How much Solar to offset Starlink?

[Dougcole]

Hi All,


In the process of installing a Gen 3 Starlink Standard and planning on adding solar panels to our bimini to offset its power draw.

Starlink says the Gen 3 draw is 75 to 100 Watts AC (it draws mroe power than the Gen 2), but some internet testers are seeing more like 55 watts once it is up and running, a little less than that when it is idle. Apparently the 100 watts is only when it is in snow melt mode.

I have three 100 watt Bouge RV "arch" flexible panels on the way, which I am going to run through a Bouge RV 40 Amp "sunflow" MPPT. Our house bank is 660 AH FLA, in good condition, so probably 290 usable AH. The Starlink will be powered by a 1500 watt inverter.

We primarily use the boat in the Bahamas in the summer, so long days, but some cloud cover and rainstorms at times. We plan to have the starlink on for about 8 hours a day when the genset is not running. We won't be on the internet that entire time, but I envision turning it on in the morning and leaving it on until bedtime.

We run the Genset at night to run the Air Conditioner, so I have no thoughts of 300 watts of solar offsetting our entire power needs. I know it won't do that. Some extra juice from solar would be nice, but mainly I just need to offset the Starlink.

I have room for a fourth panel. Do you think I will need it?


Thanks,
Doug

 

[Don L]

If you are going to run the generator at night don't worry about it, just turn on the battery charger.

but

Last year my experience was that running the SL, 40" TV and sound bar off a 500W small inverter for 4 hours used about 50Ah, so about 12 amps. The SL itself seemed to use about 50W and I only powered when I wanted to use it. Note that using all those off a small 500W inverter used less power than just turning my main inverter on and powering nothing.

So if you wanted to leave it on ALL the time you would probably need an extra 120-150W of solar

 

[DavidM]

You may be surprised.

Your Starlink needs 55 watts to operate and at eight hours daily usage, that is 440 watt hours. Three 100 watt panels will easily cover that load. Even two panels should do the job.

David

 

[Max1]

I can't say exactly advise you on how yours will work, but I can offer some data to help you understand what you would possibly need.

My biggest draw of power is my 12V fridge, and running TV's and laptop/ monitor through an inverter. When running during the day, it's a non issue because the solar is able to keep up with the power demand. It's overnight that would be a concern. fridge runs between 35 and 50w and a duty cycle as much as 1:2 to 1:4.
I am running 400W solar and 400W of usable battery and never had a problem. From overnight operations, my batts will be back to 100% by 11am. I have the capability to go as high as 800w solar and 600W battery, but I haven't added them yet because i have plenty of power as it is.

Hopefully this info helps you out.

 

[O C Diver]

Think this falls into the rule of diminishing returns. The first solar panel gets used 100% when the sun shines and not when it doesn't. The second one probably is equal to the first with a small percentage of the time that the batteries get full and utilization isn't 100% when the sun shines. The third panel probably sees significantly more time when the batteries are full on bright sunny days, so a lower utilization percentage. Keep in mind that none of the panels work on cloudy days. The fourth panel is over kill on bright sunny days and only is beneficial on partly sunny days. Obviously of no real value on cloudy days. So with each additional panel you are getting less return on your investment. For me, if you're going to run the generator anyway (especially if it's cloudy), I just don't see the return on the investment. Same thing applies for doubling the size of the battery bank. I'd rather put the money to things that I get more benefit from.

Ted

 

[socalrider]

Here's how I'd think of it:

55W x 8hrs = 440W-h, or about 36a-h @12V. Maybe 15% of your usable battery capacity (about one of your FLA batteries)

You're running the generator all night, so your batteries will be at 100% in the morning regardless.

In this use case, as much as I love solar, I don't see any point to it. Just run your batteries down a bit deeper, or buy one or two more FLAs if you really need the extra capacity, which will be cheaper and easier.