How much power does the BCD536HP draw when powered down?

[unusedusername]

Hello,

I have a Uniden BCD536HP with the with Uniden BC-GPSK installed in my vehicle. I'm having an issue with a parasitic drain killing the vehicle's battery, where the drain is measured at 800mA @13.4V. I'd like to rule out the scanner as the cause for this drain.

How much power should the scanner be drawing to be within spec when the scanner/GPS unit is powered down? I can't find this in the manual... hence asking here..

After I learn how much it should be drawing, I'm going to pull the scanner and measure it's actual draw as compered to what it should be drawing.

 

[phask]

I may be wrong, but I do not think the GPS does power down. I have a Gamin puck (not Uniden) and I know it does not.

 

[JamesO]

The GPS puck does not power down. You could configure a power source that is switched from the ignition so the GPS powers down.

What type of vehicle are you dealing with? Make, model and year?

How old is the current battery in the vehicle?

What type of battery is in the vehicle? Lead acid, AGM?

Have you had the battery properly tested at an auto parts store?

 

[KE5MC]

Without taking the time to measure my 536 I doubt its the radio. Likely when on it’s not drawing 800ma. If your numbers are correct that’s 10 Watts. More like the trunk light is stuck on.

Mike

 

[JamesO]

Read this thread, I have current measurements for the 536HP and suggestions for a better power option that Uniden should consider - https://forums.radioreference.com/u...hp-remote-power-suggestion-use-siren-app.html

I have a Uniden puck I can measure the current draw on, I may be able to do this later this evening.

 

[unusedusername]

If the scanner is only drawing 0.280mA then the scanner isn't the problem. I guess it could be the GPS puck?

Here is the details of the vehicle:
unusedusername's Jeep Profile :: Wrangler Rubicon

Heavily modified '13 Jeep Wrangler. Dual AGM batteries as power source with stock 160A alternator. A bunch of radio gear is installed. All the aftermarket stuff has been ruled out as the source of the drain excepting for the entertainment stereo and the scanner. The batteries were replaced last week and test good.

I have measured the 800mA drain from the battery by putting a meter inline with the battery (in a single-battery configuration).

The drain is on the IOD fuse... which apparently is used for anything that is supposed to have a draw while the vehicle is off. That circuit is supposed to have <30mA draw at max while the computers are sleeping, but my shop also measured the same 800mA that I saw. My shop has guessed that it's likely a factory computer not going to sleep, but the one dealership I've been to so far is playing the finger pointing game instead of working on fixing it. The aftermarket shop I use unfortunately does not have the equipment to replace the factory computers.

I do already have an appointment with a different dealership.

I'm also planning on pulling both the scanner and the puck out and measuring the drain myself in case something went wrong in the scanner. I think it's unlikely though as the scanner still works.

 

[KE5MC]

It might be possible to identify the faulty “black box” first thing in the morning when vehicle has been off all night. While they are usually tucked away behind panels and not easy to get to it worth a shot as a 10 watts source should be noticeable.

Good Luck!

Mike

 

[JamesO]

GPS puck draws 40 mA. This is also with a lighter plug that has a LED indicator in it.

800 mA draw is not from the scanner or the GPS puck. But 40 mA from the GPS is not good if left on overnight. Most vehicles should draw in total around 25-35 mA when parked and everything is shut down or in sleep mode.

You have a lot of electrical accessories in the vehicle but you should be able to isolate these easily.

As you mentioned there may be one or more of the onboard modules may be staying awake.

But if you really only have an 80 Amp alternator, I would be concerned about this based on all the potential electrical loads you could be running in the vehicle.

One thing to check as well if the Jeep has an electrical cooling fan, with all the mud and moisture you are dealing with, the electrical fans and fan controllers can often cause strange draws, easy enough to disconnect overnight on some vehicles as a test.

 

[ofd8001]

The scanner itself won't draw when powered down. It has an internal battery to deal "housekeeping" tasks (like internal clock).

The GPS device will draw power as long as it is plugged into a power point and you see the LED blinking or constantly on. It is a receiver "doing its thing".

I have my GPS device on an ignition circuit. I took a 12 volt cigarette lighter cord and removed the male end, stripped the wires and connected it to a switched circuit. The female end connected to the the male end of the GPS device. DO NOT cut the male plug off the GPS device as it has a voltage step down "thing" inside.

 

[Ubbe]

Dual AGM batteries as power source with stock 160A alternator....
I have measured the 800mA drain from the battery.....

Dual batteries is at least 100Ah and that's a week without using the vehicle to drain the batteries.
I guess the cost to locate and repair are much more than the inconvenience to use a mains charger to top up the batteries once a week?

/Ubbe

 

[JamesO]

Not sure why most modern vehicles do not offer this as an option, but I often either install additional cigarette lighter sockets that are switched with the ignition and/or modify the power source with a toggle switch where I can power the stock cigarette lighter sockets either from the battery or a switched ignition source.

This should be a relatively easy problem to find if the problem is consistent. Removing/opening the doors and open the hood and then connect an Ampmeter and start to pull fuses after the electronics are in sleep or standby mode to find the current draw.

I do not know the Jeep line so well, but most every modern vehicle that has accessories that go into a sleep or standby mode typically take between 10-20 minutes to enter the low power mode. So you wait 30 minutes and see if there is a current drop.

Again, 800 mA is a HIGH draw, you should be able to identify and find this pretty easily. While you could rely on a dealer or other shop, even many dealers and/or independent shops have few people that really understand electricity and how to locate parasitic power draws. Even leaky diodes in the alternator can be a problem and assuming you swamp the alternator in water or mud from time to time, this could be a possible problem.

If you do not have a Voltmeter for your vehicle, I would install one or get something like the wired UltraGauge with has both Voltage and Temperature threshold alarms that will alert you when there is a problem so you do not have to constantly monitor these valves, but you can still set up gauges to monitor as well. This device auto Sleeps and has saved me on many occasions. Small and easy to connect and mount.

Proper charging Voltage is typically between 13.5-14.5. Volts, you have a large accessory load and an extra battery. An alternator is not officially a battery charger, it's primary purpose is to power everything on the vehicle. As I mentioned before if the alternator is really only 80 Amps, this is severely undersized for the amount of load you are potentially running. Most modern vehicles have at least 120 Amp alternators and while the stock Jeep probably did not need this large of an alternator, with all the add ons, it probably needs at least a 120 Amp alternator and larger cabling from the output of the alternator. I have a stock vehicle that is 8 years old that has a 220 Amp alternator in it!

 

[jonwienke]

The 436 only draws about 250mA @ 5V under full load--max volume, max display brightness, and receiving a transmission. I doubt the 536 draws much more than that from 12V. If it was, something would be emitting smoke.

The GPS puck draws about 40mA on the 5V side of the converter, so about half that on the 12V side.

Look elsewhere for your problem.

 

[cmdrwill]

I had a SUV in the shop that was having the dead battery syndrome. Turned out to be the CD player was drawing almost one amp when vehicle was off. The CD and radio are powered all the time, but switched on by the ignition. I think the CD player was tying to eject a CD but no CD was found. Maybe something to look at.

Also from a master car tech, per the factory, do NOT disconnect the battery, hook up the amp meter leads first then disconnect the battery, that way no power interruption for the computer(s) and other electrical items do not get reset.

 

[JamesO]

No problem disconnecting the battery, if you are worried about volatile info you can use a back up battery in the cigarette lighter assuming the cigarette lighter is not switched. If the cigarette lighter is switched, you can feed pin 16 of the OBDII port with 12 Volts and connect the ground to Pin #4.

Something like this is best for chasing parasitic draws because you can quickly switch the Amp meter into the circuit after vehicle has gone into Sleep or Standby mode.

https://www.amazon.com/Lisle-64970-...=8-1-fkmr0&keywords=lisle+current+measurement

Something like this can be used if you do not want to put terminals directly into the OBDII port for back up power - https://www.amazon.com/VSTM-Emergen...kmr1&keywords=lisle+obdII+port+power+splitter

 

[unusedusername]

As a followup on this: We determined that there is either a short of an electrical fault in the instrument cluster that is causing the issue. A new cluster is $800 :/

I've also changed the wiring for the scanner so that it is no longer going through the factory circuit.

 

[Ubbe]

It's much cheaper to live with the problem and if you do not drive the truck more than once a week you add a $20 charger to charge the batteries when needed.

/Ubbe

 

[N9JIG]

While it appears the OP has identified the issue as unrelated to the scanner or GPS I wanted to chime in a bit here...

In a prior installation I had the Uniden GPS connected to a cigarette plug that was powered all the time at the rear of my vehicle for about 6 months until I got around to rewiring it into the ignition switch circuit. During that time I took 2 trips out of town where the vehicle was left parked at the airport for 5 or 6 days and had no issues. This was on a then brand new Pilot with the trailer package (includes larger battery, alternator and trans cooler) so I am sure that helped.

 

[JamesO]

As a followup on this: We determined that there is either a short of an electrical fault in the instrument cluster that is causing the issue. A new cluster is $800 :/

What make and model vehicle do you have?