Can I cut the power cord to, say, an Archer C7, or other similar TP-Link router, and connect the exposed ends to a 12V battery, and expect the router to work for various years? Would voltage fluctuations (12.2 to 14.5 VDC) damage the router? I would actually connect it to the load output of the charge controller of a 12v solar photovoltaic system, which might offer steady 12V, or might just pass through the battery voltage. If the Archer C7 or similar would be a bad idea, what might be better?
I see that the CPE 210/220 and 510 use 24V passive PoE, with a 16-27VDC acceptable input range. So that could work with a 24V battery, but how well would it serve as a WiFi router for 10 simultaneous clients?
It depends on the power circuitry inside the device. Over-voltage may or may not be tolerated, so without knowing the tolerances of the actual input to those circuits, it's hard to know if there could be damage. Also, consider what happens if you go somewhat below 12V -- this will have the potential to brown-out the device (usually this won't damage it, but it will often experience issues).
Same deal here, although at lest you've got the tolerances.
Generally spekaing, you should always have a basic DC voltage regulator in front of the load. You can get DC-DC regulators that are quite efficient and relatively inexpensive. So yes, you could power these devices from batteries, but you should not do it directly -- do it though a regulator.
You may want to buy a unit specifically designed for powering routers:
I am sure something equivalent also exists in your country.
Alternatively, use a powerbank compatible with the QC3.0 standard + a 12V QC trigger cable - but note that powerbanks usually do not support pass-through charging in the QC mode:
No.
Every time you start the vehicle, you are going to brown-out the router.
You need a regulator, just like psherman said.
I cannot even recommend pure sinewave inverter if your intention is to run the router 24/7 as implied. Inverters are inefficient if we are talking 12v->120v->12v and would still brown-out when you start the vehicle.
You will need a regulator and you will need to power off the router before you start the vehicle.
And leave the solar panel out of your equation; it, needlessly complicates your circut.
Yes I have done this a lot with a 12 volt battery. 24 volt batteries under charge will go up to more than 29 volts which is usually above the maximum input rating of the regulator chips in the router.
Don't connect directly to a vehicle 12 volt system as there are really bad surges on that system.
Be absolutely certain you have the polarity correct as there is no protection in the router against reversed input, and it will completely ruin it.
I also connect routers to a 12 V battery in a solar powered system. Of course the power input specification on these devices are in fact 12 V. The power fluctuates between 11.7 and 14.7 normally.
The output from the charge controller will never go below 12.5V, and probably not below 13V. The charge controller has programmable low-voltage cut off. I don't know if this would qualify as a brown-out. My intention is to install an adequate solar panel and battery such that low-voltage cutoff is never reached. I have see what might have been a brown-out mess with a Starlink router in a different installation.
I'm in Ecuador. The easiest DC-DC regulators to get are the ones made for automobiles, that do 12->24 and 24->12. Maybe I could find a 12->12 or 24->24. This regulator idea sounds wise.
This looks neat -- a 12VDC -> 12VDC voltage regulator with a little battery.
It's hard to trust that anything here in Ecuador is actually compatible with the QC standard, so I'm not going to try this.
I made no mention of any vehicle. My only vehicle is a canoe, and it doesn't have batteries. (Will my canoe have a router someday? Maybe). The solar panel is on the roof of a house, and this entire installation will be in a house. The only things connected to this battery will be a router and a PTP radio, or maybe even just the PTP device functioning as a router too, and maybe a cell phone to charge. No motors, blenders, TVs, fridges or anything else will be connected.
Thanks for pointing that out! I'll make sure to use a voltage regulator, especially with a 24V system.
@mk24 and @lleachii and others, what devices have you connected to batteries? The brands easiest to get here in Ecuador that have some compatibility with OpenWrt are TP-Link, MikroTik, Ubiquiti. Sometimes I can get LinkSys, D-Link, or other brands.
You can build a 12 V UPS using battery and charge controller cheaper than you can purchase an AC-based UPS - so I do this instead of purchasing a consumer UPS device.
You shouldn't suggest this. "Pure since wave" implies AC is somewhere in this system. The OP doesn't need to use the AC wall wart provided if it's a DC device. They just connect the router to +12VDC and -12VDC.
Yes indeed. I found the specs on the manufacturer's websites. For TP-Link, their website says the Archer C7 uses a 12V 1.5A power supply, which gives a max of 18W. For actual power consumption, I checked The Power Consumption Database TP-Link page, and found the routers use 1W to 10W, with the AX21 using almost 13W. Mikrotik gives max consumption data on their site, and most range from 5W to 20W -- those are all capable of powering over passive PoE, so I assume they're used to battery situations.
Just to see if we're talking about the same sort of batteries: I'm not using a portable battery bank. I'm using deep-cycle lead-acid gel batteries that are 12V 100Ah and weigh 32 Kg and cost $230 USD, because I want to power a 20W load for 24 hours even on very rainy days. At a 50% discharge, I get 600Wh of usable energy from a full charge. I'm curious what kind of battery and in what situation you're using the QC or PD systems with. I see things like the Anker portable chargers that cost $26 (in the US) and have 36Wh total capacity (lithium, not lead), that would power a 20W load for about 100 minutes. Where I am, there's only the energy from the solar panel, no powerlines. There is a gas-powered generator for larger loads. That QC cable that @patrakov mentioned, I could use that if I had a circuit that turned the battery power into QC power -- I'm sure these exist, but I don't have one. The DC-DC regulator from the automobile parts store seems like my best, cheapest option.
20W average load is a major overestimate. I would get a USB-PD to DC converter, they are a few bucks, and use an external battery pack like you've mentioned with passthrough charging.
@anon_openwrt
If I want to power a 7W Mikrotik LHG and a 10W router, and occasionally charge a cell phone too (5W-30W), and take into account the system inefficiencies (fortunately pretty high efficiency in this case since I won't use an inverter, but the DC-DC regulator isn't going to be 100% efficient, and there's cable loss), then thinking about a 20W load in this situation is reasonable. When you say "passthrough charging" that assumes that there's some other energy source to charge from, and as I said, there's no other energy source here. No power lines, no grid, no public utility.
As much as I appreciate the suggestions, I have already decided how to generate and store electricity.
Really, what I came here for is advice about specific router models that people have successfully powered from batteries, with or without a DC-DC voltage regulator, and whether those routers (TP-Link routers especially, and especially the ones that don't support PoE) are likely to get damaged by connecting them to a battery without a voltage regulator in between, and that question has been partially answered.
@pfassberg , did you use a DC-DC voltage regulator for the C7, or just connect it directly to the battery? Did you use a battery like mine, or a portable charger lithium battery?
@lleachii , were any of those routers not PoE? Did you use a voltage regulator?
No voltage regulator is needed, it's a 12 V solar/battery system. In all cases, I merely cut the wire to the wall jack. I wired positive to positive and negative to negative. I purchased a pack of CCTV male/female power terminals to make the connections clean. I used an ohmmeter to ensure that I was connecting +/+ and -/- and then verified the final wires before inserting into the router.
As a helper, usually, the tip is positive, and the ring is negative. Learn the terms if you don't know them. Also learn to read the diagram on DC devices with barrel connectors that explain if tip or ring is which.
The whole system is negative-grounded/Earthed. I have a device going for years.
I think the MikroTiks had PoE; but again, I used the 12 V connector.
You mentioned you had a charge controller already for this setup, correct?
And the device you have or intend to use is 12 V, correct?
They're just like any other 12 V device on planet Earth.
BTW:
On a charge controller, I connect the router into the LOAD power block, not the BATTERY block.
Feel free to place like a 1 or 2 A a fuse inline if you desire, - a blown fuse is cheaper than the equipment.
PoE is usually 24V or around 44-57V depending on what PoE standard in use. But that voltage is used to reduce the current in the tiny ethernet cables so they don’t melt.
But the actual router circuitry is pretty much guaranteed to run on 5V and/or 3,3V so if the device have 12V PSU there is a voltage regulating circuitry inside the router somewhere.
So the question is actually what the minimum input-output voltage difference and maximum input voltage is for that regulator to be able to regulate the output voltage within specs.
The thing with 12V PSU is that there are so easy to find and buy in massive numbers so they are pretty much standard on everything not needing higher voltage.
This product does not contain a 12VDC -> 12VDC voltage regulator. The input voltage is passed to the output using a low-drop MOSFET, and the output will, therefore, repeat all the irregularities of the input.
I'm using group size 31 truck batteries these are about the same capacity and cost a lot less if you don't mind the wet cell construction. It's also possible to find used ones that can no longer start a truck but will still run a router for a long time.
On a charge controller, I connect the router into the LOAD power block, not the BATTERY block.
- a blown fuse is cheaper than the equipment.