Solar regulators

[S.M.U. 15]

Alright I know people on this sight have a fair amount of knowledge and I've picked the ones that just reword goggle.

Here is the question....

If I run two regulators on two different solar panels, running to the same battery bank will they interfere with each other?

Thanks in advance.

[Island Time 1,234]

you can have as many charging sources as you want, so long as they all have their own regulator. For solar though,  why not just use a MPPT controller???

[S.M.U. 15]

So would One mppt reg do the lot? Currently have one 40 watt panel and expect to have one 100-150 watt hanging off stern. I thought (and willing to be corrected, thats why i'm here) 2 vastly different size panels could NOT go through the same reg.

 

Thanks for your consideration.

[Island Time 1,234]

Yep, one controller (of the appropriate size) can do both. the you have too decide to cable serial or parallel...

[wheels 543]

Re the two different panels part. Basically the way one individual panel works is the same. A Panel is not just one large Cell, but dozens and even hundreds of individual cells all connected in both Parallel and Series to make up on large Panel with a specific Voltage and Power output.  So adding in a different panel is no different. Except you do need to connect in Series. Otherwise as a for instance, a 12V panel will never meet full current output if connected in Parallel to a 24V panel output. In series, you would have a 36V output. The Reg then takes care of that Voltage.

Re the multiple Reg part. The issue here is that for most regs, they don't work that well together. The issue is that the greater Charge input from one, will tend to affect how any others connected will "see" the Battery. So that greater charge current will tend to make any others connected, sit back and do very little, because they think the Battery is in better charge state than it actually is. You actually need a very sophisticated Charge reg that can be "linked" and talk to one another to share the job. However, they are not usually available for normal applications and it is simply better to have one Reg that is capable of the over all Panel/s output.
 

[S.M.U. 15]

Right, thanks for your help. Parallel it is with a decent  MPPT regulator.

[Clipper 343]

Just for interest, and slightly related. If you have  house and start battery, what is best way to charge them both from one panel? Can you get regulators with 2 outputs? Or can you connect through the VSR?

[slanty 8]

I solved the two battery issue by using a sun saver duo. 

 

https://www.morningstarcorp.com/products/sunsaver-duo/

 

Independent charging channels and weighting (will put 10% effort into starter and 90 into house or 50/50.)

 

Got mine for around $200. 

[wheels 543]

Two outputs are better. HOWEVER, not all Two outputs are created the same. I have seen some cheap units that the output is simply spit using a diode. No great way to isolate the two banks and ensure a proper charge goes to both.
Better units use a better splitting circuit, which is more like you see in a proper split charging unit.
The very expensive units use two separate charge circuits. But it would be cheaper and just as good to get two good separate regulators and put one on each bank, but both supplied by the same panels. I have known one who had one panel dedicated to the Start and the others dedicated to the House. But I see no point in wasting a panel. It's better to get as many ergs as possible to which ever bank needs it, usually the House Bank.

[idlerboat 116]

You can use a nice bit of gear called an isolator / combiner..  This is not a VSR. 

try this   http://www.hellroaring.com/battery1.php

 

Good information on their site. 

I can attest to the reliability of their gear.

I have mine between my engine crank bat and house (600 AH of AGMs) and prefer to do it this way on installations.

As soon as the Engine bat is happy it starts to pulse power across till it fully connects.

Engine alternator and solar via engine crank bat ...then to house.  (You never get a flat crank Bat).

Wind direct to house.

[Black Panther 1,581]

Yep, one controller (of the appropriate size) can do both. the you have too decide to cable serial or parallel...

How does one calculate an appropriate size?

[erice 732]

^

 

you can have an 80 watt (80 watts / 12volts  =  6.7 amps), panel regulated by a 10 amp regulator

 

but if you then add a 50 watt (50 watts / 12 volts = 4.2 amps) panel in parallel

 

on a sunny day the combined 10.9  amps will probably slowly cook the 10 amp regulator

[wheels 543]

First thing you need to do, is check what the Regulator can handle as maximum input voltage. Keep that in the back of your mind.
It is always best to try and get the highest Voltage, so series is usually the best way to connect them together. This ensures the least current loss in the cable. But also, especially for an MPPT reg, you will get a much longer charge time. You will find the charger reg will turn on earlier in the morning and off later at night. It may not be a huge amount of current, but it will still be trickling in something. If you go for Parallel, you get a lower voltage and once the Sun starts to drop in angle and the voltage falls away, the Reg is going to cut off once it is below the Battery voltage.
However, remembering that max voltage comment, you do not want to connect too many panels and take the input voltage over the Regs max voltage input. It takes quite a few panels to do this for most controllers, so for most boat installs, it will never be a problem.
You also want to ensure you have a little head room re the current as well. In other words, if you have 10A of panel current, don't buy a 10A Reg. But a 15 or even 20A reg. Because on the odd occasion on a really bright mid summers day, it is possible to actually get more from the panel that some actually state they can produce. Not often something you hear, that something performs better than specified. But our Sun has some pretty strong sun bugs down here.

[Black Panther 1,581]

Ok., looking at 4x 120w, need to do some arithmetic.

[idlerboat 116]

Hey BP have a look at the actual specs of the panels, not just the nominal watts.

Generally the actual output is about half of the rated specs (on a bright sunny day).

So your 480 watts nominal will probably show around 20 amps true...

I like to run a head room of about double so a 40 amp regulator will have buckets of safety..

[wheels 543]

I can't agree with that IT. Panels are a power device. In other words, they output power (watts) rather than just Voltage or Current. To make that male more sense, they don't produce a set voltage, (say 12V) and the current goes up and down due to Sun, nor do they output a set Current (say 10A) and the Voltage goes up and down due to the Sun. As the Sunlight increases, the Voltage and Current increase proportionally, so the actual power output increases. However, that happens with the panel being OC. A load is a resistance and as soon as you introduce a resistance to the output, you change the way the panel works and the ability to produce a rated power output drops dramatically. This happens when we connect a plain brown wrapper PWM regulator. When a MPPT reg is connected, the reg tracks the output and alters the load the Panel "see's" and thus maintain's the best Voltage/Current output over the operating range as Sun intensity alters.

[180S 20]

May be a bit of a thread drift from the original thread, but as I' m in full research of solar panels I plan to use a Genasun controller on each panel. Chosen for the lowest possible night current draw 0.9mA and a reputation of having the lowest electrical noise generation of mppt controllers on the market. With regards to 1 controller or one on each; If one controller is putting out enough to close the 2nd controller down , then I'm not worried of getting every last amp.

[mattm 98]

May be a bit of a thread drift from the original thread, but as I' m in full research of solar panels I plan to use a Genasun controller on each panel. Chosen for the lowest possible night current draw 0.9mA and a reputation of having the lowest electrical noise generation of mppt controllers on the market. With regards to 1 controller or one on each; If one controller is putting out enough to close the 2nd controller down , then I'm not worried of getting every last amp.

I'm not sure you follow why one would shut down. The reg with the highest voltage set point wins, not the highest amp output. For example, say you have a 20w panel with a reg set at 14.6v, and a bank of 400w panels with a reg set at 14.4. As soon as the 20 watt panels' reg hits voltage higher than 14.4, the 400 watt banks' reg will turn off. You will only be getting max of 20 watts of charge, even though you have another 400 watts sitting there in full sun.

[180S 20]

Good point, but I' m looking at x2 50W panels, if one is at 14.4v and 4A, I'm not fussed about missing the other 4A, as they are positioned alternate sides is unlikely to both be at full power anyways. Goal is to try and get a consistent 4A.

[wheels 543]

If you have only 2 panels and only 50W, then you are totally wasting money with 2 regs. You want the highest voltage output possible from the panels, so connect them in series. The MPPT Reg will control both panels as if they are one. The higher the Voltage, the longer the charge time before shut off from poor/low light levels.
And instead of two panels on opposite sides, you are best to have them horizontal to gather the best light possible (for limitations of boat mounted that is). For instance, what if the Sun is forward or aft. You are going to lose light on the both panels. And if to one side, then only one panel is ever going to work. In fact you would be better off having one panel mounted horizontally as it is likely to operate longer than two mounted on each side. I would look at getting the biggest panel I could fit in a horizontal position and go with that single panel only, if you can't fit more in that position.