Starlink offgrid

[shaines]

Hey all, long time lurker first time poster. Hoping I can get some additional eyes on my calculations for powering a Starlink terminal at our remote camp. At the moment it’s our only option to solve the problem of what is both the best and worst part of being at camp; it’s completely cut off from all forms of communication, but because of that we don’t go nearly as often as we’d like. This the only load I need to power and I’ve measured the average draw at 110w. I had hoped for 24/7 usage so I could setup some surveillance equipment and keep an eye on the property whenever/wherever, but after running those numbers, that is impractical. 110w doesn’t seem like that much until you need the batteries for a 3 day supply and an array to recharge it. I’ve decided on a strategy of programming a timer for 15 minutes on, 15 minutes off throughout the day, that drops my requirements to 12hrs/day for three days. That’s doable if my numbers are correct. I can’t build a system above 36v unless I’m willing to submit to the powers that be and agree to permits and inspections. I’m not, so 24v it is. Enough background, on to the math.

110w x 12hours/day = 1320w
1320w x 3days = 3960w
3960w / 1200w per 100ah 12v battery = (rounded up) 4 batteries = 4800w
4800w/5hours peak sun = 960w minimum array to charge in 1 day (5 hours)
at 24v I’d need a charge controller capable of 42a so a 60a charge controller.

This doesn’t account for any inefficiencies, but I’m hoping that my built in over sizing will negate those. With this setup I only have to wait 15 minutes if I’m not on site, and when I am onsite, if I need more online time, I can reconfigure the schedule to as much as 24/7 and have enough power for 36 hours after which I could hookup the Ford F-150 pro power generator and recharge that way.

Thanks in advance for any insights.

 

[sunshine_eggo]

110w x 12hours/day = 1320w
1320w x 3days = 3960w

Assuming you mean Wh

3960Wh/0.85 (ineff) = 4,659Wh

Assuming you're using LFP batteries. LFP are generally rated for 80%DoD, so you'd need:

4659/.8 = 5823Wh, so go with 5 batteries

4800w/5hours peak sun = 960w minimum array to charge in 1 day (5 hours)

5823Wh/5h = 1165W

at 24v I’d need a charge controller capable of 42a so a 60a charge controller.

You'll rarely charge at 24V. Majority of LFP charging will be in the 27.2 -27.6V range.

1165W/27.4V = 42.5A - no need to go all the way to 60A. 40A and higher would be fine. It will be rare that your array actually puts out 1165W.

 

[FilterGuy]

It sounds like you will have a small inverter and the small inverters are not very efficient. I would plan in at least a 15% loss for the inverter.

 

[Daddy Tanuki]

why not jsut add a few more panels strategically aimed to lengthen out your solar day? current panel prices are stupidly cheap, its easier to add panels and a couple fo batteries and you could run 24/7 if you wanted.

 

[Nobodybusiness]

Hey all, long time lurker first time poster. Hoping I can get some additional eyes on my calculations for powering a Starlink terminal at our remote camp. At the moment it’s our only option to solve the problem of what is both the best and worst part of being at camp; it’s completely cut off from all forms of communication, but because of that we don’t go nearly as often as we’d like. This the only load I need to power and I’ve measured the average draw at 110w. I had hoped for 24/7 usage so I could setup some surveillance equipment and keep an eye on the property whenever/wherever, but after running those numbers, that is impractical. 110w doesn’t seem like that much until you need the batteries for a 3 day supply and an array to recharge it. I’ve decided on a strategy of programming a timer for 15 minutes on, 15 minutes off throughout the day, that drops my requirements to 12hrs/day for three days. That’s doable if my numbers are correct. I can’t build a system above 36v unless I’m willing to submit to the powers that be and agree to permits and inspections. I’m not, so 24v it is. Enough background, on to the math.

110w x 12hours/day = 1320w
1320w x 3days = 3960w
3960w / 1200w per 100ah 12v battery = (rounded up) 4 batteries = 4800w
4800w/5hours peak sun = 960w minimum array to charge in 1 day (5 hours)
at 24v I’d need a charge controller capable of 42a so a 60a charge controller.

This doesn’t account for any inefficiencies, but I’m hoping that my built in over sizing will negate those. With this setup I only have to wait 15 minutes if I’m not on site, and when I am onsite, if I need more online time, I can reconfigure the schedule to as much as 24/7 and have enough power for 36 hours after which I could hookup the Ford F-150 pro power generator and recharge that way.

Thanks in advance for any insights.

I guess my question is where do you live that stipulates permits for 48v but not 24v?

 

[shavermcspud]

As a Satrlink user here in the UK powered by PV and battery, its not a good idea to cycle the unit on and off every 15 minutes, from reports I have seen this will case the dish to think it has obstructions and you'll end up going in to a failsafe mode. The only real way to do this is via stowing and unstowing the dish as needed, but this needs to be done from the app on your phone. Add in to the mix that Starlink has no publicly routable IPV4 and is based on GCNAT, so you'd have to work around the outbound tunnel issues every time it is powered back on, I have found power usage when not doing anything is 60-80 watts with the heater off. It does sound like you would be better to go for a 48V system if you can work the permit issues.

 

[shaines]

Assuming you mean Wh

Thank you sunshine_eggo for taking the time to reply. Yes I did mean Wh. My only defense is the lateness of the hour when I posted. Lol

3960Wh/0.85 (ineff) = 4,659Wh

Another poster recommended I account for 15% inefficiency for the inverter. Is that what this is?

Assuming you're using LFP batteries. LFP are generally rated for 80%DoD, so you'd need:

4659/.8 = 5823Wh, so go with 5 batteries

Correct again, LFP batteries it is. Don’t I need an even number of batteries for 24v, or should I just stay at 12v?

5823Wh/5h = 1165W



You'll rarely charge at 24V. Majority of LFP charging will be in the 27.2 -27.6V range.

1165W/27.4V = 42.5A - no need to go all the way to 60A. 40A and higher would be fine. It will be rare that your array actually puts out 1165W.

Thanks again, I’ll incorporate this info into the final design.

 

[shaines]

It sounds like you will have a small inverter and the small inverters are not very efficient. I would plan in at least a 15% loss for the inverter.

Yes, while I haven’t settled on any of the equipment yet I will likely choose a very small inverter for such a small load. I’ll incorporate this suggestion into the final plan. Thanks!

 

[shaines]

why not jsut add a few more panels strategically aimed to lengthen out your solar day? current panel prices are stupidly cheap, its easier to add panels and a couple fo batteries and you could run 24/7 if you wanted.

Short answer: Happy wife, happy life. Longer answer: The best place for the dish is in the view shed, and I have been told in no uncertain terms that a field of solar panels is not what she wants to look at. I’m going to build a small structure to house the equipment and I’ll be limited to 2 (maybe 3) panels on the roof, and 2 (maybe 3) panels on the ground. Thanks!

 

[shaines]

As a Satrlink user here in the UK powered by PV and battery, its not a good idea to cycle the unit on and off every 15 minutes, from reports I have seen this will case the dish to think it has obstructions and you'll end up going in to a failsafe mode. The only real way to do this is via stowing and unstowing the dish as needed, but this needs to be done from the app on your phone. Add in to the mix that Starlink has no publicly routable IPV4 and is based on GCNAT, so you'd have to work around the outbound tunnel issues every time it is powered back on, I have found power usage when not doing anything is 60-80 watts with the heater off. It does sound like you would be better to go for a 48V system if you can work the permit issues.

Thanks for the heads up, I had not heard that before. I’ll have to try and contact Starlink to confirm.

 

[SparkyJJO]

I have never seen one, but does the Starlink dish just have a 120V power cord (or 240V, i don't know where you live), or does it use some sort of power brick to bring the mains voltage down to 12V or 24V DC? Could maybe avoid inverter efficiency losses by direct wiring, or a DC/DC converter, perhaps.

So you don't have a structure built yet? Make it have a big enough roof to put four 400W panels on it. Or maybe 6. A covered porch area, just because

 

[Samsonite801]

On mine, I am currently running the Starlink equipment in the original configuration with 120v input using a Bestek 300w inverter, and the 12v draw is around 4.25a...

Bestek inverter:

https://www.amazon.com/gp/product/B07KQ4Q2L5

I did buy a McCown POE so I could cut the cable (it is a typical cat5e/cat6 cable spec, 4 twisted pair), put on an RJ45, use the POE to inject my own power on the data cable to the dish (delete the Starlink router), and run my own router.

I haven't installed it all yet. I already modified a spare Starlink cable I acquired and terminated the splice on the cable-end leading to the dish with an RJ45 end (568B termination).

McCown POE (has jumpers to set proper polarities for the Starlink equipment, which is 1,2,3,6 + and 4,5,7,8 -, which is left 2 jumpers on left pins, and right 2 jumpers on right pins in the McCown POE):

McCown Technology Corporation 800-GIGE-POE GbE PoE Surge Suppressor High Voltage

KEY FEATURES:Outdoor GigE protector with midspan PoE insert/extract. Any polarity on any pair - total flexibility. Faster acting than Thyristor and Gas Tube only designs

www.streakwave.com

TDK Lambda buck/boost DC-DC Power Supply I purchased, (9-53v input, 9.6-48v screw-pot adjustable output):

https://www.mouser.com/ProductDetail/TDK-Lambda/i7C08A-C03-EVK-S1?qs=GedFDFLaBXH3lM7yP7jCZA%3D%3D

There are several FB and Reddit threads on doing this POE mod, to allow to run on DC power direct. The Starlink POE line-voltage requirement for the dish power is 48-56v (longer cable runs, better to shoot for higher end of range)...

I've been busy with bigger fish to fry for now, so I haven't switched it over yet, but it should save around 30-50w or so (more if dish heating is running).

A friend of mine here in town got his Starlink all running on his RV using my advice, and he says it works great running on DC through the POE mod cable and power supply. He did have to add a static route on his router for 192.168.100.0/24 so the phone app would still be able to connect to the dish and pull information (since he deleted the Starlink router).


For now, until I get the POE mod installed:



Reference on Starlink cable:

 

[shaines]

I guess my question is where do you live that stipulates permits for 48v but not 24v?

I live in Maryland. While talking with the permitting office for our “shed”, I mentioned solar power and was told 12v and 24v systems were considered low voltage and no permits were needed. Above that requires permits and electricians.

 

[shaines]

On mine, I am currently running the Starlink equipment in the original configuration with 120v input using a Bestek 300w inverter, and the 12v draw is around 4.25a...

It seems everyone else is using way less power than I am. I’m wondering if it’s because it’s just become available in my area and for some reason has to work harder than in other areas.

Bestek inverter:

https://www.amazon.com/gp/product/B07KQ4Q2L5

Thanks for the suggestion!

I did buy a McCown POE so I could cut the cable (it is a typical cat5e/cat6 cable spec, 4 twisted pair), put on an RJ45, use the POE to inject my own power on the data cable to the dish (delete the Starlink router), and run my own router.

I haven't installed it all yet. I already modified a spare Starlink cable I acquired and terminated the splice on the cable-end leading to the dish with an RJ45 end (568B termination).

McCown POE (has jumpers to set proper polarities for the Starlink equipment, which is 1,2,3,6 + and 4,5,7,8 -, which is left 2 jumpers on left pins, and right 2 jumpers on right pins in the McCown POE):

McCown Technology Corporation 800-GIGE-POE GbE PoE Surge Suppressor High Voltage

KEY FEATURES:Outdoor GigE protector with midspan PoE insert/extract. Any polarity on any pair - total flexibility. Faster acting than Thyristor and Gas Tube only designs

www.streakwave.com

TDK Lambda buck/boost DC-DC Power Supply I purchased, (9-53v input, 9.6-48v screw-pot adjustable output):

https://www.mouser.com/ProductDetail/TDK-Lambda/i7C08A-C03-EVK-S1?qs=GedFDFLaBXH3lM7yP7jCZA%3D%3D

There are several FB and Reddit threads on doing this POE mod, to allow to run on DC power direct. The Starlink POE line-voltage requirement for the dish power is 48-56v (longer cable runs, better to shoot for higher end of range)...

I’ve been thinking about going this route, but definitely not confident enough yet to make any cable cuts. Where did you score an extra Starlink cable?

I've been busy with bigger fish to fry for now, so I haven't switched it over yet, but it should save around 30-50w or so (more if dish heating is running).

A friend of mine here in town got his Starlink all running on his RV using my advice, and he says it works great running on DC through the POE mod cable and power supply.


For now, until I get the POE mod installed:

I’ll likely spend this season tinkering in “temporary” mode, and next season building the permanent installation. Thanks for the advice!

 

[Samsonite801]

It seems everyone else is using way less power than I am. I’m wondering if it’s because it’s just become available in my area and for some reason has to work harder than in other areas.

Not sure if this is a factor for you or not, but I disabled the dish heater setting on mine (in the Starlink app) since it isn't really necessary right now here. I remember when the dish heater was enabled, on boot-up of the Starlink, I would see the amps go up to 7a or so, for several seconds, then level back down to 4-ish amps (thinking it was doing a self-test of the heater circuit at bootup).

Thanks for the suggestion!

The Bestek 300w is certainly cheap enough. I did get 2 of them to have a spare here in case, since I work remote from out here, but this one seems to be working well for the money so far. But this allows me to leave the big 2800w inverter in my motorhome turned off so it isn't idle drawing all the time.

I’ve been thinking about going this route, but definitely not confident enough yet to make any cable cuts. Where did you score an extra Starlink cable?

I bought a whole Starlink kit on eBay (won bid of $23.50) where they had dropped the dish from 3 story building and that part was completely destroyed, but the router and cable were in new condition.

EDIT:
You can also buy Starlink cables from their Shop page for $64 bucks, to have a spare you can cut...

Starlink

shop.starlink.com

I’ll likely spend this season tinkering in “temporary” mode, and next season building the permanent installation. Thanks for the advice!

Yeah, that's kinda what I'm doing since right now since I'm more busy working on my main solar system for the RV, getting the panels installed, batteries, Victron CC's all wired in (so I don't have to run the generator anymore), then later when I get caught up, I can switch over to the POE cable and power supply.

 

[shaines]

I have never seen one, but does the Starlink dish just have a 120V power cord (or 240V, i don't know where you live), or does it use some sort of power brick to bring the mains voltage down to 12V or 24V DC? Could maybe avoid inverter efficiency losses by direct wiring, or a DC/DC converter, perhaps.

I’m in the US, our version comes with a 120v power cord that plugs into the modem, and the modem powers the dish with I believe 56v POE. I could be wrong on that voltage. There are people who have made the mod to run on DC, but I’m not ready to undertake that yet.

So you don't have a structure built yet? Make it have a big enough roof to put four 400W panels on it. Or maybe 6. A covered porch area, just because

No, no structure built yet, but I have size limitations to stay under unless I get permits and that would be messy because this area is technically in the flood plain. Never mind that it would take biblical proportions of water to flood here. Lol. I like your thinking though and we have been considering building a pavilion. Because a pavilion doesn’t have walls it’s easier to permit, and because it allows water to flow around/through it, it is also ok for the flood plain. That could be any size I could afford.

 

[sunshine_eggo]

Thank you sunshine_eggo for taking the time to reply. Yes I did mean Wh. My only defense is the lateness of the hour when I posted. Lol

I feel your pain

Another poster recommended I account for 15% inefficiency for the inverter. Is that what this is?

Yes.

Correct again, LFP batteries it is. Don’t I need an even number of batteries for 24v, or should I just stay at 12v?

DOH! I overlooked the odd number in a 24V config. Since you're not pulling high power, 12V would be an option, but that would double your MPPT current requirements.

Comes down to which is easier:

1. go with 4 and have a little less than the 3 day need.
2. go with 5 and have the 3 days, but spend more on MPPT
3. go with 6 and have 3+ days.

 

[grizzzman]

Is this a round Dishy or the newer rectangle unit?

 

[Samsonite801]

One advantage about going with a DC / POE conversion, is you can use the buck/boost DC-DC converter (in my case the TDK Lambda) which offers flexible input voltage (9-53v), so you can start with a 12v battery system, and later transition to 24v or 48v battery voltage later, and the DC converter doesn't care, it still just works no matter what you feed into it (I made sure the DC-DC converter I selected is capable of both buck and boost in same unit).

I am already in the works building a standalone outdoor repeater site for my Starlink, so I can set up mobile Ubiquiti AC clients up on my vehicles and get internet anywhere on our co-op ranch property which is more than 1200 acres. I will also be able to set up fixed clients for security cameras, remotely starting and monitoring irrigation pivots, etc...

Here is the outdoor box I am building based on a 48v system (will use with 2 405w solar panels in series):


The 2 TDK Lambda DC-DC buck/boost converters are on left side (8 amps each, will set one for 48v output for Starlink and other one for 24v output for the Ubiquiti gear), with some other POE modules I have on right side, will power 1 Starlink, 1 Ubiquiti router, and 3 Ubiquiti Rocket AC radios and 3 120-degree sector antennas (up on a tower). The 4 AGM batteries are for POC testing, may switch to LFP with heater solution later on...

 

[Nobodybusiness]

I live in Maryland. While talking with the permitting office for our “shed”, I mentioned solar power and was told 12v and 24v systems were considered low voltage and no permits were needed. Above that requires permits and electricians.

That’s insane.
Glad I don’t live in such a Draconian district.