Battery Voltage Vs External DC input

Status
Not open for further replies.

N0UDG

Member
Premium Subscriber
Joined
Aug 1, 2011
Messages
850
Have you noticed that in none of the scanners that use internal batteries does the battery voltage (when added up) match the DC volts delivered to the scanner (as stated on the side of the scanner) via a wall wart or USB cable. Although the 436 seems to come the closest.

For example the HP-1 uses four batteries but on the side of the scanner it is stated that it uses 9 Volts DC.
 

JamesO

Member
Joined
Jan 22, 2003
Messages
1,813
Location
McLean, VA
External Voltage needs to be higher than the battery cell Voltage in order to charge batteries internally.

Some of the scanners do use less than 12 Volts so the internal circuitry does not need to shed the load as extra heat.

So for example I think the HP1 and 396XT use less than 12 Volt input even in the car with a DC feed.

You will likely never see the DC adapter equal the cell Voltage if charging is required, will usually be a few Volts higher.
 

josh2484

Member
Premium Subscriber
Joined
Dec 28, 2014
Messages
21
External Voltage needs to be higher than the battery cell Voltage in order to charge batteries internally.

Some of the scanners do use less than 12 Volts so the internal circuitry does not need to shed the load as extra heat.

So for example I think the HP1 and 396XT use less than 12 Volt input even in the car with a DC feed.

You will likely never see the DC adapter equal the cell Voltage if charging is required, will usually be a few Volts higher.
Does anyone think there is an advantage to using DC power vs. batteries as far as scanner performance is concerned?
 

jonwienke

More Info Coming Soon!
Premium Subscriber
Joined
Jul 18, 2014
Messages
9,753
Location
PA
Does anyone think there is an advantage to using DC power vs. batteries as far as scanner performance is concerned?
No. The internal voltage regulators will feed the circuit board with constant power until input voltage drops below spec.
 

josh2484

Member
Premium Subscriber
Joined
Dec 28, 2014
Messages
21
No. The internal voltage regulators will feed the circuit board with constant power until input voltage drops below spec.
Thank you! I was wondering, just rec'd my power supply after running through my weight in batteries lol
 

WQPW689

Member
Premium Subscriber
Joined
Jun 9, 2014
Messages
318
Location
Palm Beach Co., FL
Thank you! I was wondering, just rec'd my power supply after running through my weight in batteries lol
I hear you. Power is fine in the house, but the best thing you can do if you use the 436 in the car is get yourself a good battery charger like a Maha or LaCrosse and run off reliable rechargeables.

I'm always leery of forgetting to turn the scanner off when I shut down the engine and then restarting and frying the scanner because of a stray voltage surge.
 

josh2484

Member
Premium Subscriber
Joined
Dec 28, 2014
Messages
21
I hear you. Power is fine in the house, but the best thing you can do if you use the 436 in the car is get yourself a good battery charger like a Maha or LaCrosse and run off reliable rechargeables.

I'm always leery of forgetting to turn the scanner off when I shut down the engine and then restarting and frying the scanner because of a stray voltage surge.
Is it legal in your area to listen in the car? Kentucky has some strict laws, which I just recently read ugh
 

WQPW689

Member
Premium Subscriber
Joined
Jun 9, 2014
Messages
318
Location
Palm Beach Co., FL
Is it legal in your area to listen in the car? Kentucky has some strict laws, which I just recently read ugh
I have an amateur radio license so I'm OK in Florida. The law is on the books that those who aren't hams can't use scanners in their cars (or businesses for that matter, go figure) but I can't remember the last time it was strictly enforced.

Not sure what the exact law is in KY, but if you have the ham license, FCC regs overrule State law, as long as you're not using the scanner to further a criminal act.

Edit: There's always a wildcard, and in this case, it's the State of New York. Their law is written in such a way that it can be interpreted that only an actual transceiver can scan the airwaves while in a car. It's led to some conflicting State Court decisions on the legality of receiving only scanners, which is still up in the air. Practically speaking, I've got a lot of Staten Island buddies who've been happily scanning in their cars for years.
 
Last edited:
Status
Not open for further replies.
Top