DC UPS

[cTurtle98]

I want to take a 12v lead acid battery (the ones for putting in garage door openers)

 

I want to cut the power cable for my router in half and add the battery there.

 

how do I hook it up? does anyone know of a product that allows me to do this?

 

The router input is 12v and I have run it off of a lead acid battery before I just want to integrate it into the power supply so my router doesen't glitch out during brownouts.

[Electronics Wizardy]

Don't just do that.

 

Lead acid batteries don't run a 12v charged, its more like 13.8. 

 

Id get a standard UPS.

5 minutes ago, cTurtle98 said:

(the ones for putting in garage door openers)

I have never seen a battery in a garage door opener, they all seem to use the standard 5-15 120v plugs.

[cTurtle98]

4 minutes ago, Electronics Wizardy said:

Don't just do that.

 

Lead acid batteries don't run a 12v charged, its more like 13.8. 

 

Id get a standard UPS.

I have never seen a battery in a garage door opener, they all seem to use the standard 5-15 120v plugs.

a standard ups is a lot less efficient  than running DC directly

 

[cTurtle98]

Will this work?

 

https://amzn.com/B005TWE4GU

[cTurtle98]

Will This Work?

 

https://amzn.com/B00JT94D4W

[Electronics Wizardy]

9 minutes ago, cTurtle98 said:

a standard ups is a lot less efficient  than running DC directly

Most home routers use about 10 watts, so this won't make a big difference, id still get a ac ups. these boards don't seems to do much. 

 

Does you router care about getting 13.8volts?

 

You could get the second unit and it should work

[tt2468]

On 10/28/2016 at 10:20 AM, cTurtle98 said:

Will This Work?

 

https://amzn.com/B00JT94D4W

First of all, don't bump. It's an unwritten rule.

 

Also, if you know so much about UPS' and their efficiency, there is NO reason we should be helping you. Obviously you are SUCH an expert.

 

Just get a normal UPS. New ones use only a few watts, which costs only cents a month in power.

[bobhays]

2 hours ago, tt2468 said:

First of all, don't bump. It's an unwritten rule.

 

Also, if you know so much about UPS' and their efficiency, there is NO reason we should be helping you. Obviously you are SUCH an expert.

 

Just get a normal UPS. New ones use only a few watts, which costs only cents a month in power.

He posted within 20 minutes of his original post, that's hardly a bump. In fact I only found this post because your reply bumped it. That being said, I agree just get a small ups its much better and simpler.

[Scheer]

On 10/28/2016 at 0:20 PM, cTurtle98 said:

Will this work?

 

https://amzn.com/B005TWE4GU

Yes, just note you need 15-18V input to charge the battery, the adapter that came with your router will not work.

 

Belkin makes a small DC UPS: http://www.ebay.com/itm/Belkin-Residential-Gateway-Battery-Backup-Unit-Rev-B-Model-BU3DC001-12V-UPS-/222293843555?hash=item33c1bede63:g:yYMAAOSwCGVX9HHi

 

 

[knightslugger]

On 10/28/2016 at 0:30 PM, Electronics Wizardy said:

Does you router care about getting 13.8volts?

Most of them don't. the voltage regulators on them work pretty well and can tolerate a wide range of voltage inputs.

[cTurtle98]

15 hours ago, tt2468 said:

First of all, don't bump. It's an unwritten rule.

 

Also, if you know so much about UPS' and their efficiency, there is NO reason we should be helping you. Obviously you are SUCH an expert.

 

Just get a normal UPS. New ones use only a few watts, which costs only cents a month in power.

I dont know very much about it,

 

my grandpa is an electrical engineer and he said its really inefficient to have your powersupply such that you are transforming into dc 12v then inverting back to 120v ac and then another transformer back to dc 12v to go to the router.

 

I was just trying to see if i could come up with a way to fix this problem.

 

I was going to build a custom circut with a battery charger I already have, a battery I already have, and some relays I already have, It got too complicated and I realized that maybe there was something I could buy to do this for alot cheeper than the cost of an UPS, its not possible to just buy part of an ups and I already have part of it.

[cTurtle98]

7 hours ago, Scheer said:

Yes, just note you need 15-18V input to charge the battery, the adapter that came with your router will not work.

 

Belkin makes a small DC UPS: http://www.ebay.com/itm/Belkin-Residential-Gateway-Battery-Backup-Unit-Rev-B-Model-BU3DC001-12V-UPS-/222293843555?hash=item33c1bede63:g:yYMAAOSwCGVX9HHi

 

 

from what I read on the description of that unit i just need to take an old lamp cable and strip the ends and screw them into the input terminal blocs. then I plug in a battery to the battery cables. and I cut the wire with the barrel jack off the transformer that came with my router and strip and screw into the output.

 

it completely replaces the power supply that came with my router

[mariushm]

Guys, chill everyone.

 

Most routers don't go as high as 10 watts of power consumption, if they did they'd heat up a lot. Think around 5-7 watts on average, but it's a good idea to be safe and

The router doesn't work directly with high voltages. The router has some DC-DC converters inside which take the 12v input and convert it down to 3.3v for chips, 1.8v or 1.5v for ram and flash storage (for firmware), and maybe 1.2v for some components like the radio transmitter.

 

So basically there's some tolerance around that 12v value, up and down, but usually there's a narrow range because the dc-dc converters inside are often very optimized for that particular voltage. If the input changes the efficiency drops, the components that are part of the dc-dc converter circuit may vibrate more and make noise, lots of things can happen. Some components may only be able to work up to a particular voltage (for example they may use 16v rated electrolytic capacitors which means the input voltage shouldn't be higher than 15v), the dc-dc converter chips themselves may blow up with more than 15v or something like that.

 

If your router says 12v i'd say the router will probably work just fine with as little as 9v but I wouldn't be comfortable suggesting powering it up directly from a lead acid battery which could have voltage as high as 14v.

 

Next, you'd connect your battery like this 

 

[ battery charger ] --- [ battery ] --- [ voltage regulator to 11-12v ] ---- [ diode  ===|>|-- ]  -----[ cable with jack] --- [ --|<|=== diode ]---- [ router power adapter ]

 

The two diodes act like one way valves, they don't let the 12v from the router adapter go into the voltage regulator after the battery and they don't let the voltage from the voltage regulator go into the router power adapter.

Only one of the two power inputs can work at any point, the one with higher voltage. So if your router's power adapter outputs 12v, you configure the voltage regulator on the battery side to output 11.8v or something like that (very close to 12v that the router won't care). While the router adapter can provide power, its voltage will be higher so it always feeds the router. When you disconnect it from the mains or you lose power in the house, the voltage naturally drops below the 11.8v that's provided by the voltage regulator on the other side so that one takes over and keeps the router happy with 11.8v.

 

There's loads of DC-DC converters on eBay which can step-down (buck) a voltage or step-up (boost) a voltage or both (sepic, synchro) so if you insist on using the 12v battery you could get a cheap step-down regulator and configure it to output 11.5-11.8v or something like that.

On the other hand, you could go for something that makes more sense and holds more energy (depending on how big the battery is) and go for one of those power banks with lithium batteries that basically have the charger built in them ... and you just have to take 5v from the battery bank and use a step-up dc-dc converter to get your 11.8-12v.

here's examples of dc-dc converter on ebay :

 

Step-Down : http://www.ebay.com/itm/Buck-Step-down-LM2596-Power-Converter-Module-DC-4-0-40-to-1-3-37V-LED-Voltmeter-/161476280982?hash=item2598bc8296:g:-kcAAOSwyDxXhIGH (twist that potentiometer and you see on the led display the output voltage)

Step-Down : http://www.ebay.com/itm/Mini-3A-DC-DC-Converter-Adjustable-Step-down-Power-Supply-Module-replace-LM2596s-/151940621403?hash=item23605de45b:g:6NQAAOSwoydWjNqS (more efficient than previous so will use the battery more efficiently but you need to solder wires to it and you need a multimeter to measure the output voltage after adjusting it, because it doesn't have display on the board)

Step-Down :   very efficient but same story, need to solder wires to it and use multimeter to measure output voltage before placing in circuit

 

Step-Up  : http://www.ebay.com/itm/DC-DC-2A-Adjustable-Step-Up-Boost-Power-Supply-Converter-Conversion-Module-NEW-/252566524112?hash=item3ace2350d0:g:Er8AAOSwpLNX8OTT ( works with as little as 2v but probably best to use 3.5v-5v or more , outputs up to 2A, twist the potentiometer to adjust voltage, use a multimeter to measure output voltage first)

 

Step-Up : http://www.ebay.com/itm/2A-Max-DC-DC-Boost-Step-Up-Conversion-Module-2V-24V-to-5V-28V-Output-LE-/281995427806?hash=item41a83cbfde:g:noUAAOSwAvJXBgFO  (this one has both solder points to solder wires at the input, or a microusb to plug a phone charger directly into it if you want)

 

Both : http://www.ebay.com/itm/New-3-15V-To-0-5-30V-Auto-DC-DC-Solar-Converter-Regulator-Boost-Buck-Module-25W-/131161611984?hash=item1e89d75ed0:g:oigAAOxyeZNTQ3zb

 

As for the protection diodes, Schottky diodes would work best, ideally some rated for 1A or more (1A at 12v means 12w, if the router pulls more than that the diode can be damaged). You can recover pairs of such diodes from old computer power supplies, they were used to create the 12v and 5v outputs.

Something like SBR2045 for example would work fine, and has both diodes in a single package and they're good for up to 20A and 45v : http://www.digikey.com/product-detail/en/diodes-incorporated/SBR2045CTFP/SBR2045CTFPDI-ND/1531957

Such components are like this inside:  [1] --- ===>| --[2]-- |<==--- [3]  so you connect the + wire from voltage regulator  to 1 and the + wire of the router's adapter to  [3] and out comes a single wire on 2 which is your new positive wire. You connect the ground wires of your voltage regulator and your router's adapter and have your new negative wire.. and these two wires go in the router.
Other names you may find on eBay if you don't want to buy from reputable distributor SBR1040, MBR2045 , MBR1040, MBR10100 , MBR1045, MBRF1060 and so on .. just make sure what you get is common cathode (that the bars of each diodes are connected internally to that middle pin)

(basically the first two numbers are the maximum current and the following numbers are maximum voltage, so 10100 means 10A, 100v max)

If you want single diodes, 1n5817 are good up to 1A ,1n5820 work up to 3A, SB520, SB 530, SB540 work up to 5A , SB330, SB340 work up to 3A .. you can go nuts on digikey.com or farnell.com/newark.com going through 30k different types of diodes.

 

[Scheer]

On 10/31/2016 at 2:52 PM, cTurtle98 said:

from what I read on the description of that unit i just need to take an old lamp cable and strip the ends and screw them into the input terminal blocs. then I plug in a battery to the battery cables. and I cut the wire with the barrel jack off the transformer that came with my router and strip and screw into the output.

 

it completely replaces the power supply that came with my router

If you are referring to the RioRand one, yes it will completely replace your power supply that came with the router.

 

I would highly recommend to use a three prong AC cord, a spare PC power cable would work nicely, as it gives you the ground pin/wire. With these cheap electronics its always best to play it safe.

 

[W-L]

On 10/31/2016 at 3:52 PM, cTurtle98 said:

-SNIP-

You may want to look into something like this, they also have a larger OpenUPS unit that does the same thing by providing a regulated 12V connection with a power in connection to the board, when power loss is detected it switches over the battery backup mode.

http://www.mini-box.com/picoUPS-100-12V-DC-micro-UPS-system-battery-backup-system?sc=8&category=981

[Scheer]

9 hours ago, W-L said:

You may want to look into something like this, they also have a larger OpenUPS unit that does the same thing by providing a regulated 12V connection with a power in connection to the board, when power loss is detected it switches over the battery backup mode.

http://www.mini-box.com/picoUPS-100-12V-DC-micro-UPS-system-battery-backup-system?sc=8&category=981

I checked into that PicoUPS and it looks like it simply outputs whichever is the higher voltage, between the battery and the power supply. The issue here is that it requires at least a 15V power supply to charge the battery, so the output will be a minimum of 15V which could cause issues with some routers.

 

You could use a step down module to take the 15V down to 12V though.

[W-L]

4 hours ago, Scheer said:

I checked into that PicoUPS and it looks like it simply outputs whichever is the higher voltage, between the battery and the power supply. The issue here is that it requires at least a 15V power supply to charge the battery, so the output will be a minimum of 15V which could cause issues with some routers.

 

You could use a step down module to take the 15V down to 12V though.

Yeah for a 12V supply you will want a buck regulator, the one previously linked by mariushm would work well. 

[corrado33]

In the news in a few days:

 

"Local internet addicted teen nearly kills self trying to make sure internet never goes out."

[cTurtle98]

11 minutes ago, corrado33 said:

In the news in a few days:

 

"Local internet addicted teen nearly kills self trying to make sure internet never goes out."

lol I would