Suniva 235

[scottrod31]

With out breaking the bank best controler  to use with 2 of these suniva 235 watt MVS235-60-5-501
Thanks scott

 

[John61CT]

Give each panel a Victron MPPT 75/15, ~$100

1:1 is ideal for any partial shade handling.

 

[jimindenver]

I have done the separate controllers per panel, it becomes a rats nest of wires, switches and fuses. Shading on big panels can be avoided simply by running them in parallel to the controller.

470 watts should have a 35 amp MPPT controller except there isn't one in that size. You either get some over paneling at 30 amps or go up to a 40 amp. The next thing to consider is what you want out of the controller such as settings and the ability to control the voltages, temperature compensation and voltage sense lines. A low cost controller that doesn't allow you to do what is needed or needs add ons isn't a good deal at all.

So now the question becomes what is the least expensive controller that meets your needs. Some of the less expensive controllers look promising but in use seem to have some unusual settings that may leave your bank not fully charged day to day. You can get away by doing work arounds or you can buy a full feature controller, those cost more but are worth it if they provide what you need.

So before anyone can say this controller is what you need, we need to know what your needs are. Personally I like Morningstar for all they offer. Cheap? no but there are no sacrifices.

 

[John61CT]

Yes Morningstar, Midnight, Outback, Blue Sky, all are also top-notch vendors.


But a rat's nest is on the installer, a neat setup is always possible, if that is important to you.

Each 75/15 is well under 4x5", protrudes a **lot** less than others, maybe a couple inches max.

And putting two panels in parallel on the one controller does not give near the same total output as each getting their own MPPT SC, in any situation where one panel is getting even slightly different insolation input compared to the other.

All these little Victrons have all the features required except a remote temp sensor wire.

Very robust and reliable, Dutch engineered for marine use, excellent build quality, 5 year guarantee, and under $100.

So if getting that 1:1 optimization happens to be at a **lower** price, that to me is a good fit.

 

[scottrod31]

I want to do the usual small 12 volt fridge, lights charge phone and tablet plus a couple of fans
But I will be in southern mi. For the next two years for work and the sun don't shine that much in the winter
I will have some acsess  to shore power but can't  rely  on it 100 %

First solar panel going in tomorrow

 

[akrvbob]

I agree with the dual controller, but I wouldn't risk over-volting them, I wouldn't want less than 20 amps for each or a 40 amp controller.

 

[John61CT]

No overpanelling at all in this case,

max volts are at 75, amps at 20+

 

[frater secessus]

I agree with the dual controller, but I wouldn't risk over-volting them, I wouldn't want less than 20 amps for each or a 40 amp controller.

That's not over-volting.  It's overpaneling (or over-currenting, if one prefers).  Many MPPT controllers are quite happy to clamp down on current when needed.  Morningstar has a page showing how to do it.

Over-volting would likely lead to the destruction of the controller.

 

[akrvbob]

Oops!

But, I'd still buy a pair of 20s or a single 40 amp controller.

 

[John61CT]

The 15A part of the specs is max output

220W / 14.4 = ~15A

The Imp limit on input is 22A, and in fact there is some headroom there too, it's just exceeding Voltage that will cause damage.

However all that is moot wrt these specific panels, this controller is in fact perfectly matched.

Unless OP thinks a remote temp sense wire is worth both spending a lot more and sacrificing the optimization of 1:1.

 

[jimindenver]

My 230w panel tracking the sun would rarely exceed 15a output. I saw 16 1/4 at altitude with cloud effect. I saw 17a at well below freezing only a mile high.

 

[jimindenver]

It would be an unusual set of circumstances but a panel rated for 36 Voc jumped to over 40 Voc for a minute until the panel got goingand then settled and held 38. I exposed it suddenly on a cold day at a mile high. I think at real altitude it could have damaged my original Eco-worthy's limited to 42 Voc. (now 50)

Then again have a fresh coating of snow slide off a tilted panel at 10,000 + ft and it be just the same.

 

[DLTooley]

Placing the controller next to the battery removes the need for a remote temperature sensor. There would also be minimal voltage losses with the shorter controller battery distance.

 

[DLTooley]

As a skeptic I am not fully convinced of the shading loss problem with a series panel installation at 24v and a single Victron. Shading is always an issue. I guess I could see where the loss from a single panel would also apply to the second. That’s less of an issue with with a 2 panel array than with four.

I am still trying to figure out the best scalable panelsize so I can upgrade in matching increments. Renogy does have a 250 watt 24v native panel that would work in parallel with a Victron. Separate chargers for different panel sizes would also work. I will keep my current cheapo for this after I buy the Victron.

 

[John61CT]

Victron makes all sizes.

Their value leader 75/15 is optimal for just a single 250w. You can't parallel two panels to a single controller, would need to go to a bigger SC costing more than double.

Note the 250w is slightly overpanelled, if a 220w were 15% or more cheaper that might be a better match. But if a 300w were only 10% more expensive I'd go for that, much higher *average* output in sub-optimal conditions, which is most of the time.

The extra efficiency of 1:1 comes from each panel's (changing, always a little different) output getting its own full MPPT optimization, rather than the SC trying to do so based on the combined average output of more than one

and yes, there is no better way to handle partial shading.

 

[highdesertranger]

most of your cheaper controllers don't have a temperature compensation circuit. so it doesn't matter where you mount them as far as temp goes. however because of voltage drop you do want them as close to the battery(s) as possible. highdesertranger

 

[scottrod31]

Suniva panels are all gone at 125.00 they went fast. Still hunting
Scott

 

[DLTooley]

This is tangential to the subject. I’d guess the smaller the panel the less precise you need your controller to be. I’ve heard it said that a 15 watt doesn’t need a controller at all. This is one reason why I am concerned about my starter battery as I increase the size of my solar.

By utilizing higher voltages one can up the utility of the Victron. If my math is correct you can do a bit over 600 watts in a 36 volt array. A 48 volt system would be risky but maybe doable. One benefit of multiple 75/15s is that you could get away with only one Bluetooth dongle.

 

[John61CT]

I thought they're only 12 or 24V.

Why would you want higher?

 

[DLTooley]

Series wiring will get you any multiple of 12. Residential systems are often 48. I don’t know why. Higher voltages allow you to get more watts out of a Victron.