Starlink power without an AC/DC inverter

[sob]

I need to be able to power the StarLink High Performance Dish without the use of an AC/DC inverter.

Proposed Solution

A clear and concise description of what you want to happen.

Alternatives considered

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Additional context

@jon-dutch take:

You'll never be able to power that Meanwell power brick of a standard 12v system. Even with a LiFePo4 battery the best you can hope for is roughly ≈15vdc. Your best bet will be to make a small 24vdc battery back specifically for running the Starlink PoE. 320w is a lot of power, though, so it may be worthwhile to convert your whole house battery setup to 24v. The upside: don't need to change the wiring as you can use small awg wires for 24v systems. The downside, obviously, will be sorting out all the other stuff to run on 24v... If you use 4 batteries and run them in a 2s2p 24v system configuration, then you could probably pull 48v direct (running a specific circuit as 4s) just for the Starlink, and run everything else at 24v.

[sob]

@jon-dutch could I go with something as small as this: https://dakotalithium.com/product/dakota-lithium-12v-7ah-battery-69/ 5.94"x 2.55"x 3.74"? Obviously the tradeoff would be aH capacity but I could look for space for 4 of these to try and keep the cost low?

Another idea would be to run this as 48v and then replace the under hood battery with this to keep 12v and 48v separate?: https://dakotalithium.com/product/dl-plus-12v-135ah-dual-purpose-1000cca-starter-car-truck-battery-plus-deep-cycle-performance/

[jon-dutch]

Not sure what you would be gaining by swapping out your start battery with the DL 135?

For the first option, yes, technically a pair of those would work, but you'd probably get about ~30m Starlink usage without being charged. Depends on how much the Starlink is pulling at any given time, but at 320w draw and those batteries only being 84wh, at 24v you'd still only have 168wh budget. Then you'd have to calculate for the losses of the Meanwell brick, too. If you run a 48v pack then you'd at least get an hour of off-grid usage.

Once we start mixing voltages we will need to be sure charging is sorted properly. For charging, you could with something like this, which would allow you to keep a 24v pack topped up with the alternator (or get one from DL, as they also have options):

Victron Energy Orion-Tr Smart 12/24-Volt 15 amp 360-Watt DC-DC Charger Isolated (Bluetooth) https://a.co/d/9xfypUL

I do think a total 24v system is not a terrible idea. If you want to get away with a smaller system, then I'd say go up a level on your small DL option to 2x 20Ah models. This would give you 480wh @24vdc, which is a better budget to pull from. You can also still pull 12v from one or both batteries, if you wanted (if need to map that out to be sure it won't fuck up charging, though).

[jon-dutch]

Was there a reason something like this wouldn't meet your needs?

https://a.co/d/iV2CzJZ

I remember we had talked about this last year, with your initial installation, but can't remember what the outcome was?

[sob]

I think we had originally planned on something like this but the POE injector page specifically recommends that Mean Well one, says it needs to be a high quality one. These no name buck converters make me a little nervous sometimes.

• Sean

On Apr 3, 2024, at 5:24 PM, jon-dutch @.***> wrote:

Was there a reason something like this wouldn't meet your needs?

https://a.co/d/iV2CzJZ

I remember we had talked about this last year, with your initial installation, but can't remember what the outcome was?

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[sob]

I've brushed off the old power calculations to see if I can plan this out a bit better and if it would make sense to have a 48v house battery that just powers the StarLink at this point: Google Sheets

I'm unsure of the power usage between Row 2 & 3. If the power supply pulls 320w, it's obviously not doubled to the PoE injector. So do I just simply use 480w or 320w and calculate the aH usage just one time?

[jon-dutch]

So, I am still thinking a 24v battery for everything, makes the most sense. You can always create a 24v-12v branch to run most of your current 12v clients. Then run the Meanwell to get 48v for the Starlink.

As far as sorting out your calculations, remember that you shouldn't ever hit the 480w of the Meanwell, if the client is only rated to 320w max. So, you'd likely be closer to ~343w usage, after considering efficiency losses (heat). Also, those should be peak numbers, unsure what you'd be figuring for standard usage. Have you taken any measurements of real world usage yet?

Lastly, for all your calculations, be sure you're making those at the source voltage: so you'd want to add some columns to get the calculations for what you'd be seeing running a 12v pack vs a 24v.

[sob]

Hey, can you take a glance at those power calculations? I'm thinking a single 24 V 100 amp hour battery will be sufficient and I can stash it behind one of the walls.

Would it be better to build a base for it and mount it under one of the seats?

[jon-dutch]

I added some comments to the Google Sheet, added a 24V column on one table, and tried to correct some assumptions.

I still think, even after corrections, that a single 100Ah battery is too small. Especially if you have a fridge on there. That said, if you're happy starting the motor every 10-12h to charge the battery, then maybe it'll be fine. If you're running enough solar you might be able to offset enough usage to make it through a day. That's putting a lot of faith and hope into solar exposure and output.