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# battery backup for modem2

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## battery backup for modem

(OP)
I am seeking battery backup for modem (DSL & cable) for 12VDC 3Amp.

Is there readily available consumer grade 12VDC battery systems so that we can power our modem and recharge our cell phones/tablets when power goes our?

Otherwise, what is the circuit available to regulate & current limiting. Also splite out lower voltages for USB charging outputs.

I prefer using commercially available rechargable 12VDC lead acid batteries.

### RE: battery backup for modem

There are a number of makers of Uninterruptible Power Supplies, also called UPS. They include A/C outlets; I expect that many offer USB style outputs as well.

### RE: battery backup for modem

(OP)
thank you for your quick replies. Yes, similar, but no need for "uninterruptible". These are industrial grade UPS for office operation, quite expensive units.

just home use for 12VDC battery power the modem and recharge cell phones & tablets.
> have connection for low cost 12VDC lead acid battery
> have both extension to recharge either by 110VAC or car cigarette plug
> have USB to charge cell phones & tablets
> DC female plug to power modem

quite like this mini DC UPS, but use inexpensive 12VDC rechargable lead acid battery

https://www.amazon.com/Application-Office-Power-Ou...

### RE: battery backup for modem

If you're willing to make a few 12Vdc connections, then this would be relatively trivial to assemble yourself.

On one side, the charging options. You could add solar if you wish.
On the other side, the various DC or DC-DC outputs.
In the middle, the deep cycle lead acid battery.

The specificity of your requirements indicates that you're looking for an off-the-shelf solution.

### RE: battery backup for modem

(OP)
yes, I would rather buy a off-the-shelf item.

but, if needed, I am willing to do some assembling, may be a markatable project and sell on Amazon?

### RE: battery backup for modem

Years ago, I had a somewhat similar unbranded (no name) commercial product. I still have it in my junk box of gadgets. It was intended to address the issue of power failures and cordless telephones. It accepted DC power from the cordless phone's original AC adapter, somehow noted the input voltage (and polarity?), charged up a very small internal lead acid battery, and then adjusted the output voltage to match the noted input voltage. When the power failed, the gadget kept the cordless phone's base unit working for many hours. Of course the cordless handsets have their own batteries.

The only reason that I bought it was that it was on clearance sale dirt-cheap; indication that the market is a tough place. Our ultimate solution was to purchase a desk phone that doesn't need any power other than that provided by the phone line. We may have to walk to the living room during power outages.

Incidentally, our present telephone, internet and one of our TV services, are via fiber optic cable. So the telephone line's power (the 48Vdc power and 90Vac Ringing Voltages) originates in the basement at the Optical Network Terminal (ONT) box. This box has a separate external power supply, and inside the power supply is - guess what? - a 12v 7A-hr lead acid battery to provide back-up so that the optical telephone line still works during power outages.

Like you, I've been eyeing the power supply (conveniently 12 Vdc) going to the connected Internet Wifi Router, wondering if it's worth providing a back-up power supply. Thing is, it's a lot easier to just turn on our smartphone's 'Hotspot' function. So I've not bothered.

Eventually I do plan to set up a 12 Vdc solar power system. But it's quite far down the list.

As I mentioned before, it's a fairly straightforward project. Just be very careful of the risks (e.g. install a fuse near the battery, etc.)

Good luck.

### RE: battery backup for modem

-Ignore this post, it contains incorrect information-
It looks like most of the Uninterruptible Power Supplies (UPS) use 6 volt batteries, however if you really want one that uses a 12 volt battery, take a look at this model: https://www.amazon.com/APC-Smart-UPS-1000VA-Batter...
Unfortunately this model doesn't include USB charging ports.

### RE: battery backup for modem

I've actually never seen a 6V UPS. I've probably torn apart 10 random ones and replaced batteries in about 20 and in one case one had a 6V battery.. two of them in series. :/ Two were 24V with 12V batteries in series. A dedicated USB UPS could certainly use a 6V battery effectively.

Keith Cress
kcress - http://www.flaminsystems.com

### RE: battery backup for modem

YouTube randomly (<- probably not) offered me the following video. The OP might find it interesting.

It's about modifying an inexpensive commercial UPS to extract the 12Vdc directly.

### RE: battery backup for modem

(OP)
Thank you for all your helpful replies. Still searching for off the shelf or easy to modify and assemble solutions

When our power went out caused by storms and triple digit super hot days, we desperately want to
1. Recharge the cell phones, tablets and laptops – 5V USB
2. Power the cable/DSL modem + WiFi router + VoIP phones – 12VDC

Only interested in cheap 12VDC rechargeable lead acid batteries – around $15 to$20
https://www.amazon.com/s/ref=nb_sb_ss_i_1_15?url=s...

Not interested in “Uninterrupted” Power Supplies. Not interested to power 120VAC desktop equipment.

### RE: battery backup for modem

Seems to me that you're underestimating your consumption requirements. If you're planning on actually using two laptops, that's potentially 40W of draw, alone, add in your other items, and your'e looking at less than 3 hours of operation. Let's not ignore the possibly of wanting fans, etc.

I also think that you miss the point of the UPS, which is that they are turn-key solutions for your stated requirements. Moreover, their batteries are ostensibly chosen so that they can tolerate long periods of float charging.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

### RE: battery backup for modem

Hi IRstuff,
You are correct. I always thought those little UPS batteries were 6 volts. Turns out they are 12 volts. The larger UPS used 2 batteries and I thought they were connected in series to make 12 volts. Apparently they are connected in parallel.
I learned something new today.

### RE: battery backup for modem

(OP)
Well, there are laptops and there are laptops.
Microsoft Surface 3 is only 13W, recharge with USB, good for 9 hours. Sorry, no huge massive big screen i7 jobs. We are minimalist.

Why do you expect to get something for nothing? You want a ready made solution by spending what a $20 battery costs... At first I though you were meaning a large flooded lead-acid battery and since then you seem to be under-estimating your power requirements with the link to that cute little SLA battery. It will power just your 12V requirements for 70 minutes assuming you only discharge it to 50% capacity. Add a 2.1A USB device charging and you won't make it to 55 minutes. If the outage is significant then you'd have a vehicle running continuously charging batteries so you might as well just take power directly from it. ### RE: battery backup for modem (OP) I do not recommend to run car to power DSL/Cable modem / router with wifi and ethernet. this car jumper is 8000 mAh / 400A for$32
https://www.amazon.com/gp/product/B0713T64TJ/ref=o...

this mini DC gets 15600 mAh for \$45.39
https://www.amazon.com/gp/product/B073V1W455/ref=o...
It would be nice I can convert this to run off 12V rechargable lead acid battery

This is nearly what would work. Need USB charge output ports. Also need circuit to charge the battery circuit by car.
http://www.ebay.com/itm/DC-UPS-60W-12V-EU-Uninterr...

### RE: battery backup for modem

There's possibility that the SK616 is using 18650 Li-ion batteries, which is actually a plus, in my mind, since those batteries are used in lots of things, like flashlights and headlamps:

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

### RE: battery backup for modem

You mean you don't want to run the car to power the equipment?

The jumper pack Keith linked says 20Wh in the specifications. You'd get <30 minutes of run time powering a 12V at 3A load with that rating. I'm not sure where the 8Ah rating because 96Wh isn't close to 20Wh. Kind of makes one skeptical of the ratings for any similar Li-ion battery device.

You do know that the smaller SLA batteries can't just be connected in parallel with a car battery and then run the car to charge them? At least not without damaging them.

### RE: battery backup for modem

What you show has no battery, so no need to charge that

Your SLA would require a separate charger that would run off your car battery directly or through an inverter connected to your car battery

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

### RE: battery backup for modem

SLA = Sealed Lead Acid (battery).

During extended power outages, unplug the Ukrainian eBay gadget from the wall, and then plug it into a 12Vdc-to-120Vac inverter that is in turn connected to your other source of nominal 12 volts.

But a car idling in driveway for hours or days on end? Not a great idea. You might be surprised how much gasoline an idling car uses. At some point, a very small generator or a solar panel system starts to make sense.

One of the killer features that *could* be offered by future electric cars would be to provide emergency power back to the house during shorter power outages. It would need to be fully integrated, and intelligently controlled.

### RE: battery backup for modem

#### Quote (VE1BLL)

One of the killer features that *could* be offered by future electric cars would be to provide emergency power back to the house during shorter power outages. It would need to be fully integrated, and intelligently controlled.
I thought Tesla had already mentioned something to that effect when they were first coming to market...

Dan - Owner
http://www.Hi-TecDesigns.com

### RE: battery backup for modem

Tesla (Musk) mentions quite a few things. Thankfully he's roughly half-accurate, which in itself is quite lovely.

### RE: battery backup for modem

SLA = sealed lead acid.

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