MPPT Solar 12v input - 48 output?

[OceanPlanet]

Originally Posted by Ironman162

Just upgraded to 500w solar with a 400 wind turbine charging 500Ah AGM battery bank through a PWM controller.

Works well but can do with more batteries!

Has anyone tried the Tesla battery?

Not many have (or will) try using 300+V NMC batteries on boats...

[foggysail]

Originally Posted by snaptwo

Yes indeedie I agree - series panels are problematic. I take it you are taking about really small panels then. Ok, one final question, what do you have that required 48VDC service? Most (almost all) commercial vessels are 24VDC. I have seen some 48VDC around, but it is so close to the 50VDC LVDC cutoff that a charge voltage exceeds 50VDC, and you are into a whole new electrical code (and cost).

Series connected modern panels with blocking diodes and a decent MPPT controller do work in shaded conditions with reduced output. Paralleled panels are not immune to shade. What I would be concerned with in the OP's case is that a series system's shaded panels could output a lower input voltage to the controller necessary for 48v output.

Most so called 12v panels operate with a Vmp around 18v so 4 panels in series have a Vmp of 72V. An entire panel could be lost and still have enough voltage input to the controller to have output power. If I had the OP's situation I would not hesitate to connect the panels in series.

[foggysail]

Originally Posted by OceanPlanet

Because on many boats it is difficult to fit on the larger array without shading issues. With four 12V nominal panels in series if one is shaded that would stop the 48V charging.

That is incorrect!

[john61ct]

3 panels times 18V is (likely we'll) under 48V, which is not enough for even PWM to output 48V, which is still well below what 48V actually needs for charging.

Blocking diodes really don't help much in practice.

[foggysail]

Originally Posted by foggysail

That is incorrect!

WEEELL....maybe, I'll soon prove this one way or another to myself after I install my new panels now in shipping

[andreas.mehlin]

Why will I use 48v in my battery bank?
-I'm about to install an electric engine which runs at 48V. I thought it would be a better idea to have one big bank instead of two banks. From 48V bank I will run an 48 step down to 12v inverter.

If I don't find any good and efficient solutions with boosting, I might need to put them in serie. I would then probably put it into 4-6 groups 48v+. Looking at about 1500W solar panels.

[44'cruisingcat]

You can get 48 v inverters too, only 1/4 the current on the DC side.

[andreas.mehlin]

Originally Posted by 44'cruisingcat

You can get 48 v inverters too, only 1/4 the current on the DC side.

Sorry but I was not that clear what I ment. What I ment was that I will have an 48 to 12v step down converter so I can run all of my 12v items.

And yes We will also have an 48-120/240 inverter (if that was what you referred to?)

[softdown]

Common recommendations for voltage output:
Under 1000 watt solar system: 12 volt
Under 2000 watt solar system: 24 volts
However, there are scenarios where 24 volts is still the best with more than 2000 watts.

I can't imagine a sailboat needing a 48 volt system.

My main house system is 48 volt. The auxiliary systems are 24 volt. I play with solar systems as a hobby of sorts. Thought about going pro....too many traps to fall into. Like guys who want to convert 12 volt to 48 volt for example.

[john61ct]

He is talking about a 48V electric PROPULSION system, which is actually much lower voltage than most.

No fossil-fuel engine to make the boat go, like EV vehicles on land.

Solar will actually be a relatively minor aspect, and yes it makes sense to have just one big bank.

And yes, it does make things expensive, nature of the beast.

[snaptwo]

Originally Posted by Ironman162

........... Has anyone tried the Tesla battery?

Ummm.... what Tesla battery do you mean?

:-)