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Date: 6 June 2014. Solar Regulators (Standard vs. MPPT)


Living off the grid often means making sacrifices, but I am not into that nonsense. Not at my age. I want and expect to have my indulgences and power plays a part in my happiness quotient. Solar panels and the regulators that go with them make a difference.

A fellow asked what he should do to get rid of the generator on his boat and live life off the grid. I have been living on the hook for a while and am almost at a suitable level of decadence. Though not quite there yet, I am closing in. Because I do not live life tied to a dock it is imperative that I generate power.


The first thing I did was buy an Air-Breeze wind generator because on the east coast there were a lot of sea breezes starting at 10 a.m.  On the Gulf side of Florida I am finding my wind generator less useful than when I was on the Atlantic coast.

Still in all, I am glad to have a wind-gen. If the sun does not shine often the wind blows. In the night those winds are charging my battery bank. That is a good thing.

This is my MorningStar ProStar-30 solar charge controller.

Next I added a 75 watt solar panel and a Morningstar10 solar regulator. I later upgraded to a Morningstar30 regulator. The small panel wasn't enough. This past year I added two more 100 watt panels and I'm closing in on perfection. I like this regulator far better because of the information provided on the screen.

Update June 2023: Baby (mine) tells me she likes having links so, well, here you go...

Affiliate Links

Primus Wind Power Air Breeze Turbine Generator

(I have an older model)

MorningStar ProStar-30 amp (12/24v)

Renogy 100 watt solar panels


Morningstar ProStar-30 solar regulator

I bought the ProStar-30 a few years back and it is still functioning perfectly. Though often folks stash these in the bilge I chose to mount mine in the galley by the dinette so I can read the numbers.

That is a West Marine cigarette lighter outlet to the right of my regulator, in case you wondered.
I have a few of those onboard Seaweed. See
What Used Boat? article for proof positive.

  • The Morningstar ProStar-30 has three numbers that slowly cycle through. The first two interest me.

  • The initial shows my Battery Voltage. 

  • The second number that flashes is the incoming Solar Amps.  I like when that number goes double-digit.

  • The third is Load Amps, but nothing is hooked to that as of yet.

  • The bottom left corner has a green LED that indicates when power is incoming. It is surprising how little daylight is required for power to be generated.

  • At the bottom right are three lights, Green, Yellow, and Red.  Green is Good!


There are slight differences in the meaning of those Green-Yellow-Red lights when charging versus after dark but essentially this is what you need to know:

Green Flashing Solid Green Yellow Red
Absorption charge or
float stage (trickle charge)
70% to 100% charged
30% - 70% charged
below 30% charge

For more information, visit http://morningstarcorp.com - they are the experts.


Though I like my Morningstar30, if I did not have real estate and was limited to the number of panels I could fit up top, I would definitely have opted for an MPPT regulator. I still wish I had one.


Here are the differences between the two types of solar regulators:

Backing up a bit... My latitude is 30 degrees, give or take. Think FL and GA border. From my solar panels I get approximately 100 amp hours per day.

Take solar panel wattage, divide by 3 and call it amps -- you can get fancy, but that is the number with a standard regulator that I am seeing this far from the equator. This was confirmed by an EE with a penchant for precision. I think all Electrical Engineers have that trait.


The ARROW is at approximately 30 degrees north.

For my overseas readers...

Latitude 30 degrees north (the RED ARROW) is much further south than the GREEN STAR on the right.

The GREEN STAR is at the southern border of Washington state at 45 degrees north.



However, there is a fellow up in WA state and he has the MPPT* regulator. He is getting the same figures as me (watts divided by 3 equals amp hours) at his latitude.

*MPPT: Maximum Power Point Tracking (a type of solar regulator)

That is the difference in a nutshell: He is getting the same amount of amp hours into his batteries as me, although he is over 1000 miles north of here.

Algae has a solar panel.

Thus, if you have real estate (lots of flat space) you could do as I did and opt for the less expensive solar regulator. On the other hand, if space is limited, I believe you should buy the more expensive but better MPPT regulators.  If money were no object, I too would have an MPPT. They really are the best.

That said, if your boat has a generator already I would not be so quick to shut it down. I have been aboard a Manatee with the genny running and could not hear it over the sound of the ice cubes in my glass.


Do not be so focused on making everything perfect that you forget to live the life. Get out here and play for a while. Soon enough your desires will determine what next to fix/upgrade or switch to.

But live with what you have at first. There is a reason your boat was outfitted as she was. Perhaps it is not apparent today, but in a few months you will know for certain. In the meantime add batteries, a great charger, and live with your generator.

In my opinion that is.  

Do you have solar panels as part of your charging system?
And, what type of regulator did you choose?

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