Powering a 19V 45 W Router from 12V batteries and solar array?

JT Strickland

Very Senior Member
How could I do it? Will one of those little digital variable voltage step up transformers do the trick? Is that all I need, or are there pitfalls with this?
I can't find a non-variable one that meets that criteria, except for a 120V, and one of those came with the router, no help there. Or I don't reckon there is.
I need a node out of my grid tied zone. I could run it thru the inverter, but rather not. Seems like a waste to convert to AC then back to DC.
Thanks,
jts
 

Tech9

Part of the Furniture
I missed the opportunity to test it for you, but my AX86U has 19.5V 2.3A PS and a new AX86S came with 12V 3A PS. There is a good chance both routers will work properly with 12V 3A. Nothing inside uses 19V, all step down converters to different PCB components like in other Asus routers.
 

Tech Junky

Very Senior Member
In my case I wanted to make my laptop run off USB for power. I also wanted to make my 5G gateway portable. With the laptop being upward of 180w when fully engaged and usb-pd only going to 100w it seemed like a hurdle but, when looking in hwinfo running normal stuff the system only really hits about 60-65w. Picked up a CLA / Power bank and started testing with a USB-C to DC 2.5*5.5 cable. Once I found the best cable it was a cake was a cake walk.

Cable is less than $15
CLA I think was $40
Power bank $80

Mind you I'm shooting for 100w output so, it would be a bit cheaper for 45-60w.
 

JT Strickland

Very Senior Member
My RT-AX86U's say 45 watt max. I've got an AX3000 on the way, and I don't want to take a chance on frying it. I expect it may not need quite that much. If I can supply a steady 45 watts DC I think it will work fine, but I'm going to test it first on an old RT-AC86U that lightning got the WAN port. It works OK, just have to do a "dual" WAN with the LAN port as primary.

I upped to the AX3000 because others say that an AC86U may not mesh well with two RT-AX86U's. I need to pick up some security cameras near the edge of my current 2 router mesh. I started to get an AX55U, but didn't see that in Merlin's downloads.
 

Tech9

Part of the Furniture
My RT-AX86U's say 45 watt max.

They have 45W power supplies. With no USB powered drives attached the power draw is about 10W. You can't fry the router with lower voltage. I strongly believe no convertors are needed in your case. Just power the AX86Us with 12V from a source with 3A max current or more.

but I'm going to test it first on an old RT-AC86U

AC86U works fine with 12V power supply.
 

Tech Junky

Very Senior Member
45 watt max
Ok, for instance my 5G box came with an adapter that has 3 options for power. 1a/2a/3a for 15/30/45w output. I put a power meter on the line and it only needs 5w of power. I already had a power bank that was capable of 100w but it wouldn't power it because it didn't supply 15v. I could power it with an ac adapter, TB port, and USBC.

So, it needed the 15v but not the high amps. The amps drop to accommodate the power needs. So, if the router needs 19v but only 45w max it will negotiate that with the power supply.
 

Tech9

Part of the Furniture
So, if the router needs 19v but only 45w max it will negotiate that with the power supply.

The power supply is up to 2.3A and will support any device with up to 2.3A current at 19.5V voltage. There is no "negotiation" between the power supply and the device. The power brick a simple switching power supply with overload protection. Asus routers use 19.5V power supplies for smaller size power adapter and thinner wires. Everything inside the routers is powered through step-down voltage converters with under 12V output.
 

Tech Junky

Very Senior Member
@Tech9

Ok, so, the point I was making is if the device (any) has a trigger point for power up based on the Voltage the amps adjust accordingly if you use an alternate PSU.

I have a few different 100W+ options between AC adapters / power banks / SATA supplemented ports on the TB card. If I plug in something that can pull the full 100W then any of those will provide the full power requirement just fine. If I plug in something that needs less then they downshift to what's being requested.

My laptop only needs ~65W for normal use and I use a USB-C trigger cable that asks for 100W from whatever I have it plugged into. Since the laptop only needs 2/3 of that it regulates to the level it needs not the full 100W. If I engage the GPU it want to get 180W to power / maintain the battery at the same time. USB-PD doesn't allow for this currently so whatever it's plugged into just flaps the power being supplied continuously until the demand comes down under 100W.

https://www.amazon.com/gp/product/B08FRC39F4/?tag=snbforums-20 - using this cable
https://www.amazon.com/gp/product/B09SH2CNP3/?tag=snbforums-20 - wall charger
https://www.amazon.com/gp/product/B089FC1TRF/?tag=snbforums-20 - wall charger
https://www.amazon.com/gp/product/B09HTTSJLV/?tag=snbforums-20 - car charger
https://www.amazon.com/gp/product/B09N3PRJZK/?tag=snbforums-20 - power bank

I don't know what size the DC tip is since no specific router has been mentioned but, you can get cables for ~$10.
https://www.amazon.com/dp/B09G5RXT2C/?tag=snbforums-20
https://www.amazon.com/dp/B07Z1SPR7P/?tag=snbforums-20
https://www.amazon.com/dp/B09MHMJTD6/?tag=snbforums-20

There's more than one way to do power. So, if you're saying all that is needed is 12V then that makes it easier to pair a power option / cable to get a functioning travel router. Or maybe going with one of the gli-net routers that are known to be low power would take the guess work out of it. Basically it boils down to this... If there's a will, there's a way to get to where @JT Strickland wants to get with this setup. It might take a little investigation but, it's doable. It's also not going to require some clunky inverter to get there. Sure, a $5 wall wart would be more ideal than spending $50-$100 but, getting where you want to be sometimes costs a bit more. Keeping it streamlined though might be the goal rather than a rats nest of stuff to deal with.
 

Tech9

Part of the Furniture
to get a functioning travel router.

As I understand @JT Strickland just needs to power home routers from the available 12V source and there is a good chance all he needs is 2x cables with proper power jacks to the routers. This will work, if the power cables are relatively short. If he really wants 19V at the routers, step-up buck converters are available at Amazon starting from $10-12. This approach can compensate for power cables length (read below).

Example:
The price shown is in CAD. This one will power 2x AX86U routers. Ideally the output voltage has to measure 19V at the routers. Longer power cables between the power supply and the routers will cause voltage drop. If this converter powers both routers at the same time, power cables have to be the same length. Again, not really necessary. The routers will be more than happy with 17-19V.


1668355284265.png


Someone left 1-star review for smaller size heatsink heating up a lot under load. This won't be an issue with 2x routers. In normal operation they will need 1A current or 1/5 of what this power converter can provide. There are other options as well. Many different DC-to-DC converters are available.
 
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JT Strickland

Very Senior Member
Yes sir, that was what I had in mind, I ordered one similar to that yesterday, hoping it would foot the bill. I'm still going to try it out on something besides a new router first.
My cord won't be as long as the cord that comes with the routers, so there won't be much loss there.

You must have a supply center closer than me. I don't receive anything any sooner than two days, usually three. :confused:
 

JT Strickland

Very Senior Member
Just measure the actual output voltage.
Well, I just got my AX3000, and it says it's 12V, 2A! Soo, change of plans. Should be easier. I'll try 12V DC with a 2A fuse in the box.
 

Tech9

Part of the Furniture
Yes, some newer models use 12V. I've seen one never AC68U with 12V PS. AX86S is also 12V. I'm sure AX86U will work on 12V too.
 

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