Can I use car battery directly to supply power for my router?

Question

I Have D-LINK ADSL router that needs 12V/1A DC power, I want to give it power from my old car battery (12V). Is that safe?

Solution

Yes, it is safe as long as you don't short out the battery. The battery's voltage is not an issue, as almost all routers contain an internal regulator, especially when they do not use a lower voltage power supply. However, a better solution would be to get a 12V 1A switching wall adapter with the right connector. Does it absolutely need to be powered by a battery?

Comments

[Moab]

Be sure you get the polarity correct, center pin is usually +, but check to be sure.

[user_1818839]

Be a little cautious - a "12V" car battery puts out considerably more than 12V, you may want an LDO regulator between battery and router, especially if the router datasheet requires "12V +/-10%". Yes the router may have its own regulator, but if they were cheapskate with the heatsink, it may overheat.

[3871968]

I have dealt with multiple routers that use a 12-volt power supply including one by D-Link. The D-Link one used an unregulated power supply putting out 16V under load. Several others used 12-volt switching power supplies that put out 13-15V under load, so it should be safe.

[Akam]

Because I am in a country that we don't have power 24h/day, I think one car battery will solve this issue for me, and for sure I will recharge the battery at night :)

[3871968]

Yes, this should work then. If this answer is helpful, make sure to mark it as accepted.

[davidgo]

You might want to look at a UPS instead. A UPS can often be had cheaper then a battery, and has built in circuitry (but watch the amp hours). Its certainly cheaper then a battery + charger.

[Jasen]

partly used car batteries can be cheaply from wreckers you;ll need a charger though, probably give longer run-time than a UPS

[Akam]

@davidgo: the car battery life for my ADSL can stand for 20 hours while UPS: I should plug in the adabter for the ADSL to conver 220v to 12 v

[davidgo]

If you have a multimeter you should try measure the actual power draw of the ADSL unit - you will probably find it uses a lot less then 1 amp in reality - Assuming it uses 1 amp 24/7 (unlikely), you will need about 22 amp hour battery in a UPS for a 20 hour runtime - in reality I suspect a smaller one would do fine. Converting 220v to 12 volts is, of-course, inefficient, although probably no more so then your solution.

[davidgo]

@Akam, You should consider leaving the charger (assuming its a decent charger) on the battery 24/7 - this will stress the battery less, be less work then remembering to charge the battery and will effectively emulate an "online" UPS.