Dc to dc booster to increase input voltage to victron mppt

[zavman]

At the moment I am installing a 300w 40v solar panel on arch to a victron 100-30 smart mppt controller to a 24v lifepo4 bank . I am also installing 2 100w 18v on Bimini. I would prefer to put them in parallel vs series for shading purposes. In series I could probably be able to put them in parallel with the 300w into 1 mppt controlller.
18v panels in parallel won’t work on mppt controller into 24v bank. So I was considering using a basic China boost converter for the 2 18v panels in parallel to get to same voltage as 300w panel and then putting them into the 1 mppt controller anyone have any thoughts about doing this.
Also thinking of using another similar boost converter 14v to 40v from alternator into the same mppt . These boost converters are non isolated, not concerned about it with the one connected to Solar panels but the one from alternator to the mppt I am not sure. I think The victron mppt input is isolated. Has anyone tried any of this before.
Sure I can spend and get 2 victron smart dc to dc 12 to 24 but curious if I can save 500 euro going this route

[Zanshin]

MPPT controllers vary the input voltage so that the maximum output power is reached. If you have a DC boost that changes the voltage I would guess that the MPPT controller could no longer perform that optimizing function.

[zavman]

I’m saying to use the boost to get the 2 18v panels in parallel up to the same voltage as the 300w panel then put booster output in parallel with 300w panel into mppt then mppt will maximize it and covert to 24v

[wyb2]

Originally Posted by zavman

I’m saying to use the boost to get the 2 18v panels in parallel up to the same voltage as the 300w panel then put booster output in parallel with 300w panel into mppt then mppt will maximize it and covert to 24v

And they are saying then the MPPT won’t be able to do its job on the 2 18v panels. It probably also won’t be able to do it’s job properly on the larger panel either.

Think about it, the voltage of a panel varies. The boost converter probably produces (or at least tries) the same output voltage regardless of input variation. So what happens when the converter is trying to output 40v while the large panel wants to function at 36? Or 44? Seems like best case scenario you lose performance, worst case the converter doesn’t like being back fed and fries.

As far as feeding an alternator into a solar controller, I mean, does it sound like it makes sense? Seems like so many potential problems.

Get a second solar controller, run the large panel on one and the 2 smaller on the other. Get an alternator that is the right voltage for your batteries.

[PaulCrawhorn]

Victron prices its lines so flexibly it really does not cost more to use several, each sized optimally for its input source.

Even one SC per panel, which truly optimizes partial shade handling.

Many use the Victron SCs as DCDC chargers from sources other than solar

so it seems silly to use another DCDC as a source.

[Pete7]

How about 4 x 50w instead of 2 x 100w connected in series each side to a pair of MPPTs?

Pete

[SailingHarmonie]

Originally Posted by zavman

At the moment I am installing a 300w 40v solar panel on arch to a victron 100-30 smart mppt controller to a 24v lifepo4 bank . I am also installing 2 100w 18v on Bimini. I would prefer to put them in parallel vs series for shading purposes. In series I could probably be able to put them in parallel with the 300w into 1 mppt controlller.
18v panels in parallel won’t work on mppt controller into 24v bank. So I was considering using a basic China boost converter for the 2 18v panels in parallel to get to same voltage as 300w panel and then putting them into the 1 mppt controller anyone have any thoughts about doing this.
Also thinking of using another similar boost converter 14v to 40v from alternator into the same mppt . These boost converters are non isolated, not concerned about it with the one connected to Solar panels but the one from alternator to the mppt I am not sure. I think The victron mppt input is isolated. Has anyone tried any of this before.
Sure I can spend and get 2 victron smart dc to dc 12 to 24 but curious if I can save 500 euro going this route

This is a clunky kludge that won't work. Adding voltage boosters is NOT the right answer here. It makes no difference how much or how little money you spend on them.

[smac999]

I would not share different panels into a single controller. you only combine identical panels. get more controllers.

I would just put them in series and see how it goes first. (into a 2nd controller)

if you get constant shading and the results are not good then maybe look at different options. other companies do make boosting solar controllers.

if one or the other is getting shaded you don't really want parallel either, you want single panel for controller. and the best result would be 3 controllers. a normal one for the the 300w and two boosting ones for the 2 small ones.

here is a boosting controller for example
https://sunforgellc.com/product/gvb-8/

[smac999]

Originally Posted by PaulCrawhorn

Victron prices its lines so flexibly it really does not cost more to use several, each sized optimally for its input source.

Even one SC per panel, which truly optimizes partial shade handling.

Many use the Victron SCs as DCDC chargers from sources other than solar

so it seems silly to use another DCDC as a source.

you can't put an 18v solar panel to a victron mppt controller to a 24v battery. price or model is not the issue. none of them will do it.

[PaulCrawhorn]

Even if you could you shouldn't.

40V and up is needed to really get the MPPT output boost even with a 12V bank.

Don't bother messing with low voltage panels