BCD396T power consumption

[KE5MC]

I have read a couple of posts about battery life. Comments had peaked my curiosity about the power used by a BCD396T so I made a small shim that allowed me to place a current meter in-line with the batteries.

Radio:
BCD396T, purchased 4 weeks ago
ID Scanning Irving & Carrollton, TX system
Using internal speaker set to volume 3

Batteries & Condition:
Stock, fresh charge and reading 3.92 upper right corner of display

Meter:
Calibrated Fluke 8020B Multimeter

Measurement (Backlight OFF):
156-158 mA

Measurement (Backlight ON):
198-200 mA

Measurement (Radio OFF):
32 uA

Audio on/off or volume level made no noticeable change to current level. Only thing I don’t try was using an ear-piece to see if that made a difference. Two-milliamp variation was rapid and seemed to be tied to switching from one system to the other but can’t say for sure.

 

[linuxwrangler]

Interesting. Of course the different draws won't influence how I actually use the thing.

2mA variation is well below the reported accuracy of the meter (+/- .75% of reading + 1 digit). At 200mA, that is +/-1.5mA or a 3mA range plus 1 digit. I'd ignore it.

Some other interesting tests:

Stop on some audio (FM broadcast, weather) and correlate draw with volume and draw with speaker vs. earpiece.

Draw while scanning vs. hold on one channel.

Draw differences if any based on system type being scanned.

 

[XTS3000]

I'd be curious what the scanner draws when camping on 1 channel with the battery saver on. I blew the fuse on my DVM - darnit

 

[KE5MC]

Update to OP

At the request of linuxwrangler & XTS3000 I made some more measurements. This time I am at home so the scanned systems are different and the meter is too.

Battery reading: 3.85
Meter: Fluke 89 IV

Reading with this meter were consistent with the original 8020A reading originally posted but with different trunked systems.

Speaker vs. Ear-piece
FM broadcast, 99.5MHz-The Wolf, Brooks & Dunn, Neon Moon (a personal favorite) - This is TEXAS don’t knock it

External Speaker (used peak detect)
Volume 3 = 160.45 mA
7 = 163.63 mA
Plugged in ear-piece and the reading were the same. Motorola mono ear-piece which I believe was originally intended for FSR radio. It has a DC resistance of 147 ohms and the audio had a slight buzz at the higher amplitude when set to 7.

Scanning vs. Hold
Scanning current was the same as with the 8020A. On hold the readings were 156.30 to 156.52 no audio. Backlight on 201.17 to 201.48. Broke squelch and reading jumped about 2 mA with a volume setting of 3.

Nothing Selected Error
In ID SCANNING mode with nothing selected the reading are 162.25 to 162.69.

Digital Mode
Grand Prairie is the only digital system I can pick up and not very well with one of the better ½ wave rubber ducks because of the distance. Current was 157 about typical for a trunked system until a mobile unit keys up. Jumps to 163 with broken but clear speech because of the weak signal and the volume was set to 3. Police is digital and Fire is analog but for both it still jump to the 163 level.

Battery Saver
Well, lets just say that what ever is being ‘saved’, I can’t for the life of me find what or how much.

In conclusion with a sample of one radio using a digital voltmeter the current draw is at least 155 mA and 200+ with backlight on. Internal speaker or external makes not difference. Trunked or conventional scanning, scanning or on hold, while the numbers are different they are not significantly so.

 

[JLM7424]

I Can say My 396t Using 2650 mAh duracells recharables fully charged
On a all P25 vhf system last about 45 minutes less then when i use it on
a all analog

 

[jon_k]

I do wish Uniden had better performance. I'm wondering if any of the new trunking RS scanners can make the cut. The pro-95 lasts DAYS. Great scanner too, but not alphanumeric.

I want a good alphanumeric trunking scanner that has good battery life.

 

[andrewccm]

With included batteries, I'd say my 396T lasts about 12hrs or so. I'll probably replace them with higher mah AA's eventually. However, 12hrs is plenty for me. Most of the time mine is plugged in.

 

[policefreak]

I found that if I leave batteries in the scanner with it plugged in but the unit off and the charger off the batteries slowly drain. Notice it more with the rechargables.

 

[KE5MC]

Policefreak,

That is typical for rechargeable batteries. Eneloop (Sanyo product) at 2100ma are considered low-self-discharge (LSD). As the battery capacity goes up so does the self-discharge rate. Something about the construction of the batteries internals that forces a trade off between the two. I like to use them in my Digital Camera because for the 1 or 2 times a month I might use it to take only a couple of pictures it is better for the batteries to still have a charge.

mike

 

[Jakemcgraw]

I do wish Uniden had better performance. I'm wondering if any of the new trunking RS scanners can make the cut. The pro-95 lasts DAYS. Great scanner too, but not alphanumeric.

I want a good alphanumeric trunking scanner that has good battery life.

Just to note, the R.S. Pro-95, does have alphanumeric.

 

[jon_k]

Just to note, the R.S. Pro-95, does have alphanumeric.

Does it? Perhaps it is the Pro-94 I'm talking about.

Before I got into scanning, I borrowed one of the Radioshack "Pro" scanners from a friend. It was a Pro-94 or Pro-95. Can't say which, but I never saw alphanumeric on the display (and I didn't program it enough to figure out if it did do alpha)

Thanks for the heads up. Alphatags are a necessity in my eyes, though my friend is perfectly OK at remembering the talkgroup#'s and frequencies.

I may pick up a Pro-95 if it supports the alpha tags.

 

[Jakemcgraw]

Yes i have one, nice scanner also, and it has the text tags.

 

[linuxwrangler]

Don't trust what is written on the package. I bought some generic 2500mAh cells at Fry's a while back (came in a 6-pack which seemed handy for a device that uses 3-cells). Never got them to test better than 2100mAh in my MH-9000 charger.

Just replaced them with some Powerex Imedion low-self-discharge 2100mAh cells. Worst cell was just under 2200mAh and best was in the upper 2200s.

So my 2100mAh cells have more capacity than the "2500mAh" ever did.

 

[XTS3000]

mcscanner, your current readings are right on with my tests.

I was more concerned with the current draw with and without the backight on. Backlight chews up about 45mA.