator, that would have been innovativ and what i expect from victron...

[Statistical]

Even with externally regulated smart alternators there is still a use for DC to DC converters/chargers.

1) For charging the starter battery
2) For powering 12V loads on a 24V or 48V boat.

[Meaban]

Originally Posted by s/v Jedi

I don’t think this model claims a 97% or higher efficiency? I don’t think I’m the only one messing this up I just checked the spec sheet and it doesn’t mention the efficiency?

It is a Victron brand converter for general car applications. Buck-boost is the model name.

You're right, several commercial web sites claim 96 or 97% efficiency, but no mention on Victron's website datasheet...I had this figure in mind and repeated it without double checking from the original source, my mistake.

[CaptainRivet]

Originally Posted by Statistical

Even with externally regulated smart alternators there is still a use for DC to DC converters/chargers.

1) For charging the starter battery
2) For powering 12V loads on a 24V or 48V boat.

For 2) Absolutley. Converters always.
For 1) a 5 till 15A version does it on most vessels below 60ft for the starter, no need for a 50A version.

The real reason that 50A exists are eg boat manufacturers that now have to offer a lithium battery option as customer request it and they can offer that with the DC2DC charger without changing their electrical install compared to lead. Thats cost savings, nothing else. And 30A charge is not enough for the electrical needs plus the stock alternator can savely do more.
But if its retrofit or semi/custom i would request for the best solution for my money and DC2Dc charger its definitly not.

[Meaban]

Originally Posted by CaptainRivet

The question with the expensive XS is why spending 450Euro, don't have a real protection of the alternator as you just limit current but the real danger is heat and you castrate an alternator thats capable of 85A constant to 50A output plus forcing to have a lead starter battery

When you get a nordkyn VSR200 for 100Euro less that without mods to the alternator turns it into a full regulated alternator that puts 85amps out, has charge profiles for the different chemistries and really protects the alternator plus can charge directly lithum so you can use a lithium starter or directly charge the LFP house (...)

Without any comment about what product is the most efficient, here in France Orion XS = 303€, VSR 200 including delivery = 390€ due to our poor € rate.

[CaptainRivet]

Originally Posted by Meaban

Tks, will contact Volvo, maybe a misunderstanding from my side if they supply the 12V alternator but in fact don't mount it (very strange way of doing...)
A full 24V system including starter and so engine battery would obviously be perfect.

Bifacial is unfortunately useless as this is a composite sandwich arch with full top part under the solar panels. Nothing is perfect. But I will add later some other panels, either fixed on lifelines (but removable for heavy passage trips), either with a double cassette system on the arch. I guess we would be comfortable with 800W.

Consumers : electrical winch, 3000W inverter that would supply a portable induction plate (complementary to gaz cooking), freezer, and later a watermaker. I'm sensible to efficiency that's why right or wrong I wish to go with 24V.
I'm not an electrical specialist but try to educate myself with skilled CF members like you, Jedi, and some other ones (even though specialists seem not so often to agree together).
One comment regarding the shipyard : They agree for me to supply a home made winston battery + BMS (they want me to add a BMS, so no question about if it's a good option or not). So they are quite open minded, but on the other hand they have their own responsibility and wish to keep control on the electrical system. And while they are very skilled regarding composite construction, deck plan, rig, and so on, I feel that the electrical system is not their best know how.

Knowing that i would recommend to stay 12V. A 3000W inverter with max 1.5m cable conected to house is still ok for 12V and is the only device that really draws current.
But that would simplify your install a lot staying 12V from using the VSR 200 with just a 2nd 115A Mitzi. That conversion up and down introducing a lot failure points and also reduce overall efficency of the install. And it also keeps the shipyards electric install in big parts as it is.

Another a bit more complex but easy scaleable way is going dual voltage means a 12V bank that starts and also supports the 12V loads plus the 12V alternator and a 24V bank that connects all the other charge sources incl. a 2nd 24V alternator. And then a 30A step down 24 to 12V charger and a step down 12 to 30A charger so you can exchange charge permanently. But with only 3000W inverter as big load that doesn't make sense.

Reg 12V alternator: volvo buys complete industrial engines ,with D2 they are Perkins, that also includes alternator and just marinize it. So you have a 12V starter as well as an 12V alternator and when you order a 24V engine they replace them with the 24V version and deliver the 12V components with as its cheaper then scraping them or selling them.

[CaptainRivet]

Originally Posted by Meaban

Without any comment about what product is the most efficient, here in France Orion XS = 303€, VSR 200 including delivery = 390€ due to our poor € rate.

So street price is around 300Euro now, official sales price was 450Euro... thats more sufficent for its value.
But still you castrate the alternator to 50 from 85A (in the first 5-10min nearly 100A) and need a lead starter.
Cheaper and simpler a 200A argofet for 120Euro and charge AGM and LFP parallel. The Mitzi can protect itself and don't need a DC2DC to do that and when your JK will cut charge when LFP is 100% SOC the AGM is always there as surge protection. Add a 2nd 115A mitzi later without changing anything additional, just connect it to the argofet in parallel and you get 170A charge. And your shipyard will like that solution too.

[noelex 77]

A new boat build is always exciting. This looks like a great project.

I would suggest installing the correct equipment from the start. You have relatively high energy demands with not much solar. A system that can deliver plenty of energy to the lithium bank is needed. None of your proposed solutions achieve this goal.

The best solution is to keep the existing alternator stock. Install a second high output 24v alternator to charge the house bank via a good alternator controller. As you have indicated a desire to manage with a single alternator, the next best alternative is to replace the existing alternator with a high output 24v model and charge the engine start battery with a DC to DC charger.